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Structural Identification of Poison I v y Components DEAR SIR:
I have read with interest the t h r e e l e t ters appearing on page 1268 of the Marcrli 30 issue of C&EN under the h e a d i r i g "Other Men's Poison." I appreciate D r . Hill's kind remark, a n d also his c o n c e r n about placing t h e credit where credit i s due in regard to the isolation of t h e toxic principle of poison ivy. T h e work of Dr. Hill and his s t u d e n t s , [/. Am. Chem. Soc, 5 6 , 2736-8 ( 1 9 3 4 ) ] , is well recognized, especially by our grouip, as t h e most fundamental contribution t h a t has been m a d e in respect to identifyim^ the structural skeleton of the poison iv~y principle. Frequent reference v>rill l > e made to his work in t h e articles which I am now preparing for publication i n c o l laboration with William F. Symes, B e r n a r d Loev, and Sakharam V. Sunthankar cover ing our recent work at Columbia Uni versity. It is evident from Dr. Hill's earlier paper and also from his recent letter t o C&EINf that h e believes t h e poison ivy principle t o be identical to Japanese Lac u r u s h i o l . Our recent studies establish that t h i s is n o t the case. All of the components of t h e two oils have t h e same carbon slceletoxi as he and his students so clearly d e m o n strated, b u t t h e higher olefinic components of o n e oil do not have t h e same struc tures as those of t h e other. It also a p p e a r s that t h e relative amounts of these com ponents in t h e two oils differ. O u r d e g radative results obtained using t h e sepa rated components in pure form e s t a b l i s h that t h e di- and triolefinic components o f the L a c urushiol do not have t h e struc tures proposed b y Majima [Ber, 5 5 Ï 3 , 1 7 2 ( 1 9 2 2 ) 1 . Likewise, t h e Majima s t r u c t u r e s are not correct for the corresponding components of t h e poison ivy oil. It i s clear, therefore, that one must differentiate b e tween Japanese Lac urushiol and poison ivy "urushiol." Our forthcoming papers will, of c o u r s e , make no claim for isolating the poison iv^y principle a n d identifying the carbom skeleton. All credit for this fundamental work rightfully belongs to the Wesleyaxi ^roup. W e do have a case, however, f o r claiming credit for proving that t h e poiso>m ivy principle is a mixture of f o u r components a n d completing their s t r u c t u r a l identification. Mason and Schwartz E/ACS, 64, 3058 (1942)1 concluded t h a t thte poison ivy principle contains at l e a s t thr&e toxic components b u t they did n o t structurally identify them nor did they prove their urushiol skeleton. W e are the first t o succeed in separating each of the f o u r components in pure form and establishing their structure. W e shall also r e p o r t o n our work on Japanese Lac and o n a ne-w method of synthesizing the various olefinic components having known geometric configurations. W e shall point out t h a t synthesis is t h e only w a y at present t o mak:e C H E M I C M
t h e s e various components available for clinical evaluation. Many remedies for the treatment of poison ivy dermatitis have been advocated; t h e . m o s t common being those based on t h e use of alkaline solutions, oxidizing agents, or complexing agents. T h e r e is m u c h conflict of opinion as to t h e effectiveness of such agents. They appear to b e moderately effective only if t h e poison ivy sap or oil has not yet penetrated t h e skin. Excellent reviews of clinical experiences with such remedies have appeared [Stevens, J. Am. Med. Assoc, 1 2 7 , 912 ( 1945 ) a n d Prokesch, Arch. Pediat., 6 7 , 267 (1950)1. Erratic a n d contradictory results have heretofore been obtained in m a n y investigations on desensitizing individuals to poison ivy b y means of injections or oral feeding of poison ivy extract. Such extracts are not uniform in composition, stability, a n d "urushiol" content. After a period of time t h e active "urushiol" m a y even become a minor component in such extracts. N o w t h a t two of t h e components of poison ivy "urushior' are available in p u r e form (synthetic) and work is in progress on the synthesis of t h e other components, a careful re-evaluation of t h e possibility of desensitization (immunization) to poison ivy c a n b e initiated. C H A R L E S R. D A W S O N
New York, Ν. Y. Avocado Avocation DEAR SIR:
In t h e comprehensive report on t h e r e c e n t National ACS meeting in Los Angeles ( C & E N , March 3 0 ) , t h e following appears o n page 1 2 9 5 : Sterols from A v o c a d o . Avacado oil shows promise as a source of sterols for iriterconversions, . . . t h e avacado is t h e best source of sterols among t h e four tropical nuts that she h a s studied. The 4400-odd members of Calavo co operative, among whom are a n u m b e r of chemists, are not h a p p y with this passage. T o b e more explicit, I work as a chemist on weekdays; b u t on week ends I slave over four acres of avocados ( n o t avacados), o n a steep hill slope, coaxing the trees to produce this fruit in sufficient quantity t o repay t h e effort. All summer long, as I climb that hill m a n y times, irrigating, picking, a n d so on, I shall b e recalling that passage. M y family a n d neighbors m a y in time catch m e m u m b l i n g to myself in growing frustra t i o n : "Avacados ( s i c ) ; avacados ( s i c ) ; rruts; Nuts; N U T S ! " Don't take m e too seriously . . . T h e neurosis has not y e t set in. B u t as a famous publicist once said: "I don't care w h a t you say about m e ; b u t spell m y n a m e right." L o u i s T. M O N S O N
L·os Angeles, A N D
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