1. A method is described for the differentiation and determination of as little as 0.2mug. of vitamins D(2) and D(3) by gas-liquid chromatography. 2. The vitamins are converted by treatment with antimony trichloride into isovitamins D(2) and D(3), which show single, separate peaks on gas-liquid chromatography, unlike the unmodified vitamins, which give twin peaks due to the formation of pyro an...

An efficient and simple one-pot approach for the synthesis of 3,4-dihydropyrimidin-2-(1H)-one derivatives using antimony trichloride (SbCl3) as a mild catalyst by means of three-component Biginelli reaction between β-keto esters, aldehyde derivatives and urea/thiourea under thermal and solvent-free conditions with excellent yields and short reaction times is reported. This m...

Retinal extracts have been prepared from dark-adapted mudsuckers by treatment of retinal tissue or of isolated outer segments of the visual cells with digitonin solution. The extracts were examined spectrophotometrically and found to absorb light maximally between the wave lengths of 488 and 510 mmicro, depending on the proportion of yellow impurities and light-sensitive pigment present. This p...

This paper deals with a new calorimetric reaction of vitamin A with glycerol 1,3-dichlorohydrin (which we henceforth will refer to as GDH) that appears to be suitable for the quantitative estimation of this vitamin. The estimation of vitamin A in vitro has been the subject of many reviews in recent years (l-6). The two widely used methods at present are the ultraviolet absorption at 325 to 328 ...

COLORIMETRIC determination of vitamin A has frequently been based upon the Carr-Price reaction, namely the production of a blue colour when vitamin A is added to a saturated solution of antimony trichloride in chloroform, which shows two absorption maxima at 606 m,u and at 572 m,u, respectively. This reaction has the following drawbacks: (1) the blue colour is not specific for vitamin A, being ...

The structures of 1,2,4-triazolium chloride (C2H4N3)Cl and its derivative with antimony trichloride (C2H4N3)2[SbCl5] ÿ (C2H4N3)Cl containing unsubstituted 1,2,4-triazolium cations were determined. (C2H4N3)Cl crystallizes in the monoclinic system, space group P21/n with the unit cell dimensions at 86 K: a = 9.425(2), b = 8.557(2), c = 11.158(2) Å, þ = 95.87(3); V = 895.2(3) Å3,Z= 8,dc = 1.566,dm...