DISCUSSION O F SOME PROBLEMS INVOLVED IN USING THE CHEMICAL LITERATURE* By BERNARD L O E V Research and Development Division, Smith Kline and French Laboratories, Philadelphia, Pa.
T h e s e c o m m e n t s should p e r h a p s m o r e a p p r o p r i a t e l y have beten titled "A Synthetic Organic Chemist.......'' f o r i t is f r o m this point of view that the l i t e r a t u r e will be d i s c u s s e d . The f i r s t half of the d i s c u s s i o n will outline briefly s o m e s o u r c e s of i n f o r m a t i o n which the c h e m i s t h a s available t o help him in the u s e of the l i t e r a t u r e . The second p a r t will d e a l with C h e m i c a l A b s t r a c t s , s o m e p r o b l e m s involved in i t s u s e , and ways in which it might be improved. The o r g a n i c c h e m i s t h a s four m a j o r i n t e r e s t s i n the u s e of the c h e m i c a l l i t e r a t u r e : I. S e a r c h i n g f o r specific compounds. 11. S e a r c h i n g f o r r e l a t e d compounds and c l a s s e s of compounds. 111. S e a r c h i n g f o r m e t h o d s of s y n t h e s i s or experimental techniques IV. Keeping a b r e a s t of c u r r e n t l i t e r a t u r e . T h e r e a r e , of c.ourse, o t h e r u s e s of the l i t e r a t u r e , but t h e s e a r e specific u s e s and do not fit into the g e n e r a l c a t e g o r y t o be d i s cus s e d h e r e .
I. L e t u s c o n s i d e r f i r s t the s i m p l e s t t a s k , the s e a r c h f o r a specific compound. Some of the s o u r c e s available t o help u s a r e : Beilstein and E l s e v i e r , C h e m i c a l A b s t r a c t s , United States P a t e n t Office Steroid P u n c h C a r d s , and Index Chemicus. C e r t a i n l y the f i r s t s o u r c e t o be consulted i s the c h e m i s t ' s m o n u m e n t a l r e f e r e n c e book, Beilstein.' F o r the p e r i o d c o v e r e d , up t o 1939, a s e a r c h of Beilstein p r o b a b l y will pick up 99% of all o r g a n i c compounds that a p p e a r e d . Elsevier,:! f o r s o m e r e a s o n , does not s e e m t o be a s well known among o r g a n i c c h e m i s t s . It i s e s s e n t i a l l y a Beilstein published in English. In addition to being i n English, i t h a s c e r t a i n other advantages o v e r Beilstein. It i s m o r e c u r r e n t ( c o v e r i n g s o m e a r e a s up t o l 9 5 8 ) , i t m a k e s g r e a t e r u s e of s t r u c t u r a l f o r m u l a s , s o that it is e a s i e r t o r e c o g n i z e specific compounds; and it often m a k e s u s e of s u m m a r y flow d i a g r a m s to show the relationship o r i n t e r c o n v e r s i o n of v a r i o u s compounds, p a r t i c u l a r l y when t h e s e a r e complex ( s e e Fig. 1).
.
Scheme I *
37-10
Some Oxidation Reactions of Santonin c-co
H ~ D ~ wZ.2 5 . L teV8CWborfiU Kid
'%tom-ketodicarbxyk acid: P I 78
'Oihydro- santonin. ketodicarbxylic acid: 0 3779
Fig. 1.-Typical summary flow diagram from Elsevier's "Encyclopedia of Organic Chemistry.
"
*Presented a t t h e Symposium on Information Retrieval and Analysis. sponsored ~ o i n t l yby the Division of Medicinal Chemistry and the Division of Chemical Literature, New York City, September. 1960.
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The big disadvantage i s , of c o u r s e , t h a t i t t e r m i n a t e d before covering all a r e a s of organic c h e m i s t r y . F o r t u n a t e l y , it c o v e r s t h e polycyclic carbocyclic compounds, a n a r e a w h e r e B e i l s t e i n i s weak. The next s o u r c e t h a t would be consulted i s Chemical Abstracts3 with its t h r e e decennial i n d i c e s and f o u r annual i n d i c e s . The p r o b l e m s i n volved i n its u s e will be d i s c u s s e d f u r t h e r on i n the paper. In the s t e r o i d a r e a , one h a s available the United S t a t e s P a t e n t Office S t e r o i d P u n c h Cards: T h e s e c o v e r all United S t a t e s and f o r e i g n r e f e r e n c e s f r o m 1957 on, and a l l United S t a t e s p a t e n t s p r i o r t o 1957. U s e of t h e s e c a r d s p e r m i t s r a p i d r e t r i e v a l of s p e c i f i c compounds f o r t h i s period. A wonderful new tool f o r the o r g a n i c c h e m i s t is t h e "Index C h e m i c u s . "Index Chemicus" is a monthly magazine which c l a i m s t h a t i t will index a l l new compounds within 30 days of a p p e a r a n c e i n a j o u r n a l . Cumulative m o l e c u l a r f o r m u l a i n d i c e s a r e t o a p p e a r q u a r t e r l y and then annually. Thus, one m a y a n t i c i p a t e t h a t a s e a r c h f o r a compound will b e no m o r e than 30 days behind the c u r r e n t l i t e r a t u r e , r a t h e r than t h e p e r i o d of up t o t h r e e y e a r s t h a t one now h a s i f he depends on Chemical A b s t r a c t s i n d i c e s . This publication h a s o t h e r outstanding f e a t u r e s . All compounds a r e l i s t e d by t h e u n a m biguous m o l e c u l a r f o r m u l a and a l s o frequently t h e s t r u c t u r a l f o r m u l a . This g r e a t l y expedites s e a r c h i n g , and e l i m i n a t e s t h e p r o b l e m s a r i s i n g due t o a r b i t r a r y nomenclature s y s t e m s . It h a s one drawback i n t h a t the p r e s e n t m o l e c u l a r f o r m u l a index t o t h i s magazine does not d i s t i n guish between d i f f e r e n t compounds having t h e s a m e molecular formula. This r e m a r k a b l e publication will not c o m p l e t e l y r e p l a c e the compound indexing by Chemical A b s t r a c t s , f o r "Index Chemicus" will s t r e s s t h e reporting of new compounds, w h e r e a s Chemical A b s t r a c t s r e p o r t s and indexes all compounds mentioned i n a publication. 11. The s e a r c h f o r compounds r e l a t e d to one i n hand, o r d e s i r e d , is a m o r e complicated p r o b l e m , Some of the s o u r c e s available a r e B e i l s t e i n and E l s e v i e r , Chemical A b s t r a c t s , Review A r t i c l e s , Review Books, and U n i t e r m Index t o Chemical P a t e n t s . H e r e a g a i n , one will v e r y l i k e l y s t a r t with B e i l s t e i n and E l s e v i e r , f o r c l o s e l y r e l a t e d c o m pounds --homologs and d e r i v a t i v e s - - a r e u s u a l l y l o c a t e d i n the s a m e a r e a . One m u s t e x e r c i s e caution i n t h e i r u s e , however, f o r c l o s e l y r e l a t e d compounds a r e not always i n t h e s a m e vicinity. Thus, phthalic a c i d , its e s t e r s and d e r i v a t i v e s , a r e i n Vol. 9, but phthalic anhydride is i n V o l . 17. Once a g a i n , one would consult Chemical A b s t r a c t s , but t h e s i t u a t i o n with r e s p e c t t o s e a r c h i n g f o r r e l a t e d compounds, o r g e n e r i c
