| 摘要 |
Quinoxalines of the formula <IMAGE> are provided, in which R1 and R2 independently are lower alkyl R3 is lower alkyl, -CH2OR5, -CH2NRR', -CH2OCOR, -CH2Cl, -CH2Br, -CH2SR, -CH2O(CH2)pOR, -CH2PO(OR5)2, -CH2PO(OR6)2, -CH2SO3R6, -O(CH2)mOR, -O(CH2)pSO3R6 or -(OCH2CH2)nOAr, R4 is hydrogen, lower alkyl or alkoxy when R3 is other than lower alkyl, or R4 is -OH, -NRR', -NHCOR, -NHCOAr', -NHSO2R5 or -NHSO2Ar', R and R' independently are hydrogen or lower alkyl, R5 is lower alkyl, R6 is hydrogen, an alkali metal cation or -N(+)(R)4, Ar is aryl or sulphonated aryl, Ar' is aryl or substituted aryl, m is 3 or 4, n is 1 to 3 and p is 2 to 4. The quinoxalines are useful as bleach catalysts, especially as dye bleach catalysts, for the photographic silver dye bleach process.
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