Patent · US Expired

Process for the preparation of naphthostyril

US4824962A · kind A · utility

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5Claims

0Family size

Assignee

Hoechst GmbH · DE

Inventors

Otto Arndt · Hofheim, DE
Theodor Papenfuhs · Frankfurt, DE

Key dates

Filing date	Mar 14, 1988
Grant date	Apr 25, 1989
Priority date	—
Expiry date	Mar 14, 2008

Classification

Technology area (CPC C)Chemistry; Metallurgy
CPC primaryC07D209/92
WIPO fieldOrganic fine chemistry
WIPO sectorChemistry

Abstract

Process for the preparation of naphthostyril by dissolving 1,8-naphthalimide in an aqueous solution of lithium hydroxide and potassium hydroxide while heating at 40.degree. C. to 80.degree. C., cooling the solution obtained to 14.degree. C. and seeding it at said temperature with a maximum of 1 mol-% of sodium 1,8-naphthalimide per 1 mol of 1,8-naphthalimide used, then adding chlorine bleaching liquor at 10.degree. C. to 20.degree. C., reductively removing excess active chlorine after the reaction has taken place, adjusting the alkaline aqueous solution produced of the alkali-metal salt of the 1-aminonaphthal-ene-8-carboxylic acid formed to a pH of 2.0 by adding acid and isolating the naphthostyril which precipitates in this process.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.