s e a r c h i n g , is quite u n s a t i s f a c t o r y . This will be commented on l a t e r . Very useful s o u r c e s of information a r e review a r t i c l e s . T h e s e a r e , i n f a c t , often t h e m o s t convenient way of locating r e l a t e d c l a s s e s of compounds. Review a r t i c l e s a r e found i n s u c h j o u r n a l s as Chemical Reviews3 and Q u a r t e r l y Reviews. A p a r t i c u l a r l y useful j o u r n a l c a r r y i n g review type a r t i c l e s is Angewandte Chemie.7 Unfortunately, t h e r e is no convenient way of telling whether or not a review a r t i c l e covering t h e a r e a i n which one is i n t e r e s t e d h a s e v e r appeared. As one way t o solve t h i s , the Science Information D e p a r t m e n t at Smith, Kline and F r e n c h h a s compiled, f o r i n t e r n a l u s e , a l i s t of all review a r t i c l e s t h a t have appeared i n s o m e 50 j o u r n a l s i n t h e p a s t 20 y e a r s . This l i s t h a s been of g r e a t value t o u s i n o u r l i t e r a t u r e s e a r c h e s e s Review books s u c h as ACS monographs, and s p e c i a l t y books s u c h a s t h o s e on phosphorus, s u l f u r , o r h e t e r o c y c l i c compounds, a r e i n the s a m e category a s review a r t i c l e s . They a r e t h e i d e a l s o u r c e f o r i n f o r m a t i o n , provided they can be l o c a t e d . Another s o u r c e f o r c a r r y i n g out g e n e r i c s e a r c h e s i n a r e s t r i c t e d a r e a i s t h e United S t a t e s P a t e n t U n i t e r m Index.g Li t h i s index, which h a s been i n e x i s t e n c e f o r only about s e v e n t o eight y e a r s , each patent is assigned a n u m b e r . Under e a c h g e n e r i c heading all p a t e n t s having p e r t i n e n t information a r e l i s t e d , Thus, i f one w i s h e s t o l o c a t e all United S t a t e s p a t e n t s dealing with phenothiazines appearing i n 1960, t h i s is done e a s i l y . In o r d e r t o f a c i l i t a t e m o r e specific s e a r c h i n g , the index is i s s u e d i n duplicate. If one wishes t o l o c a t e all phenot h i a z i n e s having trifluoromethyl g r o u p s , one p l a c e s the pages with t h e i t e m s phenothiazine and t r i f l u o r o m e t h y l s i d e by s i d e and l o c a t e s t h o s e n u m b e r s common t o both headings. The U n i t e r m Index i s r e a l l y a manual f o r m of punch c a r d s y s t e m . It i s often a useful way of rapidly scanning t h e U.S. patent l i t e r a t u r e , but t h e coverage is f a r f r o m complete. None of t h e s e s o u r c e s is e n t i r e l y s a t i s f a c t o r y . Such a s e a r c h i s v e r y l a b o r i o u s and often incomplete. 111. Now l e t u s t u r n t o t h e t h i r d a r e a i n which we d e a l with t h e l i t e r a t u r e , k, the s e a r c h for a synthetic method. Despite t h e l a r g e number of books on s y n t h e t i c m e t h o d s , a g r e a t need s t i l l e x i s t s f o r a r e a d y m e a n s of scanning t h e l i t e r a t u r e f o r g e n e r a l o r s p e c i f i c s y n t h e t i c p r o c e d u r e s . Some of the s o u r c e s t h a t m a y be consulted a r e : Review A r t i c l e s , Review Books, Books on Synthetic Techniques, Chemical A b s t r a c t s , Company Key-Word Index, and Advertis ing B r o c h u r e s . One f i r s t u s u a l l y c o n s u l t s review a r t i c l e s such a s t h o s e i n "Organic R e a ~ t i o n s , ' 'Chemical ~~ Rev i e w ~ and , ~ Q u a r t e r l y Reviews ,6 Review books, s u c h as t h e heterocyclic s e r i e ~ u, s u ~ a l~l y~have ~
PROBLEMS INVOLVED IN USING THE CHEMICAL LITERATURE
thorough r e v i e w s of synthetic m e t h o d s . One would n a t u r a l l y consult the books on synthetic techniques s u c h a s "#OrganicS y n t h e s e s " and " O r g a n i c R e a c t i o n s , " Weygand, 1938,11 Hickinbottom, 1948,12 S h i r l e y , 1951,13Wagner and Zook, 1953, Migrdi.chian, 1957, l 5 T h e i l h e i m e r , 1946t,16 Houben-Weyl, 4th Edition, 1958,17 and Rodd, 1951+.l8 None of t h e s e books r e a l l y p r o v i d e s s a t i s f a c t o r y c r i t i c a l c o m p a r i s o n s of the v a r i o u s p o s s i b l e techniques f:or c a r r y i n g out a given r e a c t i o n , although Houben-Weyl c o m e s c l o s e s t t o doing t h i s . One v e r y useful s o u r c e of i n f o r m a t i o n , usually overlooked, i s advertising brochures and booklets. Recently, f o r e x a m p l e , the du P o n t Co. d i s t r i b u t e d a v e r y c o m p r e h e n s i v e r e view of oxidations u s i n g hydrogen p e r o x i d e 19; Allied C h e m i c a l d i s t r i b u t e d a n excellent review booklet on r e a c t i o n s of sulfur t r i o x i d e P 0 ; Metal H y d r i d e s had d i s t r i b u t e d a n u m b e r of excellent b r o c h u r e s s u m m a r i z i n g the r e a c t i o n s of v a r i o u s m e t a l h y d r i d e s .21 Unfortunately, u n l e s s one s e t s up his p e r sonal f i l e , it i s v i r t u a l l y i m p o s s i b l e t o locate