Synthesis of Functionally Substituted Pyrrolo[3,2-g]quinolines from 6-Amino-7-methoxy-1,2,3-trimethylindole

Abstract

Keywords: 6-amino-7-methoxy-1,2,3-trimethylindole, acetylacetone, acetoacetic ester, dibenzoylmethane, functionally substituted pyrrolo[3,2-g]quinolines, trifluoroacetoacetic ester.Enamines prepared from 6-amino-2,3-dimethyl-7-methoxyindole (1a) and dicarbonyl compounds are converted to the corresponding pyrrolo[3,2-g]quinolines under acid conditions or via thermal cyclization [1]. Continuing our research in this area we have studied the behavior of 6-amino-7-methoxy-1,2,3-trimethylindole (1b) in reactions with the same β-dicarbonyl compounds and also with trifluoroacetoacetic ester.The result of the reaction of the aminoindole 1b with acetylacetone depends on the duration of the process. Hence refluxing compound 1b in excess acetylacetone over 1 h gives basically the enamino ketone 2a which contains traces of the pyrroloquinoline 3a. A more prolonged reflux (3 h) gives exclusively product 3a. It was unexpectedly found that the result of briefly (1.5 h) holding the aminoindole 1b with dibenzoylmethane at 180-185°C gave the corresponding pyrroloquinoline 3b immediately with an admixture of traces of the enamino ketone 2b. N R Me Me N H 2 OMe C H 2 O O R 1 R 2 N R Me Me N H OMe O R 2 R 1 N N R Me Me R 2 R 1 OMe + 1a,b 2a-c 3a,b 1a R = H; 1b, 2a-c, 3a R = Me; 2a, 3a R 1 = R 2 = Me; 2b, 3b R 1 = R 2 = Ph; 2c R 1 = Me, R 2 = OEt __________________________________________________________________________________________

Synthesis and antimicrobial activity of N-(indol-5-yl)trifluoroacetamides and indol-5-ylaminium trifluoroacetates substituted in the pyrrole ring

“…The dependence of antimicrobial activity on the nature of the substituents in the benzene and pyrrole rings of the indole system, as well as on the position of the amide group was revealed. [4][5][6][7][8][9][10] In our opinion, a signifi cant role in the emergence of biological activity belongs to the trifl uoromethyl group combined in these molecules with a substituted pharmacophore indole system. Therefore, the search for synthetic trifl uoromethyl-containing biologically active compounds is promising.…”