83055-16-7Relevant academic research and scientific papers
Substitution Reactions of Nitrothiophenes. 6. Disparate Mechanisms for Substitution Reactions at Neopentyl Carbons Bearing 4- and 5-Nitrothienyl Groups
Flower, Felicity I.,Newcombe, Peter J.,Norris, Robert K.
, p. 4202 - 4205 (2007/10/02)
The reaction of the (5-nitro-2-thienyl)- and (4-nitro-2-thienyl)neopentyl chlorides (9 and 10) with p-toluenesulfinate, azide, and p-toluenethiolate ions proceed smoothly and in high yield (70-95percent) under mild conditions (20 deg C, Me2SO) to give the sulfones 14 and 15, the azides 16 and 17, and the sulfides 18 and 19, respectively.The mechanisms of these substitutions are quite different, however.The substitutions in the 5-nitro series take place by the SRN1 mechanism, whereas those in the 4-nitro series take place by the ionic SN(AEAE) process, which involves initial attack of a nucleophile at the 5-position of the thiophene ring.
Substitution Reactions of Nitrothiophens. V Isolation and Reactions of the Exocyclic Methylene Intermediates in SN(AEAE) Reactions
Newcombe, Peter J.,Norris, Robert K.
, p. 973 - 988 (2007/10/02)
The reaction of lithium 2-nitropropan-2-ide (1) with 2-(1'-chloro-2',2'-dimethylpropyl)-4-nitrothiophen (5) gives a complex mixture of products, including the salt (15), nitro compounds (17a-c) and oximes (18) and (19).The formation of these products can be rationalized in terms of initial formation of 5--2-(1''-methyl-1''-nitroethyl)-3-nitro-2,5-dihydrothiophen (16) whose analogues have been proposed as reactive intermediates in the SN(AEAE) reaction.The diene (16), which is a stable isolable compound , reacts with the salt (1) to give the above products and with sodium p-toluenesulfinate to give the sulfone (32).The analogues chloride (6) and the acetate (7) react in a similar fashion and give the diene (21), which also reacts in part in an SN(AEAE) reaction to give the substitution product (23).
