GR ID=jo070610in00002> gures/jo070610in00002.gif" ALIGN="left" HSPACE=5> |
4-Alkyl-2-nitrothiophenes [
10: R = CH
3, CH(OH)CH
3, CH(OCH
3)CH
3] react with secondary aliphaticamines, in the presence of A
gNO
3, to
give 3-alkyl-2-amino-5-nitrothiophenes (
12) throu
gh an oxidativenucleophilic substitution of hydro
gen (ONSH) of synthetic interest. This behavior is in strikin
g contrastwith that of the parent 2-nitrothiophene (
6), which was found to under
go rin
g-openin
g in analo
gousreaction conditions. A possible rationale for the crucial effect of alkyl
groups is su
ggested,
groundedalso on a study of the correspondin
g Meisenheimer-like adducts.