any l i s t s of s u c h b r o c h u r e s . Someone could p e r f o r m a v e r y valuable s e r v i c e by publishing a l i s t of the technical b r o c h u r e s i s s u e d by c h e m i c a l c o n c e r n s , c o v e r i n g compounds, r e a g e n t s , and r e a c t i o n s ,, Many c h e m i s t s find i t helpful to s e t up t h e i r own filing s y s t e m of r e a c t i o n s and r e a g e n t s a s the q u i c k e s t way of locating r e a c t i o n s and t e c h n i q u e s . We have: found s u c h a file invaluable. C o m p a n i e s often find it valuable t o s e t up s u c h k e y - w o r d type f i l e s , p a r t i c u l a r l y t o c o v e r the s p a n of s e v e r a l y e a r s between the a p p e a r a n c e of a n a r t i c l e and i t s indexing by C h e m i c a l Abstracts. The wonderful w o r k of T h e i l h e i m e r m a y m a k e s u c h individual. f i l e s u n n e c e s s a r y , but only if t h e r a t h e r p o o r i n d e x e s a r e i m p r o v e d . As f a r a s the u s e of C h e m i c a l p b s t r a c t s f o r s u c h s e a r c h e s is c o n c e r n e d , in g e n e r a l , i t i s a p o o r p l a c e to s e a r c h f o r synthetic t e c h niques a s now indexed. A r e a c t i o n technique i s u s u a l l y not indexed, u n l e s s a n e n t i r e a r t i c l e is devoted t o i t . IV. One of the rnajor and m o s t difficult t a s k s of the c h e m i s t i s keeping a b r e a s t of the l a t e s t d e v e l o p m e n t s in c h e m i s t r y . Some of the w a y s of doing t h i s a r e t o consult individual j o u r n a l s , C h e m i c a l A b s t r a c t s , T h e i l h e i m e r Monthly S e r v i c e , r e v i e w j o u r n a l s , Seminar Reports, Dissertation Abstracts , Company P a t e n t A b s t r a c t s , C u r r e n t C h e m i c a l P a p e r s , C u r r e n t C o n t e n t s , I and EC T a b l e s of C o n t e n t s , C h e m i c a l T i t l e s , and Index C h e m i c u s . T o a t t e m p t t o keep up with a l l new developm e n t s by r e a d i n g the h u n d r e d s of j o u r n a l s in which c h e m i c a l artic:les a p p e a r i s too r i d i c u lous t o c o n s i d e r . E v e n reducing this t o the
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15-20 b a s i c j o u r n a l s i s a f o r m i d a b l e t a s k . Although C h e m i c a l A b s t r a c t s should s e r v e t o help u s out of this d i l e m m a , a s it now i s i s s u e d , t h e r e i s often l i t t l e advantage t o going to C h e m i cal A b s t r a c t s a s c o m p a r e d t o scanning the original a r t i c l e s . It i s convenient t h e r e f o r e to have r e s o u r c e t o one of the n e w e r publications, whose a i m i s t o rapidly s u m m a r i z e o r i t e m i z e new work m o r e quickly than even an a b s t r a c t journal can. By consulting t h e s e l i s t s , one can rapidly s c a n the contents of c u r r e n t c h e m i c a l j o u r n a l s , and s e l e c t only those a r t i c l e s f o r p e r u s a l which a r e r e a l l y of i n t e r e s t . One s u c h l i s t i s the monthly " C u r r e n t C h e m i c a l P a p e r s .'I6 In t h i s i s p r i n t e d the t i t l e , o r 5-10 w o r d s u m m a r y in i n s t a n c e s in which the t i t l e i s not i n f o r m a t i v e , of a r t i c l e s a p p e a r i n g in 200 -300 p e r i o d i c a l s e a c h month. T h e s e i t e m s a r e roughly c l a s s i f i e d within s e c t i o n s . E n t r i e s u s u a l l y a p p e a r in C u r r e n t C h e m i c a l P a p e r s within one to two months of a p p e a r a n c e in a journal. C u r r e n t Contents is a s i m i l a r type of publication.5 The p u r p o s e i s the s a m e , %, t o b r i n g the l a t e s t publications rapidly t o the a t tention of the c h e m i s t . This i s done by r e p r o ducing the e n t i r e Table of Contents of s o m e 600 c h e m i c a l and biological j o u r n a l s . T h i s c o m p a c t m a g a z i n e u s u a l l y gives the index p a g e s even b e f o r e the j o u r n a l s t h e m s e l v e s a r r i v e i n the l i b r a r i e s , and p e r m i t s rapid scanning of the l a t e s t j o u r n a l s without the n e c e s s i t y of c i r c u l a t ing hundreds of j o u r n a l s and h u n d r e d s of pounds of journals e a c h month. I. and E.C. Title P a g e s 3 i s exactly the s a m e , except that i t c o v e r s only the ACS j o u r n a l s . C h e m i c a l T i t l e s 3 i s a r e c e n t a t t e m p t by the ACS t o i m p r o v e on C u r r e n t Contents by having e a c h w o r d of e a c h t i t l e s e r v e a s a s e p a r a t e i n dex heading. T h e i l h e i m e r i s s u e s a v e r y fine monthly reaction a b s t r a c t service.22 It i s e a s y t o s c a n and v e r y c u r r e n t . It c o n s i s t s of a one o r two s e n t e n c e s u m m a r y with equations of a l l i n t e r e s t ing r e a c t i o n s in a n a r t i c l e . While r e v i e w j o u r n a l s a r e useful, they u s u a l l y a r e not v e r y u p - t o - d a t e . A convenient way of keeping u p - t o - d a t e on mechbanisms i s to s c a n the s e m i n a r r e p o r t s that s c h o o l s s u c h a s MIT, U n i v e r s i t y of Illinois, and P e n n s y l v a n i a State U n i v e r s i t y m a k e available. D i s s e r t a t i o n A b s t r a c t s P 3 could be a useful way of keeping up with the l a t e s t w o r k in the u n i v e r s i t i e s , if the a b s t r a c t s t h e m s e l v e s w e r e not s o u n i n f o r m a t i v e . Most c o m p a n i e s handle the patent l i t e r a t u r e e i t h e r by circulating the l a t e s t c h e m i c a l patents t o the p r o p e r p e r s o n s in the organization, o r by i s s u i n g a bulletin that gives a one s e n t e n c e s u m m a r y of the p e r t i n e n t patent. "Index C h e m i c u s , " the new index of c h e m i c a l compounds that was d e s c r i b e d e a r l i e r , m a y a l s o s e r v e a s an a l e r t i n g s e r v i c e , s i n c e not only
