Chromogenic azaphthalide compound and a colour-forming recording composition containing the same

摘要

Disclosed herein is a chromogenic compound of the formula: <IMAGE> wherein R1, R2, R3 and R4 respectively represent an alkyl group having 1 to 4 carbon atoms; R5 represents an alkyl group having 5 to 8 carbon atoms or a cycloalkyl group having 5 to 7 carbon atoms; one of X and Y represents a nitrogen atom and the other of X and Y represents a carbon atom, and a color-forming recording composition containing at least one of the chromogenic compounds.