R. I. Yakhimovich

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I. Yu. A. Azev, I. I. Mudretsova, E. L. Pidemskii, et al., Khim.-farm. Zh., No. i0, 12021205 (1985). 2. A.B. Koshokov, I. V. Iselinskii, and Yu. A. Arevkov, Zh. Org. Khim., 15, No. 6, 1331 (1980). 3. Methods in Experimental Chemotherapy [in Russian], G. N. Pershin (ed.), 2nd edn~ Moscow (1971). 4. J.R. Dudley, J. T. Thurston, F. C. Schaefer, et al., J. Am.(More)
The influence of various sources of ultraviolet radiation on the photoisomerization of provitamins D--ergosterol and 7-dehydrocholesterol--was studied under industry-like conditions. The yield of previtamins and, consequently, vitamins D was higher with the use of erythemic lamps with luminophore E-2 and luminophore E-3 than with the use of lamps PRK-2.
E a r l i e r we repor ted [1, 2] that such ini t ia tors of radical reac t ions as azoisobutyroni t r i le or benzoyl peroxide substant ia l ly acce l e ra t e the p roce s s of allyl b romina t ion of choles te ro l e s t e r s with 1 ,3 -d ib romo5,5-dimethylhydantoin in a solution of boiling ca rbon te t rachlor ide . Under these conditions the yield of(More)
The study of vitamin D esters commenced in 1927-1928 [18, 21], and up to the present, they remain of interest to many researchers [8, 13, 17]. There are many reasons for this interest. First of all, some of the investigate d vitamin D 2 and D~ esters have antirachitic activity [3, 7]. It has also been shown that part of the vitamin D 3 in the organism is(More)
It has now been established that most of the vitamin D ethers and esters are devoid of biological activity. Only those that are readily hydrolyzed in the organism are active. The latter include the acetate, ethyl carbonate, phosphate, butyrate, sulfate, and palmitate. Biologically active esters of vitamins D2 and D3 are attracting the attention of many(More)
The p r e l i m i n a r y divis ion of the modeled objects into act ive and inactive compounds, achieved with cons ide rab le saving in calcula t ion t ime , and thus enabling the r e s e a r c h e r to avoid u n n e c e s s a r y loss of t ime in the synthes is of compounds known to be inactive, shows that cyberne t ic model ing of s t r u c t u r e s and(More)
Vitamin D 3 (cholecalciferol) is p repa red by the photochemical convers ion of 7-dehydrocholes tero l (1) into the provi tamin and thermal i somer iza t ion of the la t te r . A complex mixture of photoderivatives of I and their oxidation products is fo rmed as a resu l t of these react ions . The isolat ion of crysta l l ine cholecalciferol or its complex(More)
It has been established that the fluorination of 3β-hydroxy-Δ5,7-steroids, unlike that of 3β-hydroxy-Δ5-steroids, does not lead to the formation of 3β-fluoro derivatives. The reaction products are 3α,5α-cyclo-Δ6,8(14) compounds. Consequently, to obtain the 3β-fluoro derivatives of provitamins D — 7-dehydrocholesterol and ergosterol — the 5,7-diene system(More)
During the dehydrobromination of this mixture of bromo derivatives, the benzoate of cholesta-5,7-dien-36-ol (IV) (D3 provitamin) is formed, as well as side products, the benzoate of cholesta-4,6-dien-36-ol (V) and cholesta-2,4,6-triene (VI) [3, 4], In several cases, other reaction products, i.e., the benzoates of cholesta-6~8(14)-dien-38-ol (VII) [5],(More)
In [1] we repor ted that cho l e s t a -5 ,7 -d i en -3P-o l benzoate (II) is fo rmed in suf f ic ien t lyhighyie ldwhen 7 -b romocho le s t -5 en -3 /~ -o l (!) is dehydrobromina ted with sodium bicarbonate in the p re sence of a catalyt ic amount of ~ -p ico l ine . This react ion is eas i ly c a r r i e d out under industrial conditions al~d is used in(More)