1,3,4,5-Tetrahydrobenz[c,d]indoles and related compounds. Part IV. Attempted syntheses of lysergic acid

Abstract

Attempts to devise a synthesis of lysergic acid from 3,4-dihydrobenz[c,d]indol-5(1H)-one (I)via methyl N-acetonyl-N{1,3,4,5-tetrahydro-5-oxo-1-(p-tolylsulphonyl)benz[c,d]indol-4-yl}carbamate (23) failed owing to difficulties in cyclising the latter to the tetracyclic ketone (4).

Several alternative routes were examined and, inter alia, 4,8,9,10a-tetrahydro-9-(hydroxymethyl)-9-methyl-6H-indolo[3,4-gh][1,4]benzoxazinium chloride (30) and 4-acetyl-6,6a,7,8-tetrahydro-8-imino-4H-indolo[6,5,4-cd]-indolium acetate (40) have been prepared.