Methoxyimino- acetic acid methyl ester

Eberle and Schaub (93EUP571326) describe the synthesis of a large series of 3-hydroxy-2-(2-methyl-4-prop-l-ynyl-2//-pyrazol-3-yl)acrylic acid methyl esters 26 and methoxyimino-(2-methyl-4-prop-l-ynyl-2//-pyrazol-3-yl)acetic acid methyl esters 27 by dehydrohalogenation of the corresponding chloroolefins 25 under the action of bases. In this case, the functional groups in position 5 of the pyrazole ring undergo dehydrobromination (Scheme 34). 

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