Ab Initio Study of Prednisolone, 6α-Fluoroprednisolone, 9α-Fluoroprednisolone,and 6α,9α-Difluoroprednisolone

A theoretical study of prednisolone, 6-fluoroprednisolone, 9-fluoroprednisolone, and 6,9-difluoroprednisolone has been performed at the ab initio HF/6-31G, MP2/6-31G, and B3LYP/6-31G levels. Structural information and the electronic features of prednisolone and its derivatives and the synergistic effect of 6,9-difluoroprednisolone was examined. Contrary to the AM1 and MNDO results, we found 9-fluoroprednisolone is more stable than the 6-fluoroprednisolone. The increased corticosteroid activity of the 6,9-difluoroprednisolone is most likely due to electronic effects, mainly related to the receptor binding.     

Synthesis of symmetrical acetylenic hydrocarbons and their α,ω-di-derivatives from α,α,α-trichloro- and α,α,α,ω-tetrachloro-alkanes

Summary By the action of sodium in xylene on polychloro hydrocarbons containing -CCl₂-CCl₂- or- CC1=CC1-, groupings the corresponding symmetrical acetylenic hydrocarbons containing 10,14, and 18 carbon atoms in the molecule were obtained. From ,-disubstituted tetrachloroalkanes by the same method 1,10-diethoxy-5-decyne, 1,14-diethoxy-7-tetradecyne, and 1,14-bisdiethylamino-7-tetradecyne were obtained.The spectra were determined in the Optical Laboratory of the Institute of Heteroorganic Compounds of the USSR by N. A. Chumaevskii, who we thank.     

Conformation of α,α,α′-Trisubstituted Cyclododecanone

Ten α,α,α′-trisubstituted cyclododecanones were synthesized and characterized by elemental analyses, infrared, 1^H NMR and 13^C NMR spectra, and X-ray diffraction. NMR data could not give conformational information clearly, but some of their ring skeleton conformations of cyclododecanone moiety were showed to remain the unchanged [3333]-2-one conformation with little distortion, while the others were changed to the [3324]-2-one conformation in their crystal structures. These are consistent with the results of molecular mechanics calculation with Sybyl 6.9 software and Tripos force field, and semi-empirical quantum calculation with AM 1 method in Gaussian 98 software. Two geminal substituting groups are located at α-corner carbon atom, and the third group is at α-side-exo carbon atom in both conformations. Both [3333]-2-one and [3324]-2-one conformations are present in a dynamic equilibrium in the solution, but only one preferred conformation exists in the crystal solid.     

Automatic assembly of skeleton structures. 3. Stereoselective synthesis,stereochemistry, and cyclization ofd,l-α,α'-dioxy-α,α'-di-tert-butylglutaric acid

Stereoselective synthesis of d,l-,-dioxy-,-di-tert-butylglutaric acid hydroxyiminolactonitrile (3) was conducted by the reaction of dipivaloylmethane with HCN in ether. The corresponding hydroxylacetonitrile (4) and amide (5), acid (6), and its ester (7), from which dilactone (8) was synthesized with preparative yields, were obtained from3. Benzyl amide (9) was obtained by the reaction of8 with BnNH₂. The iminolactone structure3 of dipivaloylmethane bis-cyanohyrin, thecis-pseudo-a orientation of the functional substituents in3–7 and9, and the structure of the dilactone8 were confirmed by the¹H,¹³C NMR,IR and mass spectra.For previous communication, see [2].N. N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, 117977 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 7, pp. 1591–1601, July, 1992.     

