NEW MATERIAL:A phthalide compound expressed by formula I (R1, R2, R4 and R5 are H, alkyl, cycloalkyl, substituted alkyl, aralkyl, aryl, allyl or alkinyl; R3 is alkyl, provided that R1 and R2 and R4 and R5 may be mutually linked to form heterocyclic ring).
EXAMPLE: 3-{P-[N-Methyl-N-(p-dimethylaminophenyl)amino]phenyl}-6-dimethyl aminophthalide.
USE: Useful as a precursor for coloring phthalide compound having near-infrared ray absorbing ability.
PREPARATION: A compound expressed by formula II is subjected to condensation reaction with a 3-aminobenzoic acid derivative expressed by formula III (R6 is H or alkyl group) in the presence of a dehydro- or dealcoholic condensing agent to provide the compound expressed by formula I. The compound expressed by formula II and compound expressed by formula III are preferably used in the range of 1:1W1:1.5 molar ratio.
IIYAMA KIYOTAKA
NAKADA KATSUHIRO
OHARA KOJI
SHOWA CHEM
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