Simple and highly efficient preparation and characterization of (−)-lupanine and (+)-sparteine

In a simple and convenient way, we have improved the non-chromatographic isolation of optically pure (−)-2-oxosparteine ((−)-lupanine) and (+)-sparteine. The fast and efficient method for the determination of the ee of bisquinolizidine alkaloids has been proposed. A relatively simple simple ¹H NMR method has been applied for evaluation of the % ee of enantiomers of the lupanines and sparteines with the chiral dibenzoyltartaric acids as the shift reagents. The ¹H NMR spectra of the bases and the new salts in polar solvents have been measured.The results are confirmed by chiral HPLC method. Additionally, for the first time X-ray analysis of the salt of (−)-lupanine has been performed. The improved method of purification of bisquinolizidine alkaloids will considerably facilitate the employment of these alkaloids as chiral ligands in asymmetric reactions and as pharmacological tools.     

A comparative study of NMR chemical shifts of sparteine thiolactams and lactams

The ¹³C and ¹H NMR spectra of the four possible thiolactams of sparteine (1) were recorded and the thiolactam group effects were determined. Most of the effects are greater than those of the lactam group in the oxo analogs. A good linear correlation between the ¹³C chemical shifts of CS and those of CO was found. The effects could help in assignment of the spectra and determination of conformation of thiolactams and related thiocarbonyl compounds.     

Reaction of R-(+)-2-benzylideneaminobutan-1-ol with ethylene phosphorochloridite. Stereospecific formation of (3R,5R)-2-(2-chloroethoxy)-5-ethyl-2-oxo-3-phenyl-1,4,2-oxazaphosphorinane

The reaction of R-(+)-2-benzylideneaminobutan-1-ol with ethylene phosphorochloridite afforded phosphorus-epimeric (3R,5R)-2-(2-chloroethoxy)-5-ethyl-2-oxo-3-phenyl-1,4,2-oxazaphosphorinanes. The phosphorinane-ring closure proceeded stereospecifically and occurred only from one of the diastereofacial sides (re) of the C=N bond.     

Stereoselective synthesis of dendrobate alkaloid (+)-241D and its C-4 epimer

An efficient stereoselective synthesis of dendrobate alkaloid (+)-241D and its C-4 epimer was achieved from the inexpensive, commercially available starting material decanal (10) in an overall yield of 21.9% and 21.1%, respectively. This synthesis utilizes the key steps of Maruoka asymmetric allylation, one-pot epoxidation followed by nucleophilic addition of an organomagnesium reagent (Forsyth’s protocol) and subsequent functional group transformations.     

微生物酶催化的不对称还原反应合成(S)-(+)-4-苯基-2-丁醇

以LB培养基培养Pseudomonas monteilii TA-5,将其整细胞作为生物催化剂（Cat）,催化4-苯基-2-丁酮(1)的不对称还原反应,对映选择性地合成了(S)-(+)-4-苯基-2-丁醇。在最佳反应条件［1 10 mmol·L^-1, c（Cat） 30 g cdw·L^-1, 10%丙三醇,pH 8.0, 300 r·min^-1,于30 ℃反应24 h］下,转化率82%, ee值91%。     

Study of alkaloids from the flora of the Siberian and Altai regions. 6. Crystal and molecular structure of songorine Z-oxime

Oximation of songorine afforded a mixture of its Z- and E-oximes. The crystal and molecular structure of the Z-isomer was established by X-ray diffraction analysis. Its structure was also confirmed by the spectral data (2D ¹H—¹H and ¹³C—¹H NMR spectroscopy and mass spectrometry). The structure of isomeric E-oxime was established by comparing its NMR spectroscopic data (¹H and ¹³C) with the data for the Z-isomer.     

Synthesis and Biological Activities of 2,4-Dichlorophenoxyacetyl(thio)urea and S-(+)-3-Methyl-2-(4-chlorophenyl)butyramide Derivatives

2,4-Dichlorophenoxyacetyl(thio)urea and S-(+)-3-methyl-2-(4-chlorophenyl)butyramides were synthesized via acylation,aminolysis,esterification and addition reactions,and the partial new compounds have desirable bioactive activity.     

Determination of the solubility,dissolution enthalpy and entropy of R-(+)-2-(4-hydroxyphenoxy) propanic acid in different solutions

The solubilities of R-(+)-2-(4-hydroxyphenoxy) propanic acid in acetone, ethyl acetate, acetonitrile, glycol ether, DMF, MIBK, n-butyl alcohol, THF and pyridine were measured at temperatures ranging from 273.15 K to 323.15 K at atmospheric pressure using a laser detecting system. First, the solubility data of R-(+)-2-(4-hydroxyphenoxy) propanic acid in selected solution were compared by the solubility parameter. Then, the solubility data were correlated by the Buchowski–Ksiazczak λh equation and modified Apelblat equation. Compared with the Apelblat equation, the Buchowski–Ksiazczak λh equation can fit the solubility data well. The dissolution enthalpy, entropy and Gibbs free energy of R-(+)-2-(4-hydroxyphenoxy) propanic acid were predicted by the van’t Hoff and Gibbs equation.     

