Studies in the cycloproparene series; heterocyclic substituted methylidenecyclopropa[b]naphthalenes

Abstract

1H-Cyclopropa[b]naphthalene 7 is converted into a range of 6π 5-atom-substituted methylidene derivatives 12e–j, the pyridyl analogues 12k and 1, and the phenylsulfanyl analogue 12m by way of the 1,1-disiIyl compound 9 and Peterson olefination in improved procedure. The spectroscopic properties of the compounds are reported and their behaviour as possible lumophores assessed. Crystal structures of the dimethylaminophenyl 12c,d, and the thienyl 12e derivatives are presented. The permanent dipole moments of the mono-substituted 12e and k have been measured as 2.76, and 3.37 D, respectively, and that of the dithenyl 12f as 9.06 D.