NOMENCLATURE OF CARBOHYDRATES By R . STUART TIPSON' National Bureau of Standards, Washington 25, D. C.
In 1939, b e c a u s e of the confusion t h e n e x isting in the n a m i n g of c a r b o h y d r a t e s , a c o m m i t t e e w a s appointed by the A m e r i c a n C h e m i c a l Society Divisions of S u g a r C h e m i s t r y and Technology, C h e m i c a l E d u c a t i o n , and Biological C h e m i s t r y to develop a r a t i o n a l s y s t e m of carbohydrate nomenclature. Carbohydrate c h e m i s t s w e r e widely c a n v a s s e d f o r t h e i r opinions. The C o m m i t t e e r e p o r t e d the r e s u l t ing r u l e s in 1944 a t t h e April ACS m e e t i n g ; they w e r e l a t e r m o d i f i e d , w e r e a p p r o v e d by the ACS Council in A p r i l 1 9 4 8 , a n d w e r e published i n C h e m i c a l and E n g i n e e r i n g News. 1 L a t e r , t h e Division of C a r b o h y d r a t e C h e m i s t r y appointed ;3 new C o m m i t t e e on C a r bohydrate N o m e n c l a t u r e , which r e - e x a m i n e d t h e r u l e s , and extended and p a r t l y r e v i s e d t h e m a s a r e s u l t of e x p e r i e n c e gained a n d s u g g e s t i o n s r e c e i v e d i n the i n t e r i m . A f i n a l d r a f t of t h e s e r u l e s w a s m a d e i n 1 9 5 2 , a f t e r e x c e l l e n t collaboration with a c o u n t e r p a r t B r i t i s h c o m m i t t e e . They w e r e adopted by the 2 ACS o n a tentative b a s i s and published, and w e r e s i m u l t a n e o u s l y adopted a n d published by The C h e m i c a l Society. T h e t e r m " s u g a r " h a s been u s e d in two w a y s . Originally, i t w a s specific f o r c a n e o r beet s u g a r ( s u c r o s e ) , which, of c o u r s e , is s t i l l the l a y m a n ' s u s a g e . It t h e n w a s extended t o grape sugar (glucose), fruit sugar (fructose), and eventually to any :mono- o r o l i g o - s a c c h a r i d e o r derivative thereof. 4 The " c a r b o h y d r a t e s " m a y be r e g a r d e d a s c o m p r i s i n g ( a ) aliphatic and a l i c y c l i c polyhydroxy a l d e h y d e s a n d polyhydroxy k e t o n e s (and d e r i v a t i v e s t h e r e o f ) , c a l l e d )simple s u g a r s o r m o n o s a c c h a r i d e s ; and ( b ) t h e i r condensation p r o d u c t s ( f o r m e d by e l i m i n a t i o n of w a t e r m o l e c u l e s ) , called o l i g o s a c c h a r i d e s and p o l y s a c c h a r i d e s . T h e o l i g o s a c c h a r i d e s a r e subdivided into d i s a c charides, trisaccharid,es, tetrasaccharides, etc. In developing any s y s t e m of n o m e n c l a t u r e , o n e is confronted i m m e d i a t e l y with the l e g a c y of the past; and e x p e r i e n c e h a s shown that i t is usually w i s e not to t a m p e r with t h i s any m o r e t h a n n e c e s s a r y . A c c o r d i n g l y , we have u s e d as m u c h of i t a s p o s s i b l e , a s a foundation. F i r s t of all, t h e r e a r e c o m m o n o r t r i v i a l n a m e s . Of c o u r s e , co:mmon n a m e s , s u c h a s s u c r o s e , l a c t o s e , and imaltose, will a l w a y s find u s e b e c a u s e they a r e c o n c i s e and convenient; but, s i n c e those n a m e s w e r e given to compounds before we knew what they w e r e c h e m i c a l l y , the n a m e s n a t u r a l l y cannot be r a t i o n a l . T o a s s i g n a n a m e by a r a t i o n a l s y s t e m , one m u s t a d h e r e t o one g r e a t c r i t e r i o n - - n a m e l y , t h a t , given the
n a m e , the f o r m u l a c a n be w r i t t e n , and, given the f o r m u l a , the n a m e c a n be w r i t t e n . The r u l e s of c a r b o h y d r a t e n o m e n c l a t u r e w e r e d e v i s e d p r i m a r i l y f o r the E n g l i s h l a n g u a g e . Rule 1 s t a t e s that " c a r b o h y d r a t e n o m e n c l a t u r e should follow the g e n e r a l p r i n c i p l e s of established organic nomenclature Rule 2 s t a t e s t h a t "as f e w c h a n g e s as, p o s s i b l e will be m a d e i n t e r m i n o l o g y u n i v e r s a l l y adopted." (Rule 3 ) T h e r e d u c i n g s u g a r s fall into two c l a s s e s . In a n a l d o s e , the r e d u c i n g function i s a n aldehyde, a n d i t s c a r b o n a t o m is a t o m n u m b e r one. In a k e t o s e , the r e d u c i n g function is a ketone, and the c a r b o n y l c a r b o n a t o m is a s s i g n e d the l o w e r p o s s i b l e n u m b e r . F o r indicating the n u m b e r of c a r b o n a t o m s i n the n o r m a l chain, the a p p r o p r i a t e one of t h e s e n a m e s i s used: t r i o s e , t e t r o s e , pentose, h e x o s e , heptose, octose, nonose, decose, e t c .
