SYNTHESIS OF 3-METHYLISOXAZOLE- 5-CARBOXAMIDES AND 5-[(1H-PYRAZOL-1-YL)CARBONYL]- 3-METHYLISOXAZOLES

ABSTRACT

The one-pot synthesis of six 3-methylisoxazole-5-carboxamides 2 [where the N-substituents are R¹ = H, Me and R² = Ph, CH₂Ph, n-Bu, C(CH₃)₂Et, 3-methylisoxazol-5-yl] and twelve 5-[(1H-pyrazol-1-yl)carbonyl]-3-methyl isoxazoles 3 and 4 [where the pyrazole substituents are R³ (C5/C3) = CO₂Et, CF₃ and R⁵ (C3/C5) = H, Me, Et, Ph] from the 3-methyl isoxazole-5-carboxylic acid, thionyl chloride and the corresponding amine or pyrazole is reported. In the synthesis of 5-[(1H-pyrazol-1-yl)carbonyl]-3-methylisoxazoles we obtained a mixture of 1,3- and 1,5-isomers 3 and 4 in variable ratios, i.e., the substituent R³ (CO₂Et and CF₃) are present in position 3 or 5 on the pyrazole ring.

ACKNOWLEDGMENTS

The authors thank the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq/PADCT), Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul (FAPERGS) for financial support. The fellowhips from CNPq, CAPES and FAPERGS are also acknowledged.