Synthesis of 2-Alkoxy-1,3,4-thiadiazoles.

Åkerblom, Eva; Skagius, Kurt; Hoeven, Marcel G. van der; Ryhage, Ragnar; Stevens, Roger

doi:10.3891/acta.chem.scand.18-0174

Cited by 8 publications

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“…Thus, the reaction of substituted thiosemicarbazides 563 with aldehydes yields the corresponding thiosemicarbazones 564, which by oxidative cyclization, achieved with iron(III) chloride or K 3 Fe(CN) 6 , lead to substituted 1,3,4-thiadiazoles 565 in good yields (Scheme 14.153) [289]. 2-Alkoxy-2-amino-1,3,4-thiadiazoles 567 have been prepared, in good yields, by oxidation of the corresponding O-alkyl 2-carbamothioylhydrazinecarbothioate 566 with hydrogen peroxide (Scheme 14.154) [290].…”

Section: Thermodynamic Aspectsmentioning

confidence: 99%

Thiadiazoles

Chiacchio

Romeo

2011

Modern Heterocyclic Chemistry

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Section: Thermodynamic Aspectsmentioning

confidence: 99%

Thiadiazoles

Chiacchio

Romeo

2011

Modern Heterocyclic Chemistry

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Synthese von heterocyclen. V. 1, 3, 4‐thiadiazol‐2 (3 H)‐one

Kristinsson

Winkler

1982

Helvetica Chimica Acta

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A new and highly versatile method for the synthesis of 1,3,4-thiadiazol-2 (3 H)ones 1 is described. Methoxy-l,3,4-thiadiazoles 5, which are readily available by condensation of 0-methyl thiocarbazate (2) with acid derivatives 3, undergo an efficient cleavage to 1 and methyl chloride with hydrochloric acid in an anhydrous medium. Many new 5-substituted thiadiazolones, unavailable by earlier routes, were synthesized. Preparative as well as mechanistic aspects are discussed. With the aid of I3C-NMR. spectroscopy, the tautomerism of 1 was studied, and the tautomeric equilibria was shown to be dependent on the nature of the substituent in the 5-position. The thiadiazolones 1 exist predominantly in the 0x0 form. The percentage of the hydroxy form, however, increases with strongly electron withdrawing substituents in the 5-position. A good correlation with pK,-and 0-values was observed. ') *)3 )

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Cyclization of 1‐substituted‐3‐thiosemicarbazides to triazole derivatives under alkaline conditions

Altland

Graham

1978

Journal of Heterocyclic Chem

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Under both weakly and strongly alkaline conditions, 1‐alkyl‐2,5‐dithiobiureas (1‐alkyl‐thiocarbamoyl‐3‐thiosemicarbazides) form 4‐alkyl‐5‐amino‐1,2,4‐triazoline‐3‐thiones and 4‐alkyl‐1,2,4‐triazolidine‐3,5‐dithiones in varying proportions. 1‐Alkoxythiocarbonyl‐3‐thiosemicarbazides expel hydrogen sulfide under weakly basic conditions to form the corresponding 5‐alkoxy‐1,2,4‐triazoline‐3‐thiones. In a strongly alkaline environment, however, these alkoxy‐thiocarbonyl thiosemicarbazides eliminate alcohol to form the appropriate 1,2,4‐triazolidine‐3,5‐dithiones. 1‐Alkoxycarbonyl‐3‐thiosemicarbazides eliminate alcohol in both weakly and strongly basic media to give 5‐thiono‐1,2,4‐triazolidine‐3‐ones. Cyclization mechanisms of these thiosemicarbazides are postulated.

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Synthesis of 2-Alkoxy-1,3,4-thiadiazoles.

Cited by 8 publications

References 0 publications

Thiadiazoles

Thiadiazoles

Synthese von heterocyclen. V. 1, 3, 4‐thiadiazol‐2 (3 H)‐one

Cyclization of 1‐substituted‐3‐thiosemicarbazides to triazole derivatives under alkaline conditions

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