Bisphthalide lactones, their preparation and the use thereof in

Abstract

Bisphthalide lactones of formula ##STR1## wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are each independently of one another hydrogen, alkyl of at most 12 carbon atoms which is unsubstituted or substituted by halogen, hydroxy, cyano, tetrahydrofuryl or lower alkoxy; or are acyl of 1 to 12 carbon atoms, cycloalkyl of 5 to 10 carbon atoms or unsubstituted aralkyl or aryl, or aralkyl or aryl each substituted by halogen, cyano, nitro, trifluormethyl, lower alkyl, lower alkoxy, lower alkoxycarbonyl, --NX'X'-- or 4--NX'X--'phenylamino, wherein X' and X' are each independently of the other hydrogen, lower alkyl, cyclohexyl, benzyl or phenyl, or the pairs of substituents --NR.sub.1 R.sub.2 and --NR.sub.3 R.sub.4 are each a 5- or 6-membered, preferably saturated, heterocyclic radical, V.sub.1 and V.sub.2 are hydrogen, halogen, lower alkyl, C.sub.1 -C.sub.12 alkoxy, C.sub.1 -C.sub.12 -acyloxy, benzyl, phenyl, benzyloxy, phenyloxy, or benzyl or benzyloxy, each substituted by halogen, cyano, lower alkyl or lower alkoxy, or are the group --NT.sub.1 T.sub.2, in which T.sub.1 and T.sub.2 are each independently of the other hydrogen, lower alkyl, C.sub.5 -C.sub.10 cycloalkyl, unsubstituted benzyl or benzyl which is substituted by halogen, cyano, lower alkyl or lower alkoxy, or are acyl of 1 to 8 carbon atoms, and T.sub.1 is also unsubstituted phenyl or phenyl which is substituted by halogen, cyano, lower alkyl or lower alkoxy, and the rings A.sub.1 and A.sub.2 are each independently of the other an aromatic or heterocyclic radical of 6 ring atoms which may contain an aromatic fused ring, which rings A.sub.1 and A.sub.2 as well as the fused rings may be substituted. These bisphthalide lactones can be used as color forming components in pressure-sensitive or heat-sensitive recording materials and, when used in conjunction with a condensation component and an acid developer, form intense colored images.