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can one s e e what new compounds have a p p e a r e d , b;ut o f t e n t h e chemical t r a n s f o r m a t i o n s t h a t they undergo. Having d i s c u s s e d s o m e of the s o u r c e s which t h e c h e m i s t h a s t o a s s i s t h i m i n the u s e of t h e l i t e r a t u r e , we s h a l l now t u r n t o the c h e m i s t ' s m o s t i m p o r t a n t key t o t h e l i t e r a t u r e , Chemical A b s t r a c t s ; we s h a l l d i s c u s s s o m e of t h e p r o b l e m s involved i n t h e u s e of Chemical A b s t r a c t s , and suggest ways i n w h i c h . i t might b e improved. L e t u s c o n s i d e r Chemical A b s t r a c t s and its r e l a t i o n s h i p t o t h e {irst i t e m d i s c u s s e d , k., locating a s p e c i f i c compound. One of the m o s t common p r o b l e m s encount e r e d i n t h e u s e of Chemical A b s t r a c t s is the difficulty with which t h i s is done. In attempting t o l o c a t e a compound by n a m e i n t h e s u b j e c t index, usually one m u s t first spend a g r e a t d e a l of t i m e determining the approved n a m e -- with n o g u a r a n t e e t h a t one is r i g h t , o r t h a t t h e same n a m e will have been u s e d i n a l l i n d i c e s . Most c h e m i s t s , t h e r e f o r e , find i t w i s e s t t o go d i r e c t l y t o the m o l e c u l a r f o r m u l a index, s i n c e t h i s provides the m o s t fool-proof method of locating t h e d e s i r e d compound. We h a v e , f o r e x a m p l e , had occasion t o look up t h e compounds shown below:
Phenethylamine, D: -methyl
Phenol, 4-(2-aminoPropyl)
p-Cresol, D: -amino-
To l e a r n t h e Chemical A b s t r a c t s n a m e f o r amphetamine, r e c o u r s e w a s m a d e t o t h e f o r m u l a index. Subsequently, when we wished t o look up t h e l - h y d r o x y d e r i v a t i v e , we w e r e unable t o l o c a t e i t by any reasonable modification of the previous n a m e and, once again, we had t o go t o the f o r m u l a index. The t h i r d example i s a p a r t i c u l a r l y a t r o c i o u s example of naming, and t h i s compound could only be l o c a t e d by r e c o u r s e t o the f o r m u l a index. In f a c t , no one in o u r l a b o r a t o r i e s , even t h o s e "expert" i n the Chemical A b s t r a c t s nomenclature r u l e s , was able t o p r e d i c t the n a m e under which it was l i s t e d . The u s e of the f o r m u l a index as now cons t r u c t e d is not without i t s p r o b l e m s a l s o . In Fig. 2 we s e e a p o r t i o n of a typical Chemical A b s t r a c t s f o r m u l a index. If one h a s a g r e a t n u m b e r of compounds t o look u p , p a r t i c u l a r l y if they a r e complex
Fig. 2
Vol. 50
PRESENT CA MOLECULAR FORMULA INDEX
C12H1002S Benzenesulfonic acid, Ph ester, 219cd. 4-Biphenylsulfonic acid, 15475f. Phenol, (phenylsulfonyl)-. 219e, 2231, 12187c, 14617e. Phenyl sulfite, 12816a. 2-Thiopheneglycolic acid, D: -phenyl-, 2579g. 2 -Thiophenemethanol,D: -(3,4- methylenedioxpheny1)- 13865d. C12H1004 (See also Quinhydrone.) Acetic acid, (6-hydroxy-2-naphthyloxy)-, 16955h. Benzopyrancarboxylic acid, dimethyl-4-oxo-. 7 7 5 5 ~ .15349d. - , 2-oxo-, Et ester, 10715ch, 10717a. Biphenyltetrol, 379a, 64021, 6403b. Chromone, 3-acetyl-7-hydroxy-2-methyl-, 1788b. Coumarin, 6-acetyl-5-hydroxy-4-methyl-, 4928b. Crotonic acid, 3-hydroxy-2-(o-hydroxyphenyl)-, Y -lactone, acetate 25611. 3,9-Dodecadiene-5,7-diynedioicacid, 185a. 2-Indancarboxylic acid, 1,3-dioxo-, Et ester, 13851d. 7-Indeneacetic acid, 3-carboxy-, 7831a. Ketone, 3-hydroxy-2-benzofuranyl methyl, acetate, 25611. Naphthazarin, 2, &dimethyl-, 7157f. - , 2-ethyl-, 106921. 2-Naphthoic acid, l-hydroxy-4-methoxy-, 9397g. 1,4-Naphthoquinone, dimethoxy-. 775Sc, 93971. C12H1004S 1,4- Naphthoquinone, 2-(1,2- dihydroxyethy1thio)-, 115261. Phenol, sulfonyldi-, 2231, P12110h. Raorcinol, (phenylsulfony1)- 12 038ef. - , 4,4'-thiodi-, P 98L Cl2HlOO4S2 Phenyl disulfone, 12873f. C12HI004S2 Benzenesulfonic acid, thiol-, anhydrosulfide, 7049g.
208F
C H 0 S T e Telluride, bis(phenylsulfonylthio), 9091i, 13552s CI2H1 004 %,5-Benzofurandiol, diacetate, 3295a. 122R~1~Benzopyran-8-aceticacid, 7-methoxy-2-oxo-, 15743g. 4H-l-Benzopyran-6-carboxaldehyde, 5.7-dihydroxy-2, 8-dimethyl-4- oxo-, 4928g. -, 7-hydroxy-5-methoxy-2-methyl-4-oxo-, 1792b. 2H-1-Benzopyrancarboxylic acid, hydroxy-4-methy1-2-0~0-, Me ester, 4926ab. -, hydroxy-2-oxo-, Et ester. 1 3 8 9 5 ~14727g. 2,3',4,5', 6-Biphenylpentol, 11991g. Citropten, 6-fomyl-, 8614a. Dicarboxylic acid, m. 278-.80°, 370d. 2-Furaldehyde, 5,5'-(oxydimethylene)di-, 10073g. 2-Indancarboxylic acid, 2-hydroxy-l,S-dioxo-, Et ester, 13851f. 1,4-Naphthoquinone, 2-hydroxydimethoxy-, 7758bf, 7760h, 7762a. Phlorogluci de, 119 91g. C12H100 jS 1,4-Naphthoquinone. 2-(1,2-dihydroxyethylthio)-3hydroxy-. 11526f. Resorcinol, 4,4'-sulfinyldi-, P98i. C12H1006 4H-1-Benzopyran-6-carboxaldehyde. 7-hydroxy-2(hydroxymethy1)- 5-methoxy-4-oxo-, 1792b. 1H-2-Benzopyran-3-carboxylic acid, 7,8-dimethoxy-l-oxo, 2563e. 2.2',4,4', 6,6'-Biphenylhexol, 11992f. Terephthalaldehyde. 2,5-dihydroxy-, diacetate, 7 099b. C12H1OO~P2Th, 2360i C12H1 4,4'-Biphenyldisulfonic acid, 97431, 15475f. CI2Hl0O7 lH-2-Benzopyran-4-propionic acid, 5,6,7-trihydroxy-loxo-, 1041i. Cl2Hl0O1S2 Benzenesulfonic acid, 4,4'-oxydi-. 11671h.
31
PROBLEMS INVOLVED IN USING THE CHEMICAL LITERATURE
s u b s t a n c e s , a c o n s i d e r a b l e amount of t i m e m u s t be spent j u s t in the d e c i p h e r i n g of e a c h s y s t e m atic name. We s u g g e s t , t h e r e f o r e , that the s t r u c t u r a l
f o r m u l a s be included u n d e r the m o l e c u l a r f o r m u l a s a s shown in Fig. 3 . T h i s would c e r tainly p r o v i d e the m o s t rapid and fool-proof method of s e a r c h i n g f o r a p a r t i c u l a r compound.
