… with 3??Hydroxy??1H??pyrazoles: 3??Carboxyisoalkyloxy??1H??pyrazoles–bicyclic acylpyrazolium salts and γ??Lactams–3??Carboxyisoalkyloxy??4, 5??dihydro??1H??pyrazol??5 …

H Dorn, R Ozegowski

Index: Dorn, Helmut; Ozegowski, Ruediger Journal fur Praktische Chemie - Chemiker - Zeitung, 1998 , vol. 340, # 5 p. 437 - 449

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Citation Number: 3

Abstract

Abstract 1-Substituted 3-hydroxy-1H-pyrazoles 1 react with chloroform, NaOH, and aceton resp. butan-2-one O-regiospecifically to yield 2-methyl-2-[(1H-pyrazol-3-yl) oxy]-propanoic resp.-butanoic acids 14via a dichlorocarbene (12)–dichlorooxirane (9) pathway. Chlorides 17 of 14 easily cyclize to N-acylpyrazolium salts 18/19, which quantitatively afford esters 22– 26 and amides 27–29 of 14. Enantiomers of the butanoic acid 14th, obtained via their ...