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Phthalides and 1,3-indandiones. XXVIII. Preparation of 5- and 6-substituted 3-benzalphthalides by the Perkin reaction

P. Hrnčiar and Ľ. Kuruc

Faculty of Natural Sciences, Comenius University, Bratislava

Abstract: CA 67: 32503r. The condensation of 4-X-substituted phthalic anhydride (X = Cl, Br, I, and NO2) at 200-220° with phenylacetic acid is described. With X = Cl, Br, and NO₂, 2 position isomers were formed, but with X = I, only 1 isomer was formed. The isomers were sepd. chromatographically on silica gel with benzene. The structure of the isomers was detd. (Zimmer and Barry, CA 58: 5602b). For the prepn. of 5- and 6-X-substituted 3-benzalphthalides, the Perkin reaction was applied by heating 0.05 mole 4-X-substituted phthalic acid to 230° for 25 min. and adding 0.05 mole phenylacetic acid and 0.5 g. AcOK and heating for 2 hrs. at 200-220°. To det. the structure of the isomers, 5- and 6-amino-3-benzalphthalides, m. 183-5° and 210-11°, resp., were prepd. by redn. of 5- and 6-nitro-3-benzalphthalides with SnCl₂.2H₂O in concd. HCl. After diazotization and the Sandmeyer reaction, 5- and 6-chloro-3-benzalphthalides, m. 193-5° and 156-8°, resp., 5- and 6-bromo-3-benzalphthalides, m. 200-2° and 174-6°, resp., and with KI, 5- and 6-iodo-3-benzalphthalides, m. 203-5° and 177-9°, resp. were prepd. By acetylation, 5- and 6-acetamido-3-benzalphthalides, m. 272-3° and 274-5°, resp., were prepd.

Full paper in Portable Document Format: 214a267.pdf (in Slovak)

Chemical Papers 21 (4) 267–273 (1967)