Vitamin dinitrobenzoate

Irradiated ergosterol was found not to be as antirachitic in the chick as in the rat, whereas the chick could be protected by direct kradiation. The provitamin in cholesterol was shown not to be ergosterol. Rygh (14) in 1935 found that 1 rat unit of cod Hver oil was 100 times more potent in chicks than 1 rat unit of vitamin D2. Brockmann (15) in 1936, prepared the pure crystalline 3,5-dinitrobenzoate derivative of vitamin D obtained from tuna Hver oil... 

The acid chloride is useful for the isolation of low-niellinit alcohols reaction in pyridine gives an ester of lower solubility and higher melting point. For example, vitamin D (m,p. 82-84°) from fish liver oil concentrates was isolated by esterification with 3,5-dinitrobenzoyl chloride, and purification by chromatography and crystallization as the 3J5-dinitrobenzoate, ra.p. 132°. ... 

The isolation of the biologically active metabolite of vitamin D3 in a pure state, and the determination of its structure as 25-hydroxycholecalciferol (401) has been rapidly followed by its synthesis via irradiation of 25-hydroxycholesta-5,7-dien-3j -ol by three independent groups. The first synthesis of pre-calciferola (405) has been achieved by reaction of the lithium derivative of the chloro-ketone (402) with the en-yne (403) to give (404) which was treated with bis(ethylenediamine)chromium(ii) and then partially reduced catalytically. The thermal isomerisation of (405) (as 3,5-dinitrobenzoate) to vitamin D3 represents the first non-photochemical synthesis. 

Vitamin D2 3,5-dinitrobenzoate Ergocalciferol, 3,5-dinitrobenzoate (8,9) (4712-11-2) Ethyl p-dimethylaminobenzoate Benzoic acid, p-(dimethylamino)-, ethyl ester (8) Benzoic acid, 4-(dimethylamino)-, ethyl ester (9) (10287-53-3) tert-Butyl methyl ether Ether, tert-butyl methyl (8) Propane, 2-methoxy-2-methyl-(9) (1634-04-4)... 

Early investigators showed that superficially purified cholesterol and activatable foods contained a provitamin, or precursor, which was converted into the vitamin on irradiation. Ultimately, two vitamin D precursors were identified. Provitamin D2 was found to be ergosterol (la). WiNDHAUS 194) and Askew (6) independently isolated pure crystalline vitamin D2 (2 a) via its 3,5-dinitrobenzoate from the complex and unstable irradiation products of ergosterol. Provitamin D3 was more difficult to identify, but it was found by Windhaus 195) to be 7-dehydro-cholesterol (lb). On irradiation crystalline vitamin D3 (2b) was obtained, which was identical with that isolated from tuna-liver oil by Brock-MANN 29). Vitamins D4 and D5 have been found in nature, each one differing from the other and the ones mentioned above in the constitution of the side chain. 

Vitamin Dg 3,5-dinitrobenzoate stirred 3 hrs. at room temp, in benzene with AI2O3 previously treated with aq. KOH vitamin Dg. Y 97%.—Other adsorbents like talc and G-black also give good results. F. e. s. Z. Ecsery, Magyar K m. Folydirat 66, 264 (1960). 

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