Kwon S K, Park Y N
College of Pharmacy, Duksung Women's University, Seoul, Korea.
Arch Pharm Res. 2000 Aug;23(4):329-31. doi: 10.1007/BF02975442.
4-(p-Chlorophenyl)tetralone (6) and 7-chloro-5-(p-chlorophenyl)tetralone (9) are key intermediates for the development of benzazepinone derivative haftens. These compounds could be synthesized from 4-phenyltetralone derivatives by triflic acid catalyzed Friedel-Crafts reaction. The reaction mechanism of Friedel-Crafts alkylation/acylation with lactones in triflic acid is presented. According to our tentative research, ring opening of protonated lactone (2) occurs in alkyl cleavage and the rate of the reaction is not dependent on concentration of triflic acid. So, alkylation of lactone in Friedel-Crafts reaction is presumed to be A(AL)1. In second step, intramolecular acylation of the intermediates 4 to 6, 4 can be transformed to a triflic acid-carboxylic anhydride and then the cyclization is undergone after leaving of the triflate anion.
4-（对氯苯基）四氢萘酮（6）和7-氯-5-（对氯苯基）四氢萘酮（9）是开发苯并氮杂䓬酮衍生物哈夫滕斯的关键中间体。这些化合物可通过三氟甲磺酸催化的傅克反应由4-苯基四氢萘酮衍生物合成。本文介绍了在三氟甲磺酸中用内酯进行傅克烷基化/酰化的反应机理。根据我们的初步研究，质子化内酯（2）的开环发生在烷基裂解过程中，且反应速率不依赖于三氟甲磺酸的浓度。因此，傅克反应中内酯的烷基化被推测为A(AL)1。在第二步中，中间体4到6进行分子内酰化，4可转化为三氟甲磺酸 - 羧酸酐，然后在三氟甲磺酸根阴离子离去后发生环化反应。