."
An aldohexose ( I - , NOT 6 - )
A k e t o h e x o se ( 2 - , NOT 5 - )
Now, the s i m p l e s t possible s u g a r having a n asymmetric carbon atom is a triose, glyceraldeh y d e , It c a n e x i s t i n two optically active f o r m s HO
HO
H20H
H20H
L-Glycerose
D-Gly c e r o s e
T h e f o r m u l a on the r i g h t w a s a s s i g n e d a r b i t r a r i l y to D - g l y c e r o s e ; t h i s h a s p r o v e d to be a lucky g u e s s , a s Bijvoet and c o - w o r k e r s (1949, 1 9 5 1 ) have p r o v e d that the e s t a b l i s h e d convention c o n f o r m s to r e a l i t y , and s o t h i s f o r m u l a d e s c r i b e s a n absolute o r i e n t a t i o n , (Rule 4) T h e small capital l e t t e r s D and L a r e pronounced "dee" and "ell" a n d a r e not to be confused with optical rotation; i f t h i s is to be i n d i c a t e d , i t i s done by adding ( d e x t r o ) or ( l c ) , o r by adding (t) o r ( - ) . R a c e m i c m o d i f i c a t i o n s a r e indicated by the p r e f i x e s DL or ( + ) , By a p r o c e s s of chain extension, any h i g h e r s u g a r can be built up e i t h e r f r o m the L- o r the D - g l y c e r o s e , as indicated
*Presented before joint meeting of the Division of Chemical Literature nnd Diriaion of Organic Chemistry, American Chemical Society Meeting, Chicago, Illinois, September 8, 1958.
R . S t u a r t Tipson
FHO t
D-Gly c e r o s e
D- T h r e o s e
L -Gly c e r o s e
L Threose
-
$:"
Trivial
FHO OH
D-Glycerose (D D-Erythrose series) L -Arabinose D -Gluco s e
D -E r y t h r o s e
one two three four
D-gly c e r 0 -T r i o s e D-erythro-Tetrose L-arabino Pentose D-gluco -Hex0 s e
-
T h e following i l l u s t r a t e s application to s u g a r s higher than hexoses.
L -Er ythro s e
Hence, R u l e 5 s t a t e s t h a t " c a r b o h y d r a t e s having the s a m e configuration of the highest n u m b e r e d a s y m m e t r i c c a r b o n a t o m a s t h a t of D- gly c e r os e belong t o t h e D- configurational s e r i e s ; t h o s e having the opposite configuration belong to the L - s e r i e s . " (Rule 6 ) E a c h s u g a r h a s one or m o r e a s y m m e t r i c c a r b o n a t o m s . Instead of naming e a c h a c t i v e c e n t e r individually, as with the s t e r o i d s , we have r e t a i n e d e a r l i e r p r a c t i c e i n the s u g a r f i e l d , and we n a m e all the c e n t e r s collectively. T h e s e n a m e s w e r e d e v i s e d by t h e s i m p l e p r o c e s s of lopping off t h e final 'I-se" f r o m t h e n a m e s a l r e a d y u s e d f o r the f i f t e e n a l d o s e s u g a r s f r o m t r i o s e t h r o u g h h e x o s e . T h e conf i g u r a t i o n of a, g r o u p of c o n s e c u t i v e , but __ not n e c e s s a r i l y contiguous, a s y m m e t r i c c a r b o n a t o m s i s d e s i g n a t e d by t h e a p p r o p r i a t e one of t h e s e p r e f i x e s : Asymmetric carbon atoms
Sv s t e m a t i c
HCOH
I-
}
CHZOH
-
D-gly c e r o Dgluco-Heptose
H20H D-erythro-Lgluco -Nonulose
Since t h e configurational p r e f i x d e s c r i b e s a g r o u p of c o n s e c u t i v e , but not n e c e s s a r i l y contiguous, a s y m m e t r i c c a r b o n a t o m s , the next e x a m p l e s a r e all D - e r y t h r o .