Fig. 3 PROPOSED MOLECULAR FORMULA INDEX
219ed
7758. 01971
86140
1 54751
370d 115261 219. 1W73.
2231 12187~ 14617.
2231 Pllltch 12816s
2179s
138511
12038.1 77ylbl 776oh
n62. 138656
P981 IlWI.
1695%
ll52bl
128731
775% 153496 P981 70490 1071%h 10716. 3790 64028 M03b
l792b
WIN 135121
1788b
2563. 497%
329%
OOH
1 IW2I 25611 15743~
70Wb 18.k
49281
lYl5ld
13bQ
1792b
4978.b
10418 1389% 14727~
IlWlD
-
l167lh
b,
Whenever this s u g g e s t i o n is m a d e , the u s u a l r e s p o n s e i s -- fine ! But what about the s p a c e and c o s t p r o b l e m s ? T h e r e would b e l i t t l e , if any, i n c r e a s e in c o s t , s i n c e one would employ the v e r y inexpensive photog r a p hic r e p r o d u c t i o n technique , r a t h e r than the currlently e m p l o y e d , v e r y e x p e n s i v e , l e t t e r p r e s s technique.
It has b e e n e s t i m a t e d that by the u s e of m i c r o p r i n t f o r m u l a s , t h e r e would b e a t m o s t only a 10% i n c r e a s e in s p a c e . T h i s is a s m a l l p r i c e t o pay f o r the g r e a t e r s p e e d , reliability, and convenience that would r e s u l t . F u r t h e r m o r e , since this type of s t r u c t u r a l m o l e c u l a r f o r m u l a index p r o v i d e s an unequivoca1 m e a n s of locating a compound, the inclusion
32
BERNARD LOEV
of compound n a m e s i n the subject index b e c o m e s expendable, and the v a s t t i m e , money, and effort going into chemical naming f o r the subject index could be s h a r p l y c u r t a i l e d . It i s not, in f a c t , inconceivable that single compound n a m e s could be dropped f r o m the subject index. Elimination of compound n a m e s f r o m the .sub j e c t index probably would r e s u l t i n a saving of 30% in s p a c e ; t h u s , the u s e of this s t r u c t u r a l m o l e c u l a r f o r m u l a index s y s t e m would r e s u l t in an o v e r a l l 207'0 d e c r e a s e in volume of the indices, Elimination of s y s t e m a t i c n a m e s f r o m the subject index would not only give this g r e a t saving in s p a c e and expense, but would g r e a t l y speed up publication of the indices by e l i m i n a t ing the v e r y time-consuming p r o c e s s of n a m ing of the compounds. Since the compilation of s u c h a s t r u c t u r a l f o r m u l a index can be done s o readily (probably mechanically), t h e r e should be l i t t l e o r no t i m e lag between the a p p e a r a n c e of an a b s t r a c t and the p e r t i n e n t index reference. We have j u s t suggested r e d u c i n g the s i z e of the subject index by elimination of single compound n a m e s . Now we would like t o suggest expansion of the subject index by having m o r e complete c r o s s -indexing and g e n e r i c l i s t i n g . Inasmuch a s single compounds would be m o r e readily a c c e s s i b l e f r o m the s t r u c t u r a l f o r m u l a index, we p r o p o s e a shift in e m p h a s i s t o m o r e complete g e n e r i c listing. As an i l l u s t r a t i o n of the deficiencies of the present s y s t e m , let u s consider a s e a r c h for phenothiazines. At p r e s e n t , if one s e a r c h e s under t h i s heading, one might locate alkyl, amino, o r halo d e r i v a t i v e s , but not carboxy o r carboxamide d e r i v a t i v e s . In f a c t , we m a d e a c a r e f u l study of the subject index one y e a r and found that a t l e a s t 30% of the phenothiazines in the index w e r e not l i s t e d u n d e r that g e n e r i c heading. We m a k e the obvious suggestion that a l l r e l a t e d compounds be l i s t e d u n d e r the a p p r o p r i a t e g e n e r i c heading. By g e n e r i c listing we r e f e r not only t o m o r e complete indexing u n d e r compound c l a s s (%., t e t r a z i n e s , naphthoquinones, phenothiaz i n e s ) , but u n d e r o t h e r g e n e r i c headings, such (antihistamines, insecticides, and as p a r t i c u l a r l y types of r e a c t i o n s (oxidations, Under this l a t t e r sulfonation, amination, g e n e r i c heading we could have indexing such a s i s u s e d in "Organic S y n t h e s e s , ' ' and i l l u s t r a t e d below. T h u s , a s e a r c h f o r dehydration t e c h niques would l i s t a l l techniques d e s c r i b e d that year.
e.),
use
e.).
Dehydration by Anhydrides, 23 If h e a t , 1722 g, 9463a H2SO4, 364b, 12364g KHS04, 426d 12, 1733b ( H 3 P 0 4 ) n , 6423a, 1473d, 27c.
This s e r v i c e of the subject index would be invaluable to the practicing o r g a n i c c h e m i s t . As p a r t of t h i s expansion of g e n e r i c l i s t i n g in the subject index, we recommend the i n c o r poration of P a t t e r s o n ' s Ring Index System 24 into the subject index. So frequently, when looking up an unfamiliar o r complex ring o r h e t e r o cyclic s y s t e m , one m u s t f i r s t consult t h i s s o u r c e anyway. By incorporating t h i s into Chemical A b s t r a c t s subject index, one could simplify and facilitate s e a r c h e s , p a r t i c u l a r l y f o r complex h e t e r o c y c l e s . L e t u s now t u r n f r o m comments about the a b s t r a c t indexes t o c o m m e n t s regarding the abstracts themselves. A b s t r a c t s should have two functions: (1) they should s e r v e a s a m e m s of locating information i n the original l i t e r a t u r e , and (2) they should s e r v e t o a l e r t o r make t h e r e a d e r a w a r e of the l a t e s t developments i n a given area. By definition, an " a b s t r a c t " should not cept in the c a s e of o b s c u r e j o u r n a l s ) be i t s e l f the r e p o s i t o r y of t h i s information; and yet, we find m o r e and m o r e that Chemical A b s t r a c t s i s s t r e s s i n g this l a t t e r objective. The a b s t r a c t s a r e becoming i n c r e a s i n g l y m o r e a r c h i v a l i n n a t u r e . Often, t h e r e i s little point t o going back to the original a r t i c l e , since all of the information in full detail i s given in the a b s t r a c t . C o n v e r s e l y , t h e r e i s often l i t t l e a d vantage t o p e r u s i n g the a b s t r a c t , f o r i t i s no longer a concise s u m m a r y of the contents of an a r t i c l e , and i s frequently m o r e difficult to read. Long a b s t r a c t s of p a p e r s f r o m o b s c u r e j o u r n a l s a r e c e r t a i n l y worthwhile, but wonders about the validity of having page a f t e r page of the m o s t detailed a b s t r a c t s of s u c h iournals a s J. Am. Chem. SOC.,J . Org. Chem., and t h e like. The p r e s e n t a b s t r a c t s a r e c e r t a i n l y i n adequate a s f a r a s a l e r t i n g the r e a d e r to new developments. A typical a b s t r a c t i s shown in Fig. 4. The difficulty with which t h i s can be scanned i s quite obvious. An i n f o r m a l s u r v e y of c h e m i s t s i n the Philadelphia a r e a shows that r a r e l y does one any longer find someone who " r e a d s " o r s c a n s Chemical A b s t r a c t s , a s one should an a l e r t i n g s e r v i c e . This i s b e c a u s e being i n such fine p r i n t , and e s s e n t i a l l y devoid of s t r u c t u r a l f o r m u l a s , i t t a k e s such a g r e a t deal of t i m e and effort to d e c i p h e r the a b s t r a c t s . Usually one m u s t employ pencil and p a p e r t o t r a n s l a t e the a b s t r a c t s into recognizable reactions and equations. We suggest that the organic a b s t r a c t s i n Chemical A b s t r a c t s be modified to contain flow d i a g r a m s of all r e a c t i o n s run with v i r t u a l l y no d e s c r i p t i v e m a t t e r , u n l e s s p e r t i n e n t t o the philosophy of the work. The a b s t r a c t , modified a s we s u g g e s t , i s shown in F i g . 5.
