Ammonia → 2-Chloroadenosine

Participants

Reaction Steps

The starting material, 2-chloroadenosine of the formula (II) used in the above Process 1 can be obtained in high yield from 6-chloroguanosine or a 2',3',5'-triacyl-6-chloroguanosine as disclosed in Japanese Patent Application OPI No. 48,496/1973. That is, 6-chloroguanosine or a 2',3',5'-triacyl-6-chloroguanosine, e.g., 2',3',5'-triacetyl-6-chloroguanosine, is first reacted with sodium nitrite and hydrochloric acid in ice-water and thereafter the reaction mixture is neutralized with, for example, aqueous ammonia. The resulting reaction mixture is then extracted with a solvent such as methylene chloride and the extract containing 2,6-dichloropurine riboside is treated without isolation of the riboside, with a methanolic solution saturated with anhydrous ammonia gas and the mixture is allowed to react at a temperature of about 100°C for about 5 hours in a sealed tube to obtain the desired 2-chloroadenosine of the formula (II) in about 60% yield. The preparation of the starting material of the formula (II) will be hereinafter described in greater detail in Reference Example 1.

Provenance & Evidence