3-Amino-5-mercapto-l, 2, 4, triazole

A mixture of K-3-benzoyldithiocarbazate, 2 moles 95%-hydrazine, and water refluxed 0.5-1 hr. with stirring 5-phenyl-4-amino-3-mercapto-4H-l,2,4-triazole. 

Klink, K.J. and Meade, B.J., Dermal exposure to 3-amino-5-mercapto-l,2,4-triazole (AMT) induces sensitization and airway hyperreactivity in BALB/c mice, Toxicol. Sci., 75, 89, 2003. 

Amino-5-mercapto-l,2,4-triazole [16691-43-3] M. 116.1, m 298 , pKeskd 3.0, pKEst(2) Recrystd from H2O and dried in vacuo. The acetyl derivative has m 325° (dec) after recrystn from H2O. [Beilstein 26, 3rd/4th SuppI p. 1351.] Also recrystd from EtOH/H20 (3 1, Ig in 50 mL, 50% recovery), m 300-302° dec subject to heating rate (Xmax 263nm, log e 4.12), and S-Benzyl derivative when crystd from CgHg/EtOH (20 1), or CHClj/EtaO has m 109-111° [Godfrey and Kruzer J Chem Soc 3437 7960]. 

Respiratory sensitization to chemicals may be acquired via dermal contact. I26l An example of this is the induction of airway sensitization in workers in a herbicide-producing plant that manufactured 3-amino-5-mercapto-l,2,4-triazole (AMT) by dermal contact. Experiments with mice confirmed the sensitization potential of AMT)27 ... 

Ahnlich reagiert 5(3)-(4-Amino-5-mercapto-4H-l,2,4-triazol-3-yl)-3(5)-mcthyl-lH-pyrazol mit Triethoxy-methan1975 ... 

An improved synthesis of 5-substituted 4-amino-3-mercapto-(4H)-1,2,4-triazoles (105) has been reported which involves the reaction of thiocarbohydrazide with carboxylic acids at the melting temperature. The crude triazoles (105) then provided easy access to the 3,6-disubstituted l,2,4-triazolo[3,4-b][l,3,4]thiadiazoles (106) by reaction with carboxylic acids or their acid chlorides <97JHC1255>. 

A modified electrode using a functionalized triazole polymer film may serve as electrochemical sensor for L-methionine [89]. There, a glassy carbon electrode is modified with an electropolymerized film of 3-amino-5-mercapto-l,2,4-triazole. The sensor works at physiological pH. L-Methionine is an essential amino acid which occurs in human blood plasma, serum, and urine. An abnormal concentration of L-Methionine may cause coronary artery disease. 

C2H5N5, 5-Amino-2-methyltetra20le, 20, 636 C2H5N5S, 3-Hydrazino-5-mercapto-l,2,4-triazole, 22, 758 C2H6N2, 3-Methyldiaziridine (gas-ed), 42B, 1028 C2H6N6S, 4-Amino-3-hydrazino-5-mercapto-1,2,4-triazole, 37B, 114 C2H7BrNe, 3,4,5-Triamino-1,2,4-triazole hydrobromide, 39B, 151 C2H9N4Na03S, Sodium 4-amino-5-mercapto-1,2,4-triazole trihydrate, 39B, 152... 

Sensitization of the respiratory tract may result from dermal contact with a sensitizing chemical [30-32], Several studies have made this association for chromate [33], latex [34], the herbicide 3-amino-5-mercapto-l,2,4-triazole [35], and trimelUtic anhydride, which is a respiratory sensitizer when inhaled [36, 37],... 

Coumarinyl-substituted thiazolo[3,2-h][l,2,4]triazoles have also been reported. They are available in one step by reaction of 5-aryl-3-mercapto[l,2, 4]triazoles with 3-bromoacetylcoumarin (ethanol, reflux, 8 h yield 44-65%) (81AP435) or in a two-step reaction from the corresponding S-alkylated intermediates with PPA [93MI2 94IJC(B)579]. 2-Aminothiazolo[3,2-h][l,2,4]triazoles are also available from 3-mercaptotriazoles. Treatment of 5-amino-3-mercaptotriazole with chloroacetone (DMF, K2CO3) and subsequent acid-catalyzed cyclization yields 146 [90JAP(K)02/142797]. 

Treatment of the 3-amino- or 3-mercapto-l,2,4-triazolo[4,3-c]pyrim-idines 80 with aqueous hydrochloric acid at reflux caused further fragmentation of the pyrimidine ring to give the 3-acetonyl-5-amino- or 5-mercapto-1,2,4-triazoles 81 in addition to the corresponding alkanoic acid (63JCS5642 65JCS3369) (Scheme 35). 

In the course of their work on meso-ionic five-membered heterocyclic systems, Grashey et ai described the production, by several routes, of 2-amino-1,3,4-thiadiazolium salts (115), and their ready conversion, by alkalis, into the meso-ionic l,2,4-triazole-3-thiones (116) (see also these Reports, Vol. 2, p. 746, ref. 105). It probably occurs by deprotonation of (115), attack by the nucleophile at position 5, followed by ring-cleavage and recyclization to (116). Transformations involving 2-mercapto-analogues... 

Two 4-amino-3-mercaptol,2,4-triazole residues linked by a two-carbon bridge have been prepared by the reaction of thiocarbohydrazide with succinic acid 157a or malic acid 157b to give l,2-bis-(4-amino-5-mercapto-477-l,2,4-triazol-3-yl)ethan-l-ol 158a or l,2-bis-(4-amino-5-mercapto-477-l,2,4-triazol-3-yl)ethane 158b in yields of 56% and 60%, respectively (Equation 49) <2006PS(181)2361>. 

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