Notes- Formation of Girard-T Derivatives

The Girard reagents

“…A further separation was obtained by reacting each of the ketone fractions separately with Girard-T reagent and then hydrolyzing the hydrazones at decreasing pH, when the saturated ketones were first liberated (7). A later kinetic study (8), carried out by titrating the un-reacted Girard-T reagent iodometrically (9), has confirmed that a, /3-unsaturated ketones react more readily but that their hydrazones are hydrolyzed less rapidly.…”

Carbonyls in Oxidizing Fat. VI. The Girard T Reagent in the Isolation and Determination of Micro Amounts of N‐Aliphatic Aldehydes and 2‐Alkanones

“…Water remains, but the literature has generally implied that the reaction should be conducted under anhydrous conditions. However, Wheeler et al (1961) reported the successful use of water in kinetic studies of the Girard T reaction. Effect of water in the reaction mixture.…”

“…An adverse affect of heat in the as a substitute for glacial acetic acid. This Girard T reaction has also been commented modification has been used recently by on by Wheeler et al (1961). Where reac-several investigators (Gaddis et al, 1960, tion was reluctant, as in the 2-alkanones, Stanley et al, 1961).…”

The Girard Reagents.

“…The Girard-T reagent, m.p. 192°with decomposition, is very soluble in water, soluble in cold ethanol (1 part in 150), soluble in methanol, 2-propanol (201), glycerol and ethylene glycol, very soluble in acetic acid, but insoluble in nonhydroxylic organic solvents (70,172). It is very hygroscopic and develops a disagreeable odor on standing, but can be purified by washing the crystals with ethanol (130).…”

“…Quantitative Aspects of the Reaction A. Determination of the Reagents It has been shown recently that the Girard-T reagent can be titrated iodometrically under certain conditions (201). The reaction with iodine is slow in acid solution, but proceeds rapidly at pH 7-8, being complete and corresponding to the equation analogous to the determination of semicarbazide (10) (CH3)3N +CHsCONHNH2 + 2h + HsO -(CH3)3N+CH2C02H + N2 + 4HI…”