Diimide, formation

Aziridine hydrazides, e.g. (310), undergo an interesting fragmentation reaction which results in ring opening and diimide formation (68JA3592). 

It is important to exclude air in all hydrazone-type reductions involving olefins (otherwise, over-reduction occurs due to diimide formation) in the above example, as an added precaution cyclohexene was used as a solvent. 

MeNHNH2. This reagent was used to prevent diimide formation, which resulted in acetylene reduction." ... 

Further support for diimide formation in the N2ase system is provided by results on the interaction of a nitrogen complex of Re with Mo (110), A postulated Re==N=N—Mo is formed with a corresponding large decrease in N-N stretching frequency towards that characteristic of diimide. 

The mechanism of sulfo(IV)diimide formation (75) during the reaction of an aminosulfenyl chloride with trimethylsilyl azide can be depicted by nitrene interception and the subsequent elimination of chlorotrimethylsilane from the adduct. 

N,N - Bis(trimethylsilyl)sulfur(rV) diimide Me3SiN=S=NSiMc3 is an especially versatile source of the N=S=N functionality in the formation of both acyclic and cyclic S-N compounds. It is conveniently prepared by the reaction of NaN(SiMc3)2 and thionyl chloride (Eq. 2.5). 

The photolysis of 10.3a in pentane or the reaction of 10.3a with PPhs generate the corresponding sulfur diimide ArN=S=NAr (Ar = 2,4- Bu2-6-MeC6H2) as the major product, presumably via the intermediate formation of the thionitrosoarene." By contrast, thermolysis in arene solvents results in ring closure to give the 2,1-benzisothiazole 10.4 and the corresponding aniline."... 

The dimeric tellurium diimides can act as chelating or bridging ligands. In the cis,exo,exo conformation, the formation of A. TV -chclated complexes is... 

The reduction of dienes by diimide depends on the nature of the substitution of the diene. Several studies of relative reactivity have been carried out and they indicated that an increasing degree of alkyl substitution on the double bond results in decreasing reactivity82. In the case of allenes, the reduction of the less substituted allenic double bonds and the formation of the thermodynamically less stable cis olefin can be explained by the steric control of the approach of the diimide (equation 23)83. 

Alkyl-5-alkyliminothiatriazolines (50) decompose slowly around 40-60 "C and rapidly at 125°C with formation of sulfur, nitrogen, and carbodiimide (51) (Equation (4)). However, the carbo-diimides (51) formed react with undecomposed thiatriazoline (50), which in part explains the low yields of isolable carbodiimide. It has not been possible by trapping experiments to decide whether the decomposition involves an intermediate as addition of electron-rich alkenes or heterocumulenes induces immediate nitrogen evolution in a bimolecular reaction (see Section 4.19.5.2) <78JCS(P1)1440>. 

Davis and Goddard calculated that the heat of formation (298 K) of singlet H2NN is 90.1 kcal/mol. This value is only 14 kcal/mol below that of molecular nitrogen and two hydrogen atoms, and is 54 kcal/mol above A//f(298 K) for frani-diimide determined experimentally by Willis et al. The relative energies of 1,1- and frani-1,2-diazene have been calculated by several methods these studies have been reviewed by Parsons and Dykstra. It was found using the... 

The unsaturated four-membered P2N2 ring is also stabilised by the formation of diadducts with Lewis acids, which are surprisingly formed in the reaction of Ph2PCl with bis(trimethylsilyl)sulfur diimide with Gads or AICI3 [eqn... 

The redox reactions of hydrazine toward main-group and transition metal oxidants have been reviewed (73). Different stoichiometries have been found, with N2 appearing as the N-containing oxidized product, sometimes accompanied by the formation of NH3 and/or HN3. The mechanisms have been analyzed in terms of the one- or two-electron nature of the oxidants, and imply both outer-and inner-sphere routes, depending on the oxidant. The very reactive, key intermediate, diazene (diimide), N2H2, has been proposed in most of these reactions. 

The intercalation of polycyclic aromatic compounds into duplex DNA structures was used to develop nucleic acid-based electrochemical sensors.66 For example, the bis-ferrocene-tethered naphthalene diimide (16) was used as a redox-active intercalator to probe DNA hybridization.67 The thiolated probe was assembled on a Au electrode, and the formation of the duplex DNA with the complementary analyte nucleic acid was probed by the intercalation of (16) into the double-stranded nucleic acid structure and by following the voltammetric response of the ferrocene units (Fig. 12.17a). The method enabled the analysis of the target DNA with a sensitivity that corresponded to ca. 1 x 10-20mol. 

The favored formation of a nucleoside 3 -(alkyl phosphate) was observed on treating the diphenyl phosphate anhydride of uridine 2, 3 -cyclic phosphate with benzyl alcohol.273 In a somewhat related reaction, on treatment with dicyclohexylcarbodiimide in aqueous pyridine, adenosine 2 (3 )-phosphate gave, initially, the 2, 3 -cyclic phosphate, which, on further reaction with the diimide, gave a mixture of the N-phosphonourea nucleoside 44 and its 2 -isomer, in unequal amounts.269 This type of reaction does not seem to occur with... 

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