1H-pyrrolo 1, 2-b1, 2, 4 Triazole derivatives and their preparation via 1H-1,2,4-triazole derivatives

摘要

The novel 1H-pyrrolo[1,2-b][1,2,4]triazole derivative represented by formula (III) wherein R₁ represents an aliphatic group which may be substituted or an aryl group which may be substituted; R₂ and R₃ each represents an electron-withdrawing group having a Hammett's substituent constant σ_p of from 0.2 to 1.0; Y represents -C(=O)-R₅, -SO₂R₆ or -P(=O)(R₇)(R₈),wherein R₅, R₇ and R₈ each represents a hydrogen atom, an aliphatic group which may be substituted, an aryl group which may be substituted, an aliphatic oxy group which may be substituted, an aryloxy group which may be substituted, or a group represented by -N(Ra')Ra, and R₇ and R₈ may be bonded to each other to form a ring; and R₆ represents an aliphatic group which may be substituted, an aryl group which may be substituted, or a group represented by -N(Ra')Ra, and wherein Ra and Ra' each represents a hydrogen atom, an aliphatic group which may be substituted, or an aryl group which may be substituted, and Ra and Ra' may be bonded to each other to form a ring, which is useful as an intermediate for physiologically active substances can be efficiently synthesized by using as intermediates the novel 1H-1,2,4-triazole derivatives represented by formulae (I) and (II) wherein R₁ represents an aliphatic group which may be substituted or an aryl group which may be substituted; R₂ and R₃ each represents an electron-withdrawing group having a Hammett's substituent constant σ_p of from 0.2 to 1.0; R₄ represents a hydrogen atom, an aliphatic group, or an aryl group; and X represents a halogen atom.;The 1H-pyrrolo[1,2-b][1,2,4]triazole derivative represented by formula (III) according to the present invention has a pK_a value higher by about 1 than that of the 5-chloro-substituted corresponding compound and is thermally stable.