Oxadiazepines

Dichloropyridazine-4-carbonyl chloride (1) reacts with hydroxyguanidines 2, prepared in situ from tertiary cyanamides R R2NC = N and hydroxylamine (see Houben-Weyl, Vol. E4, p618ff), to give 3-substituted 7-chloropyridazino[4,3-/]-l,2,4-oxadiazepin-5(2/f)-ones 3.3 2... 

No fully unsaturated 1,2,6-oxadiazepines have been described. 

The pyrazine I reacts with singlet oxygen to yield the endoperoxide 2, which is converted into the 1,3,6-oxadiazepine 4 on treatment with triphenylphosphanc. It is thought that the reaction involves deoxygenation to the bicyclic oxirane 3 as the key intermediate.320... 

Dimethoxy-2- l- 2-(tetrahydropyran-2-yloxy)ethyl]vinyl -l,3,6-oxadiazepine (4) Single Procedure 320... 

Annulated 1,3,6-Oxadiazepines 3,1,5-Benzoxadiazepines Synthesis by Ring-Closure Reactions... 

The dibenzoxadiazepine 1 is converted into 5.6-dihydrodibenz[/>,/][l,4,5]oxadiazepine (3) by treatment with hydrazine in the presence of Raney nickel153 or with lithium aluminum hydride or with zinc and sodium hydroxide.325 The product reverts to the starting material by the action of mercury(II) oxide153 or on exposure to air.325... 

A facile route to l,3,4-oxadiazepin-2-ones has been developed by Komatsu et al. involving acid-catalysed cyclisation of carbazate derivatives derived from the reaction of N, A -di-tert-butyldiaziridinone and a-hydroxy ketones with BF3.Et20 catalysis <00H(52)541>. 

Cyclization of amidoxime O-ether 402 in the presence of NaH in MeCN leads to 1,2,4-oxadiazepine 403 (equation 175) . ... 

Hexahydro-3,6-dinitro-1,3,6-oxadiazepine or 3,6-Dinitro-1 -oxa-3,6-d iazacy cloheptane,... 

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