2-Diethylamino-3H-azepine

Doering and Odum have examined the photoreaction of phenyl azide in the presence of bases and other nucleophiles. On irradiation of phenyl azide in either aniline, diethylamine or liquid ammonia, 2-anilino-3H-azepine (137), 2-diethylamino-3H-azepine (139) and 2-amino-3H-azepine (140) were isolated respectively. Treatment of phenyl azide with hydrogen sulphide gave a very small yield of 2-thio-3H-azepine. The structure of the cyclic amidines was established chemically by hydrogenation and subsequent hydrolysis to the e-aminocaproic acid and the corresponding base. The u.v. spectra were similar to that of acetamidine and also the absence of —NH— absorption in the infrared together with a strong absorption at 1600 cm are in accord with the proposed structure. Most important, the n.m.r. spectrum of the product proved unequivocally the presence of a 3H-azepine. 

Deoxygenation [1, 1242-1244 p. 1244, after citation of ref. 22]. Deoxygenation of nitrosobenzene by triphenylphosphine or tributylphosphine in the presence of di-ethylamine results in ring enlargement to 2-diethylamino-3H-azepine 22a... 

Nitrobenzene, diethyl methylphosphonite, and a large excess of diethylamine refluxed 5 days at 55° under Ng 2-diethylamino-3H-azepine. Y 83%. - Diethyl methylphosphonite had the highest reducing activity of a series of phosphorus(III) reagents. F. e. s. J. I. G. Cadogan and M. J. Todd, Soc. (C) 1969, 2808. 

H-Azepin 5-Brom-2-diethylamino-E16c, 199 (Nitro-aren/Amin) Malonsaure... 

H-Azepin 2-Diethylamino-3-(difluormethylen)- E16c, 176 (Nj-Benzol-Der./Amin)... 

THF (25 mL) was distilled from CaH2 under N2 into a carefully dried 250-mL flask containing ethyl 2-(diethylamino)-5-phenyl-3//-azepine-3-carboxylate (13, 0.394 g, 1.26 mmol). The flask was placed in a bath at 20 C and dry 2,2,6,6-tetramethylpiperidine (0.5 mL, 0.42 g, 3.0 mmol) was added with a syringe. After 5 min of stirring 1.32 M BuLi in hexane (1 mL, 1.3 mmol) was added with a syringe. A black-violet color formed. After 30 min iodomethane (2mL, 4.56g, 32.1 mmol) was added at once. After 3h at 20°C EtOH was added, the solvent was evaporated in vacuo and the product was isolated by preparative TLC [silica gel, petroleum ether (bp 60-80°C)/EtOAc/MeOH 10 9 1, Rf 0.37] to give 14 as an oil yield 0.226g (55%) ptcrate mp 138-139.5°C (EtOH, - 30"C). 

The molecular dimensions have been determined by x-ray crystallography for a considerable number of complex molecules. Of the more simple and representative structures, data have been reported for a number of oxazolo- and oxazinoazepine derivatives <84Mi 90i-03>, 2,2-dimethyl- 1 -phenyl-1 f/-azepin-3(27f)-one <89JCS(Pl )425>, 3-methyl-3,5-diphenyl-5H-benz[c]azepine <92JCS(P1)1709>, 2-diethylamino-3-isopropyl-5-phenyl-3H-azepine <84RTC225>, 3,4,6,7-tetraphenyl-3/f-azepine <87H(25)387>, and a number of tetrahydroazepines <86AX(B)478>. 

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