Hydrogen Bonding and the Stereochemistry of Hydrazones and Hydrazides derived from 1,3-Dicarbonyl Compounds involving Imino Nitrogen

Department of Chemistry, Banaras Hindu University, Varanasi-221 005

Manuscript received 5 August 1991, revised 8 June 1992, accepted 3 July 1992

β-Diketones form hydrazones with N' ,N' -diacylhydrazines and exhibit a six-membered hydrogen bonded cyclic ketiminyl system involving the imino nitrogen. ¹H nmr spectra of the hydrazones obtained from N-amino -α, β- (9,10-dihydroanthracene-9,10-endo-diyl)succinimide and acetylacetone demonstrated restricted rotation about N-N bond and a planer hydrogen bonded cyclic system orthogonal to the succinimidyl plane. β-Ketoester behaved differently and reacted in enolic form to give intramolecularly hydrogen boaded hydrazide whose stereochemistry has been established with the help of an asymmetric cage moiety. Both hydrazones and hydrazides adopt Z-configuration about its olefinic part and the methyl of the ketimino or enamine takes a syn-orientation.