Diazol-4-imines

3-Diazol-4-imines (Anhydro-4-amino-l,3-diazolium Hydroxides) (98) 

The meso-ionic l,3-diazol-4-imine (98, R1 = R2 = Ph, R3 = Me, R4 = H, R3 = COPh) has been prepared60 from the nitrile (99, R3 = Me) and benzoyl chloride followed by treatment with sodium hydrogen carbonate. This compound (98, R1 = R2 = Ph, R3 - Me, R4 == H, R3 = COPh) undergoes a 1,3-dipolar cycloaddition with dimethyl acetylene-dicarboxylate in boiling benzene during 10 minutes, yielding the pyrrole 

Amidines (101) and halogenoacetonitriles (XCH2CN) yield 4-amino-1,3-diazolium salts (102) directly.61 These salts (102) could not be transformed into the corresponding meso-ionic heterocycles (98) with base  

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Schiff bases are obtained from 2-aminoimidazothiadiazoles with aldehydes (77M665). Hydrazones and oxime ether formation of imidazothia-diazole-5-carbaldehydes and -5-ketoesters was reported (84FES585 95EUP662477). Reduction of 122 with Al/FIg yields the tautomeric imine 128 of the corresponding amine (83JHC1003). 

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