2//-Azepin-2-one

The early unsuccessful search for aromatic character in 2//-azepin-2-one (14) and 47/-azepin-4-one (15), the 6n-monoaza analogs of tropones, has been surveyed.46... 

UV data of other l//-62-63 and 3//-azepines,34,64-66 2//-azepin-2-ones,67 3-hydroxy-2//-azepin-2-ones and their methyl ethers48,52 are available. 

Formal charge densities have been calculated for 3//-azepine and for the 3/7-azcpinium cation using MNDO methods,70 and 7>charge densities for 2//-azepin-2-one, 3//-azepin-3-one, and 4//-azepin-4-one have been calculated using the semiempirical method of Pariser. Parr and Pople.97... 

Dehydrogenation is a rarely used method for the production of fully unsaturated azepines, and there are no examples of its use for the formation of simple monocyclic systems, although 3-hydroxy- and 3-methoxy-2//-azepin-2-ones can be obtained by dehydrogenation of the corresponding l,5-dihydro-2//-azepin-2-ones with 2,3-dichloro-5,6-dicyano-l,4-benzoquinone (DDQ) in benzene in a sealed tube at 100 48-51-52-67... 

Reductive ring opening of the [i-lactam 10 (X = O), obtained by [2 + 2] cycloaddition of chloro-sulfonyl isocyanate and tetraphenylcyclopentadiene followed by treatment with /7-cresol, with sodium hydride in anhydrous tetrahydrofuran yields 3,5,6,7-tetraphenyl-2//-azepin-2-one (11, X = O).41 Surprisingly, similar treatment of the reduced /Mactam 10 (X = H2) is reported to yield 3,5,6,7-letraphenyl-2//-azepine (11, X = H2), the first monocyclic 277-azepine to be isolated and characterized. Physical data for this compound, however, are inconclusive and attempts to reproduce this synthesis have failed.291... 

There is evidence from a detailed study of the photolyses of 2-alkyl-substituted aryl azides 40 in diethylamine that A3,7V-diethyl-1 //-azepin-2-amines are formed as oxygen-sensitive, meta-stablc intermediates that can give rise to a variety of byproducts, including 5-acyl- A%V-diethyl-pyridin-2-amines and 6-alkyl-7-(diethylamino)-2//-azepin-2-ones 11 however, formation of these oxidation products can be avoided by refluxing the photolysate mixture with methanol prior to exposure to oxygen, in which case practicable yields of the /V,/V-diethyl-3W-azepin-2-amines 41 result. 

Lysine and its derivatives are used for the preparation of e-caprolactams. From L-Lys or its ester, (5)-3-aminohexahydro-2//-azepin-2-one is prepared (43JCS39 57JCS4830 78S614 79JOC4841 80TL2443). 

PHOTO-INDUCED RING EXPANSION OF l-TRIISOPROPYLSILYLOXY-1-AZIDOCYCLOHEXANE PREPARATION OF e-CAPROLACTAM [2 Azepin-2-one, hexahydro- from Silane, [(1-azidocyclohexyl)oxy]tris(1-... 

An alternative and surprising transformation to the 2//-azepin-2-one system has been noted on reaction of DBU, normally regarded as non-nucleophilic, with saccharin derivatives <03SC1937>. 

When 6-chloro-4,4-dimethyl-l,3,4,5-tetrahydro-2/ azepin-2-one (87) is treated with methoxide the addition/elimination product (88) is obtained (Scheme 14) <93AJC135>. Sodium in either t-butyl alcohol or ammonia reduces (87) to give 4,4-dimethyM,3,4,5-tetrahydro-2 T-azepin-2-one (89) in good yield. 

Because authors have approached similar topics from different viewpoints, index entries to those topics may appear under several headings. Thus a reader interested in, for example, the synthesis of acetyl-3Tf-azepin-2-ones should refer both to general entries (e.g. Azepinones, Azepin-2-ones, 3JT-Azepin-2-ones) and to specific entries (e.g. 3JT-Azepin-2-one, 3-acetyl- 3f7-Azepin-2-one, 7-acetyl-). 

