# US 5,703,233 A · Quinilone disulfide as intermediates

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- Number: US 5,703,233 A
- Document ID: US5703233A
- Status: Granted
- Kind: A
- Application number: 08/494,353
- Filed: 1995-06-26
- Granted: 1997-12-30
- Earliest claimed: 1993-10-27
- Assignees: Archimica GmbH
- Inventors: Pietro Bellani
- Web page: https://patentgrep.com/patent/US5703233A

## CPC

- C07D 215/56: with oxygen atoms in position 4
- C07D 513/06: Peri-condensed systems
- C07D: HETEROCYCLIC COMPOUNDS (macromolecular compounds C08)

## Abstract

A process for preparing rufloxacin using a compound of the formula I ##STR1## as a starting material is described, where R is herein defined.

## Claims

### Claim 1

A process of preparing rufloxacin, a compound of formula (A) ##STR9## and its pharmaceutically acceptable salts, in which is used a quinolone disulfide of the formula (I) ##STR10## wherein R represents a C.sub.1 -C.sub.4 -alkyl group, and its salts which comprises reducing a compound of formula (I) with a suitable reducing agent and cyclyzing the resultant compound with a base to afford a compound of Formula (A') ##STR11## and then hydrolyzing a compound of formula A' to afford a compound of formula (A) and, if required, preparing its pharmaceutically acceptable salts.

### Claim 2 (depends on 1)

A process according to claim 1 wherein in Formula I, R is ethyl and its acid addition salts.

### Claim 3 (depends on 2)

A process according to claim 2 wherein the acid addition salt is the dihydrochloride.