Azepine 1.4- benzox

The reaction of 5-chloro-l,4-benzoxazepine (4), whose preparation is described below, with tributyltin hydride catalyzed by tetrakis(triphenylphosphane)palladium(0) gives 1,4-benzox-azepine (5).32... 

Garanti et al. (30a) reported a synthesis of the l,2,3-triazolo[l,5-a][4.1]benzox-azepine 149 via an intramolecular cycloaddition of an aryl azide with an acetylene (Scheme 9.30). By using a similar strategy, the l,2,3-triazolo[l,5-a][l,4-l ]benzo-diazepine 150, an analogue of Flumazenil, was also reported (30b,c). As an extension of this method, the l,2,3-triazolo[l,5-a][l,4]benzodiazepine-6-one 153 was synthesized using an intramolecular 1,3-dipolar cycloaddition of an azide with a cyano group (30d). 

By Ring Contraction 6.3.1.1.4.1. From Seven-Membered Heterocyclic Compounds From 4,1 -Benzox azepine-2,5( 1 on es... 

The preparation of 3,1-benzoxazepines by photochemical isomenzation of quinoline iV-oxides constitutes a rather general entry into this class of seven-membered heterocycles Since the structure of the photoisomer of 2-phenylquinoline yV-oxide was first recognized as 2-phenyl-3,l-benzox-azepine by Buchardt et al the scope of this method for oxidative nng expansion of six-membered heterocyclic A-oxides to 1,3-oxazepines has been extensively explored For example, irradiation of 2-cyano-, 2-phenyl-, and 2-methoxyquinoline A-oxides affords the corresponding 2-substituted 3,1-benzoxazepines in 70-90% yield However, isolation of the moisture-sensitive parent compound was only recently accomplished in the submitters laboratories ... 

The reactions of 3-formylchromones, e.g. (186), with various ort/io-substituted anilines (Y = S, O, or NH) provide a high-yielding route to the fused benzo-pyrano-compounds (187)." Various substituted 2,3-dihydro-l,4-benzox-azepin-5(4H )-one-7-acetic acid esters were prepared by the Schmidt reactions of chromanone derivatives." ... 

The transition metal-catalyzed reductive carbonylation of o-substituted nitrobenzenes is a useful method for the synthesis of nitrogen heterocycles. Application of this methodology to the preparation of l,4-dihydro-2/f-3,l-benzoxazin-2-one derivatives and to the synthesis of the 3,1-benzox-azepin-2-one (42) has been reported <93JOM(451)157>. Reaction of 2-(2-nitrophenyl)ethanol (41) (100% conversion) with carbon monoxide in the presence of a palladium(Il) catalyst gave (42) in 60% yield, together with some of the macrocyclic dimer (43) ( nation (2)). It is suggested that a nitrene complex may not be involved with the palladium catalyst in view of the reaction path selectivity observed <93JOM(45i)l57>. 

Hydroxy-5-methylbenzophenone was converted to the corresponding substituted diphenyl-methylamines (22), which on treatment with 1,2-dibromoethane and KOH gave the 1,4-benzox-azepines (23) in good yield. Alternatively, the amine (22) was also converted to the same benzoxazepines (23) through 0,0,A -tritosylate, followed by cyclization with KOH and reduction with LiAlH4 (Scheme 7) <89UC592>. 

Cyclodehydration of substituted 7V-(2-phenoxyethyl)benzamides to the corresponding benzox-azepines (32) (with POCI3— P20s in xylene) has been one of the main routes for benzoxazepine synthesis (Equation (5)) <82JHC537>. 

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