14 Synthesis of N e w Sugar Derivatives of Biogenic Amines LASZLO MESTER and MADELEINE MESTER Institut de Chimie des Substances Naturelles, Centre National de la Recherche Scientifique, 91190 Gif sur Yvette, France
Many s p e c i f i c r o l e s have been proposed for the biogenic amines i n p h y s i o l o g i c a l processes. Serotonin (1) i s a powerful agent for p l a t e l e t aggregation, a neurotransmitter and its r o l e i n the i n t r o d u c t i o n of sleep i s w e l l e s t a b l i s h e d . Catecholamines (2,3) are im portant regulators for many basic b i o l o g i c a l processes and involved i n diseases, such as manic depressive psy c h o s i s , Parkinsonism and e s s e t i a l hypertension. The po lyamines (4) spermine, spermidine and putrescine have a r o l e i n the b a c t e r i a l cell d i v i s i o n and in the growth of aminal cells. Sugar D e r i v a t i v e s of Serotonin and of Catecholamines In s p i t e of the impressive number of studies on serotonin i n the l a s t two decades, our knowledge on the mode of a c t i o n of t h i s biogenic amine i s h i g h l y specula tive (5). In 1971 we have reported (6) the enzymically cata lysed i n c o r p o r a t i o n of C l a b e l l e d N-acetyl-neuraminic acid i n t o the p l a t e l e t membrane (Figure 1). The higher sialic acid content increased the serotonin induced ag gregation of blood p l a t e l e t (7). The i n c o r p o r a t i o n of N-acetylneuraminic acid accelerated the uptake of sero tonin by the p l a t e l e t s (8) and also the serotonin cata lysed transport of potassium ions through the p l a t e l e t membrane (9). These effects suggest that sialic acid i s a component of the primary receptor for serotonin on the p l a t e l e t membrane. However, serotonin can react i n other b i o l o g i c a l processes i n a d i f f e r e n t way. Alivisatos and coworkers (10) suggested a Schiff-base type i n t e r a c t i o n to explain the mode of a c t i o n of serotonin i n the c e n t r a l nervous system (Figure 2 ) . The presence of a Shiff-base s t r u c ture has been demonstrated by chemical methods. 14
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Amines
SIALOTRANSFERASE (homogenized rat liver)
of the normal sialic acid content
Figure I. Incorporation of C-labeled sialic acid into the platelet membrane using CMP-N-( C)-acetyl neuraminic acid and rat liver sialyltransf erase 14
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Figure 2.
Mode of action of serotonin in the central nervous system ( 10)
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S Y N T H E T I C M E T H O D S FOR
CARBOHYDRATES
The S c h i f f - b a s e s t r u c t u r e advanced by A l i v i s a t o s to e x p l a i n t h e mode of a c t i o n of t h i s biogenic amine, i n c i t e d us to i n v e s t i g a t e the i n t e r a c t i o n of reducing sugars w i t h the p r i m a r y amino group of serotonin (11) (Figure 3). Between a l a r g e number of s u b s t i t u t e d serotonin d e r i v a t i v e s , prepared i n order to u n d e r s t a n d the role of 5-HT i n h e a l t h and d i s e a s e (J_2^ , o n l y t w o sugar d e r i v a t i v e s of serotonin (J_3,J^4) h a v e s o f a r b e e n r e ported. However, the presence of h y d r o p h i l i c groups may have a d e c i s i v e effect on the t r a n s p o r t and metabolism of t h e a m i n e . One o f these sugar d e r