6-Benzyl-3-methyl-1,2,4-triazolo

Triazole ring cleavage of the 7-amino-5-benzyl-5-mercapto-l,2,4-triazolo-[l,5-c]pyrimidinium iodide 135 at the N3-N4 bond occurred upon treatment with potassium carbonate to give the 4-amino-2-benzylmercapto-l-methyl-... 

In the reaction of 4-benzyl-3-amino-1,2,4-triazole and 1-ethoxyethyli-denemalonate under the previous circumstances, 7-methyl-l,2,4-triazolo[l, 5-a]pyrimidin-7-one (1127) was prepared in 10% yield [67JCS(C)503]. 

A prototropic allylic rearrangement took place during the Dimroth rearrangement of 8-allyl-5-benzyl-7-methyl-l, 2,4-triazolo[4,3-c]pyrimidine... 

A one-pot synthesis of 3,5-disubstituted 7-hydroxy-3//-l,2,3-triazolo[4,5-d]pyrimidines (130) has been carried out by using benzyl azide, cyano-acetamide, ethyl or methyl esters of the appropriate carboxylic acid, and sodium ethoxide as catalyst. The reaction proceeds via a 5-amino-l-benzyltriazole-4-carboxamide intermediate (85JHC1607). 7-Amino-3H-l,2,3-triazolo[4,5-d]pyrimidines 133 (R2 = H) were prepared starting from benzyl azide, malononitrile, and an aliphatic or aromatic nitrile, or by reaction of 130 with phosphorus oxychloride followed by amination. Compound 132 was formed in most reactions from two molecules of the 5-amino-4-cyano-l-benzyltriazole intermediate by an intermolecular nucleophilic at-... 

Finally, 96 (and its 2-methyl analog), when heated in pyridine with carbon disulfide and triethylamine (bath at 115°C, 6 h), yielded 95% of 7- and 8-methyl-1,6-dihydro-8-azapurine-2-thione. Derivatives of a new ring system were produced instead of azapurines when the 3-methyl and 3-benzyl analogs of 96 were treated similarly, giving 3-alkyl-3,7-dihydro-3//-1,2,3-triazolo[4,5-[Pg.169]

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... 

The electron impact mass spectra of a number of the tricyclic 5-substi-tuted-9-methyl- l,2,4-triazolo[4,3-c]tetrazolo[l,5-a]pyrimidines 131 were reported (790MS227). Tricyclic intermediates were proposed to explain the mass spectral fragmentation of the 8-allyl-5-benzyl-7-methyl-l,2,4-triazolo[4,3-c]pyrimidine 132 (93KGS1545). 

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