Synthesis of (24R)-3β,5,14α-trihydroxy-5α-stigmast-7-en-6-one 3-benzoate

An ecdysteroid analog has been synthesized from -sitosterol.Institute of Bioorganic Chemistry, National Academy of Sciences of Belarus', 220141, Belarus', Minsk, ul. Akad. Kuprevich, 5/2. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 488–491, July–August, 1999.     

Synthesis of (22E,24R)-ergosta-4,7-22-triene-3,6-dione and its 14α-hydroxy- and 9α,14α-dihydroxy derivatives

^4,7-3,6-Diketosteroids have been synthesized from ergosterol (1).Institute of Bioorganic Chemistry, National Academy of Sciences of Belarus', 220141, Belarus', Minsk, Ul. Akad. Kuprevicha, 5/2. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 354–358, May–June, 1999.     

New synthesis of benzo[a]quinolizines by the [3+3]cyclocondensation of 1-ALKYL-3,4-dihydroisoquinolines with aminomethylenemalonates

The interaction of 1-alkyl-3,4-dihydroisoquinolines with dimethyl dimethylaminomethylenemalonate has been studied.Institute of Bioorganic Chemistry, Academy of Sciences of the Republic of Belarus', Minsk, fax (017) 263 72 74. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 432–433, May –June, 1997.     

Recent advances in the chemical synthesis of ecdysteroids and compounds related to them

This review generalizes information on methods of synthesizing ecdysteroids and substances structurally close to them published in the literature during the last decade.Institute of Bioorganic Chemistry, Belarus Academy of Sciences, 220141, Belarus', Minsk, ul. Zhodinskaya, 5/2. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 655–682, September–October, 1997.     

Solvolysis of sterol tosylates in aqueous dimethylformamide

It has been established that the heating of the sterol tosylates (1a–c) in aqueous dimethylformamide in the presence of sodium acetate leads to the formation of the 3a,5-cyclo-6-alcohols (2), the sterols (3), the 3,5-dienes (4), and the sterol formates (5).Institute of Bioorganic Chemistry, National Academy of Sciences of Belarus', 220141, Belarus', Minsk, Ul. Akad. Kuprevicha, 5/2. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 359–363, May–June, 1999.     

Synthesis of (24R)-3β-hydroxystigmast-5-en-7-one

The natural compound (24R)-3-hydroxystigmast-5-en-7-one has been synthesized from -sitosterol.Institute of Bioorganic Chemistry, National Academy of Sciences of Belarus', 220141, Belarus', Minsk. Ul. Akad. Kuprevicha, 5/2. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 484–487, July–August, 1999.     

The synthesis of labeled sterols

This review presents a discussion of methods for the chemical synthesis of sterols labeled with hydrogen and carbon isotopes.Institute of Bioorganic Chemistry, Belarus National Academy of Sciences, 220141 Belarus', Minsk, Ul. Akad. Kuprevicha, 5/2. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 413–441, July–August, 1999.     

Synthesis of 11-N-arylaminomethylene derivatives of 8-azasteroies. A new rection of cyclic Schiff's bases

Institute of Bioorganic Chemistry, Belarus' Academy of Science, Minsk, 220141. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 266–267, February, 1995. Original article submitted December 15, 1994.     

Reaction of 3β-chloro-5α,6α-epoxysteroids with trifluoroacetic acid

It has been established that on the interaction of the 5,6-epoxysteroids (1a–c) with trifluoroacetic acid in chloroform the 6-trifluoroacetates of the 5,6-diols (2a–c) are formed in high yield. The alkaline hydrolysis of the trifluoroacetates (2a–c) leads to the corresponding diols (3a–c).Institute of Bioorganic Chemistry, Belarus' National Academy of Sciences, 220141, Belarus', Minsk, ul. Akad. Kuprevicha, 5/2. Translated from Khimiya prirodnykh Soedinenii, No. 2, pp. 201–204, March–April, 1999.     

2-Acylcycloalkane-1,3-diones. Occurrence in nature,biological activity,biogenesis, chemical synthesis

This review systematizes information on 2-acylcyclohexane-1,3-diones and 2-acylcyclopentane-1,3-diones isolated from natural sources. Questions of their biological and chemical synthesis, their natural functions, and the biological activity that they exhibit are discussed.Institute of Bioorganic Chemistry, Academy of Science of the Republic of Belarus 220141, Belarus', Minsk, ul. Zhodinskaya, 5/2. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 635–663, September–October, 1995. Original article submitted December 29, 1994.     

