Diaziridines reduction

These reductions are not important for preparative purposes. The same can be said for reductions with LiAlH4, and with hydrogen over a catalyst, converting diaziridines to a mixture of amines including products of reductive amination of the former carbon atom of the diaziridine ring. 

Reductions of the N —N double bond yield diaziridines and were carried out for proof of structure, using for example sodium amalgam or catalytic hydrogenation. They are unimportant beyond that, because most diazirine syntheses start with diaziridines. 

Diaziridines are stable toward alkalies. Aciueous alkali attacks pentamethylenediaziridine on heating not more quickly than does pure water. Further investigation has not yet been undertaken. However, reductive fission and hydrolytic fission in acid media have been studied in detail. 

The amines which are formed by the iodide reduction [Eq. (41)] can be isolated and used in the proof of structure of the diaziridines. For example, ammonia and cyclohexylamine were obtained from 1-cyclohexyldiaziridine [Eq. (42)] cyclohexylamine and phenylurea were obtained from the acylated diaziridine 58 [Eq. (43)]. ... 

Lithium aluminum hydride only reacts with diaziridines if at least one of the N-atoms is unsubstituted. Here again an NN-fission occurs. However, the reduction can give products other than those formed from catalytic hydrogenation. Thus the reduction of compound 59 with lithium aluminum hydride gave as the main product n-propyl-cyclohexylamine with ammonia [Eq, (45)]. The reduction of 3,3-... 

The action of strong reducing agents on diazirines leads to basic products. Diaziridines can be detected as intermediates in the reaction. The reduction of 3,3-diethyldiazirine to 3,3-diethyldiaziridine [Eq. (61)1 serves as a proof of structure of the diazirines. 

Because the diaziridines can easily be further reduced, their isolation from the reduction of the diazirines is only possible in poor... 

The electrochemistry of diazirines and diaziridines was discussed in Part I.1 Di-tert-butyldiaziridone (178) can be reduced in aprotic media in an irreversible two-electron reduction.275 Whereas diaziridines require acidic conditions for the splitting of the N—N bond and are electrochemically inert toward reduction in alkaline solutions, 178 is reduced in aprotic media to di-tert-butylurea [Eq. (108)]. 

The iV-diaziridinyl anion 33 has been generated from diazirine 32 in a Fourier transform mass spectrometer by reduction of the diazirine (Scheme 6). The acidity of its conjugate acid and the electron affinity of its corresponding radical were measured and used to calculate the N-H bond strength in /r J-diaziridine (88 4kcalmoP ) <1999IJM179>. 

The syntheses of diazirines and diaziridines are closely related due to the relative ease of interconversion between the species by reduction/oxidation <1996GHEC-II(1A)347>. Consequently, diazirines and diaziridines are both commonly synthesized by the well-established methods of Schmitz <1961CB2166> (Scheme 18) and Graham <1965JA4396> (Scheme 19), and these are described in previous editions <1984CHEC(7)195, 19%CHEC-II(1A)347>. 

Diazirines are polarographically reducible in acid solution in a four-electron reduction to a g w7-diamine, which is hydrolyzed to a carbonyl compound, and in alkaline medium in a two-electron reaction [298] to a diaziridine. Diaziridines are reducible only in acid solution... 

The protonated diaziridine is more easily reducible than the diazirine, which has too weakly basic properties to be protonated in aqueous solution. In alkaline medium in which both are unprotonated, the diazirine is the more easily reducible. This explains why it has been difficult to obtain good yields of diaziridine by chemical and catalytic reduction of a diazirine if such a reduction is to result in a high yield of diaziridine, it must be performed in an alkaline medium. 

Prepared by lead tetraacetate oxidation of the corresponding diaziridine, bis(trifluoromethyl)diazirine (263) has also been made by hypochlorite oxidation of hexafluoroacetone aminal 262. Instead of by oxidation, ring formation in the case of difluorodiazirine (265) has been achieved by mild reduction of bis(difluor-... 

---