No abstract

No abstract

The very rapid deoxygenation of certain heterocyclic mono-and di-Noxides with excess of phosphorus trichloride in chloroform a t 25" is kinetically complex. The reactions are strongly inhibited by small amounts of hydrochloric acid, and the results are reproducible only when this is removed by the addition of another base (2,6-lutidine). In the presence of this base the deoxygenation of 4-nitropyridine l-oxide and phenazine 5-oxide are firstorder in phosphorus trichloride and second-order, with respect to time but not with respect to concentration, in N-oxide. The rate constants decrease rapidly with increasing initial concentration of N-oxide.The di-AT-oxides of quinoxaline and phenazine are deoxygenated stepwise, by way of the mono-oxides, but azoxybenzene and 3,4-benzocinnoline 5-oxide and 5,6-dioxide are inert to phosphorus trichloride under these conditions.

No abstract