| 摘要 |
<p>1,138,726. Purine nucleosides. TAKEDA CHEMICAL INDUSTRIES Ltd. 7 Feb., 1966 [5 Feb., 1965], No. 5288/66. Heading C2C. Purine nucleosides are obtained by heading together in the molten state in the presence of 0À1 to 10% by weight of a halogen compound consisting of halogen atoms, based on the total weight of the starting materials, a compound of the formula wherein R<SP>1</SP>, R<SP>2</SP> and R<SP>3</SP> are the same or different and may be hydrogen, hydroxy, acyloxy, amino, acylamino, lower (up to C 4 ) alkylthio or halogen, the acyl group of the acyloxy group or of the acylamino group being a carboxylic acyl group having up to 18 carbons, R<SP>4</SP> and R<SP>5</SP> are the same or different lower alkyl having up to four carbons, A is attached to the nitrogen at the 7 or 9 position and is hydrogen or carboxylic acyl having up to 18 carbons, and the dotted line shows a double bond at the 7 or 8 position, with a compound of the formula wherein Acyl is a carboxylic acyl group having up to 7 carbons, A<SP>1</SP> is hydrogen or a carboxylic acyl group having up to 7 carbons and n is 2 or 3. The halogen compound may be iodine, bromine or iodine tetrachloride, and the reaction may be effected at a temperature of from 120‹ to 195‹ C. The protecting groups in the products may be removed in a conventional way, e.g. by alkaline hydrolysis.</p> |