(ex-
one
33
P R O B L E M S I N V O L V E D IN USING THE CHEMICAL LITERATURE
Fig. 4 1959
PRESENT CA ABSTRACT
16134-16135
2.2-Dimethyl-6-quinuclidone, a mesomerism-free acid amide. Horst Pracejus (Univ. Halle, Ger.). Chem. Ber. 92, 988-9(1959). - 2.2Dimethyl-6-quinuclidone (I) was prepd in a 12-step synthesis. I is not capable of acid amide mesomerism because of steric reasons. The basicity, reactivity, and spectral behavior of I are investigated and discussed. M%C:CHC02H and concd. NH40H heated in an autoclave at 150°, the crude product refluxed with alc. HCl, and the sirupyester HC1 salt treated with KOH and distd gave about 50% Me C(NH ) CHCO2Et(II), b1364-80. II(145.1g.). 119 cc.CH2:CHC0 E?, and?1.6 cc. glacial AcOH heated 24 hrs. at 50°, and 48 hrs. a t 600,dild. with 300 cc. Et20, washed with 2070 aq. K2CO3, dried, and evapd., and the residue fractionated ave 218-25 g. Et02-CCH2CH2NHCMqC02Et (111), b1.5 111-14O, nDo 1.4418, d20 0.988. IIJ(122.5 g.) in 600 cc.
5
dry C6H6 treated dripwise with stirring successively with 61 cc. BzCl and 74 cc. Et3N, kept 3 hrs., heated 1 hr. on the steam bath, cooled, and filtered, the residue washed with CgHg and the combined filtr t s worked up gave 157-6Og. N-Bz deriv. (IV) of In, b2-3 210-150, nD 1.5043. IV(139.6 g.) added i:o 9.40 g. Na sand in 400 cc. dry C6H6, treated with about 1 cc. abs. EtOH, heated 12-15 hrs. on the steam bath with stirring, and decompd., with stirring with 280 cc. 10% AcOH, the C6H6 layer dild. with an equal vol. Et 0, filtered, cooled to Oo, and extd. with N NaOH, the alk. ext. acidiyied immediately with dil. H2SO4 and extd. with E 3 0 , the ext. washed with d i t aq. NaHC03 and H20, dried, concd. to about 200 cc., and cooled to - l o o gave 1-benzoyl-2, 2-dimethyl- 5(7)-carbethoxy-4-piperidone (V); the mother liquor concd. to 60 cc. gave a 2nd 'crop; the combined product (44-8 g.) recrystd from Et20 gave pure V, m. 79.5-81.0°. V (30.3 g.) and 0.103 mole N KOH shaken to soln., heated 18 hrs. on the steam bath, cooled, washed by decantation with H20, dried, boiled 15 min. with 200 cc. EtgO, allowed to stand at least 2 hrs. under Et20, and filtered gave 12.8 g. product; the mother liquor washed with 2N NaOH and H 2 0 dried, and evapd. gave an addnl. 6.4 g. product (total) yield, 19.2 g.; the crude product recrystd. from Et20 yielded pure l-benzoyl-2.2-dimethyl-4piperidone (VI), m. 116-17°(Et20). V I (23.1 g.), 11.9g. NCCH2C02Et, 2.3 g.NH40Ac, 5 cc. glacial AcOH, and 25 cc. C6H6 refluxed 4 hrs., dild. with 400 cc. CsHg, washed, dried, concd. to 300 cc., filtered through 1 0 0 g. A 1 2 0 3 , and evapd., the residue boiled with 100 cc. E k O and allowed to stand, and the crude product (29.0 g.) recrystd. fromiso-PrOH and then MeOH yielded a mixt. of Et cis- and trans-lbenzoyl-2.2-dimethyl-4-pipsridylidenecyanoacetate (VII), m. 131-6.5'. VI1 (32.6 g.) in 300 cc. dry dioxane hydrogenated about 10-15 hrs. over 340 mg. Pro2 under ambient conditions yielded the 4-piperidyl analog (VIII) of VII. a m i x t of the diastereoisomers, b0.001 143-7O, m. 81105'. VIII(O.l mole) treated with 350 cc. H 2 0 and 84 g. solid KOH, the mixt. distd to remove during 2 hrs. 100 cc. H20 (together with NH40H and dioxane), the res:idue heated 24 hrs. in an autoclave a t 140-50°, boiled filtered, acidified with 6N HCl, allowed to stand briefly, and filtered gave 10.'7 g. BzOH; the filtrate concd. in vacuo dild. with 2 vols. EtOH, cooled to - l o o , filtered after several hrs., and evapd. to dryness in vacuo, the residue heated 1 hr. at 200°. refluxed 2 hrs. with 300 cc. abs. alc. HC:l, and evapd. in vacuo, the esterification repeated in the same manner, the m i x t evapd., the sirupy residue dis-
1%
16135-36
solved in 35 cc. dry E%O, neutralized with shaking dropwise with 10N NaOH. treated with 12 cc. 10N NaOH, and extd. with E$0, and the e x t worked up gave 12.0 g. Et ~-2,2-dimethyl-4-piperidylacetate (IX), bOa582-30 n i o 1.4588; the forerun and residue combined with the sq.-alk. residue, acidified with HC1, worked up in the usual manner, and the crude product reesterified gave about 2.7 g. IX. IX in Et20 contg. a small amt. of EtOH treated in the usual manner with dry HC1 gave 93% IX.HC1, m. 144-6.5' (abs. EtOH-Et20); picrate m. 169.5-71' (Et20). IX (5.98 g.) in 5 cc. abs. EtOH treated with 3.67 g. 111' (EtOH), in 30 dibenzoyl-d-tartaric acid monohydrate, o; cc. abs. EtOH, the m i x t dild. with 5 cc. abs. EtOH. kept 6 hrs. at room temp., and 18 hrs at Oo, and filtered, and the residue washed with EtOH and E$O, dried, and recrystd. yielded 3.57 g. dibenzoyl-d-tartrate (X) of L-IX, m. 190-3O (decompn.), @ o: 62.5 2 0.5' ( c 1, abs. EtOH). The X in 1.8 cc. abs. EtOH treated with dry HCl, the soln. dild. with 20 cc. E%O, and then with dry E 5 0 to about 