Tosyl-triazoles

A related triazole synthesis utilizes phosphorous ylids, such as 264. The initially formed triazenes cyclize with elimination of triphenylphosphine oxide. The reaction proceeded sluggishly with phenyl azide, but good results have been obtained with acyl or sulphonyl azides. Tosyl azide and 264 yielded 98% of the 1-tosyl-triazole 265. The tosyl group could be removed by solvolysis in boiling ethanol... 

Treatment of tris(trimethylsilyl)phosphite with ethyl chloroformate followed by pyridine affords pyridinium ethoxycarbonylphosphonate which upon condensation with 2, 3 -0,0-isopropylideneuridine using tosyl triazole affords 2, 3 -0,0-isopropylidene 5 -(ethoxycarbonyl)phosphonate, which may be... 

A rhodium-catalyzed transannulation of tosyl-triazoles 9 with silyl or alkyl enol ethers 10 was developed that allows for the synthesis of substituted pyrroles 11 with regiocontrol.The addition ofTsOH promotes the final dehydration step to afford pyrroles with different functionality. The method can also be adjusted to allow for the synthesis of 3-pyrrolin-2-ones by using silyl ketene acetals as one of the coupling partners (14TL6455). 

In a related way, Rh(II)-imino carbenes (97), easily formed from alkynyl A -tosyl triazoles (98), have been suggested to cycloisomerize via a metathesis mechanism to Rh(II)-carbenoid intermediates (99) which are converted into the corresponding fused pyrroles (100), ° ... 

Abbreviations aapy, 2-acetamidopyridine Aik, alkyl AN, acetoniuile Ar, aryl Bu, butyl cod, 1,5-cyclooctadiene COE, cyclooctene COT, cyclooctatetraene Cp, cyclopentadienyl Cp , penta-methylcyclopentadienyl Cy, cyclohexyl DME, 1,2-dimethoxyethane DME, dimethylformamide DMSO, dimethyl sulfoxide dmpe, dimethylphosphinoethane dppe, diphenylphosphinoethane dppm, diphenylphosphinomethane dppp, diphenylphosphinopropane Et, ethyl Ec, feirocenyl ind, inda-zolyl Me, methyl Mes, mesitylene nb, norbomene orbicyclo[2.2.1]heptene nbd, 2,5-norbomadiene OTf, uiflate Ph, phenyl PPN, bis(triphenylphosphoranylidene)ammonium Pi , propyl py, pyridine pz, pyrazolate pz, substituted pyi azolate pz , 3,5-dimethylpyrazolate quin, quinolin-8-olate solv, solvent tfb, teti afluorobenzobaiTelene THE, tetrahydrofuran THT, tetrahydrothiophene tmeda, teti amethylethylenediamine Tol, tolyl Tp, HB(C3H3N2)3 Tp , HB(3,5-Me2C3HN2)3 Tp, substituted hydrotiis(pyrazol-l-yl)borate Ts, tosyl tz, 1,2,4-triazolate Vin, vinyl. 

When a solution of phenacyl halide 258 and excess tosyl hydrazide in methanol is heated to reflux, l-(tosylamido)-4-aryltriazole 261 is formed. The reaction proceeds presumably via dihydrazide derivative 259 that subsequently undergoes intramolecular cyclocondensation to triazoline 260. In the following step, the triazoline must be oxidized to the final triazole product 261. Mechanism of the oxidation is not quite clear, but the probable oxidant is the starting phenacyl halide, as a half of it is converted to the corresponding acetophenone tosylhydrazone that is isolated as the main side product of the reaction (Scheme 37) <2004H(63)1175>. 

Aminopyrazoles 257 substituted at the C-4 and C-5 positions react with a variety of imidate hydrochlorides giving iV-hydroxyamidines 258, that after tosylation and intramolecular cyclization afford the corresponding pyrazolo[ 1,5-4 )-[l,2,4]triazole derivatives 259 (Scheme 21) <1998CPB287, 1998CPB69>. 

Two general methods have been described for the synthesis of this new class of meso-ionic compounds (196). The most convenient method is by the treatment of 4-bromo-l,2,3-triazolium salts (197, X = Br) with sodium sulfide in dimethylformamide. Alternatively, N-methylation of the isomeric 4- or 5-alkylmercapto-1,2,3-triazoles 198 or 199 with methyl tosylate gave intermediate triazolium salts (197, X = SR, Y = Tos), which yielded meso-ionic l,2,3-triazole-4-thiones (196) by 5-dealkylation by heating with piperidine. 

Treatment of 1,3-dimethyl-1,2,3-triazolium tosylate (490) with sodium hydride in dimethylformamide gives the ylide (491). Oxidation of this ylide (491) using oxygen and cupric chloride catalyst gave the meso-ionic l,2,3-triazol-4-one 176, Ri = R = Me, R - H. ... 

A new and convenient method of preparing the meso-ionic 1,2,3-triazole-4-thiones (196) has been reported. This involves the direct thiation of 1,3-disubstituted 1,2,3-triazoIium tosylates (492) using sulfur and sodium hydride in dimethylformamide. ... 

Junjappa and co-workers (9) reported the cycloaddition of sodium azide to the polarized ketene-(5,5)-acetal 33 to give the tiiazole 35 they also reported an intermolecular cycloaddition of tosyl azide 37 with the enamine 36 to give an unstable triazoline intermediate 38. Ring opening 38 followed by a Dimroth rearrangement afforded the triazole 41 (Scheme 9.9). 

Acetylenic esters react with alkyl azides, aryl azides, carbo-alkoxy azides, and tosyl azide yielding triazoles in all cases studied.102-302-306 When dimethyl acetylenedicarboxylate (92) is the starting material, the 1-substituted 4,5-dicarbomethoxy-1,2,3-triazoles 93 are obtained. 

The oxidation of diazo compounds to triazoles may proceed via an iminodiazo compound in equilibrium with the triazole (Scheme 119)285 3" an iminodiazo compound is formed quantitatively in the reaction of tosyl azide with ethoxyethylene.400... 

When R1 = CN, a molecule of hydrogen cyanide is lost and the 5-amino-triazole is obtained.249 Spontaneous amine elimination also occurs when R2 is hydrogen and an aliphatic secondary amino group is present,214 which is similar to what is observed in the addition of tosyl azide to /3-enamino esters233 and nitriles.402 Thermal elimination of amine proceeds more... 

Anomalous products have been observed in several cases. Azide addition to malonodinitrile yields a triazole only when the reaction is conducted in aqueous sodium hydroxide solution,425,428 and the triazoles obtained (83 and 84) are determined by the structure of the azide (Scheme 134). The product from the action of phenylcarbamyl azide is not a triazole (Scheme 134).425 Methylmalononitrile and tosyl azide lead to fragmentation products of the triazole such as imidazolone.429... 

Azidotropolone and its methyl ether and tosylate react with active methylene compounds to yield tropolones and azulenes bearing the triazole ring as a substituent (Scheme 137).419... 

When active methylene compounds in basic medium react with tosyl azide, triazoles are never formed (Section IV,A,4), but the unstable triazoline intermediate undergoes a diazo transfer reaction in a Dimroth-type rearrangement.447 A typical example is the addition of tosyl azide to a 1,3-diketone... 

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