abstract |
Process for the preparation of cyclic 9'-thiapeptide- ergot alkaloids of the formula I in which either R1 is methyl and R2 is isobutyl or benzyl, or R1 is ethyl and R2 is benzyl, or R1 is isopropyl and R2 is isopropyl, sec- butyl, isobutyl or benzyl, in the form of the free bases or their acid addition salts. <IMAGE> |