4-Phenyl-1,2,4-triazoline-3,5-dione

Chemical Properties

4-PHENYL-1,2,4-TRIAZOLINE-3,5-DIONE is Red Solid

Uses

4-Phenyl-1,2,4-triazoline-3,5-dione (PTAD) can be used as an efficient and selective reagent for the oxidation of thiols to disulfides.
It can also be used:

• As a dehydrogenating agent to synthesize annulated dihydropyridazines by inverse [4+2] cycloaddition reaction between cyclic alkenes and 1,2,4,5-tetrazines.
• As a dienophile to synthesize cycloaddition products by fast hetero-DielsAlder reactions.
• As an efficient oxidizing agent for the synthesis of pyridine derivatives from 1,4-dihydropyridines.
• In the synthesis of urazoles via [3+2] cycloaddition with allylsilanes.

Uses

4-PHENYL-1,2,4-TRIAZOLINE-3,5-DIONE is used in the methods for determining levels of 1,25 dihydroxyvitamin d2 and d3 in biological and food samples and dietary supplements.

Uses

4-Phenyl-1,2,4-triazoline-3,5-dione may be used as a derivatizing reagent for the determination of trace levels of 25-hydroxyvitamin D and its C-3 epimer in biological samples and cholecalciferol (vitamin D₃) in fortified infant formula, milk and milk powder using liquid chromatography–tandem mass spectrometry (LC–MS/MS)technique.

Synthesis Reference(s)

Synthetic Communications, 17, p. 409, 1987 DOI: 10.1080/00397918708063918

General Description

4-Phenyl-1,2,4-triazoline-3,5-dione, also known as Cookson reagent, is a strong dienophile, which gives a stable Diels-Alder adduct quantitatively within a short time and under mild conditions. It is commonly used as a protecting group of the diene moiety for the synthesis of vitamin D₃ (VD₃)-related compounds.

Purification Methods

PTAD forms carmine red needles by sublimation (ice cold finger) at 100o/0.1mm, and/or by recrystallisation from EtOH. IR: 1760 and 1780 cm-1 . [Cookson et al. Org Synth 51 121 1971, Moore max et al. J Org Chem 39 3700 1974, Beilstein 26 I 57, 26 III/IV 540.]