Pr ef i x e s
gly c e r o erythro , threo a r a b i n o , lyxo, r i b o , xylo a-l l o , a l t r o ,~ g a l a c_ t o , gluco, _ gulo ido, manno , - - - - tal0
T h e r e a r e thus f i f t e e n configurations n a m e d c o l l e c t i v e l y , and e a c h m a y be D o r L , giving a t o t a l of t h i r t y . At t h i s point we stop; all h i g h e r c o l l e c t i o n s of a s y m m e t r i c c a r b o n a t o m s a r e n a m e d (Rule 22) by u s e of combinations of t h e s e prefixes. In naming a compound, the configurational p r e f i x i s added as the l a s t step: i t i m m e d i a t e l y p r e c e d e s t h e p r e f i x giving t h e n u m b e r of c a r b o n atoms. By f o r m a l i z i n g the configurational p r e f i x e s , we h a v e , i n e f f e c t , provided, f o r the f i f t e e n a l d o s e s ( f r o m which they w e r e d e r i v e d ) , a c c e p t a b l e , s y s t e m a t i c n a m e s which m a y be useful to s t u d e n t s .
D - e r y t h r o ( p r i n c i p a l function a t X ) An inability t o apply Rule 6 i s r e s p o n s i b l e f o r e r r o n e o u s n a m e s applied by s o m e w o r k e r s t o k e t o s e s and deoxy s u g a r s , which I s h a l l next discuss. (Rule 7) K e t o s e s having the c a r b o n y l g r o u p a t c a r b o n a t o m n u m b e r two a r e n a m e d by m e a n s of the suffix "-ulose." If the c a r b o n y l g r o u p is a t s o m e o t h e r position, the s u g a r is n a m e d by adding the a p p r o p r i a t e n u m e r a l .
+=0
H O ~ H H ~ O H HCOH
CH OH 1 2 HO$H =O
H H!IIOH OH
h 2 o H D - a r a b i n o -Hexulose (D-Fructose)
D-arabino-3-Hexulose
NOMENCLATURE O F CARBOHYDRATES
5
H o w e v e r , certain. n a m e s a r e still being u s e d f o r k e t o s e s which a r e inacceptable to the o r g a n i c c h e m i s t a s definitive n a m e s , b e c a u s e they have i nc o r r e c t s t r u c t u r a1 i m pli cations :
(iH20H
L=0 Inacceptable
LHO
-
1,:) -Dihydroxy 2 - p r opanone
Gly c e r ulo s e
-diose
5
I
AH20H
CH20H
-0sulo s e
- diu1o s e
D-glycero-Tetrulose
D- T h r eulo s e
-
D e r ythr o P e ntulo s e
-
D R i bul o s e D - Lyxulo s e D-Xylulose
I
Systematic
-I
}
-
D-,threo P e n t u l o s e
a n d the c o r r e s p o n d i n g n a m e s f o r the L f o r m s E a c h n a m e i n the left c o l u m n shows one a s y m m e t r i c c a r b o n a t o m m o r e than is actually present! (Rule 8) The s a m e kind of p r o b l e m i s e n c o u n t e r e d when we c o m e to naming t h o s e s u g a r s i n w h i c h a n alcoholic hydroxyl g r o u p is r e p l a c e d by a h y d r o g e n a t o m . We have c h o s e n to n a m e t h e s e by m e a n s of the p r e f i x "deoxy-" p r e c e d e d by the a p p r o p r i a t e n u m e r a l .
