摘要:
The photochemical reaction of 4-methoxystyrene (2a) with tetranitromethane in dichloromethane gives the nitro-trinitromethyl adduct, 2-(4'-methoxyphenyl)-1-nitro-2-trinitromethylethane (1), which on chromatography on silica gel yields the (E)-nitroalkene, (E)-4'-methoxy-2-nitrostyrene (3); in acetonitrile solution adduct 1 is also the major product together with minor adducts. Similar reaction of trans-1-(4'-methoxyphenyl)-1-propene (2b) in dichloromethane gives exclusively the stereoisomeric nitro-trinitromethyl adducts, 1-(4'-methoxyphenyl)-2-nitro-1-trinitromethylpropanes 6 and 7, but in acetonitrile adduct 7 is the major product together with a small amount of adduct 6 and a mixture of minor adducts. The base-catalysed reactions of adducts 1 and 6 gave nitroalkenes (E)-4'-methoxy-2-nitrostyrene (3) and (E)-1-(4'-methoxyphenyl)-2-nitro-1-propene (8), respectively, but reaction of adduct 7 gave a product of unknown structure. Kinetic studies of the base-catalysed reactions of nitro-trinitromethyl adducts 1, 6 and 7, and a nitro-trinitromethyl adduct derived from naphthalene, cis-1-nitro-4-trinitromethyl-1,4-dihydronaphthalene, are reported. A mixture of (E)- and (Z)-4-methoxycinnamonitrile did not react on extended photolysis with tetranitromethane. The photochemical reactions of 4-methoxystyrenes 2a and 2b with tetranitromethane are assumed to proceed via a radical chain reaction mechanism.