US 5,177,209 AGranted

Process for preparation of asymmetric isoindoline pigments

AssigneesMiles Inc., Bayer Aktiengesellschaft

InventorsBarbara J. Wagner, Bernd Kaletta

Life of this patent

Estimating the term…

Loading patent…

Abstract

This invention relates to a process for preparing asymmetric isoindoline pigments of the formula ##STR1## in which R.sup.1 is an electron-withdrawing group, R.sup.2 and R.sup.3 are independently hydrogen, alkyl, or aryl, and R.sup.4, R.sup.5, R.sup.6, and R.sup.7 are independently hydrogen, halogen, alkyl, alkoxy, or aryloxy. The process employs an initial reaction of a 1,2-dicyanobenzene with an alcohol in an organic medium in the presence of a base. The resultant imino-isoindoline intermediate composition reacts without isolation with a cyanomethylene compound NC--CH.sub.2 --R.sup.1 to form a partly condensed product that is then condensed without isolation in the presence of water with barbituric acid or a derivative thereof to form the asymmetric isoindoline pigment.

Claims21

Dependent claims

A process for preparing, without isolation of intermediates, an asymmetric isoindoline pigment of the formula ##STR30## wherein R.sup.1 is an electron-withdrawing group;

R.sup.2 and R.sup.3 are independently
(1) hydrogen,
(2) C.sub.1 -C.sub.6 alkyl, or
(3) C.sub.6 -C.sub.10 aryl;
and
R.sup.4, R.sup.5, R.sup.6, and R.sup.7 are independently
(1) hydrogen,
(2) halogen,
(3) C.sub.1 -C.sub.6 alkyl,
(4) C.sub.1 -C.sub.6 alkoxy, or
(5) C.sub.6 -C.sub.10 aryloxy;
comprising
(a) reacting a 1,2-dicyanobenzene of the formula ##STR31## wherein , R.sup.4, R.sup.5, R.sup.6, and R.sup.7 are defined as above, with an alcohol in an organic medium in the presence of a base, thereby forming an imino-isoindoline intermediate composition;
(b) reacting the imino-isoindoline intermediate composition, without first isolating said intermediate composition, with 0.9 to 1.5 molar parts, relative to the 1,2-dicyanobenzene, of a cyanomethylene compound of the formula
NC--CH.sub.2 --R.sup.1
wherein R.sup.1 is defined as above, thereby forming a semi-condensed product of the formula ##STR32## wherein , R.sup.1, R.sup.4, R.sup.5, R.sup.6, and R.sup.7 are defined as above;
and
(c) condensing the semi-condensed product, without first isolating said semi-condensed product, in the presence of water at a temperature of 30.degree. C. to 100.degree. C. and at a pH between 1 and 6 with 1 to 3 molar parts, relative to the 1,2-dicyanobenzene, of a barbituric acid derivative of the formula ##STR33## wherein R.sup.2 and R.sup.3 are defined as above, thereby forming the asymmetric isoindoline pigment.

15 more elements

Dependencies are inferred from the claim text.