Indole derivatives. I.β-(3-indolyl) ketones

A number of -skatyl--substituted acetoacetic esters (ethyl, tert. -butyl, and benzyl) are prepared by treating gramine with sodium derivatives of -substituted acetoacetic esters. When ethyl -alkyl--skatylacetoacetates are heated with dilute alkali, they are split into indole and a substituted acetoacetic ester, while saponification with concentrated alcoholic alkali gives -substituted-(3-indolyl)propionic acids. 3-Skatyl-heptan-2-one can be obtained by pyrolysis of 3-skatyl-3-carbo-tert. -butoxyheptan-2-one, or by hydrogenolysis of 3-skatyl-3-carbobenzoxyheptan-2-one over a palladium catalyst. Alkylation of cycloheptanone and cyclohexanone enamines by gramine gives cyclic-(3-indolyl)ketones, viz., 2-skatylcyclopentanone and 2-skatylcyclohexanone.