Patent ID: 8258318

Claim:
A process for producing a coumarin dimer compound, comprising: obtaining coumarin dimer compounds represented by Formula (2) and Formula (3): wherein R 1 , R 3 , and R 4 independently represent a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or a halogen atom; R 2 represents a hydroxy group; and R 5 and R 6 independently represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, by subjecting a coumarin compound represented by Formula (1): wherein R 1 , R 2 , R 3 , R 4 , R 5 and R 6 represent the same meaning as defined above, to a photodimerization reaction in a solvent selected from aliphatic ketones having 3 to 10 carbon atoms, aliphatic carboxylic acid esters having 2 to 10 carbon atoms, aliphatic alcohols having 1 to 10 carbon atoms, aliphatic nitriles having 2 to 10 carbon atoms, ethers having 4 to 10 carbon atoms, amides having 3 to 10 carbon atoms.