900, kept 1 day at Oo, and the solid deposit filtered and recrystd. from EtOH-Et20 yielded 2.01 g. I-IX.HC1, m. 131.5- 3.5O, 11.3 2 0.50 (c 1, abs. EtOH). The 1st mother liquor from X treated with a small excess of abs. alc. HC1, the m i x t evapd. in vacuq, the residue treated with 3 cc. HC1-EtOH and 200 cc. Et20 kept a t -loo, and filtered, and the residual 4.37 g. d-IX. HC1, m. 122-8O, Fj 2 o about 5.7O, fractionally crystd. from EtOH-Et20 yielded 1.7 g. a - I X , HC1, and about 2.6 g. - 1 X . HC1, m. 120-60, 20 8.0 2 0.7O (c 1, abs. EtOH). $-IX (1.99 g.) (or 2.36 g. dl-IX. HClPrefluxed 3 hrs. with 1 5 cc. 6N HCl and evapd. in vacuo, the soln evapd. in vacuo, and the residue dried gave 10070 a - i s o m e r of 2, 2-dimethyl-4-piperidylacetic acid-HC1 (XI. HCI), m. 222-5O (abs. EtOH-Et20). In exactly the same manner was prepd.1-Xl. HCl. m. 2 0 9 - 1 3 . 5 ° , 0 i 0 - 11.22 0.5O(c 1, H20). g - X I . HCl(1.245 ) a n d 5 cc. SOC12 heated 3 hrs. a t 60° and evapd. in vacuo below 35,' the residual glassy acid chloride kept several days under dry E 5 0 to crystallize, the cryst. solid washed by decantation with Et20 powdered, dried 9 1 mixed with 20 cc. dry EbO. some quartz sand, and a few glass beads, stirred 9 hrs. at room temp. with 1.70 cc. Et3N, kept overnight, and filtered, the residue washed with dry Et20, the combined filtrates evapd. in vacuo! and the residue sublimed at 40-65O/ 0.5-2 mm. gave 370-600 mg. g - i s o m e r of 2,2-dimethyl-6-quinuclidone 2o (XII), m. 48-51'. Similarly was prepd. L(+)-XII, m. 47-50' 2.5' (c 1.5, C6H6), in 26-40ojp yield. 1(+)-XIin abs. C6H6 treyted with a small excess of dry HC1 in C6H6 and filtered after 1 0 min. gave 2 o 45O (c 1, abs. nearly lOO%~-XII. HC1, m. 133-6O (decompn.), EtOH), 39' (C 1. H20). The dissccn. const. of g - 8 1 was measured to be 5.33. The ultraviolet absorption spectrum of XI1 in cyclohexane is recorded. l--(+)-XII. HC1 (0.17- 0.34 millimole) dissolved rapidly in H20 or abs. EtOH at 20°, dild. to 5.00 cc., and the rotation measured gave a half-life of 162 1 min. for the hydrolysis, and of 12 hrs. for the alcoholysis a t 20.0 2 0.lo. While XI1 is very rapidly hydrolyzed in acidic soln., it is only very slowly attacked by H20 at 200. Cryst. XI1 is fairly stable at room temp. but small amts. of polymer material is formed during 1-2 days,
-
3° -
a
F. W. Hoffman
Fig. 5. -PROPOSED ABSTRACT 22.Dlin+lwinucliLnd.
0
V o l 53
m*.onurlsndrr acid .miid., H. Pnceius,
Chm.
&..
W W 8 (19)4).
H
PI.
( 4 md (4 i-mod.
xu
( d =d ( 4
i.on*n mod.
pm
Cpd., b.p., yield: I, b3 64-8", 50%; 11, b1.5 111-14*, 8070;III. b2 210, 90%; IV, etc. VI11 is incapable of steric mesomerism. The basicity, reactivity, and spectra of VI11 are discussed.
34
BERNARD LOEV
Inclusion of p h y s i c a l constants, reaction conditions, and yields i s e a s i l y accomplished. A s t a t e m e n t of the author's p u r p o s e and conclusions might be i n c o r p o r a t e d , and we believe that this could m o s t r e a s o n a b l y be a c c o m p l i s h e d by u s e of the a u t h o r ' s own s u m m a r y -- edited i f n e c e s s a r y . This inclusion of the p u r p o s e and conclusion of the w o r k i s now lacking in p r e s ent a b s t r a c t s . Modification of a b s t r a c t s a s we have r e c ommended would b e p a r t i c u l a r l y useful in a r t i c l e s involving o r g a n i c reaction m e c h a n i s m s . This i s a n a r e a e s s e n t i a l l y ignored by Chemical Abstracts, In F i g u r e 6 i s a C h e m i c a l A b s t r a c t s a b s t r a c t of an a r t i c l e in which is d e s c r i b e d a novel reaction and a proposed m e c h a n i s m . The C h e m i c a l A b s t r a c t s a b s t r a c t m a k e s no mention of the f a c t that a m e c h a n i s m i s p r o p o s e d . Our p r o p o s e d a b s t r a c t gives the m e c h a n i s m and r e action and c a n be scanned a t a glance. Fig. 6
The Ortho of phaolr. Alfred J. Kolka, John P. Napolitano, md George G . Ecke (Ethyl Corp., Detroit, hlich.). J . Org. Chmn. 21. 71ZB(lQM)).-Phenob wealkylated with olefins in the presence of catslytic am&. of (PhOMl(1) to %ve %mono- and P,&dialkylated phmob. Heating PhOH w'" C+ and 8-4 mole% I 10 hrr. at 320' and6&8001b./~.m.pves24%o-EtQ&OH, b.201-2°,rv 1.5372 (+EtCd-LOCHd%H deriv.,m. la8-40°j,and 8%2,6Et2CcH,0H,b.219°,m.87-80. Alkyhtion o PhOH mth MeCH:CHs2 hm.at 230-40° and 2001600 lb. /aq. in. given 61% 2,~MolCH)&+OH, b* l a * , m. 1Q0,rff 1.6134. Alkylauon of PhOH with MeC:CH* 4 hrs. at 106-1Sosnd 30-100 lb./sq. in. gives 6% rcQ)vcrcdPhOH,46% + M e C GH4OHS b 120°, nv 1.5288s ? 'I +bomw,56%2,6(M+ C)rC+H:OH(11), h 147O, m.&La8, and some highw-boilbg products. By changing the reaction time, m e , snd temp. products contg. from 0 to 80% II may be obtained. F. E. B.
