2- Anilino-1,2,4-triazolo pyrimidines

Diaminopyrimidines (22) were also cyclized with cyanogen bromide (90JHC851) or phenyl isothiocyanate (97PHA753) to give the corresponding 2-amino- or 2-anilino-l,2,4-triazolo[l,5-c]pyrimidines 30 and 31 respectively (Scheme 15). 

Heating 5-hydroxy-3-mercapto-7-phenyl-1,2,4-triazolo[4,3-a]pyrimidine (145) with aniline gave the 2-anilino-4-hydroxy-6-methylpyrimidine (144)... 

A derivative of a hitherto unknown nucleus was produced when 4-amino-5-aminomethyl-3-methyltriazole was refluxed with carbon disulfide and triethylamine in pyridine, which yielded 3-methyl-3,7-dihydro-l,2,3-triazolo-[4,5-d][l,3]thiazine-5-thione (98) (3 hr, 53%) the 3-benzyl analog was made similarly (63%) [80JCS(P1)2009]. Cyclization of 4-anilino-5-ethoxycarbonyltriazole with polyphosphoric acid produced 1 f/-triazolo-[4,5-h]quinol-4-one (99) [80EUP(A)2562]. Similarly, ring closure of 4-(2-pyridylamino)triazole-5-carboxylic acid (or its esters) gave l//-pyrido-[l,2-a]-l,2,3-triazolo[4,5-d]pyrimidin-4-one (100) (77GEP2757929). 4-Amino-5-formyl-3-methyltriazole and pentane-2,4-dione, set aside in 20% sulfuric acid, yielded 3,5-dimethyl-3//-l,2,3-triazolo [4,5-6] pyridin-6-yl... 

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