1.2.4- Triazolid-3-ones

The esterification can also be carried out as a one-pot reaction without isolation of the azolide for example, an 80% yield of crocetin bis(/ -D-glucosyl ester) was obtained via the triazolide. 1953 Reactions of 8 -apo-/ -carotene-8 -oic acid with D-galactose or lactose were claimed to proceed also with a high degree of regioselectivity.11963... 

Among the 1,2,4-triazolides benzenesulfonyl-, p-toluenesulfonyl-, mesitylenesulfonyl-, triisopropylsulfonyl-, and p-nitrobenzenesulfonyltriazole (IV), the latter is the most reactive one (room temperature, 24 h, pyridine). 1151 341 1261 It was therefore also used for large-scale synthesis of fully protected di-, tri-, and hexadeoxyribonucleotides of defined sequence. 341 1161... 

Amidino-5-imino-l,2,4-triazolid-3-ones from carbodiimides... 

Phenyl isocyanate added to a soln. of the startg. azomethine imine in dry CCI4, and stored 3 days diethyl 3,3,4-triphenyl-1,2,4-triazolid-5-one-l,2-dicarboxy-late. Y 86%. F. e. s. G. F. Bettinetti and P. Grunanger, Tetrah. Let. 1965, 2553. 

C2-carbon of the acetylide forms the first covalent C-N bond, producing the geminal dicopper intermediate 21. Formation of the second C-N bond eliminates one Cu centre to generate the Cu-triazolide which is protonated to regenerate the catalyst. 

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