4-(Methylthiomethoxy)butyric acid (13a) and 2-(methylthiomethoxymethyl) benzoic acid (14a) have been prepared in 53 and 64% overall yields from γ-butyrolactone and phthalide, respectively. Thymidine reacts regioselectively with (13a) and (14a), in the presence of an appropriate condensing agent, to give the corresponding 5′-O-acyl derivatives [(20) and (21), respectively], both in 70% yield. The latter compounds undergo deacylation relatively slowly when treated with concentrated aqueous ammonia but, following treatment with mercury(II) perchlorate in the presence of 2,4,6-collidine in slightly wet tetrahydrofuran, are both converted back into thymidine under very mild conditions of basic hydrolysis.
Two new protected acyl protecting groups for alcoholic hydroxy functions
SINDONA, Giovanni
1984-01-01
Abstract
4-(Methylthiomethoxy)butyric acid (13a) and 2-(methylthiomethoxymethyl) benzoic acid (14a) have been prepared in 53 and 64% overall yields from γ-butyrolactone and phthalide, respectively. Thymidine reacts regioselectively with (13a) and (14a), in the presence of an appropriate condensing agent, to give the corresponding 5′-O-acyl derivatives [(20) and (21), respectively], both in 70% yield. The latter compounds undergo deacylation relatively slowly when treated with concentrated aqueous ammonia but, following treatment with mercury(II) perchlorate in the presence of 2,4,6-collidine in slightly wet tetrahydrofuran, are both converted back into thymidine under very mild conditions of basic hydrolysis.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