Application of vibronic spectroscopy to conformational analysis. Investigations of molecules of carbonyl compounds

Application of vibronic spectroscopy to the conformational analysis of molecules in the ground and excited electronic states is reviewed. The basic concepts of the method as well as its methodological and technical aspects are discussed. The abilities of vibronic spectroscopy are exemplified by the results obtained for molecules of carbonyl compounds.The review is based on a report at the Vibrational Spectroscopy Conference dedicated to the 80th birthday of B. I. Stepanov (Minsk, Belarus', October 3–5, 1993).Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 783–791, May, 1994.This work was performed with the partial financial support of the Russian.Universities State Program.     

Salts of alkyl-substituted 3,4-dihydroiso-quinolines with 2-acetylcyclopentane-1,3-dione

Reactions of alkyl-substituted 3,4-dihydroisoquinolines, with 2-acetylcyclopentane-1,3-dione were used to prepare 3,4-dihydroisoquinolinium 2-acetylcyclopentane-1, 3-dionates, which could not be converted into ABCD-tetracyclic derivatives of the 8-azagonane series (benzo[a]cyclopentano[f]quinolizines). The salts obtained were studied and characterized by physicochemical methods. It was shown by combining the NMR and H/D-isotope exchange methods that for 1-alkyl-3,4-dihydroisoquinolines and their salts in solutions, an imine-enamine (iminium-enaminium), and for the 2-acetylcyclopentane-1,3-dione anion, a keto-enol tautomeric equilibrium takes place.Institute of Bioorganic Chemistry, National Academy of Sciences of Belarus', Minsk 220141. Chemical Engineering Institute, Russian Academy of Sciences, Perm'614000. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 681–690, May, 1998.     

Photochromism of 1′,3′,3′-trimethyl-6-piperidinospiro [indoline-2′,3-3H-naphth [2,1-b][1,4]-oxazine]

The effect of the piperidine substituent on the spectral and photochromic properties of spiro(indoline-naphthoxazines) (SINO) in different solvents is studied. The introduction of this substituent into the naphthoxazine fragment of SINO results in the appearance of fluorescence of the initial formA of SINO at low temperatures. This fluorescence gradually disappears as the temperature increases. The temperature and concentration dependences of the spectral parameters of photoinduced formB of SINO make it possible to assume thatB molecules aggregate in non-polar solvents. In all solvents studied, form B, unlike the photoinduced form of the non-substituted spiro naphthoxazine, is stabilized as a bipolar ion with a positive charge on the nitrogen atom of the piperidine substituent. The increase in the rate of thermal decolorization as the medium polarity increases is explained.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 684–688, April, 1995.The authors are grateful to the Belarus' Foundation for Basic Research for financial support of this work.     

Reaction of acetyltetramic acid witho-phenylenediamine

Acetyltetramic acid forms 3-[-(2-aminophenylamino)ethylidene]-2,4-pyrrolidinedione (Ia) witho-phenylenediamine. NMR spectroscopy showed that compound Ia in solutions of CDCl₃ and DMSO exists as an equilibrium mixture of two rotational isomers caused by hindered rotation around an exocyclic double bond. The analysis of the¹³C NMR spectra of compounds of type I and the results of quantum chemical calculations indicate preferred chelation of amide carbonyl and predominance of the corresponding rotamer. The reaction of a Ia with hydrochloric acid yields 10-methyl-1H-benzo[b]pyrrolo[3,4-f]-1,4-diazepin-1-one.Riga Technical University, Riga LV-1658; Latvian Institute of Organic Synthesis, Riga LV-1006; Institute of Bioorganic Chemistry, Academy of Sciences of Belarus' Minsk 220141. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp336–342, March, 1995. Original article submitted December 29, 1994.     

Synthesis of steroids containing a vicinal diol group in the side chain via isoxazoline intermediates

A sequence of conversions including 1,3-dipolar cycloaddition of nitrile oxides to steroid 22-enes and modification of the isoxazolines obtained by hydroxylation to the 4′ position and splitting of the heterocycle leads to steroids with a polyfunctional open chain, 22,23-dihydroxy 24-ketones. For preliminary report see [1]. Institute of Bioorganic Chemistry, Academy of Sciences of Belarus', Minsk 220141. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 542–548, April, 1997.     

Neutron activation analysis of asbestos from Canada

Concentrations of Al, Au, Br, Ce, Cl, Co, Cr, Fe, K, La, Mg, Mn, Na, Ni, Sb, Sc, Sm, Srm and V were determined in 6 samples of asbestos from Canada. They were equal to (in ppm): Al 1660–3430; Au 0.03–0.04; Br 3.1–11.7; Ce 1.7–4.8; Cl 116–331; Co 35–83; Cr 200–2060; Fe 29300–42200; K 125–867; La 0.28–1.03; Mg 24–25.9%; Mn 418–545; Na 364–1610; Sb 0.65–1.46; Sc 3.73–5.57; Sm 0.09–0.3; Sr 26.7–41.4; V 8.4–14.3. Five toxic elements were found in asbestos; Cr, Mn, Ni, Sb and V.     

