Synthesis and crystal structures of three Schiff bases derived from 3-formylacetylacetone and benzyl-, <i>tert</i>-butyl- and (<i>S</i>)-methylbenzylamine

Treatment of 3-formylacetylacetone with the amines benzylamine, tert -butylamine and ( S )-methylbenzylamine led to formation corresponding Schiff bases 3-[(benzylamino)methylidene]pentane-2,4-dione, C 13 H 15 NO 2 1 ), 3-[( -butylamino)methylidene]pentan-2,4-dione, 10 17 ) 3-{[( )-benzyl(methyl)amino]methylidene}pentane-2,4-dione, 14 3 ). The molecules all three compounds exist as enamine tautomers that contain a nearly planar amino-methylene-pentane-2,4-dione core strong intramolecular N—H...O hydrogen bridge. R group attached N atom has no significant influence on bond lengths angles core. supramolecular structures in – are mainly based weak C—H...O bonds.