Showing papers by "Kunisuke Izawa published in 1996"
TL;DR: In this paper, a practical synthetic method of d4T from 5-methyluridine (2a) was developed, which was modified using 2′,3′-O-methoxy-ethylidene-5-methylURidine (10) as an intermediate to afford 1-(3,5-di)-O-acetyl-2-bromo-2deoxy-β-D-ribofuranosyl)thymine (6a) in high yield with less formation of by-products.
Abstract: A practical synthetic method of d4T (3) from 5-methyluridine (2a) was developed. The Marumoto-Mansuri method was modified using 2′,3′-O-methoxy-ethylidene-5-methyluridine (10) as an intermediate to afford 1-(3,5-di-O-acetyl-2-bromo-2-deoxy-β-D-ribofuranosyl)thymine (6a) in high yield with less formation of by-products. The reaction mechanism was also discussed. †Dedicated to Dr. Yoshihisa Mizuno on the occasion of his 75th birthday.
21 citations
Patent•
21 Feb 1996TL;DR: In this article, an easily removable substituent in the 7-position of a purine base of natural purine nucleosides obtained through fermentation or derivatives thereof is synthesized by hydrolyzing the ribose moiety to form purine derivatives.
Abstract: Purine derivatives in which a desired substituent is introduced into the 9-position only are synthesized by first introducing an easily-removable substituent in the 7-position of a purine base of natural purine nucleosides obtained through fermentation or derivatives thereof, then hydrolyzing the ribose moiety to form purine derivatives having the substituent in the 7-position, subsequently introducing the desired substituent in the 9-position, and then removing the substituent in the 7-position.
19 citations
TL;DR: Mizuno et al. as mentioned in this paper developed a practical method to produce 2′,3′-dideoxypurinenucleosides from 9-(2,5-di-O-acetyl-3-bromo-3deoxy-β-D-xylofuranosyl)purines.
Abstract: Practical method to produce 2′,3′-dideoxypurinenucleosides from 9-(2,5-di-O-acetyl-3-bromo-3-deoxy-β-D-xylofuranosyl)purines (1) was developed. High ratio of 2′,3′-dideoxynucleoside to 3′-deoxyribonucleoside was obtained by selecting the reaction conditions (solvent, pH and/or base), or changing 2′-acyloxy leaving group. The reaction mechanism was studied by deuteration experiments of 1a and 1-(3,5-di-O-acety1-2-bromo-2-deoxy-β-D-ribofuranosyl)thymine (12). †Dedicated to Dr. Yoshihisa Mizuno on the occasion of his 75th birthday.
16 citations
Patent•
16 Aug 1996TL;DR: In this article, an industrial process for producing 2-acyloxy-4-oxo-4 -arylbutyric acid or its ester is presented. But this process is not suitable for the use of synthetic compounds.
Abstract: Provided is an industrially useful process for producing an optically active 2-hydroxy-4-arylbutyric acid or its ester. An optically active acyloxysuccinic anhydride is reacted with an aromatic compound in the presence of a Lewis acid to produce an optically active 2-acyloxy-4-oxo-4-arylbutyric acid. The 2-acyloxy-4-oxo-4-arylbutyric acid is converted to an optically active 2-acyloxy-4-arylbutyric acid through catalytic reduction. The 2-acyloxy-4-arylbutyric acid is hydrolyzed in the presence of an acid or an alkali to produce an optically active 2-hydroxy-4-arylbutyric acid. The 2-hydroxy-4-arylbutyric acid is reacted with an alcohol in the presence of an acid to produce an optically active 2-hydroxy-4-arylbutyric acid ester.
2 citations