
%0 Journal Article
%A Newcombe, PJ 
%A Norris, RK 
%T Substitution Reactions of Nitrothiophens. III. Radical and Ionic Reactions of 4- and 5-Nitro-2-thienyl-methyl and -ethyl Chlorides and Acetates
%J Australian Journal of Chemistry
%D 1979/12/01
%V 32
%N 12
%P 2647-2658
%K 
%R https://doi.org/10.1071/CH9792647
%U https://www.publish.csiro.au/paper/CH9792647 
%X The reactions of 4-nitro-2-thienyl-methyl and -ethyl chlorides and acetates with lithium 2-nitropropan-2-ide (1) give excellent yields of the C-alkylates, 2-(2-methyl-2-nitropropyl)- and 2-(1,2-dimethyl-2-nitropropyl)-4-nitrothiophen. These reactions proceed by a novel ionic substitution process involving initial nucleophilic attack on the thiophen ring. The 5-nitro derivatives react to give complex mixtures of products, which arise from SRN1, SN2, elimination, electron transfer and radical coupling processes. For example, 2-(1-chloroethyl)-5-nitrothiophen (23) reacts with the salt (1) under nitrogen to give the C-alkylate, 2-(1,2-dimethyl-2-nitropropyl)-5-nitrothiophen (24), formedby an SRN1 reaction, the alkene, 2-(1,2-dimethylprop-1-enyl)-5-nitrothiopen (25), derived from (24) by elimination of nitrous acid, 1-(5-nitro-2-thienyl)ethanone (26) and 1-(5-nitro-2-thienyl)ethanol(27) produced by SN2 O-alkylation, and 2,2'-(1,2-dimethylethene-1,2-diyl)bis(5-nitrothiophen) (28) formed by electron transfer and radical coupling reactions. 
