2-[(3-Indolyl)carbonyl]-4/5-carboxybenzoic acids
AssigneeSterling Drug Inc.
InventorsNathan N. Crounse, Paul J. Schmidt
Life of this patent
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Abstract
3-Aryl-3-indolylphthalides, 3-aryl-3-pyrrolylphthalides and 3-aryl-3-carbazolylphthalides prepared by interaction of the appropriate 2-(heteroaryl)carbonylbenzoic acid and the appropriate phenylamine, and 3,3-bis(indolyl)phthalides prepared by the interaction of the appropriate 2-(indolyl)carbonylbenzoic acid and the appropriate indole are useful as color formers in pressure-sensitive carbonless duplicating systems, thermal marking systems and hectographic copying systems.
Claims2
A 2-{[(1-R.sup.6 -2-R.sup.5 -5/6-Y.sup.1)-3-indolyl]carbonyl}-3-R.sup.0 -4-R.sup.1 -5-R.sup.2 -6-R.sup.3 -benzoic acid of the formula ##STR32## wherein R.sup.0, R.sup.3 and one of R.sup.1 and R.sup.2 are each hydrogen, and the other of R.sup.1 and R.sup.2 represents carboxy;
- R.sup.5 represents hydrogen, C.sub.1 to C.sub.3 alkyl or phenyl,
- R.sup.6 represents hydrogen, C.sub.1 to C.sub.18 alkyl, C.sub.2 to C.sub.4 alkenyl, benzyl or benzyl substituted in the benzene ring by one or two of halo or C.sub.1 to C.sub.3 alkyl;
- and
- Y.sup.1 represents one or two of hydrogen, C.sub.1 to C.sub.3 alkyl, C.sub.1 to C.sub.3 alkoxy, halo or nitro.
Dependencies are inferred from the claim text.