0000000000958920
AUTHOR
Giuseppe Guanti
Thiophene series. Substituent effect on thiophenoxy debromination of various 2-nitro-3-bromo-5-X-thiophenes
The kinetics of the reaction of a series of 2-nitro-3-bromo-5-X-thiophenes with sodium thiophenoxide in methanol were determined. The plot of log k against σ-values gave ρ-value + 4.51 at 20°. Good correlation was observed pointing out the validity of the Hammett relationship for reactions occurring directly on the thiophene ring at the β-position with respect to the heteroatom.
The behaviour of 2-nitrothiophene and of 3-nitrothiophene with some nucleophiles
The reactivity of 2-nitrothiophene (1) and of 3-nitrothiophene (II) with some nucleophiles has been studied. According to calculated electronic densities I can receive nucleophilic attack at C3 and C5 depending on the nucleophile used, but II only at C2. With N-lithium piperidine both I and II also give coupling products (VII and XI respectively) of the hithienyl type.