Ajinomoto Co., Ltd.

Keizo Yamashita

Kunisuke Izawa

Hiroshi Shiragami

Satoshi Katayama

Yumiko Uchida

A process for preparing 7-benzylpurine derivatives is provided. An acetylpurine nucleoside is reacted with a benzyl halide to benzylate the 7-position of the purine base, and an acid is then added to the reaction mixture to hydrolyze the glycoside bond. The 7-benzylpurines may be used to prepare 9-substituted purine derivatives. Specifically, a process for producing a 7-benzylpurine compound of Formula (5):

Process for producing purine derivatives

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.

9-Substituted purine derivatives of formula (4) ##STR1## are prepared by debenzylating a compound of formula (3): ##STR2##

A process for preparing 7-benzylpurine derivatives is provided. An acetylpurine nucleoside is reacted with a benzyl halide to benzylate the 7-position of the purine base, and an acid is then added to the reaction mixture to hydrolyze the glycoside bond. The 7-benzylpurines may be used to prepare 9-substituted purine derivatives.

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Kawasaki, Japan

Keizo Yamashita