The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 21, 1987
Filed:
Nov. 01, 1985
Johannes Pfenninger, Marly, CH;
Abul Iqbal, Ettingen, CH;
Alain C Rochat, Fribourg, CH;
Olof Wallquist, Marly, CH;
Ciba-Geigy Corporation, Ardsley, NY (US);
Abstract
The invention relates to a process for the preparation of pyrrolo[3,4-c]pyrroles of formula (1) ##STR1## wherein each of R.sub.1 and R.sub.2 independently of the other is an alkyl or aralkyl group or an isocyclic or heterocyclic aromatic radical, which process comprises reacting an ester of formula (2) or (3) ##STR2## with a nitrile of the formula R.sub.2 CN, in which formulae each of R and R' independently of the other is an alkyl or aryl group, and R.sub.1 and R.sub.2 are as defined above, in the presence of a strong base in an organic solvent. The invention also relates to compounds of formula (8) ##STR3## wherein R.sub.3 in an alkyl or aralkyl group or an ortho-substituted isocyclic or heterocyclic aromatic radical and R.sub.4 is an alkyl or aralkyl group or an isocyclic or heterocyclic aromatic radical. The pyrrolopyrroles obtained are valuable pigments for coloring compounds of high molecular weight such as plastics and lacquers in yellow to red shades of excellent fastness properties.