# US 4,400,520 A · Novel process for preparing isoindoline derivatives

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- Number: US 4,400,520 A
- Document ID: US4400520A
- Status: Granted
- Kind: A
- Application number: 06/299,432
- Filed: 1981-09-04
- Granted: 1983-08-23
- Earliest claimed: 1980-09-10
- Assignees: Hisamitsu Pharmaceutical Co., Inc.
- Inventors: Kanji Noda; Akira Nakagawa; Toshiharu Motomura; Hiroyuki Ide
- Web page: https://patentgrep.com/patent/US4400520A

## CPC

- C07D 209/46: with an oxygen atom in position 1
- C07D: HETEROCYCLIC COMPOUNDS (macromolecular compounds C08)

## Abstract

A process for the preparation of an isoindoline derivative of the following general formula (II): ##STR1## wherein R.sup.2 is a hydrogen atom or lower alkyl group and X is a carboxyl group, carboalkoxy group, amide group or cyano group, which comprises cycling a benzylidene derivative of the following general formula (I) ##STR2## wherein R.sup.1 is a hydrogen atom or lower alkyl group, and R.sup.2 and X are as defined above, in the presence of a reducing agent such as sodium boron hydride. In one embodiment, the benzylidene derivative may be substituted by a reaction mixture containing the same, the reaction mixture being prepared by reacting o-phthalaldehydic acid or its ester with an aniline derivative.

## Claims

### Claim 1

A process for preparing an isoindoline derivative represented by the following general formula (II) ##STR16## wherein R.sup.2 is a hydrogen atom or lower alkyl group and X is a carboxyl group, carboalkoxy group, amide group or cyano group, which comprises
cyclizing a benzylidene derivative represented by the following general formula (I) ##STR17## wherein R.sup.1 is a hydrogen atom or lower alkyl group, and R.sup.2 and X are as defined above, in the presence of a reducing agent.

### Claim 2

A process for preparing an isoindoline derivative represented by the following general formula (II) ##STR18## wherein R.sup.2 is a hydrogen atom or lower alkyl group and X is a carboxyl group, carboalkoxy group, amide group or cyano group, which comprises
reacting a member selected from the group consisting of o-phthalaldehydic acid and its ester represented by the following general formula (III) ##STR19## wherein R.sup.1 is as defined above, with an aniline derivative represented by the following general formula (IV) ##STR20## wherein R.sup.2 and X are as defined above, to obtain a reaction mixture containing a benzylidene derivative represented by the following general formula (I) ##STR21## wherein R.sup.1, R.sup.2 and X are as defined above, and then cyclizing the thus obtained reaction mixture without previous isolation of the benzylidene derivative of the formula (I), in the presence of a reducing agent.

### Claim 3 (depends on 1, 2)

A process for preparing an isoindoline derivative according to claim 1 or 2, wherein the reducing agent is a member selected from the group consisting of sodium boron hydride and potassium boron hydride.