Another r e a s o n a b l e p r o p o s a l u n d e r cons i d e r a t i o n is that k e t o s e s having two ketonic c a r b o n y l g r o u p s will be n a m e d by m e a n s of t h e s u f f i x I (-diulose .I1 A t h i r d p r o p o s a l u n d e r c o n s i d e r a t i o n is that d i a l d e h y d e s , f o r m e d f r o m a l d o s e s by oxidation of the t e r m i n a l h y d r o x y m e t h y l g r o u p to -CHO, be n a m e d by u s e of the suffix We m a y now c o n s i d e r the n a m e s a s s i g n e d t o the p r o d u c t s obtained o n ( a ) r e d u c t i o n of a n a l d o s e or ( b ) f u r t h e r oxidation of the above compounds, 6H20H I
FHO
FOOH
I
I
I
I
I
LH~OH
CH~OH
kOOH
-it01 (Rule 23)
-onic a c i d (Rule 25)
- u r o n i c acid (Rule 26)
HbOH AOOH
H20H
-
2-Deoxy- D - e r y t h r o pentose("2-Deoxy-Dr ibos el')
-
3-Deoxy -D- r i bo
-ulosonic acid
COOH - a r i c acid (Rule 28)
hexose
I h a v e put "2-Deoxy-Dl-riboset1 i n quotation m a r k s b e c a u s e it m e a n s "that 2-deoxypentose having the D - r i b o configuration," w h i c h is a n i m p o s s i b i l i t y , s i n c e a 2-deoxypentose h a s only two h y d r o x y l g r o u p s om a s y m m e t r i c c a r b o n atoms T o r e t u r n t o R u l e 7 f o r the s u g a r s , the C o m m i t t e e is a t p r e s e n t c o n s i d e r i n g the p r o p o s a l t h a t a s u g a r which i s both a n aldose a n d a k e t o s e will be n a m e d by r e p l a c i n g t h e f i n a l "e" i n t h e n a m e of the ( f o r m a l l y ) p a r e n t aldose by the suffix "-ulose," p r e c e d e d by the a p p r o p r i a t e n u m e r a l , a n d then adding the a p p r o p r i a t e configurational p r e f i x e s . ( T h i s a n d the next two p r o p o s a l s a r e p u r e l y t e n t a t i v e , and a r e not t o be r e g a r d e d as r u l e s , as they h a v e not been officially a c c e p t e d . )
.
4.0
None of t h e s e endings is new t o s u g a r c h e m i s t r y . We m e r e l y r e c o m m e n d using t h e m s y s t e m a t i c a l l y , and m a n y v e r y old n a m e s would r e m a i n unchanged: f o r e x a m p l e , m a n n i t o l , mannose, mannonic acid, and mannuronic acid. H o w e v e r , f o r u s e in d i s c u s s i o n s of s u g a r chemistry, certain well-established names would r e q u i r e c h a n g e . And, to be c o m p l e t e l y f a i r , I will give you the e x a m p l e which would n e e d a l m o s t c o m p l e t e changes-the s e r i e s , d e r i v e d f r o m D - g l y c e r a l d e h y d e , of compounds which have b e e n thoroughly studied outside s u g a r c h e m i s t r y . The n a m e s would be: Suggested Name
Usual Name
Gly c e r ito1 D-Glycerose Glycerodiose D-Glyceronic acid D-Glyceruronic acid G l y c e r a r i c acid
Gly c e r ol D-Glyce r a l d e h y d e Tartronaldehyde D-Glyceric acid T a r t r o n a l d e h y d i c acid Tartronic acid
I
~ H ~ O H -ose -ulose a n d t h e i r oxidation p r o d u c t s , n a m e l y
In c e r t a i n a r e a s of o v e r l a p between s p e c i a l i z e d s u g a r c h e m i s t r y and g e n e r a l o r g a n i c c h e m i s t r y , two a c c e p t a b l e n a m e s f o r a single
6
R . S t u a r t Tipson
compound m a y be desirable--one f o r the s u g a r c h e m i s t and the o t h e r f o r the g e n e r a l o r g a n i c chemist. (Rule 1 7 ) The a c y c l i c n a t u r e of a s u g a r or d e r i v a t i v e containing a n uncyclized CHO or GO g r o u p a s the p r i m a r y function i s i n d i c a t e d by i n s e r t i n g the i t a l i c i z e d p r e f i x aldehydo or keto, r e s p e c t i v e l y , i m m e d i a t e l y befor e the configur a tional p r e f i x and s t e m n a m e , a s in: aldehydoD-glucose p e n t a a c e t a t e ; keto-D-fructose pentabenzoate. (Rule 15) Now, s o f a r , I have depicted the s u g a r s a s open chains; but, a s you know, they and t h e i r d e r i v a t i v e s c a n e x i s t a s r i n g f o r m s , a n y one of which h a s two a n o m e r i c f o r m s , c a l l e d a and 8. T h i s a n o m e r i c p r e f i x , which c a n only be u s e d i n conjunction with a configurational p r e f i x ( D o r L ) , i m m e d i a t e l y p r e c e d e s the l a t t e r . In the D - s e r i e s , t h e m o r e d e x t r o r o t a t o r y a n o m e r is d e s i g n a t e d a and the h e m i a c e t a l hydroxyl g r o u p of the a n o m e r i c c a r b o n a t o m i s w r i t t e n to t h e r i g h t i n the F i s c h e r p r o j e c t i o n f o r m u l a . The l e s s d e x t r o r o t a t o r y a n o m e r i s d e s i g n a t e d P and the hydroxyl g r o u p i s w r i t t e n t o the l e f t . The r e v e r s e holds f o r t h e a and F a n o m e r s in the L s e r i e s .
