Synthesis of 3(5)-substituted 1,2,4-triazoles by lithiation of 1-(1-pyrrolidinomethyl)-1,2,4-triazole

Article abstract of DOI:10.1016/S0040-4020(01)85445-4

1,2,4-Triazole 1 is readily converted into 3(5)-substituted 1,2,4-triazoles 4 by a three-step sequence: (i) Mannich reaction with formaldehyde and pyrrolidine; (ii) lithiation of 1-(1-pyrrolidinomethyl)-1, 2,4-triazole 2, followed by addition of an electrophile; (iii) deprotection of the N-aminal groups of the N-protected 3-substituted 1,2,4-triazoles 3 using sodium borohydride (NaBH₄) in ethanol. 3(5)-Substituted 1,2,4-triazoles 4 result in good overall yields.