Synthesis of 1,1,1-trihalo-4-methoxy-4-[2-heteroaryl]-3-buten-2-ones, the corresponding butan-1,3-dione and azole derivatives

The synthesis of 1,1,1-trihalo-4-methoxy-4-[2-thienyl]-3-buten-2-ones, 1,1,1-trihato-4-methoxy-4-[2-furyl]-3-buten-2-ones and the respective trihalomethyl 1,3-butanone derivatives by trihaloacylation of dimethoxy acetals derived from 2-acetylthiophene and 2-acetylfuran are reported. This is a convenient method to obtain fluorinated and chlorinated 1,3-dielectrophiles from 2-acetylthiophene and 2-acetylfuran. The fluorinated 1,3-dielectrophiles were used to synthesize five new 2-thienyl- and 2-furylazoles. The structure of all products were assigned by (HH)-H-1- and C-13 NMR and mass spectrometry. (C) 2002 Elsevier Science Ltd. All rights reserved.