A New Convenient Preparation of 2-, 4-, and 5- Thiazolecarboxaldehydes and Their Conversion into the Corresponding CarbonitrileN-Oxides: Synthesis of 3-Thiazolylisoxazoles and 3-Thiazolylisoxazolines
A New Convenient Preparation of 2-, 4-, and 5- Thiazolecarboxaldehydes and Their Conversion into the Corresponding Carbonitrile<i>N</i>-Oxides: Synthesis of 3-Thiazolylisoxazoles and 3-Thiazolylisoxazolines
The title aldehydes are prepared in high Yieids by quenching 2-lithiothiazole, 4-litho-, and 5-litho-2-trimethylsilylthiazole with N-formylmorpholine followed by protodesilylation in the latter two cases. The aldehydes are transformed through their oximes and hydroxamoyl chlorides into nitrile oxides which react with alkene and acetylene dipolarophiles to give 3-thiazolylisoxazolines and 3-thiazolylisoxazoles in moderate to good yields