# US 5,705,650 A · Process for preparing 1,2,4-thiadiazole derivatives

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- Number: US 5,705,650 A
- Document ID: US5705650A
- Status: Granted
- Kind: A
- Application number: 08/657,170
- Filed: 1996-06-03
- Granted: 1998-01-06
- Earliest claimed: 1991-09-12
- Assignees: Katayama Seiyakusyo Co., Ltd.
- Inventors: Kuniaki Tatsuta; Yasuyuki Kurita; Takashi Inagaki; Ryonosuke Yoshida
- Web page: https://patentgrep.com/patent/US5705650A

## CPC

- C07D 285/08: 1,2,4-Thiadiazoles; Hydrogenated 1,2,4-thiadiazoles
- C07D 261/14: Nitrogen atoms
- C07D: HETEROCYCLIC COMPOUNDS (macromolecular compounds C08)

## Abstract

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-aminoisoxazole compounds is disclosed herein. The title compounds are useful as acylating agents for the production of 7-acylaminocephalosporins.

## Claims

### Claim 1

A process for production of 1,2,4-thiadiazolylacetic acid compound of the formula: ##STR33## wherein R.sup.1 is lower alkyl, and R.sup.2 is lower alkoxy, phenoxy, benzyloxy, lower alkyl and phenyl optionally substituted by nitro or halogen, which comprises reacting an isoxazole of the formula: ##STR34## with an isothiocyanate of the formula:
SCN--COR.sup.2
at 0.degree.-10.degree. C. in tetrahydrofuran or acetonitrile and subjecting to rearrangement reaction in a reaction system without any base to give the compound (II).