To cleave the cyclopropane ring of the subject compound by hydrogenating a specific cyclopropane ring-contg. compound in the presence of a magnesium compound under reduced hydrogen gas pressures with slight byproduct formation while obtaining the objective compound in high yield.
A cyclopropane ring-contg. compound of formula I [B is an organic group; X1 and X2 are each H or a halogen; Y1 and Y2 are each COR1 or COOR2; R1 and R2 are each H, (substituted) 1-7C alkyl or the like] [e.g. 2-amino-9-(2,2-dichloro-3,3-dicarbomethoxycyclopropyl)-6-chloropurine] is hydrogenated pref. in the presence of a magnesium compound such as magnesium oxide and a catalyst such as palladium-carbon, pref. at 50-90°C to cleave the cyclopropane ring of the above compound. The above method affords pref. a compound of formula II.
YASUOKA JUNICHI
NISHIKAWA JUNICHI
