7- -3- 2-methyl-1,3,4-thiadiazol

In the presence of an acetylene, thiophene is produced. The addition occurs across the C-S bond of the thiirene, producing 2,3-substituted thiophenes. Photolysis of 4-methyl or 5-methyl thiadiazole yields only one thiophene, methylated in the 5-position, indicating a preferential addition on the unsubstituted side of the thiirene ring ... 

C2N2S s N N — — 5-Acylamino-3-methyl-l,2,3-thiadiazole 5-phenyl-l,2,3-thiadiazole 3-oxide... 

Value for 5-acetyl-3-methylsydnonimine (800MR(I3)274>. Value for 2-amino-5-methyl-l,3,4-thiadiazole 78H(ii)i2i>. 

For both azole and benzazole rings the introduction of further heteroatoms into the ring affects the ease of quaternization. In series with the same number and orientation of heteroatoms, rate constants increase in the order X = 0requires stronger reagents and conditions methyl fluorosulfonate is sometimes used (78AHC(22)71). The 1-or 2-substituted 1,2,3-triazoles are difficult to alkylate, but methyl fluorosulfonate succeeds (7IACS2087). 

Amino-l,2,5-thiadiazole is chlorinated or brominated at the 4-position at 20°C in acetic acid. 3-Methyl-l,2,5-thiadiazole can also be chlorinated in the 4-position (68AHC(9)107). Bromination of 2-amino-l,3,4-thiadiazole succeeds in the 5-position (65ACS2434). 

Pyrazblin-5-one, 3-alkyl-(l,2,4-thiadiazol-5-yl)-reactions, 6, 483 2-Pyrazolin-5-one, 3-amino-tautomerism, 5, 215 2-Pyrazolin-5-one, 4,4-diazido-rearrangement, 5, 720 2-Pyrazolin-5-one, 3-hydroxy-tautomerism, 5, 215 2-Pyrazolin-5-one, 3-methyl-1 -phenyl-reactions, 5, 252... 

Pyridinium iodide, 4,4 (l,3,4-thiadiazole-2,5-diyl)-bis(l-methyl)-reduction, 6, 564 Pyridinium ion, Af-methyl-as metabolite of pyridine, 1, 234 Pyridinium ions hydrogen bonding to water mass spectrometry, 2, 135 magnetic circular dichroism, 2, 129 NMR, 2, 121... 

Thiadiazole, 2-amino-5-methyl-melting point, 6, 555 sulfonamide derivatives... 

Thiadiazole, 2-methyl-5-pheny 1-reactions with butyllithium, 6, 563... 

Several thiadiazolo-triazoles 43 have been synthesized that show antifungal and cytotoxic properties. hiadiazoles 45 were prepared from hydrazones 44 by treating them neat with thionyl chloride at room temperatures. The thiadiazoles were formed regio-selectively on the methyl group of the hydrazone. 

The structure of only one 1,2,4-thiadiazole salt has been determined. Unambiguous synthesis of the imino compound obtained on alkali treatment of the salt formed by the reactions of methyl iodide with 5-amino-1,2,4-thiadiazole established that the salt possesses structure 7 136 pjjjg quatemization exactly parallels the reaction occurring in... 

Ethyl iodide and 5-amino-2-methyl-l,3,4-thiadiazole react at 110° to give the N-3 salt (78 R = Me, R = NH2, R" = Et), as shown by the presence of the very reactive methyl group this salt is also used to prepare cyanine dyes. The slow quatemization at the ring-nitrogen atom furthest from the amino group is consistent with the reactions observed in other ring systems. As would be e pected, 5-alkylthio-2-methyl-l,3,4-thiadiazoles form salts at the N-3 (78 R = Me, R - S-alkyl).i ... 

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