Benz indole, 4,5-dihydro

Suginome and coworkers discovered the novel [3+2] regioselective photoaddilion of 2-amino-1,4-naphthoquinones with electron-rich alkenes to afford lH-benz[/] indole-4,9-diones (Schane 16, equation 1) [112]. Likewise, amino-1,4-benzoquinones with alkenes gave lH-indole-4,7-diones (equation 2). If the initial photoproducts could not indolize by loss of alcohoL then the corresponding dihydro compounds were isolated. Parker and Mindt found that qui-none monoimides were smoothly photocyclized to the respective 5-hydroxyindoles (equation 3) [113]. 

Thermolysis of the vinyl azide 26 in xylene yields ethyl 8-(mcthoxymcthyl)-l,8-dihydro-benz[2,3]azepino[4,5- >]indole-2-carboxylate (27) by attack of the vinyl nitrene at the 2-phenyl group.83... 

CN 5-(4,5-dihydro-2-phenyl-3//-benz[e]indol-3-yl)-2-hydroxybenzoic acid... 

Dihydro-l//-benz[e] indole or 2,3-dihydro-l//-3-azacyclopenta[a] naphthalene (not 1,2-dihydro-3//-benz[c>) indole)... 

A mixture of 20.0 g (0.076 mole) of 2-phenacyl-l-tetralone, 11.6 g (0.076 mole) of 5-aminosalicyclic acid, and 70 ml of glacial acetic acid was heated under reflux for 4 hours, cooled, diluted with 10 ml of water and filtered. The filter cake was washed with water and dried to provide 15.5 g of solid, 5-(4,5-dihydro-2-phenyl-3H-benz[e]indol-3-yl)-2-hydroxy-benzoic acid. MP 215°-218°C. Recristallization from benzene-cyclohexane gave 6.5 g (22%) of yellow crystals, MP 245°-247°C. 

Dihydro-lH-benz[g]indoles 7a,b and their N-vinyl derivatives 8a,b were prepared from oximes 9a,b with acetylene and MOH-DMSO (M = Li, K) (Equation (2)) (00JOC2900). 

Dihydro-2-phenyl-3//-benz[c]indol-3-yl)salicylicacid C25Hi9N03 = 381.4 CAS—53597-27-6... 

The azepino[3,2,l-/i,/]indole skeleton has been formed by intramolecular Friedel-Crafts cycli-zation of l-(2-methylthioethanoyl)-4,5-dihydro-benz[ft]azepine with NCS <88JHC937>. Treatment of the hydrazinophosphonium tetrafluoroborate (119) with nitrosonium hexafluorophosphate in acetonitrile brings about ring contraction to phenanthridine together with a smaller amount of 5H-dibenz[c,c]azepine <82ZN(B)88l>. 

Chloro-l,4-dihydro-9-methylnaphthalen-l,4-imine is converted into isomeric dihydrocyclo-but[(j]indoles by direct photolysis, which are in turn converted into 6- and 9-chloro-1-methyl-1//-benz[/)]azepines upon heating in toluene. The azepines are converted back into the dihydrocyclo-but[/)]indoles by light, from which it has been postulated that the azepines may be the primary products in the reaction <85TL2827>. The isomerization of a number of l,4-dimethyl-9-halogeno-l,2,3,4-tetrahydro-l,4-iminonaphthalenes to 2,3,4,5-tetrahydro-l//-benz[/>]azepines by AgBp4 in benzene/methanol mixtures has been reported <86TL407i>. Under similar conditions, the 1,4-dihydro-derivatives are converted into quinolines. 

Substituted 7,12-dihydroindolo[3,2-c(][l]benzazepin-6(5/0ones 2a and 2b were first reported in 1958 by MacPhillamy et al. [33] as the last intermediate in an 11-step synthesis of 4-ethyl-5,6,7,12-tetrahydro-2-methylindolo[3,2-t/][l]benzazepine. In 1992, Kunick reported the preparation of six indolo[3,2-d][l]benzazepin-6(5/f)ones [34] in a three-step procedure. The crucial step was the decarboxylation reaction of 2,3-dihydro-5-hydroxy-2-oxo-l/7-benz[(t]azepin-4-carboxylic acid ethyl ester into 3,4-dihydro-lH-benz[ ]azepin-2,5-dione, which made possible the subsequent Fischer indole synthesis, with formation of the desired 7,12-dihydroindolo[3,2-fiT [l]benzazepin-6(5/f)ones. 

Pinna, G.A., M.A. PMsi, and G. Paglietti. 1990. Addition reactions of acetylenic esters upon 6-substituted-a-tetralone ketoximes and conversion of the adducts into 4,5-dihydro-l//-benz[g]indoles. J Chem Res Synopses 11 360-361. 

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