H-Azepinium perchlorate, 6,7-dihydro-formation, 7, 512 Azepinoindoles synthesis, 7, 537 Azepin-2-one, hexahydro-chlorination, 7, 517 synthesis, 7, 530 Azepin-2-one, 3-hydroxy-methylation, 7, 518... 

H -Azepin-2-one, 4-allyloxytetrahydro-Claisen rearrangement, 7, 508 1 H-Azepin-2-one, hexahydro-conformation analysis, 7, 499 mass spectra, 7, 501... 

H-Azepin-2-one, 3-acetyl-synthesis, 7, 542-543 3/f-Azepin-2-one, 7-acetyl-synthesis, 7, 542-543 3H-Azepin-2-one, 3-acyl-rearrangements, 7, 505 3/f-Azepin-2-one, 3-acyl-2-alkoxy-formation, 7, 542-543 3H-Azepin-2-one, 1-alkyl-rearrangements, 7, 505 3/f-Azepin-2-one, N-alkyl-synthesis, 7, 511 Azepinones... 

H-Dibenz[6,eJazepin-6-one, 11-hydroxy-ring contraction, 7, 516 11H-Dibenz[6,ejazepin-1 l-one, 6-phenyl-synthesis, 7, 532 Dibenz[6,/]azepin-2-one synthesis, 7, 525... 

A suspension of 100 g of 7-chloro-6-phenyl-1-methyi-3-hydroxy-1,3-dihydro-2H-1,4-benzodi-azepin-2-one in 700 ml of anhydrous pyridine, kept stirred between 0°C and -t5°C, is slowly treated, during 20 to 30 minutes, with 54.5 ml phenyl chlorocarbonate. The temperature is gradually allowed to rise to 20°-25°C and stirring Is maintained at this temperature during 24 hours. 

Chemical Name 5-(o-Chlorophenyl)-7-ethyl-1,3-dihydro-1-methyl-1H-thieno[2,3-e] -1,4-di-azepin-2-one... 

Chemical Name 7-Chloro-1 cllhvdro-5-phenvl-1-(2,2 -trifluoroethvl)-2H-1,4-benzodi-azepine-2-one... 

That material was hydrogenated in cyclohexane using a Raney nickel catalyst. The product after distillation was recrystallized from ethyl acetate affording 10.0 g of 6-ethyl-6-(m-meth-oxyphenyl)hexahydro-2H-azepin-2-one, MP87°C to 88°C. 

Attempts to effect cycloaddition of 1/7-azepines with 2//-pyran-2-one have failed however, the more electron-deficient inethyl 2-oxo-2/7-pyran-5-carboxylate undergoes slow addition with ethyl 1//-azepine-1-carboxylate to give a mixture of the [2 + 4] 32 and [6 + 4] 33 7t-cycload-ducts.260 In contrast, prolonged reaction of methyl 1 //-azepine-1 -carboxylate with the isomeric... 

By analogy with the formation of3//-azepines by cycloaddition of 2//-azirines withcyclopenta-dienones, l,3-diphenyl-2//-inden-2-one (58) and its dibenzo analog 60 enter into [4 + 2] cycloadditions with 27/-azirines to give 3//-2-benzazepines 59 and phenanthro[9,10-e]azepincs 61, respectively.96... 

Reduction of 2/f-dibenz[/i,/]azepin-2-one (55) with aqueous sodium dithionite (Na2S204) yields 5tf-dibenz[6,/]azepin-2-ol (56), which, in the presence of oxygen and a strong base, undergoes retrooxidation to the dibenzazepinone 55.13h... 

Oxidation of 5//-dibenz[7>,/]azepine (12) with Fremy s salt [ON(S03K)2] yields a mixture of acridine-9-carbaldehyde (13) and 2//-dibenz[A,/]azepin-2-one (14).215 The dibenzazepin-2-one 14 is also obtained in 46% yield with bis(trifluoroacetoxy)pentafluoroiodobenzene [PhI(OCOCF3)2] in acetonitrile as the oxidant.221... 

Inclusion of the amide in oxazolidinone functionality can be used to overcome diene statial disposition issues, for example in the conversion of 19 into 20 yields of 20 were generally high (Table 2). Ring opening of the oxazolidine moiety with or without loss of the mandelic acid moiety then afforded the corresponding azepin-2-ones <06TL3625>. 

---