Ionic liquid-promoted Wagner-Meerwein rearrangement of 16α,17α-epoxyandrostanes and 16α,17α-epoxyestranes

Ionic liquids 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim](+)[PF(6)](-)) and 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim](+)[BF(4)](-)) were found to promote an unusual Wagner-Meerwein rearrangement of steroidal 16α,17α-epoxides leading to unnatural 13-epi-18-nor-16-one derivatives as the main products. These compounds were isolated in good to excellent yields. 16α-Hydroxy-Δ(13)-18-norsteroids, the results of the usual rearrangement, were obtained as minor components of the reaction mixtures. The ionic liquid [bmim](+)[PF(6)](-) was shown to induce C-ring aromatization of 16α,17α-epoxyestranes due to the formation of HF, the hydrolysis product of [PF(6)](-). Increasing amounts of HF and [PO(2)F(2)](-) were detected by (19)F and (31)P NMR when the ionic liquid was reused. The structures of the steroidal products, 16-oxo-18-nor-13α-steroid derivatives, 16α-hydroxy-Δ(13)-18-norsteroids, and C-aromatic compounds were determined by two-dimensional NMR techniques and high-resolution mass spectrometry (HRMS). The ionic liquids were recirculated efficiently.     

α,ω-Bis-N-aziridinoalkanes

By reactions of ,-diamines with 1,2-dihaloethanes there were synthesized ,-bis-N-aziridinoalkanes (la-g) and bis-N-aziridinoethyl ether (II). From 1,3-diaminopropane and dichloroethane bis-aziridine (III) was isolated in addition to (Ia). NMR spectra of the products were studied.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 882–885, April, 1991.     

抗meso-四(α,α,α,α-O-苯乙酰苯)卟啉抗体的酶学性质研究

利用小分子ｍｅｓｏ－四(α,α,α,α－Ｏ－苯乙酰苯)卟啉作为全抗原免疫小鼠,通过细胞融合等技术制备了单克隆抗体(ＭｃＡｂ)１Ｆ２,利用高效液相色谱(ＨＰＬＣ)、基质辅助激光解吸飞行时间质谱(ＭＡＬＤＩ/ＴＯＦＭＳ)证明纯化得到的单抗是很纯的．ＭｃＡｂ１Ｆ２的保留时间是２．６３ ｍｉｎ,亚型为ＩｇＧ２ａ,相对分子量为１５６ ６７８．８．ＭｃＡｂ １Ｆ２－卟啉复合物形成时,卟啉Ｓｏｒｅｔ带最大吸收峰从４０８ｎｍ红移到４１６ｎｍ,并有增色效应,说明ＭｃＡｂ１Ｆ２－卟啉是刚性且紧密结合．抗体酶稳定性很高,但比活力只有４．６８７ ５ Ｕ/ｍｇ,为天然酶ＨＲＰ的１．８９９%．抗体酶的Ｋｍ＝２０．２９ ｍｍｏｌ/Ｌ,ｋｃａｔ＝３９６．８２ ｍｉｎ－１,ｋｃａｔ/Ｋｍ＝１．９５５ ７×１０４Ｌ·ｍｏｌ－１·ｍｉｎ－１．     

Überα,α'-Dichlordimethyläther

Ohne ZusammenfassungMit 1 Abbildung.     

α,α,ω-三氢全氟醇类的化学

四氟乙烯与甲醇在游离基引发剂的作用下发生調节聚合反应,生成一系列的低級調聚产物,即含有奇数碳原子的α,α,ω三氫全氟醇类: nC_2F_4+CH_3OH→H(CF_2—CF_2)_nCH_2OH(n=1—12)这些产物具有多氟化合物特有的稳定性和不燃性,又含有活泼的伯醇基,所以是氟有机化学中的一类重要合成中間体,又是制备某些特殊材料如高溫潤滑剂、介     

A facile synthesis of α,α,ω,ω-tetrahalo-α,ω-dicarboxylic esters

The synthesis of some α,α,ω,ω-tetrachloro and tetrabromo-derivatives of the hypolipidemic 3,3,14,14-tetramethylhexadecanedioic acid from α,ω-dihalo-esters, carbon tetrahalides and lithium diisopropyl amide has been described. Interaction of α,ω-dichloro esters with CBr₄ was shown to give the expected α,ω-dibromo-α,ω-dichloro compounds, but treatment of bis(l-methylethyl) 2,15-dibromo-3,3,14,14-tetramethylhexa-decanedioatewith CCl₄ was found to result in halogen exchange yielding the tetrachloro-diester as the major product.     

