Squarylium compounds, and processes and intermediates for the synthesis of these compounds

Abstract

Squarylium compounds of the formula: wherein Q1 and Q2 are each independently a pyrylium, thiopyrylium, selenopyrylium, benzpyrylium, benzthiopyrylium or benzselenopyrylium nucleus, and R1 and R2 are each independently an aliphatic or cycloaliphatic group, can be prepared by reacting a squaric acid derivative of the formula: with a compound of the formula Q2CH2R2 in the presence of a base. The derivatives of Formula II may be prepared by condensing a 2,3,4,4-tetrahalocyclobut-2-en-1-one with a compound of the formula Q1CH2R1 in the presence of a base to produce a compound of the formula: wherein Q1 and R1 are as defined above, and X represents chlorine or bromine, and hydrolyzing the compound of Formula III. Alternatively, the derivatives of Formula II may be prepared by reacting a diester, monoacid chloride monoester or diacid chloride of squaric acid with a compound of the formula Q1CH2R1 in the presence of a base, followed by hydrolysis of the resultant monoacid chloride or monoester derivative of the compound of Formula II to the parent compound.

Dependencies are inferred from the claim text.