4H-l,2-Diazepin-4-ones

A soln. of 2-acetyl-5-methyl-6-phenyl-2,3-dihydro-4H-l,2-diazepin-4-one in methanol exposed 3 hrs. to sunlight in a Pyrex flask -> 2-acetyl-5-methyl-6-phenyl-l,2-diazabicyclo[3.2.0]-6-hepten-4-one. Y 88%. F. e. s. J.-L. Derocque,W. J. Theuer, and J. A. Moore, J. Org. Chem. 33, 4381 (1968). 

Dihydro-4H-l,2-diazepin-4-ones from 3-diazoacety 1-/4 -pyrazolines... 

Ring contraction. 5,6-Dihydro-4-oximino-3,7-diphenyl-4H-l,2-diazepine refluxed 2.5 hrs. with aq. 10%-NaOH 2,3-diphenylcyclopent-2-en-l-one oxime. Y 70%. N. A. Evans, R.B. Johns, and K.R. Markham, Australian J. Ghem. 20, 713 (1967). 

Dihydro-4H-benzo[/]pyrrolo[l,2-fl][l,4]diazepin-4-one 220 is a product of reductive cyclizations of ester nitrile 219a (R = COOMe, = CN), while amido... 

Cl3H12CIN3O2S, 7-Chloro-l,3,5-trimethyl-5H-pyrimido[5,4-b] 1,4)ben-zothiazine-2,4(1H,3H)-dione, 38B, 398 Cl3H12N2O2S, 5,6-Dihydro-6-(2-oxo-propyl)-4H-pyrrolo[1,2-a]thieno-[3,2-f][1,4-diazepine]-4-one, 45B, 380 Cl3H14N2O2S, 2-Amino-4,5-dihydro-7,8-dimethoxynaphtho[1,2-d]thia-zole, 43B, 483... 

A range of multicomponent processes have been reported including an acid-free Ugi reaction for the synthesis of 5H-benzo[e][l,4]diazepines (14SL1680), an interesting post-Ugi copper-catalyzed intramolecular UUmaim coupling approach for the synthesis of 4H-benzo[/]imidazo[l,4]diazepin-6-ones (14TL2070) and a reaction between aromatic 1,2-diamines, Meldrum s acid, an isocyanide, and an arylidene malononitrile for the preparation of l,2,4,5-tetrahydro-2,4-dioxobenzo[l)][l,4]diazepines (14T9512). 

---