| 摘要 |
Lactones of the formula I <IMAGE> in which R1 and R2 are identical or different and each is a hydrogen atom, a halogen atom, an alkyl or alkoxy group, the hydroxyl, carboxyl or sulpho group, are prepared by reacting a phthalic anhydride of the formula II <IMAGE> with R1 and R2 of the abovementioned meaning, with resorcinol in the presence of excess phosphorus oxychloride, and subsequently treating the reaction products with alkalis. This novel process can be carried out without isolation of intermediates and in the absence of organic solvents. The reaction takes place particularly favourably when it is carried out initially at 50 to 60 DEG C and then continued at 100 to 140 DEG C. The compounds of the formula I are valuable intermediates for the preparation of xanthene dyes.
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