Synthesis of Derivatives of ω-Isocyanato-α-methylamino, ω-Ureido-α-methylamino, and Nα-Methyl-α, ω-diamino Acids

 Homochiral N^α-methyl-2,3-diaminopropionic and N^α-methyl-2,4-diaminobutyric acid derivatives 8a,b were obtained via a stereoconservative four-step synthesis starting from hexafluoroacetone protected L-aspartic and L-glutamic acid 2a,b, respectively. Hexafluoroacetone protected ω-isocyanato-α-methylamino acids 4a,b– the key intermediates of the synthesis – are versatile building blocks for amino acid and peptide modification and promising candidates for combinatorial chemistry. Upon reaction with alcohols, compounds 4 give activated N ^ω-urethane protected ω-amino-α-methylamino acid derivatives 5–7; upon reaction with amines, ω-ureido-α-methylamino acid derivatives 10–12 and 3-methylamino-pyrrolidin-2-ones 13 are available.     

(α,3pxn) or (α,αpxn) reactions on natural dysprosium

The (EC, ⁺) decay of¹⁶⁸Hf, produced by the¹⁵⁶Gd (¹⁶O,4n) reaction, has been studied, with high efficiency HPGe coaxial detectors, using on-line measurements with the RACHEL setup. Off-line measurements were also carried out using catcher collection technique. Energies and intensities of 119 -lines are reported among these only two were known in the earlier study ofChu andReednick. The¹⁶⁸Lu level scheme built on the basis of single - and X-spectra and - coincidence measurements, allows the interpretation of 79 -transitions, between 38 excited states reported for the first time.     

α,α-Difluoro-α-phenylsulfanyl-α-trimethylsilylmethane as a difluoromethyl building block: A general strategy to α,α-difluoromethyl aryl ketones

The synthetic utility of α,α-difluoro-α-phenylsulfanyl-α-trimethylsilylmethane (PhSCF₂SiMe₃; 1) as a difluoromethyl building block providing a general strategy to α,α-difluoromethyl aryl ketones was demonstrated. Oxidation, by using m-chloroperoxybenzoic acid, of the readily available 1-aryl-2,2-difluoro-2-phenylsulfanyl-1-trimethylsiloxyethanes obtained from fluoride-catalyzed nucleophilic addition of PhSCF₂SiMe₃ with aromatic aldehydes followed by flash vacuum pyrolytic elimination provided α,α-difluoromethyl aryl ketones in moderate overall yields.     

Atom Transfer Radical Polymerization of Methyl Methacrylate with α,α-Dichlorotoluene or α,α,α-Trichlorotoluene as Initiator

lnAtomTransferRadicalPolymerization(ATRP),whichisanew"living"/contr0lledradicalp0lymerizati0ntechniquedevel0pedindependentlybyMatyjaszewskieIallandSawam0t0eIaP,anyalkyIhalidewithactivatedsubstituents0na-carbonsuchasaryl,carb0nyl0rallylcanbeusedasinitiatoe.Benzy1haIideandpolymerswithbenzylhalideendgr0upwerereportedtobeefficientinitiator0rmacroinitiatorfortheATRPofstyrene".H0wever,whenbenzylhalidewasusedt0initiateMMAp0Iymerization,itwasfoundthattheinitiationefficiencywasveryIowinourlabo…     

苯硫酚还原α,α,α-三溴甲基酮类化合物的研究（英文）

以苯硫酚为还原剂,在绿色溶剂、室温下将α,α,α-三溴甲基酮类化合物还原成α,α-二溴甲基酮类化合物.此反应适用于芳香族、脂肪族和杂环类α,α,α-三溴甲基酮类化合物,产率高达97%.进一步的机理研究表明,该反应是自由基反应.     

A convenient synthesis of α',β-diamino-α,α-difluoroketones,new dipeptide isosteres

A convenient and versatile synthesis of α′,β-diamino-α,α-difluoroketones is described. These compounds represent a new class of true isosteres useful for the design of serine protease inhibitors.