| 摘要 |
PROBLEM TO BE SOLVED: To obtain a 1,3-benzodithiol compound capable of coloring in yellow to orange, excellent in coloring property and storage stability and useful as electron-donating colorless dye for recording materials, especially pressure- sensitive recording materials. SOLUTION: This compound is represented by formula I (R1 is H or a 1-4C alkyl; R2 to R5 are each H, a 1-4C alkyl or a 1-4C alkoxyl), e.g. 3-[1,3-(4- methylbenzodithiol)-2-yl]-1-methyl-2-phenyl-1H-indole. The compound of formula I is obtained by converting, e.g. the corresponding indole compound to aldehyde derivative thereof by using phosphorus oxychloride and subjecting the resultant compound of formula II (e.g. 1-methyl-2-phenylindole-3-aldehyde) to condensation with a compound of formula III (e.g. toluene-3,4-dithiol) through dehydration by using a condensing agent such as hydrogen chloride. |
