Process for preparing griseolic acid derivatives

摘要

Griseolic acid and dihydrodesoxygriseolic acid derivatives having an alkyl or aralkyl group as a substituent on the amino group at the 6-position are prepared by reacting the unsubstituted compound with a compound R7-X (where R7 is alkyl or aralkyl and X is halogen or sulfonyloxy). The group first substitutes and quaternizes the 1-nitrogen atom. The compound is then subjected to an appropriate combination of temperature and pH to cause ring cleavage, rearrangement and ring closure involving the 6-amino group and this quaternized 1-nitrogen to give a 6-alkylamino or 6-aralkylamino derivative.