Details for Patent: 5,684,153

Title:	Process for the preparation of purine derivatives
Abstract:	The present invention provides a process for the synthesis of penciclovir and famciclovir by 9-substituting the compound 2-amino-6-chloropurine (ACP) with 2-acetoxymethyl-4-(leaving group)-but-1-yl acetate, followed by displacement of the 6-chloro moiety with a hydroxy moiety (i.e. to form a guanine derivative) or with hydrogen (to form the 2-aminopurine derivative), respectively.
Inventor(s):	Geen; Graham Richard (Stansted Mountfitchet, GB2), Jarvest; Richard Lewis (Surbiton, GB2)
Assignee:	Beecham Group plc (Brentford, GB)
Filing Date:	Jun 10, 1994
Application Number:	08/258,167
Claims:	1. A process for the preparation of i) penciclovir or ii) famciclovir which process comprises the reaction of 2-amino-6-chloropurine with 2-acetoxymethyl-4-(leaving group)-but-1-yl acetate; to give 9-(4-acetoxy-3-acetoxymethylbut-1-yl)-2-amino-6-chloropurine; and thereafter: i) hydrolysing to give penciclovir: or ii) reducing to give famciclovir. 2. A process according to claim 1 wherein the leaving group is halo. 3. A process according to claim 2 wherein the halogen is chlorine. 4. A process according to claim 2 wherein the halogen is bromine. 5. A process according to claim 2 wherein the halogen is iodine.