1.3.4- Benzotriazepin-5-ones

A new efficient synthesis of dihydro-1,3,4-benzotriazepin-5-ones is referred to in a report by Al-Abadelah et al. The strategy is based on ring construction starting with the reaction of anthranilic acid and the hydrazonoyl chlorides 292 to give compounds 293, followed by CDI-mediated cyclisation to 294. While 294 could also exist as the tautomer 295, single crystal X-... 

Ring contraction of 1,4-dihydro-1,3,4-benzotriazepin-5-ones by the action of NaOEt gave l-methyl-2-methylamino-4(l W)-quinazolinones 154b via rearrangement of l,3-dimethylquinazolinone-3-imines 153b (78JOC 3427). 

Benzo[b]thiophenium, 1,2,3,5-tetramethyl-theoretical methods, 4, 3 Benzo[b]thiophenium salts preparation, 4, 723-724 Ben2o[b]thiophen-4-one, 4,5,6,7-tetrahydro-synthesis, 4, 905-906 5H-Benzo[b]thiophen-4-one, 6,7-dihydro-synthesis, 4, 900 Benzo[b]thiophyne, 4, 750 1H- 1,3,4-Benzotriazepine, 2,3-dihydro-synthesis, 7, 637 1H-1,2,4-Benzotriazepines synthesis, 7, 638 1,2,5-Benzotriazepines synthesis, 7, 640... 

Diazotization of diethyl [(2-aminobenzoyl)[alkyl(or aryl)]amino]malonates 6 gives the cyclized products 7, which on treatment with sodium hydroxide in the cold undergo hydrolysis and partial decarboxylation to the acids 8. The latter afford l//-1.2,4-benzotriazepin-5(47/)-ones 9 when heated in xylene.347... 

Phenyl-l//-l,3,4-benzotriazepin-2(3//)-one (5a) Typical Procedure (Method A) 352 2-Aminobenzophcnonc scmicarbazone (1.27 g, 5 mmol) was heated at 190-197 C for 1 h. The melt was cooled and treated with EtOH (50 mL) and the filtered solution was evaporated. The residue was washed with CH2C12 (30 mL) and recrystallized (EtOH) to give the product yield 0.24g (20%) pale-yellow... 

Alkylamino)- or 2-(arylamino)-3//-l, 3,4-benzotriazepin-5(4//)-ones 15 are obtained from 2-aminobenzoic acid hydrazide. Treatment with isothiocyanates yields the thiosemicarbazides 14, which readily cyclize under the influence of dieyclohexylcarbodiimide. Selected examples are given.357... 

Alkylamino)- and 2-(Arylamino)-3f/-l,3,4-benzotriazepin-5(4//)-ones 15 General Procedure 357... 

Diazotization of the amines 1, obtained by catalytic hydrogenation of the corresponding nitro compounds, gives the esters 2 directly. Alkaline hydrolysis of the latter yields the acids 3, which can be decarboxylated to l//-l,2,5-benzotriazepin-4(5/7)-ones 4. Yields were not reported.372... 

Catalytic hydrogenation of 5-methyl-l//-l,2,5-benzotriazepin-4(5//)-one results in ring fission to the intermediate 1, which reacts further to yield a mixture of the quinoxazolinone 2 and compound 3.372... 

Dihydro-l/7-imidazo[l,2-a] l,3,5 benzotriazepin-5(67/)-ones 6a-d and the Analogous -benzotriazepine-5(6//)-thiones 6e-j General Procedure 378... 

The single crystal X-ray structures of three new 1,2-dihydro-3//-l, 3,4-benzotriazepines has been reported <06CHE907>. A compact synthesis of dihydro-1,2,4-benzotriazepin-5-ones has also been described <06M1349>. 

Phthalimide 325 when refluxed with triethylphosphite yields iminophosphorane that further transforms into 5H-isoindolo[l,2- 7][l,3,4]benzotriazepin-5-one 326... 

Pyrrolo[l,2-(7][l,2,5]benzotriazepin-ll-one 329 is the product of a sequence starting from N-(2-nitrophenyl)-lH-pyrrol-l-amine 327. The pathway included alkylation, reduction of the nitro group, formation of the isocyanate from intermediate 328 and intramolecular thermal cyclization (Scheme 69 (2000JHCl539)). 

Ring contraction of the triazepine ring of 6-ary 1-6,7-dihydroquinolino-[3,2-d 1,3,4-benzotriazepin-9(5//)-ones (616) was affected with lead tetraacetate to give quinazolino[3,2-c]l,2,3-benzotriazin-8-one (615) [871J C(B)983]. 

Condensative cyclization of 3-amino-3-(2-aminophenyl)quinazolin-4-one (696) with aromatic aldehydes gave 6-aryl-6,7-dihydroquinazolino [3,2-d] 1,3,4-benzotriazepin-9(5/0-ones (616) [87IJC(B)983]. 

H-4,5-Dihydro-1,2,5-benzotriazepin-4-ones (516 R =C02Et or CN) can be prepared by cyclization of the diazonium salts (515). 

The stereochemistry and conformational behavior of a series of 20 2-methyl-2-alkyl(aryl)-4-fV-methyl-1,2,3,4-tetra-hydro-57/-l,3,4-benzotriazepin-5-ones 19-38 and their open-chain hydrazone isomers 39-58 (Scheme 3) in various solvents were studied by 1-D and 2-D NMR techniques in the temperature range from 193 to 410 K <1997JOC5080>. The authors wanted to establish the species present in solution and to study the effect of the different substituents in the ring/open-chain equilibrium. 

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