Preparation of 3‐Hydroxyoxindoles with Dimethyldioxirane and Their Use for the Synthesis of Natural Products.

Abstract

Treatment of indoles and oxindoles with dimethyldioxirane offers a practical and widely applicable method to prepare 3-hydroxyoxindoles. It can be employed successfully to the synthesis of the alkaloids (IIa) and (IId), the flustraminol B analogue (VII), and the precursor (IIc) of natural donaxaridine. Starting from the amide (XI) the furoindole (XII) is obtained, a ring system which is present in natural madindolines A and B. -(SUAREZ-CASTILLO*, O. R.; SANCHEZ-ZAVALA, M.; MELENDEZ-RODRIGUEZ, M.; CASTELAN-DUARTE, L. E.; MORALES-RIOS, M. S.; JOSEPH-NATHAN, P.; Tetrahedron 62 (2006) 13, 3040-3051; Cent. Invest. Quim., Univ. Auton. Estado Hidalgo, 42001 Pachuca Hidalgo, Mex.; Eng.) -Jannicke 30-123

Synthesis of Indolylindolines Mediated by tert-BuNH2

“…In general, such oligomerizations are effected under harsh reaction conditions in the presence of strong acids or toxic metals and tedious workup procedures are generally required. 5 Recently, the InCl 3 /MeOCOCl/CH 2 Cl 2 system has been used as catalyst in the synthesis of indole dimers and trimers. 2k Indole dimerization to indolylindolines is usually carried out by the acid-induced 3H-indolium cation which can react with an unprotonated indole molecule leading to indole dimers and/or 3,3'-(aminophenethylidene)diindoles.…”

C-6 Regioselective Bromination of Methyl Indolyl-3-acetate

“…1 H NMR (CDCl 3 , 400 MHz):  8.40 (1H, br s, H-7), 8.07 (1H, s, H-2), 7.48 (1H, d, J = 8.5 Hz, H-4), 7.41 (1H, dd, J = 8.5, 1.9 Hz, H-5), 4.05 (3H, s, NCO 2 CH 3 ), 3.86 (6H, s, 2 CO 2 CH 3 ). 13 cm -1 . 1 H NMR (CDCl 3 , 400 HMz):  8.27 (1H, d, J = 1.9 Hz, H-7), 7.49 (1H, d, J = 8.4 Hz, H-4), 7.38 (1H, dd, J = 8.6, 1.6 Hz, H-5), 5.11 (1H, s, H-8), 4.10 (3H, s, NCO 2 CH 3 ), 3.76 (6H, s, 2 CO 2 CH 3 ).…”

“…1 H NMR (CDCl 3 , 400 HMz):  8.27 (1H, d, J = 1.9 Hz, H-7), 7.49 (1H, d, J = 8.4 Hz, H-4), 7.38 (1H, dd, J = 8.6, 1.6 Hz, H-5), 5.11 (1H, s, H-8), 4.10 (3H, s, NCO 2 CH 3 ), 3.76 (6H, s, 2 CO 2 CH 3 ). 13 C NMR (CDCl 3 , 100 MHz):  168.2 (2 C=O ester), 150.6 (C=O carbamate), 136.9 (C-7a), 126.9 (C-5), 126.3 (C-3a), 121.3 (C-4), 118.9 (C-6), 118.4 (C-7), 116.0 (C-3), 112.6 (C-2), 54. Dibromo-3-bromomethyl-1-carbomethoxyindole (12a).…”

“…IR (KBr)  max : 3120, 2954, 2921, 2851, 1729, 1542, 1440 cm -1 ; 1 H NMR (CDCl 3 , 300 MHz):  8.09 (1H, dd, J = 1.9, 0.5 Hz, H-7), 7.65 (1H, dd, J = 8.5, 0.6 Hz, H-4), 7.42 (1H, dd, J = 8.5, 1.9 Hz, H-5), 4.56 (2H, s, H-8), 4.01 (3H, s, NCO 2 CH 3 ). 13 C NMR (CDCl 3 , 75 MHz):  150.5 (C=O), 136.5 (C-7a), 127.5 (C-3a), 126.3 (C-5), 123.2 (C-3), 121.3 (C-4), 117.8 (C-7), 117.7 (C-6), 110.1 (C-2), 54.9 (C-8), 54.8 (NCO 2 CH 3 ). EIMS: m/z 429/427/425/423 [M + ] (1.4/2.3/1.7/0.8), 348 (51), 346 (100), 344 (44), 304 (17), 303 (5); anal.…”

“…1 H NMR (CDCl 3 , 300 MHz):  8.26 (1H, br s, H-7), 7.73 (1H, d, J = 8.5 Hz, H-4), 7.43 (1H, dd, J = 8.5, 0.9 Hz, H-5), 5.86 (1H, s, H-8), 4.11 (3H, s, NCO 2 CH 3 ), 3.79 (3H, s, CO 2 CH 3 ). 13 C NMR (CDCl 3 , 75 MHz):  167.1 (C=O ester) 150.4 (C=O carbamate), 137.1 (C-7a), 126.9 (C-3a), 125.2 (C-5), 121.7 (C-4), 119.4 (C-6), 118.46 (C-3), 118.43 (C-7), 111.9 (C-2), 54.5 (NCO 2 CH 3 ), 53.7 (CO 2 CH 3 ), 39.9 (C-8); EIMS: m/z 406/404/402 [M + -80] (52/100/49), 376 (10), 332 (8), 302 (5), 266 (54); anal. C 32.02%, H 1.83%, N 2.87%, calcd for C 13 H 10 NO 4 Br 3 , C 32.27%, H 2.08%, N 2.89%.…”