Synthesen niederer Methyl‐zucker

Abstract

form6 par reaction entre 1 moI6cule d'anhydride malkique et une molGcule d'ozone.Deux des essais ont donne respectivement comme aldPhydit6 3,5 et 4 millimol. gr.Un essai a donne comme acidite 4,s millimol. gr. Les chiffres obtenus pour l'aldChydit6 e t I'aciditB doivent dtre trop faibles, car l'ozonide (qui s'est quelquefois sBpar6 sous forme d'une neige blanche) ou sit solution a subi partiellement une decomposition spontanee, dBgageant un gaz dans lequel nous avons reconnyde l'osyde de carbone et du gaz carbonique.111. Oxonation dans le chlorure d'e'thjle ir -80° environ.

The Mechanism of Action of Aldolases

“…The mechanism shown in figure 1 is consistent with the early theoretical considerations which led to the postulate that the aldolasetype reaction is catalyzed both by a Schiff base (49)(50)(51) and by a base catalyst (2,(18)(19)(20)(21). It is interesting to compare this mechanism with the results reported by Westheimer and Cohen (50), who found that an aldol cleavage was catalyzed by an amine (thought to form a Schiff base complex) together with hydroxide ion.…”

The Saccharomyces cerevisiae RIB4 Gene Codes for 6,7-Dimethyl- 8-ribityllumazine Synthase Involved in Riboflavin Biosynthesis

“…6,7-dimethyl-8-ribityllumazine and 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione were synthesized as described (10). 3,4-dihydroxy-2-butanone was synthesized from acetol and formaldehyde under previously described conditions (11). Restriction enzymes and DNA modification enzymes were from Pharmacia Biotech Inc., New England Biolabs, or Boehringer Mannheim.…”

1,2-Isopropylidene D-Glyceraldehyde as a Chiral Synthon for g-Butyrolactone

“…In a recent deveolpment on the total synthesis of optically active natural products, 1.2-isopropylidene 1 D-glyceraldehyde (1) has been used as a chiral synthon for s number of biolodcal active compounds 5 6 such as prostaglandins2, brefeldin A~, ipsdieno14, prestalotin and leukotriene A 4 . We have shown, in a previous paper7, 3(S)-[ 3-hydroxy-1(E)-propylenyllcyc10pentanone (2) derived from 1 was a potential intermediate leading to antirhine and brefeldin A In our continuous efforts on the synthesis of natural products, secologanin and sesquiterpene lactones, we required a synthesis of the y-butyrolactone possessing an appropriate substituent at C3 and C4.…”