n
HCOH
H ~ O H -D
P
Se ptano s e (7-atom ring)
If the r i n g s i z e is known, the a p p r o p r i a t e one of t h e s e should be u s e d , u n l e s s the n u m b e r i n g of s u b s t i t u e n t s m a k e s i t obvious. F o r e x a m p l e , 2,3,5-tr i -2-benzoyl - D - r ibofuranose c a n be c o n t r a c t e d t o 2,3,5 t r i 2-benzoyl -D- r i bo s e . (Rule 20) A glycoside is a m i x e d a c e t a l r e s u l t i n g f r o m the exchange of a n o r g a n i c r a d i c a l f o r the h y d r o g e n a t o m of t h e h e m i a c e t a l hydroxyl g r o u p of a cyclic f o r m of a s u g a r . It is n a m e d by substituting "idel' a s a suffix i n place of t h e t e r m i n a l "e" of the c o r r e s p o n d i n g s u g a r n a m e ; before t h i s w o r d is placed the n a m e of the o r g a n i c s u b s t i t u e n t , s e p a r a t e d by a s p a c e (Rule 1 2 ) .
- -
kH2OH
I
1'3 - D
kH20H a
O
Furanose Pyranose (5-atom ring) (6-atom ring)
H ~ O H
tH2OH a
H
"-side" by "furanoside," "pyranoside," o r " s e p t a n o s i d e .'I
-L
kH20H
P -L (trans)
(cis)
The s t e r i c a r r a n g e m e n t of t h e g r o u p s on the a - D a n o m e r i c c a r b o n a t o m is t h e s a m e as t h a t on t h e 9 - L a n o m e r i c c a r b o n a t o m ; t h a t on the a -L a n o m e r i c c a r b o n a t o m i s the s a m e as t h a t on the B-D a n o m e r i c c a r b o n a t o m . T h e aforms are and the @ f o r m s a r e t r a n s , as r e g a r d s t h e r e l a t i o n of t h e a n o m e r i c t o the configurational carbon atom. (Rule 1 9 ) The r o o t "glyc" is u s e d i n a g e n e r i c s e n s e , t o denote any s u g a r or d e r i v a tive t h e r e o f ; a s i n "glycose" and "glycoside." (Rule 18) T h e s i z e of t h e r i n g i n the h e t e r o c y c l i c f o r m s of m o n o s a c c h a r i d e s m a y be indicated by r e p l a c i n g , i n the s u g a r n a m e , the l e t t e r s " s e " by " f u r a n o s e " f o r the 5-atom r i n g "pyranose" f o r the 6 - a t o m r i n g , and " s e p t a n o s e " f o r the 7 - a t o m r i n g
a -D-Glucopyranose
Methyl a -D-glucopyranoside
(Rule 21) If the h e m i a c e t a l hydroxyl g r o u p i s detached f r o m a c y c l i c modification of a s u g a r , t h e r e s i d u e i s a glycosyl r a d i c a l ; i t m a y be glycof u r a n o s y l , glycopyranosyl, or glycoseptanosyl. Note that a glycosyloxy r a d i c a l is identical with a glycoside r a d i c a l .
