Synthesis and analysis of compounds having the skeleton of ergot alkaloids with the nitrogen atom in the D-ring transposed

Alkylation-amination of the enamine 2 in the presence of ethyl α,α-bis(dibromomethyl)acetate, triethyl-amine, and methylamine lead to the construction of the aza-transposed ergoline 3 . Sequential reduction, hydrolysis, reesterification, and indolization of 3 , produced three diastereomers of 6 . The structure of these three diastereomers was assigned on the basis of nmr and ir spectral analysis to be (α-cis) syn, (β-cis) anti, and (α-trans) syn. The isomer (β-cis) anti was reduced with lithium aluminum hydride to the corresponding alcohol.