2,2-DIMETHYLPENTA-3,4-DIENAL DERIVATIVES - PREPARATION, NMR-SPECTRA, AND CRYSTAL-STRUCTURE

The preparation of some new 2,2-dimethylpenta-3,4-dienal derivative's starting by Claisen-Cope rearrangement of the pyrolytic product of the corresponding acetales and followed by condensation reactions is desc ribed. The synthesis of homoallenylketone 5 from homoallenylaldehyde 3 by Grignard reaction and followed by the oxidation of the formed alco hol using potassium chlorochromate (KCC) is reported. All new compound s are characterized by IR, MS, H-1, and C-13 NMR spectroscopy. The ful l assignment of the NMR signals is based on HETCOR and FLOCK pulse seq uences. The molecular and crystal structure of 2,2-dimethylhexa-3,4-di enal 2,4-dinitrophenylhydrazone is presented.