反应详情

If the 3-(2'-carboxybenzoyl)-1-ethyl-2-methyl-indole in Example 1 is replaced by an equimolar amount of 3-(2'-carboxybenzoyl)-1-benzyl-2-methyl-indole, with the procedure otherwise being as described in Example 1, there is obtained 4.5 g of a phthalide compound of the formula ##STR12## which melts at 138°-142° C. This colour former develops on silton clay a blue colour of λmax. 600 nm.