| 摘要 |
NEW MATERIAL:Compds. of formula I, wherein R1 and R2 are each a lower alkyl; L is a (lower alkyl-substd.) methylene; and l is 1 or 2. EXAMPLE:A compd. of formula II. USE:Light-absorbing photographic dyes having excellent irradiation-preventing effect, a antihalation effect and filter effect and suitable for use in photographic silver halide materials. PREPARATION:3-Ethoxycarbonyl-1-methyl-5-pyrazolone and pentadienedianil are dissolved in, e.g., ethanol and triethylamine is added thereto. The mixture is stirred at room temp. for about 1hr and heated on a water bath in a vacuum to distill of the solvent. Satd. brine is added to the residue to precipitate the product. The resulting crude dye is recovered by filtration, washed with brine and then with a mixture of methanol and ethanol and dried to obtain Na salt of the dye having a m.p. of not lower than 300 deg.C and formula II as a greenish brown crystal powder. |
