150215-34-2Relevant academic research and scientific papers
Practical preparation of (Z)-2-(5-amino-1,2,4-thiadiazol-3-yl)-2-methoxyiminoacetic acid: A side-chain of the fourth generation of cephem antibiotics
Tatsuta,Miura,Gunji,Tamai,Yoshida,Inagaki,Kurita
, p. 1701 - 1707 (1994)
A Z-isomer (4) of 2-(5-amino-1,2,4-thiadiazol-3-yl)-2-(methoxyimino)acetic acid, which is the common acyl moiety of clinically useful cephem antibiotics, has been prepared from the aminoisoxazoles through the skeletal rearrangement in several routes. Reaction of 3-amino-5-methoxyisoxazole (7) with alkoxycarbonyl isothiocyanates gave methyl 2-(5-alkoxycarbonylamino-1,2,4-thiadiazol-3-yl)acetates (8), which were converted into the target compound 4 through the reaction of the corresponding keto ester with O-methylhydroxylamime. Compound 4 was prepared similarly from 3-aminoisoxazole (10). Also, O-methylation of 2-hydroxyimino-2-(5-methoxycarbonylamino-1,2,4-thiazol-3-yl)acetate (15) with methyl iodide or dimethyl sulfate in the presence of barium oxide and barium hydroxide octahydrate was found to afford exclusively the desired Z-isomer (14a) of methyl 2-(5-methoxycarbonylamino-1,2,4-thiadiazol-3-yl)-2-(methoxyimino)aceta te, which was led to 4.
Process for preparing 1,2,4-thiadiazole derivatives
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, (2008/06/13)
An improved process for the production of 5-amino-1,2,4-thiadiazol-3-yl-(2-(lower)-alkoxyimino)acetic acids starting from 5-substituted- or unsubstituted-3-amino-isoxazole compounds is disclosed herein. The title compounds are useful as acylating agents for the production of 7-acylaminocephalosporins.
