Flash Vaccum Pyrolysis of Substituted Tetrazoles and its Applications to the Synthesis of Bioactive Indazoles.

PAOLA LUCERO; ELIZABETH L. MOYANO; GLORIA I. YRANZO; ZSUZANNE RIEDL; GYORGY HAJOS

FLORIANOPOLIS, BRASIL

Congreso; 12th BRAZILIAN MEETING ON ORGANIC SYNTHESIS; 2007

The indazole ring system has an interesting chemistry and is an effective pharmacophore in medicinal chemistry.1 Some derivatives are potent nNOS inhibitors2 and other are potent tubulin inhibitors with high cytotoxicity to tumor cells in culture.3 On the other hands, indazole acrylic acids appear to be the candidate compounds for male  contraception.4 Due to the importance of these heterocyclic compounds many synthetic methodologies have been developed to obtain  different derivatives in a simple way and high yields. It is known that flash vacuum pyrolysis (fvp) technique has found widespread use in several applications ranging from mechanistic studies to preparative organic chemistry.5 In this work we present the application of fvp reactions in the preparation of (E)-3-(5-methoxy-1H-indazol-3-yl)-acrylaldehyde (2a) and (E)-3-(5-chloro-1H-indazol-3-yl)-acrylaldehyde (2b) from (2E)-3-[2-(4-methoxyphenyl-2H-tetrazoyl]-5-acrylaldehyde (1a) and (2E)-3-[2-(4-chlorophenyl-2H-tetrazoyl]-5-acrylaldehyde (2b) respectively.