Windaus

Windaus in 1933 derived the skeletal stmcture of vitamin D2. He found the elemental formula to be The side chain was unequivocally... 

Perbenzoic acid gave a doubly unsaturated triol monobenzoate. Only two hydroxyl groups could be acetylated, and one was tertiary. The saturated triol reacted with lead tetracetate to give an a glycol. When reacted with chromic acid, it gave a hydroxy lactone. From these observations, Windaus and Gmndmann (11) described the correct stmcture for ergosterol (1). 

The observation that the uv spectmm of provitamin D changed with uv inradiation and also produced antirachitic activity led to the conclusion that vitamin D was derived from the provitamin. Windaus found the vitamin D2 formula to be isomeric with the provitamins. 

Windaus and Boch (13) isolated and characterized 7-dehydrocholesterol in 1937 from pig skin. They further showed that vitamin D could be generated from the provitamin by uv inradiation. 

Dehydrocholesterol has also been made from cholesterol by the Windaus procedure (Pig. 2) the 3,7-dibenzoate (16) is obtained (via (14) and (15) by oxidation and reduction), which undergoes thermal elimination to give the 7-dehydrocholesteryl benzoate (11) (42—44). However, the yields are substantially lower than those achieved by the brornination—dehydrobrornination method. 

A. Windaus and F. Bock, Z. Physiol Chem. Hoppe-Seglers 245, 168 (1937). 

A second benzene ring is indieated by the faet that eolehieine, eolehi-eeine and trimethyleolchicinic acid are aU oxidised by hot permanganate to 3 4 5-trimethoxyphthalie aeid. This represents ring A in the Windaus formula. 

The location of a methoxyl group at position 4 in ring A was proved indirectly by Windaus, whence it follows that the three vicinal methoxy groups in that ring must occupy positions 2-, 3- and 4-. The positions of all four methoxyl groups in colchicine were later clearly settled by Barton, Cook and Loudon (p. 653). 

For the synthesis of phenanthrene derivatives whieh may be regarded as an approaeh to eolehieine as formulated by Windaus, see Windaus and Eiehel, Sharp, and Grewe. ... 

A. Windaus (Gottingen) constitution of the sterols and their connection with the vitamins. 

Synthetic methods. / / -Dimethylglutaric acid (prepared from mesityl oxide) was converted into the di-silver salt, which, by an improvement of the method of Windaus and Klanhardt, was converted into / / -dimethyl-y-butyrolactone. The latter on treatment with constant-boiling hydrobromic and sulphuric acid gave y bromo /i/ dimethylbutyric acid which readily gave its ethyl ester. The pure fluoro ester was obtained from this by heating with silver fluoride, although the yield was low. 

Cholesterol C27H45OH, an unsaturated secondary alcohol, contains the same ring system as the bile acids and is closely related to them genetically. Pseudocholestane, indeed, which is a stereoisomer of the parent hydrocarbon of cholesterol, cholestane, can be oxidised to cholanic acid by chromic acid with elimination of acetone (Windaus). 

Ergosterol CjgH OH, a trebly unsaturated alcohol, is derived from the same ring system. It is produced in relatively large amounts by fungi, in particular by yeast, and on irradiation it is isomerised to the anti-rachitic vitamin, vitamin-D (Windaus). 

Adolf Windaus Germany sterols relationship with vitamins... 

This assumption of Pauly s was confirmed by Knoop and Windaus, who found that histidine is resistant to reduction by sodium and alcohol whereas the pyrimidine rii is very unstable towards this reagent. On reducing Frankel s oxydesaminohistidine, which is obtained from histidine by the action of nitrous acid, they obtained /8-imidazole-propionic acid. This compound was identical with the synthetical product prepared from glyoxylpropionic acid, ammonia and formaldehyde — ... 

Windaus and Vogt in 1908 showed that FrSnkel s chlorohistidine carboxylic acid was the hydrochloride of /3-imidazole-propionic acid. 

In connection with histidine, the work of Windaus and Knoop on the formation of methylimidazole from glucose must be mentioned on account of the possible synthesis in the animal body of both histidine and purine bases. 

F. Knoop und a. Windaus. Die Konsiitution des Histidins. Beitr. chem. Physiol. Path.,... 

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