Azoxyalkane

Das ebenfalls entstandene O-alkylierte Produkt zcrfallt unter Stickstoff-Verlust in den Dialkylether bzw. in Ethanol und 1- bzw. 2-Buten. Hierdurch sind die Ausbeuten der Reaktion beschrankl. Die gebildeten Azoxyalkane besitzen die trans-Konfiguration2. 

The reaction between alkyl halides and alkanediazotates (108) gives azoxyalkanes.960 R and R may be the same or different, but neither may be aryl or tertiary alkyl. The reaction is regioselective only the isomer shown is obtained. 

AtoxyaUumes The reaction of alkane diazotates (probably syn) with triethyl-oxoaium fluoroborate in CHjQz suspensions gives azoxyalkanes in 50-60% yield ... 

Alternatively, azoxyalkanes can be prepared by the reaction of alkane diazotates with alkyl halides (preferably iodides) in hexamethylphosphoric triamide. 

AZINES Polyphosphoric acid. AZIRIDINES Benzenesulfonyl azide. AZOALKANES r-Butyl h3rpochlorite. AZOXYALKANES Triethyloxonium flu-oroborate. 

DmckreyH. 1970. Production of colonic carcinomas by L2-dialkylhydrazines and azoxyalkanes. In Burdette WJ. ed. Carcinoma ofthe colon and antecedent epitlielium. Springfield, IL Charles C. Thomas, 267-279. 

Even a triphenylmethyl group distal to oxygen does not accelerate azoxyalkane thermolysis, as illustrated by 4, which decomposes with AG (290 °C) = 43.0 kcal/mol (ti/2 = 50 min.) When oxygen is placed proximal to the radical stabilizing substituent as in 5, homolysis of the benzhydryl to N bond is greatly facilitated. Now both radicals 6 and 7 benefit from resonance stabilization, reducing AG (150 °C) to 33.3 kcal/mol (ti/2 = 3.2 h). The same effect is... 

The greater thermal stability of azoxyalkanes than azoalkanes carries over to compounds that lose N2O or N2 by concerted pericyclic retrocycloaddition. Thus the activation energy for N O... 

In contrast to intermolecular radical attack on the azoxy group, the intramolecular case is well established. Thermolysis of 31 or 32 at 120 °C affords a mixture of azoxyalkanes 3 and 36,... 

While generation of aryl substituted a-azoxy radicals like 79 is not difficult, " almost nothing is known about their aliphatic counterparts. One reaction that presumably gives such a radical is P-scission of 60 but in this case we were unable to isolate any product attributable to 62. Although we have found no published ESR spectra of purely aliphatic hydrazonyl oxides, such radicals must exist because free radical bromination of azoxyalkanes (e g. 20) gives the expected substitution products. ... 

Exclusive N-alkylation of diazotates (97) with both Meerwein s reagent and alkyl iodides to give /ra 5-azoxyalkanes has been reported. 

A previously reported process has been generalized to provide a flexible and directed synthesis of azoxyalkanes (Scheme 130). The Z-E thermal isomerization of aliphatic azodioxy-compounds (dimeric nitroso-alkanes) has been shown to occur exclusively by a dissociation-recombination mechanism. 

Lythgoe and co-workers synthesized azoxymethane and other azoxyalkanes. The photolysis of azoxymethane led to a decomposition to give nitrogen, nitrous oxide, methane, and ethane (Scheme 47)."° Azoxy-t-butane stabilized by t-butyl groups, however, resulted in the formation of 1,3-di-t-butyloxadiaziridine upon UV irradiation at 10°C (Scheme 48). "... 

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