1H-1,2-Diazepines

H-1,2-Diazepine, 1 -acyl-3,5,7-triaryl-synthesis, 7, 602 If/-1,2-Diazepine, 2,3-dihydro-cycloaddition reactions, 7, 604 If/-1,2-Diazepine, 4,5-dihydro-synthesis, 7, 599 4//-1,2-Diazepine, 5,6-dihydro-synthesis, 7, 597, 598... 

An ethyl 1H-1,2-diazepine-l -carboxylate (2-5 mmol) in xylene or mesitylene (30- 50 mL) was healed under reflux for a specified time. The resulting solution was evaporated under reduced pressure and the residue was chromatographed (Sephadex LH-20, hcxane/CHCl3 1 4). 

Decomplexation of 152 (R = CH2Ph) affords the labile 153 (R = CH2Ph) which is the first example of a simple Af-alky 1-1H-1,2-diazepine. 

Treatment of 1H- 1,2-diazepines, e.g. (95), with alkoxide bases results in ring opening to give (96) via primary abstraction of the proton at C-3 the product may then undergo cyclization to a 2-aminopyridine (97) (81ACR348). 

The first fully unsaturated monocyclic 1,3-diazepines (61) have been prepared only recently. In the thermolysis of 1H- 1,2-diazepines it has been found that cleavage of the N—N bond in (58) is favoured by electron release from groups in the 4- and 6-positions so that 1,3-diazepines (61) are then formed rather than pyridinium iV-imides (59) (79JOC2683, 80CC444). It has also been shown (81H(16)137> that 1,3-diazepines are produced by the thermolysis of 1,2-diazepine photoproducts of type (54). 

The X-ray crystal structure of the 1 -tosyl-1H-1,2-diazepine (10) shows a boat conformation with N(l) at the prow (Figure 1) (72T581). Double bonds are clearly localized at N(2)—C(3) 1.255 A, C(4)—C(5) 1.326 A, and C(6)—C(7) 1.333 A, and the imine bond is isolated, whereas bond delocalization is present in the butadiene-like part C(4)—C(5)—C(6)—C(7). In contrast, when the diazepine is complexed with Fe(CO)3, for example (11), the iron atom is bound to the butadiene moiety C(4) to C(7), as also occurs in the lf/-azepine and l-methoxycarbonyl-l//-azepine complexes the N(l) atom adopts a planar sp2 configuration and the seven-membered ring consists of the two planar parts bent along the C(4)... C(7) line by 140° (70AG(E)958). 

Typical imine reactivity is also displayed in 1H- 1,2-diazepines which react with phthaloyl acetyl chloride in the presence of triethylamine to give a /3-lactam fused system (76H(5)47l). 1H- 2,3-Dihydro- 1,2-benzodiazepines, obtained by the lithium aluminum hydride... 

H-1,2-Diazepin 1 -Acetyl-3-methyl-E9d, 339 (Py-l-acetylimin/hv) Essigsaure -(4-amino-anilid) E18, 659 (N02 NH2)... 

Divinyl- X/3, 862 Carbamidsaure N-(l-Amino-2-phenyl-ethyliden)- -methylester E4, 225 (Cl-COOR + Amidin) Decandisaure 2,9-Dioxo- -dinitril E5, 1470 [I-OC-(CH2)6-CO-I + H3C-CN] 1H-1,2-Diazepin l-(2-Ethoxycarbo-nyl-ethenyl)- E9d, 342 (Dekom-plex.)... 

Diethyl-3,5-dioxo- EI7f, 659 (cycl. En-amin -f In) 1H-1,2-Diazepin... 

Benzol 1,4-Bis-[2-amino-ethy]]-2-nitro- (Dihydrosulfat) X/l, 552 1H-1,2-Diazepin 5-Dimethylamino-... 

Diazen (a-Hydroperoxy-benzyl)-phenyl- X/3, 474 1H-1,2-Diazepin l-Benzoyl-3-methoxy- E9d, 339 (Py — 1 -aroylimin/hv) 1H-1,4-Dlazepin l-Benzoyl-5-methoxy- E9d, 387 f. (NH - N-CO-Ar)... 

Bernsteinsaure -anilid-ethoxycarbo-nylamid E4, 232 (Umamidier.) Cyclohexan l-Nitro-l-(4-nitro-benzyl)- X/l, 162f. 1H-1,2-Diazepin 1-(1,2-Diethoxycar-bonyl-ethenyl)- E9d, 342 (NH -v N-R)... 

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