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A s t a t e m e n t of the p u r p o s e and conclusions ( m o s t expertly p r e p a r e d by the e x p e r t the author) with p e r h a p s the proposed m e c h a n i s m i l l u s t r a t e d is readily comprehended and m o s t useful. An a b s t r a c t journal of the f o r m we have j u s t outlined would be s m a l l e r than the p r e s e n t journal, would be i s s u e d a t l e s s than the p r e s ent c o s t , and would be r e a d avidly by the m a j o r i t y of o r g a n i c c h e m i s t s , We s u s p e c t that the n u m b e r of p e r s o n a l subscriptions would show a m a r k e d i n c r e a s e , thus f u r t h e r a s s i s t i n g the lowering of p r i c e . It should a l s o b e pointed out that a b s t r a c t s of the type that we have d e s c r i b e d would be e a s i e r t o w r i t e and p r o o f r e a d , hence should g r e a t l y r e d u c e the t i m e lag between a p p e a r a n c e of the original a r t i c l e and the a p p e a r a n c e of the a b s t r a c t and indices. Once again, the objection m a y b e r a i s e d a s to the cost of printing t h i s type of a b s t r a c t . Once again, the obvious a n s w e r i s t o change f r o m the p r e s e n t expensive l e t t e r p r e s s printing t o the m u c h l e s s expensive and m o r e v e r s a t i l e photographic reproduction p r o c e s s . To s u m m a r i z e , we believe that modifying the a b s t r a c t s t o p r o v i d e flow d i a g r a m s would g r e a t l y i n c r e a s e the value to the c h e m i s t , would m a r k e d l y r e d u c e a b s t r a c t i n g t i m e and space, and facilitate e a r l y a p p e a r a n c e of the a b s t r a c t . We a l s o believe that the u s e of a s t r u c t u r a l m o l e c u l a r f o r m u l a index would g r e a t l y facilitate compound s e a r c h i n g , and that the e a s e and r a p i d ity with which s u c h indexes c a n be p r e p a r e d would permi': i s s u a n c e of a n index with e a c h i s s u e of C h e m i c a l A b s t r a c t s . The c o n s i d e r a b l e saving in t i m e , resulting f r o m t h e s e modifications, would probably r e s u l t in i s s u a n c e of a b s t r a c t and index within s i x months of a p p e a r a n c e of the original a r t i c l e .
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Fig. I
THE ORTHO ALKYLATION OF PHENOLS. A. J. Kolka, J. P. Nopolitano, G. G. Ecke (Ethyl Corp., Dotroit, Michigan). J. Org. Chmn. 712-13 (1956). S y n h i s of 241kyl and 2,6-diolkyl substituted phenols by m c t i o n of on olefin oad plrmol cetalyzod by oluminum phenoxide, of 2.300' ond 2-500 psig. Suwoskd nnchonism:
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L I, R =H, b 201-029
ng 1.5372, 24%; I, 2-t-Bu,
I
b,,
120', 46%; II, R =H, m.p. 37-8'. 8%;
11, R =CH,, m.p. 19'. 61%; Ii, 2.6-di-t-Bu, map. 36.5'. 36%.
II
35
PROBLEMS INVOLVED IN USING THE CHEMICAL LITERATURE
Acknowledgement.--We w i s h t o thank t h e o t h e r m e m b e r s of t h < ? C o m m i t t e e on A b s t r a c t ing and Indexing of th.e P h i l a d e l p h i a Section of the A m e r i c a n C h e m i c a l Society, f o r helpful c o m m e n t s and d i s c u s s i o n s of t h e s e points. We would p a r t i c u l a r l y l i k e t o thank D r . Maxwell
Gordon, C h a i r m a n of the C o m m i t t e e , who s u g g e s t e d m a n y of the modifications outlined, A n a r t i c l e d e s c r i b i n g m a n y of t h e s e points i n g r e a t e r detail has appeared in the January, 1961, i s s u e of t h e P h i l a d e l p h i a Section p u b l i c a tion "The Catalyst."
REFERENCES
(1) "Beilsteins Handbuch der organischen Chemie," 1918-, Springer Verlag, Berlin. (2) "Elsevier's Encyclopedia of Organic Chemistry." F. Radt, Ed., Elsevier Publ Co., New York, N. Y. (3) American Chemical Society, Washington, D. C. (4) United States Patent Office, Washington, D. C. (5) Institute for Scientific InfcNrmation. Philadelphia 23, Penna. (6) The Chemical Society, London W. 1, England. (7) Gesellschaft Deutscher Chsmiker, Frankfurt, Germany. (8) I t was called to our akention at the Symposium that Chemical Abstracts has just issued such a list of review articles, but covering the years 1958-1959 only. (9) "Uniterm Index t o Chemical Patents." Information for Industry, Inc.. Washington 8. D. C. (10) "Heterocyclic Compounds," R C. Elderfield, Vols. I to VI., 1950-1957, John W h y and Sons, New York, N. Y.; "The Chemistry of Heterocyclic Compounds, A Weissberger, Ed., Vols. I to XIV. 1950-1960, Interscience, New York, N. Y. (11) "Organic Preparations, C. Weygand, 1938, Interscience PubL, Inc., New York, N. Y. (a later printing of this book (also ref. 12) is available, but the information has not been up-dated). (12) "Reactions of Organic Compounds," W. J. Hlckinbottom, 1948, Longmans, Green and Co., New York, N. Y. (13) "Preparation of Organic Interdemiates," D. A. Shirley. 1951, John Wiley and Sons. New York, N. Y. "
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(14) "Synthetic Organic Chemistry, " R B. Wagner and H. D. Zook, 1953, John Wiley and Sons, New York, N. Y. (15) "Organic Syntheses," V. Migrdichian, 1957, Reinhold Publishing COT., New York, N. Y. (16) "Synthetic Methods of Organic Chemistry, " W. Theilheimer. 1946+, Interscience Publishers, Inc., New York, N. Y. (17) "Methoden der Organischen Chemie, (Houben- Weyl), E. Muller, Ed,, 4th Edition, 1958, G. Thieme Verlag. Stuttgart, Germany. (18) "Chemisuy of Carbon Compounds," E. H. Rodd, Vols. I to IV, 1951-1959, Elsevier PubL Co., New York N. Y. (19) "Hydrogen Peroxide in Organic Chemistry," J. G. Wallace, 1960, E. I. du Pont, Inc., Wilmington, Delaware, (20) "Reactions of Sulfur Trioxide, " Technical Wllletin SO3-A, 1958, Allied Chemical Corporation, New York, N. Y. (21) For example, Bulletin 507C, "Sodium Hydride, Metal Hydrides Inc., 1958, Beverly, Mass (22) W. Theilheimer, c / o Hoffman-Labche. Inc., Nutley, New Jersey. (23) Dissertation Abstracts, University Microfilms, Inc., Ann Arbor, Michigan. (24) "The Ring Index," A. M. Patterson, .L T. Capell, and D. F. Walker, 1960, American Chemical Society, Washington, D. C. "
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