Addition of secondary amines to diacetylenic ketones

Abstract

Secondary amines add across the free ethynyl group of unsubstituted diacetylenic ketones. Reactions of piperidine with 1-phenylhexa-2,4-diyn-1-one (7), a methyl-substituted derivative, afford 1-phenyl-5-piperidinohex-4-en-2-yn-1-one (17), 3,5-dipiperidinobiphenyl (20), and a diadduct (21); in the presence of water 1-phenyl-3-piperidino-hex-2-ene-1,5-dione (27) is also obtained. Strong solvent-induced shifts, of up to 40 nm, are observed in the u.v. spectra of the adducts. Some unstable alkyl diacetylenic ketones [(4)–(6)] have been obtained.