i v a t i v e s i s the 0(3-D-glycopyranosy1)-serotonin (1) showing an i n c r e a sed h y d r o s o l u b i l i t y , but h a v i n g p r o p e r t i e s very close to the w e l l s t u d i e d group of O - e t h e r s of serotonin. The s e c o n d one i s the N - g l u c o s i d e (2), w h i c h i s of l i m i t e d i n t e r e s t b e c a u s e of i t s easy h y d r o l y s i s i n t o 5-HT and D-glucose i n aqueous s o l u t i o n even at room temperature. Thus, the p r e p a r a t i o n of a stable N - s u b s t i t u t e d sugar d e r i v a t i v e of s e r o t o n i n i s of b i o l o g i c i n t e r e s t . O n l y v e r y few a t t e m p s h a v e b e e n mad to prepare (_1J5,JM6) 1 - d e s o x y - 1 - a m i n o - D - f r u c t o s e d e r i v a t i v e s (Amador i c o m p o u n d s ) (J_7) a r i s i n g from s u b s t i t u t e d phenylethyl a m i n e . The p r e p a r a t i o n of t h i s type of compounds from 5-HT i s r e n d e r e d even more d i f f i c u l t b e c a u s e of the for m a t i o n of t e t r a h y d r o - n o r h a r m a n (3) d e r i v a t i v e s (J_8) . T o overcome these d i f f i c u l t i e s , the oxalate s a l t of serot o n i n e was u s e d f o r the r e a c t i o n with sugar, to obtain the corresponding Amadori compound, the 1-desoxy-l(5-hydroxy-tryptamino)-D-fruetose (4). Oxalic acid is o f t e n used to i s o l a t e A m a d o r i compounds a f t e r the reac t i o n between the sugar and the amine. S t a r t i n g w i t h the oxalate s a l t of serotonin, the 1-desoxy-1-amino-D-fruc tose d e r i v a t i v e is s t a b i l i z e d i n _ s i t u , preventing sero tonin from undergoing other r e a c t i o n s . The r e s u l t i n g p r o d u c t is a pale yellow m i c r o c r y s t a l l i n e powder, e a s i l y soluble i n water, slowly i n ethanol, i n s o l u b l e i n ethyl acetic ester, e t h y l ether or acetone. The o x a l a t e s a l t of 1-desoxy-1 -(5-hydroxyt r y p t a m i n o - ) - D - f r u c t o s e is stable i n aqueous s o l u t i o n and does not show m u t a r o t a t i o n . As f o r a l l Amadori com pounds prepared from D-glucose, the o p t i c a l rotatory power is negative ( 1 9 ) . N M R s p e c t r u m i n D2O c l e a r l y shows that the 5 - h y d r o x y - i n d o l e fragment of the molecu le, c h a r a c t e r i z e d by f o u r t y p i c a l proton signals i n the r e g i o n from 6.5 to 7.5 ppm, i s u n c h a n g e d a n d no trace of any other condensed s y s t e m c o u l d be d e t e c t e d . Carbon13 NMR s p e c t r o s c o p y s h o w s the A m a d o r i compound to exist i n D2O m a i n l y a s t h e β - p y r a n o s e s t r u c t u r e i n t h e Reeves 1C c o n f o r m a t i o n (20). The s i g n a l of C-2 i s l o c a t e d at
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DF-5 HT
Time (Min.)
Figure 4. Metabolism of serotonin (5-HT) and desoxy-fructo-serotonin (DF-5-HT) by rat brain MAO expressed by the rate of oxygen uptake in conventional Warburg manometric technique
o
tryptaraino)-D-fructose
1-Desoxy-l-(5-methoxy-
tryptamino)-D-fructose
1-Desoxy-l-(5-hydroxy-
COMPOUND l
C
2
96.3
96.3
C
a
70.9
70. 9
c= secondary carbon
b= t e r t i a r y carbon
a= quaternary carbon
53.8
53.8
C
b b
5
69.9
69. 9
C
b
confirmed by o f f resonance decoupling
70.4
70.4
SUGAR CARBONS 6
64.9
64. 8
C
C
CARBON-13 N.M.R. DATA OF AMADORI TYPE SUGAR DERIVATIVES OF TRYPTAMINE IN D 0
TABLE I.