e,
L i k e w i s e , f o r the g l y c o s i d e s , the s i z e of t h e r i n g m a y be shown by r e p l a c i n g t h e s y l l a b l e
CH~OH a -D-Mannopyranosyl
a -D-Ribofuranosylamine
fluoride (Rule 9 ) Now, as r e g a r d s naming of s u b s t i t u t e d s u g a r s , i t s o happens t h a t substitution is a l m o s t a l w a y s on oxygen, and only o c c a s i o n a l l y on c a r b o n or n i t r o g e n . When the hydrogen a t o m of a n alcoholic hydroxyl g r o u p of a c a r b o h y d r a t e
7
NOMENCLATURE O F CARBOHYDRATES
is substituted, a n italic capital l e t t e r 0 (for oxygen) is a t t a c h e d by a hyphen d i r e c t l y before 0 p r e f i x need not the s u b s t i t u t i n g p r e f i x . T h e be r e p e a t e d f o r m u l t i p l e s u b s t i t u t i o n by one g r o u p . S i m i l a r p r i n c i p l e s apply t o s u b s t i t u t i o n on n i t r o g e n ( p r e f i x , N),a n d t h e p r e f i x C m a y be u s e d t o i n d i c a t e s u b s t i t u t i o n on c a r b o n , t o avoid p o s s i b l e a m b i g u i t y . F u r t h e r m o r e , ( R u l e 10) t h e n a m e of the p a r e n t compound m a y be r e t a i n e d as t h e r o o t f o r t h e s u b s t i t u t e d compound. We t h u s have s u c h n a m e s as
1,6-di-G- benzoylgalactitol methyl - a -D- gluc o s e 2,3,4,6 - t e t r a -0(Rule 1 1 ) Ester:! a l s o m a y be n a m e d i n a n a l t e r n a t i v e way; and s o m a y e t h e r s ( R u l e 1 3 ) .
1
H 2 0 - C O C 6H5
H OH HoCH H OCH3 H OH
1
z j _ 1
Non-reducing D i s a c c h a r i d e
HO H
H HI F OHz o H
H OH H
H2OH H20H
Sucrose:
or
B -D-Fructofuranosyl
a -D-glucopyranoside
a -D-Glucopyrano s y l g-D-f r uctofur a n o s ide
A r e d u c i n g d i s a c c h a r i d e is n a m e d a s a n 2 - g l y c o sylglycose. Reducine Disaccharide
H
-
Ho!IzO COC 6H; (Rule 10) 1 , 6 - D i - g benzoylgalactitol ( R u l e 11) G a l a c t i t o l 1,6-dibenzoate
LH20CH3 2 ,3 , 4 , 6 - T e t r a -0m e t h y l - a-D-glucose (Rule 13) a -D-Glucopyranose tetramethyl ether
Rule 14 s t a t e s t h a t s u b s t i t u e n t s s h a l l be w r i t t e n i n t o the n a m e i n a l p h a b e t i c a l o r d e r : a c e t y l - a n h y d r o - d e o x y - , e t c . ( r e g a r d l e s s of t h e i r n u m b e r : tri-O_-acetyl - d i a n h y d r o - (mono)deoxy - ) and R u l e 16 s t a t e s t h a t h y p h e n s s h a l l be u s e d i n c o n f o r m i t y with e s t a b l i s h e d p r a c t i c e , I s h a l l o m i t c o n s i d e r a t i o n of R u l e s 27 and 30-34, which a r e c o n c e r n e d w i t h r a t h e r s p e c i a l i z e d p r o b l e m s i n s u g a r n o m e n c l a t u r e , and p a s s t o the f i n a l r u l e (Rule 35) which is c o n c e r n e d w i t h naming d i s a c c h a r i d e s , t r i s a c c h a r i d e s , e t c . Non-reducing d i s a c c h a r i d e s a r e n a m e d a s glycosyl glycosides.
H20H a - L a c t o s e : 4 - 0 - ,%D-Galactopyranosyl-a-Dglucopyranose or _O- /3-D-Galactopyranosyl-( 1 + 4 ) - a - D glucopyranose Non-r educing T r i s a c c h a r i d e
CH2OH Raffinose: O-a-D- G a l a c t o p y r a n o s y l - ( 1 + 6 ) - a - D glucopyransoyl/3-D-fructofuranoside Reducine T r i s a c c h a r i d e
REFERENCES
'Chem. Eng. N e w s , 26, 1623 (1948). 'Chem. Eng. N e w s , 31, 1776 (1953). 3J. Chem. SOC., 5108 (1352). 4 0 n matters not explicitly coverrd by the R u l e s , the opinions e x p r e s s e d are t h o s e of the author. 'Recently changed
to
"-hialdose."
H H H20H a -Cellotriose :
2 - p - D-Glucopyr ano s y l - ( l-. 4) -Q-P
-Dg l u c o p y r a n o s y l - ( I-. 4 ) - a - D glucopyranose
