CHLOROSULFONATION OF 3-(BENZYLIDENE) D-CAMPHOR AND 3-(BENZYLIDENE) ISOPINOCAMPHORONE

A new improved synthesis of 3-benzylidenecamphor (1) is described; the procedure has also been applied to the conversion of isopinocamphorone (4) into 4-benzylidenepinocamphorone (6a). In the latter reaction, 1 H NMR spectral data and X-ray crystallography proved that inversion of the C-2 methyl group had occurred. A mechanism for the base-catalysed interconversion of isopinocamphorone (4) and pinocamphorone (10) is presented. 4-Benzylidene-pinocamphorone (6a) reacted with excess chlorosulfonic acid to yield the p-sulfonyl chloride (11) which was characterized by the formation of 6 sulfonamide derivatives. The 1 H NMR spectra confirmed that sulfonation occurred in p-position of the phenyl ring; the various compounds were required for screening as potential pesticides and pharmaceutical agents.