The Chemistry of Heterocyclic Betaines Derived from Even Alternant Hydrocarbon Dianions

The Chemistry of Heterocyclic Betaines Derived from Even Alternant Hydrocarbon Dianions 

Only one system of this type appears to be known. The stable yellow pyrazinium-2,6-diolates 482 (R = = SAr, R and R = Ar or Me) have 

5-disubstituted derivative (482 R = R = SPh, R = R = Ph) gives cycloadducts with maleic anhydride and formaldehyde.  

An alternative method of generating the betaines 482 in solution involves photolysis of the bicyclic aziridines 4gi,33i-333 irradiation in the presence 

Only one system of this type appears to be known. The stable yellow pyrazinium-2,6-diolates 482 (R = R = SAr, and R = Ar or Me) have been obtained by reaction of 2,6-dioxopiperazines (480) with arylsulfonyl chlorides in pyridine. 27-329 3 q.Unsubstituted derivatives (482 R = R = H) are not isolated, but the 1,4-diphenyl compound (482 R = R = H, 

In their chemical reactions these betaines 482 are clearly behaving like the mesomeric betaines described in Section III. 

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