Abstract A chromogenic compound having the structural formula ##STR1## wherein R 1 , R 2 , R 3 , R 4 and R 6 represent hydrogen, an alkyl group, a benzyl group or an aryl group; R 5 represents hydrogen, an alkyl group, a benzyl group, an aryl group or Y, wherein Y represents ##STR2## and R 3' and R 7 represent hydrogen, an alkyl group, a benzyl group or an aryl group; with the proviso that when R 5 represents Y, R 6 represents hydrogen and Y is at the 2 position, and n is an integer of 1 to 6. The aforesaid compound may be provided in a pressure-sensitive copy system wherein a visible image is formed upon reaction of the above chromogenic compound with an electron-accepting material of the Lewis acid type to produce a black image.
A chromogenic compound represented by the formula ##STR17## wherein each of R 1 and R 2 represents alkyl having 1 to 5 carbon atoms, or phenyl, R 3 and R 3' are the same and represent alkyl having 1 to 5 carbon atoms, benzyl or phenyl, R 7 represents alkyl having 1 to 5 carbon atoms, or phenyl, the alkylene bridging group (CH 2 ) n is attached to either the 2' or 3' position and either to the 2''' or 3''' position, and n is an integer from 1 to 6.
Claim 2
Dependent Claim
92 words
A chromogenic compound represented by the formula ##STR17## wherein each of R 1 and R 2 represents alkyl having 1 to 5 carbon atoms, or phenyl, R 3 and R 3' are the same and represent alkyl having 1 to 5 carbon atoms, benzyl or phenyl, R 7 represents alkyl having 1 to 5 carbon atoms, or phenyl, the alkylene bridging group (CH 2 ) n is attached to either the 2' or 3' position and either to the 2''' or 3''' position, and n is an integer from 1 to 6.
Claim 3
Dependent Claim
21 words
The chromogenic compound of claim 1 wherein R 1 and R 2 each represent alkyl having 1 to 5 carbon atoms.
Claim 4
Dependent Claim
13 words
A chromogenic compound in accordance with claim 1 represented by the formula: ##STR18##
Claim 5
Dependent Claim
13 words
A chromogenic compound in accordance with claim 2 represented by the formula: ##STR19##
Claim 6
Dependent Claim
13 words
A chromogenic compound in accordance with claim 2 represented by the formula: ##STR20##
Claim 7
Dependent Claim
13 words
A chromogenic compound in accordance with claim 2 represented by the formula: ##STR21##