NITRATION OF 5-FORMYL-SUBSTITUTED 2-CYCLOPROPYLFURANS AND 2-METHYLFURANS AND THE CORRESPONDING THIOPHENES

Article abstract of DOI:10.1007/BF00552770

In the nitration of 5-formyl-substituted 2-cyclopropylfurans and the corresponding thiophenes, in addition to the formation of the corresponding 3-nitro derivative the replacement of the formyl group by a nitro group takes place.For a thiophene derivative the latter direction of the reaction is observed to a substantially smaller degree.Under nitration conditions, 5-formylsylvane is converted only into 5-nitrosylvane, while the corresponding formylmethylthiophene is nitrated exclusively in position 3.The difference observed in the behavior on nitration of the furans and thiophenes studied is explained by the different degrees of participation of the heteroatom in the delocalization of the charges in the heterocyclic ipso-ions formed as intermediates.