3H-1,2-Diazepines

Toluenesulfonyl-3,4-dihydro-l,2-diazepines (24 R = Ts) react with alkoxides under aprotic conditions at ca. 100 °C to provide a synthesis of 3H- 1,2-diazepines (25). 

Electrocyclization of dienyldiazoalkanes, e.g. (129), provides a general route to 3H-1,2-diazepines, e.g. (131). In the example shown the eight-ir-electron cyclization is followed by a 1,5-sigmatropic hydrogen shift in (130) (83CC1003). Such hydrogen shifts are rapid at room temperature and the isomer ratio reflects thermodynamic stability. 

As with many other unsaturated seven-membered heterocyclic systems 1,2-diazepines form organometallic complexes of various types. The stable tricarbonyliron complexes of H- 1,2-diazepines, e.g. (79), have been much studied and found useful in synthesis (81ACR348), and it has been recently shown that 3H- 1,2-diazepines (5) and analogous benzodiazepines form complexes of a quite different type (105) involving the azo group only (81TL353). 

H-1,2-Diazepine gehen thermisch Ringkontraktion zu 4-(l-Alkenyl)-lH-pyrazolen ein1295,1296 jn 3 7-Position ungleich substituierte 3H-1,2-Diazepinc liefern Isomeren-Gemi-... 

H-1,2-Diazepines. /3-Alkyl-a, 7,6-unsaturated ketones (1) react with tosylhydrazine to form 3,4-dihydro-2-tosyl-l,2-diazepines (2) rather than tosyl-hydrazones. The products eliminate p-toluenesulfinic acid when treated with base to form 3H-l,2-diazepines (3). Formation of (2) has been observed only... 

Diaza-Dewar benzene, 56 3H-1,2-Diazepines, 599 Diaziridines, 253 a-Diazoacetophenone, 577 Diazoalkanes, 514, 577... 

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