Enhanced reactivity of the methyl group of 2‐t‐butyl‐5‐methyl‐1,3,4,6,9b‐pentaazaphenalene allowed acetic anhydride‐catalyzed condensation reactions with several aromatic aldehydes, and base‐catalyzed alkylation reactions with several alkyl halides to take place, albeit in low yields. Of the many nucleophiles tried, only salts of carboxylic acids, in the presence of 18‐crown‐6, were able to displace bromine from 2‐(bromomethyl)‐5‐methyl‐1,3,4,6,9b‐pentaazaphenalene.

A much improved synthesis of the heretofore difficultly obtainable 2,6‐diaminopyrazine (4) was afforded by the low‐pressure catalytic hydrogenation (palladium on carbon) of 2,6‐diazido‐pyrazine (2); reaction of 2,6‐dichloropyrazine (1) and sodium azide gave 2 in 84% yield. The outcome of the reduction was found to be solvent dependent: 1,2‐dimethoxyethane containing aqueous ammonia gave 4 in 83% yield; 1,2‐dimethoxyethane alone gave 5‐aminotetrazolo[1,5‐a]‐pyrazine (3) in 26% yield. Additional alternative syntheses of 3 and 4 are described. A number of acyl and azo derivatives of 4 were prepared. Reactions of 2 with dimethyl acetylenedicarboxylate and ethyl acetate (base catalyzed) leading to vic‐triazole derivatives are also described.

Dimethyl‐pentaazaphenalen (I) kondensiert mit Benzaldehyd zu den Styrylderivaten (IIa) bzw. (IIb).

2,6‐Dichlor‐pyrazin (Ia) liefert das Diazid (Ib), das zum Diamin (Ic) hydriert werden kann.