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96,3 p p m , t h e C - 3 , C«-4 a n d C - 5 s i g n a l s a p p e a r as three peaks a t 7 0 . 9 , 70.4 and 69.9 ppm. The s i g n a l s at 64.8 and 53.8 ppm c o r r e s p o n d to the C-6 and C - l carbons r e s p e c t i v e l y (ppm r e l a t i v e to TMS=0). (Table I ) . I n 0.1 Ν NaOH s o l u t i o n a t pH = 1 1 , 2 4 ° C , 1-desoxy-1-(5-hydroxytryptamino)-D-fuctose reduced 1.5 moles of T i l l m a n s reagent (2J_) . 1-Desoxy-1 -(5-methoxy-tryρtamino)-D-fruetose been prepared i n a s i m i l a r way and c a r b o n - 1 3 NMR troscopy shows a very s i m i l a r s t r u c t u r e .
has spec
Due to t h e i r s t r o n g r e d u c i n g power and h i g h s t a b i l i t y , these new s u g a r d e r i v a t i v e s of serotonin show i n t e r e s t i n g b i o l o g i c a l p r o p e r t i e s . _^ At a f i n a l concentration of 1x10 mol, 1-Desoxy1- ( 5 - h y d r o x y - t r y p t a m i n o ) - D - f r u c t o s e i n d u c e d an aggrega t i o n of human p l a t e l e t s i n c i t r a t e d PRP (plasma r i c h i n p l a t e l e t ) , w h i c h was s i m i l a r to the aggregation induced by s e r o t o n i n i t s e l f (22) , but the i n c o r p o r a t i o n of the l^C l a b e l e d (spec.act. 0.1 mC/mM) s u g a r d e r i v a t i v e into the p l a t e l e t s d u r i n g 1 hour of i n c u b a t i o n (_23) was very l i m i t e d . Tested on r a t u t e r u s , the minus l o g a r i t m i c dose response for serotonin (5-HT) was h i g h e r t h a n f o r 1-desoxy-1(5-hydroxy-tryptamino)-D-fructose (DF-5-HT). However, b o t h are i n h i b i t e d by M e t h y l s e r g i d e , showing b o t h a c t i v i t i e s to be of t h e same n a t u r e (_24) . Serotonin is r a p i d l y metabolised, w h i l e 1-desoxy1(5-hydroxy-tryptamino ) D-fructose i s only slowly o x i d i z e d by monoamine oxidase (MAO). T h i s was demonstra ted by the r a t e of uptake of oxygen at v a r i o u s i n t e r v a l s as a n i n d e x of m e t a b o l i s m of r a t b r a i n m i t o c h o n d r i a l MAO, using serotonin and i t s s u g a r d e r i v a t i v e as substrates in conventional Warburg manometric technique (2_5) ( F i g u r e 4) . Using various concentrations of DF-5HT and 5-HT, the s u b s t r a t e a c t i v i t y curves show t h a t desoxyfructoserotonine has much l e s s substrate a f f i n i t y t o w a r d s MAO than serotonine i t s e l f . When L i n e w e a v e r - B u r k p l o t s were drawn, the M i c h a e l i s constant for d e s o x y f r u c t o - s e r o t o n i ne was found to be two and h a l f time higher than for serotonine ( F i g u r e s 5 and 6). An o sugar d e r g i v e n by lamines) r a t e d by and c o u l d
ther f i i v a t i v e the cat becames Barton be tra
e l d , where the s y n t h e s i s of Amadori type s i s of great b i o l o g i c a l i n t e r e s t , i s e c h ο l a m i n e s . A new t y p e of b i s - ( c a t e c h o a v a i l a b l e through the s y n t h e s i s , elabo and h i s coworkers (2_6) for the alcaloïde, nsformed i n sugar d e r i v a t i v e s (Figure 7).
SYNTHETIC METHODS
30
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25
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20
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FOR CARBOHYDRATES
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