1.1- Enediamines nitro-substituted

Except for the electrophilic reagents discussed above, the reaction of other electro deficient reagents has been tried with 1,1-enediamines. Nitro-substituted 1,1-enediamines ediamines 174 easily undergo reactions with phenylsulfenyl chloride and with the aryldiazo cation to yield products 189149,150 and 190137, respectively (equations 76 and 77). 

Although secondary 1,1-enediamines always undergo C-alkylation under neutral conditions, N-alkylation is effected with the aid of a strong base24. The nitro-substituted... 

In a patent138 a nitro-substituted cyclic enediamine was acylated by l-methyl-3-(phenoxycarbonyl)imidazolium chloride, prepared from the reaction of phenoxycarbonyl chloride and imidazole, to give product 168. Hydrolysis of 168 leads to the / -carbon atom acylated product 169. Unlike the alkylation which occurs only at the /7-carbon atom, acylation takes place both at the / -carbon and at the secondary nitrogen atom giving 168 (equation 63). 

Rajappa and coworkers20 used isothiocyanates as a probe to examine the enaminic reactivity of nitro-substituted enamines and enediamines. The results were usually consistent with predictions based on the chemical shift of the vinyl proton and on extended Huckel calculations. However, cyclic enediamine 7 was found to be unreactive toward aryl and alkyl isothiocyanates (see Section II.A). Very recently, the same reaction has been re-examined21 and it has been found that cyclic enediamine 7 indeed reacts easily with aryl isothiocyanate to give the addition products 176 in 54-65% yield (equation 68). 

On the other hand, oxidation of secondary 1,1-enediamines 176 with bromine results in the formation of isothioazole derivatives 179. The yields of the oxidation-cyclization reaction depend strongly on the substituent R2 (equation 71)21,143. It is noteworthy that oxidation of 177 under the same conditions does not furnish isothioazoles but, instead, benzothiazoles 180 are formed (equation 72)21. A similar product, 180, has been obtained in the case of the nitro-substituted enediamines of pyrrolidine143. The different outcomes of these reactions reveal that the reactivity of the secondary amino group of 1,1-... 

Diphenylcyclopropenone (194) reacts with nitro-substituted 1,1-enediamines 7 in the presence of K2C03 to give a fused heterocyclic compound 195155 (equation 80). 

The reaction of cyclic 1,1-enediamines 7 and 8 with azides appears interesting. Nitro-substituted 1,1-enediamines 7 reacted with benzenesulfonyl azide to give triazoles 225 in moderate yields. Other secondary 1,1-enediamines analogues gave similar products in comparable yields. The reaction has been postulated to proceed by a sequence of 1,3-cycloaddition to 223, a Dimroth rearrangement to 224 and deamination to 225 (Scheme 12)174. Junjappa and coworkers175 have reported that 1,1-enediamines... 

Catalytic reduction of nitro-substituted 1,1-enediamines 174 gives the aminomethyl amidines 238 in good yields. Apparently, reduction of the nitro group gives the triamine intermediates 237 which undergo a rapid prototropic shift to afford 238 (equation 97) . Attempts to reduce the benzoyl-substituted 1,1-enediamines 8 were unsuccessful . These results are not unexpected, since the double-bond character in 8 is reduced due to the strong conjugation effect. 

Imino esters derived from benzoyl, nitro and ester-substituted acetonitriles behave as ketene A O-acetals in yielding 1,1-enediamines when reacted with amines29,89,90. For example, cyclic 1,1-enediamines 8 have been prepared by the reaction of imidates 54 and diamines (equation 19)29. 

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