82834-44-4

The reactivity of some 5-bromo-2-nitro-3-R-thiophens (Ia-g; R=H, Me, Et, Prn, n-hexyl, Pri, and But), 3,4-dibromo-2-nitro-5-R-thiophens (IIa and b; R=H and Me), 3-bromo-2-nitro-5-R-thiophens (IIIa and b; R=H and Me), and 2-bromo-3-nitro-5-R-thiophens (IVa and b; R=H and Me) with amines and sodium benzenethiolate has been studied in methanol at various temperatures.Piperidinodebromination of compounds (Ia and c) has also been studied in benzene, in dioxan, and in dioxan-water (60:40 and 10:90).Independent of the position of the alkyl group (meta or para with respect to the leaving bromine), an unexpected alkyl activation has been observed, which represents a further exception to the electron-releasing behaviour of alkyl groups.