Verfahren zur Herstellung von Purinnucleosiden

摘要

Compounds of Formula I or II wherein each of R1 and R2 represents hydrogen, hydroxy, or amino, each of R3 and R4 represents hydrogen, hydroxy, amino or methyl, and Y represents a glycosyl radical derived from an aldopentose or aldohexose, are prepared by reacting compounds of Formula I or II in which Y represents hydrogen, with either a tri-lower alkyl-chlorosilane in the presence of a tertiary amine under anhydrous conditions, or with a hexa-lower alkyl-disilazane under anhydrous conditions, and then reacting the product with an acylhalogeno-pentose or acylhalogeno-hexose and removing the acyl group from the acylated product obtained. Any amino groups present in the starting materials of Formula I and II are preferably first protected with an acyl group.ALSO:Tri-alkylsilyl derivatives of compounds of Formula (III) or (IV) wherein R1 and R2 are hydrogen, hydroxy or amino, and R3 and R4 are hydrogen, hydroxy, amino or methyl, are prepared by reacting the compounds of Formula (III) or (IV) with a tri-alkyl-chlorosilane in the presence of a tertiary amine under anhydrous conditions, or with a hexa-alkyl-disilazane under anhydrous conditions. Examples 1 and 2 indicate the preparation of bis-(trimethylsilyl) hypoxanthine and bis-(trimethylsilyl) uracil of formulae The remaining examples show the preparation of bis-trimethylsilylthymine, bis-trimethylsilyl - N - acetylcytosine, bis - trimethylsilyl - N - benzoyladenine, tris - trimethylsilylxanthine, and tris-trimethylsilylguanine.