Process for preparation of asymmetric isoindoline pigments
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United States of America Patent
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Jan 5, 1993
Grant Date -
N/A
app pub date -
Apr 22, 1991
filing date -
Apr 22, 1991
priority date (Note) -
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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.
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- 7 Citation Count
- C07D Class
- 18.56 % this patent is cited more than
- 32 Age