3//-l,3,4-Benzotriazepines

Ar-Arylbenzimidoyl)tetrazoles t, prepared from JV-arylbenzimidoyl chlorides and 5-(dimethylamino)- or 5-aryltetrazole, give 3//-l,3,4-benzotriazepines 4 on thermolysis. It has been proposed that the reaction proceeds by way of the dipolar compounds 2, which undergo [l,7]-antarafacial 871-electrocyclization to 3. The process is completed by a symmetry-allowed [1.5]-hydrogen shift. Selected examples are given.349-350... 

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... 

A -Alkyl-5-phenyl-3//-l,3,4-benzotriazepin-2-amines 26 General Procedure 365... 

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>. 

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

A mixture of 3-methyl-l //-l,3,4-benzotriazepine-2,5(3//,4//)-dione (20) and the acylated derivative 21 is obtained upon cyclization of the semicarbazide 19.362... 

The l,3,4-benzotriazepine-2-thiones 24 react with amines in the presence of lead(II) acetate by replacement of sulfur.363... 

A 7-chloro-5-phenyl-l//-l,3,4-benzotriazepine-2(3//)-thione24 (2.5 mmol) in dioxane (l 5 mL) was treated with powdered Pb(OAc)2 (1.63 g. 5 mmol) and an amine was passed for 30 min into the suspension. The mixture was left for a specified time. H,S was passed through the mixture and the precipitated lead sulfide was filtered off. The filtrate was evaporated in a stream of air to leave the product, which was recrystallized (cyclohexane). 

Diinethyl-2-(methylsulfanyl)-3fl-l,3,4-benzotriazepine Hydriodide (27a HI) Typical Procedure 366... 

Carboxymethylsulfanyl)-7-chloro-5-phenyl-3I/-l,3,4-benzotriazepine (27c) Typical Procedure 367... 

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

Benzimidazol 2-Amino-l-(ethoxy-methyl)- E14a/2, 191 (Cl -> N) lH-l,3,4-Benzotriazepin 3,4-Dime-thyl-5-oxo-2,3,4,5-tetrahydro-EI4a/3. 562 [(2-NH2-Ar)-CO-N(CH3)-NH-CH3 + CH20]... 

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