Beecham Group Plc

Trevor J Grinter

Graham R Geen

Kenneth T Veal

Martin J Parratt

Peter M Kincey

Stephen Moore

A process for the preparation of a compound of formula (A): ##STR1## wherein X is hydrogen, hydroxy, chloro, C.sub.1-6 alkoxy or phenyl C.sub.1-6 alkoxy and R.sub.a and R.sub.b are hydrogen, including acyl and phosphate derivatives thereof; which process comprises:

Process for the preparation of purine derivatives as antiviral agents

A process for preparing pharmaceutically active compounds of formula (A): ##STR1## wherein X is hydrogen, hydroxy, chloro, C.sub.1-6 alkoxy or phenyl C.sub.1-6 alkoxy; and R.sub.a and R.sub.b are hydrogen, or acyl or phosphate derivatives thereof, which process comprises the preparation of an intermediate of formula (I): ##STR2## wherein R.sub.1 is C.sub.1-6 alkyl, or phenyl C.sub.1-6 alkyl in which the phenyl group is optionally substituted; R.sub.2 is hydrogen, hydroxy, chlorine, C.sub.1-6 alkoxy, phenyl C.sub.1-6 alkoxy or amino; and R.sub.3 is halogen, C.sub.1-6 alkylthio, C.sub.1-6 alkylsulphonyl, azido, an amino group or a protected amino group, via the reaction of a compound of formula (II): ##STR3## wherein R.sub.2 and R.sub.3 are as defined for formula (I) with: (a) a compound of formula (III): ##STR4## wherein R.sub.4 and R.sub.5 are independently hydrogen, C.sub.1-6 alkyl, or phenyl, or R.sub.4 and R.sub.5 together are C.sub.5-7 cycloalkyl; or

Process for preparing purine derivatives and intermediates thereof

A process for the preparation of a compound of formula (I) or a pharmaceutically acceptable salt thereof: ##STR1## which process comprises reacting a compound of formula (II): ##STR2## wherein the amino group is optionally protected, Y is iodo, optionally substituted benzylthio or (phenacylmethyl)thio, with a compound of formula (III): ##STR3## wherein Q is a leaving group, R.sub.x and R.sub.y are protected hydroxymethyl or acyloxymethyl, or group(s) convertible to hydroxymethyl or acyloxymethyl; and R.sub.z is hydrogen or a group convertible thereto; and thereafter converting Y to X is hydroxy by means of hydrolysis, or to X is hydrogen by means of reduction; converting R.sub.x and R.sub.y when other than hydroxymethyl or acyloxymethyl, to hydroxymethyl or acyloxymethyl, optionally converting R.sub.x /R.sub.y hydroxymethyl to acyloxymethyl or vice versa, deprotecting the 2-amino group where necessary and converting R.sub.z, (when other than hydrogen) to hydrogen; and optionally forming a pharmaceutically acceptable salt thereof.

Process for the preparation of purine derivatives

An improved process for the preparation of 3-substituted thiophenes. The thiophenes are useful for the preparation of penicillins and cephalosporins. The process is for the preparation of a thiophene of formula (I): ##STR1## where R.sup.1 represents a carboxylic acid group, or an ester or amide thereof or a nitrile group; R.sup.2 represents a group suitable for use as an .alpha.-substituent in the side-chain of a penicillin or cephalosporin; which comprises treating under basic conditions a compound of formula (II): ##STR2## wherein X represents halogen or optionally functionalized hydroxyl, Y represents halogen, hydroxyl, or alkoxy; with a source of nucleophilic sulphur ionically bound to a polymeric support.

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Betchworth, United Kingdom

Trevor J Grinter