Functionalization of 8-aza-D-homogona-1,3,5(10),13-tetraene-12,17a-diones at positions 11 and 17 under the conditions of the claisen ester condensation. Synthesis and properties of 11- and 17-acylsubstituted 8-aza-d-homogonanes

It was shown that 8-aza-D-homogona-1, 3, 5(10),13-tetraene-12,17a-diones enter into the Claisen ester condensation at the C(₍₁₁₎H₂ and C₁₇H₂ groups, whereas the C₍₁₅₎H₂ group is inert under the investigated conditions. It was established that the direction of the reaction is determined by the structure of the 8-azasteroid substrate. In the presence of a bulky gem-dimethyl group at position 16 the reaction takes place exclusively at the C₁₁H₂ group, while in the absence of this restriction the C₍₁₁₎H₂ and C₍₁₇₎H₂ groups are equivalent. The data from IR, UV, and¹H and¹³C NMR spectroscopy of the initial and synthesized derivatives of 3-aza-D-homogonanes are presented and discussed.Institute of Bioorganic Chemistry, Academy of Sciences of Belarus', Minsk. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 959–965, July, 1995. Original article submitted May 6, 1995.     

Multielement measurements in Mexican cigarette tobacco

The concentration of 21 elements in cigarette tobacco in nine different brands manufactured and commercially available in Mexico has been determined using neutron activation analysis. The concentration range of the measured elements (in g g^–1) were: As, (four brands) <0.55–3.24; Ba, 64–251; Br, (four brands) 49–136; Ce, <0.3–1.7; Co, 0.29–0.55; Cr, <0.8–2.4; Cs, 0.091–0.40; Eu, <0.03; Fe, 420–680; Hf, <0.03–0.13; K, (four brands) 18300–40300; La, (four brands) <0.2–0.66; Na, (four brands) 309–566; Rb, 19–50; Sb, <0.7; Sc, 0.13–0.22; Se, <0.7; Sm, (four brands) 0.07–0.14; Sr, 227–472; Th, <0.1–0.17 and Zn, 14–56. The results are compared with the literature values for the concentration of the above elements in cigarette tobacco from other countries.     

Synthesis,electrochemical and magnetic properties of new macrocyclic copper(II) complexes derived from 2,6-diacetyl-4-4-methylphenol

A series of binuclear macrocyclic copper(II) complexes [Cu2Lm,n](ClO4)2·xH2O have been prepared in which the two copper(II) ions are placed in two geometrically distinct co-ordination environments. The macrocycles with two 2,6-bis(iminomethyl)-4-methylphenol entities combined through two different lateral chains, –(–CH2–)–m and –(–CH2–)–n (m = 2 or 3, n = 2 to 5) were synthesized by stepwise cyclization. Cyclic voltammetry shows the presence of two reduction couples: CuIICuII CuICuII and CuIICuI CuICuI. The comproportionation constants, Kcom, for the mixed valence CuICuII complexes have been determined electrochemically. The Kcom value increases in the order of the macrocycles: (L2,2)^2–<(L2,3)^2–<(L2,4)^2–<(L2,5)^2– and (L3,3)^2–<(L3,4)^2–<(L3,5)^2–. Cryomagnetic investigations (80–300K) reveal a moderately strong antiferromagnetic spin exchange between the copper(II) ions within each complex (J = –210 to –390 cm–1).     

Radioisotope excited EDXRF analysis of sediment core samples from the southern part of the Black Sea +

In all 43 sediment samples were collected as gravity cores in depthfrom 70 to 150 cm, from the 20 sampling sites of the continental slope ofthe southern part of the Black Sea, during 1978. The samples were quantitativelyanalyzed by radioisotope excited energy dispersive X-ray fluorescence spectrometry(EDXRF) using fundamental parameter technique (FTP). The investigated sedimentsamples were the organic rich-mud components of the core samples, which wereknown as rich in metals. The metal concentration ranges were as follows: Ca(3.1–12.9%), Ti (1000–2000 µg/g), V (40–150 µg/g),Cr (30–200 µg/g), Mn (200–1500 µg/g), Ni (25–100µg/g), Cu (20–70 µg/g), Zn (20–50 µg/g), Br(15–670 µg/g), Rb (5–90 µg/g), Sr (80–700 µg/g),Y (10–20 µg/g), Mo (10–111 µg/g), Zr (20–190µg/g), Cd ( <1–5 µg/g), Sb ( <1–5 µg/g),I (10–430 µg/g), Ba (100–1650 µg/g), La (5–18µg/g), Ce (12–38 µg/g) and Nd (6–17 µg/g). Thesediment cores systematically collected in 1978 by Mineral Research and ExplorationInstitute of Turkey (MTA) are the oldest available sediment samples from theTurkish coastline of the Black Sea. Therefore, the results may be used asreferences for monitoring possible future metal pollution.