Sodium azide, reaction with imides

The reaction of S2C12 with gaseous ammonia in DMF at ca. -10 °C, followed by hydrolysis with cold dilute hydrochloric acid, is a standard preparation of these cyclic sulfur imides.199 The reaction of sodium azide with elemental sulfur in (Me2N)3PO is an excellent source of S7NH. The tetraimide 69 is prepared by reduction of S4N4 with methanolic SnCl2.2H20. 

The cyclic sulfur imides S NH and 1,3-, 1,4-, and l,5-S(j(NH)2 are obtained by acid hydrolysis of the deep blue intermediate formed from the reaction of SjClj with ammonia in polar solvents, e.g. DMF or by the reaction of sodium azide with elemental sulfur in HMPA The blue chromophore formed in both these reactions is S4N and it has therefore been suggested that this anion is involved in equilibria with cyclic sulfur-nitrogen anions which are the precursors of the imides... 

Reaction of dichorobenzaldoxazine with sodium azide followed by 1-propa-nethiol-triethylamine gave the tetrazine imide 367 as the major product. Its formation is thought to involve the reaction sequence shown which includes an unprecedented electrocyclization of the nitrile imine 366 as the final step (210). 

Another quinoxaline-yielding rearrangement, reported by Hanaineh-Abdelnour and coworkers, entailed treating imides 182 with sodium azide to produce quinoxalines 183 in moderate to good yields <99H2931, 99T11859>. The reaction presumably proceeds by a nitrene insertion to close the pyrazine ring. 

A step-wise procedure for the preparation of Al-sulfonylamidines via A-sulfonylimidates has also been reported [34]. Similar multi-component reaction using alcohols gives N-sulfonylimidates, which are converted to Al-sulfonylamidines by treatment with primary and secondary amines in the presence of catalytic amount of sodium cyanide (NaCN) [24a] (Scheme 3.19). This indirect process sometimes shows abetter yield than the above direct method for example, the one-pot reaction of phenylacetylene (R = Ph), p-toluenesulfonyl azide (R = Ts) and morpholine (2R = CH2CH2OCH2CH2) provides amidines in 19% yield, whereas product is obtained in 72% yield in the step-wise procedure via imidate (R = Me). 

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