N 1-Alkylation of Dihydrolysergic Acid

A new procedure for alkylating dihydrolysergic acid (1) on the indole nitrogen is reported. Previous procedures involved reaction of the indoyl anion with an alkyl halide. As the alkyl group gets larger, dehydrohalogenation of the alkyl halide becomes the preferred reaction and little or no N 1-alkylation occurs. By using alkyl tosylates in place of alkyl halides, we have been able to alkylate 1 on the indole nitrogen with a wide variety of alkyl groups in high yield.