Molecular and crystal structures of (6R, 7R, 14S)-6,14-etheno-7-[(1R)-1-hydroxyethyl]- and (6R, 7R, 14S)-6,14-etheno-7-[(1S)-1-hydroxyethyl]-6,7,8,14-tetrahydro-17-nor-17-phenylthebaine

The crystal structures and absolute configurations of (6R,7R,14S)-6,14-etheno-7-[(1R)-1-hydroxyethyl]-6,7,8,14-tetrahydro-17-nor-17-phenylthebaine and (6R,7R,14S)-6,14-etheno-7-[(1S)-1-hydroxyethyl]-6,7,8,14-tetrahydro-17-nor-17-phenylthebaine were established by X-ray diffraction analysis. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2245–2250, November, 1998.     

A theoretical and NMR lanthanide‐induced shift (LIS) investigation of the conformations of lactams.

Molecular mechanics (MM) with MMFF94 and MMX force fields and ab initio (RHF/6‐31G*,RHF/6‐311G**, and B3LYP/6‐311G**) calculations are used with lanthanide‐induced shift (LIS) to investigate the conformations of N‐methyl‐2‐pyrrolidone 1 , N‐methyl‐2‐piperidone 2 , ε‐caprolactam 3, γ‐valerolactam (1,5‐dimethyl‐2‐pyrrolidone) 4, 2 ‐ azetidinone 5 , 4‐methyl azetidinone 6 , 4‐phenyl azetidinone 7 , and N‐methyl‐4‐phenyl azetidinone 8 . The Yb(fod)₃ paramagnetic induced shifts of all the ¹H and ¹³C nuclei are measured and the corresponding diamagnetic complexation shifts obtained by the addition of Lu(fod)₃. The complexation model (two‐, three‐, or four‐site) used depends on the relative rates of the processes involved. The amide inversion is the same order as that of the 5‐ and 6‐membered lactam rings and much faster than the lanthanide complexation and the inversion of the 7‐membered ring. Both MM and ab initio calculations give an envelope conformation for 1 with C‐4 out of the ring plane in agreement with the LIS analysis. For the piperidone ring of 2 , the half‐chair is calculated as the most stable form. The LIS analysis confirms this but cannot exclude a small amount (<2%) of the boat conformation. For 3 , the LIS analysis gives a minimum for 90:10% chair to boat conformation, and 4 exists in two envelope conformations with the C₅‐Me ps‐eq and ps‐ax in an eq/ax ratio of 94:6%. In 2‐azetidinone 5 , the ab initio calculations gave both ring and nitrogen planar, but the MMFF94 calculations give a butterfly ring and pyramidal nitrogen. The LIS analysis for 5 gave good agreement (Rcryst 0.46%) for the MMFF94 geometry with endo NH but the planar ab initio geometries worse agreement (Rcryst = 1.1%). For 4‐methyl‐2‐azetidinone 6 , the MMFF94 geometry gave good agreement (Rcryst 0.96%) with two butterfly conformations with axial and equatorial methyl groups in 1:1 ratio. All the planar geometries gave worse agreement (Rcryst >1.5%). In 4‐phenyl azetidinone 7 , the MMFF94 geometry with 60% of the axial conformer gave Rcryst 1.2% but the other geometries Rcryst >1.5%. In contrast the N‐methyl‐4‐phenyl‐2‐azetidinone 8 gave good agreement for all the geometries. The butterfly conformation gave Rcryst 1.1% for 80% of the axial conformer and the planar geometries Rcryst 0.98%. The LIS results confirm the ab initio and MM optimised geometries, but the conformer energies at times differ from the calculated values. They also differ considerably from the corresponding values for the lactones studied previously, and possible reasons for this are discussed.     

Stereoselective synthesis of C1-C9 and C9-C17 fragments of (+)-13-deoxytedanolide

An efficient and highly stereoselective asymmetric synthesis of C1-C9 and C9-C17 fragments of (+)-13-deoxytedanolide have been achieved. Utilization of desymmetrization technique to prepare the triol with five stereogenic centers, regioselective Sharpless asymmetric dihydroxylation, Evans' aldol reaction, chiral methylation, and Wittig olefination are highlights of the synthesis.     

Tautomerism and Rotamerism in 2-(2-Phenylhydrazino)pyridine

The title compound is shown by X-ray crystallography and NMR spectroscopy to exist both in the solid state and in solution as such. Deuterium-induced shifts confirm the phenylamino structure for 2-phenylaminopyridine.     

Novel oxorhenium complexes with 2-(2′-hydroxyphenyl)-2-benzothiazolinato ligand: X-ray studies,spectroscopic characterization and DFT calculations

The [ReOX₂(hbt)(EPh₃)] (X = Cl, Br; E = As, P) chelates have been prepared in the reactions of [ReOX₃(EPh₃)₂] complexes (X = Cl, Br; E = P, As) with 2-(2′-hydroxyphenyl)-2-benzothiazole (hbtH) in acetone. From the reactions of [ReOX₃(PPh₃)₂] with hbtH two kind of crystals [ReOX₂(hbt)(PPh₃)] · MeCN and [ReOX₂(hbt)(PPh₃)] with different arrangement of halide ions (cis and trans) were isolated, whereas the [ReOX₃(AsPh₃)₂] oxocompounds react with hbtH to give only cis-halide isomers. The complexes were structurally and spectroscopically characterised. The electronic structures of both [ReOBr₂(hbt)(PPh₃)] isomers have been calculated with the density functional theory (DFT) method. The TDDFT/PCM calculations have been employed to produce a hundred of singlet excited-states starting from the ground-state geometry optimized in the gas phase of cis- and trans-halide isomers of [ReOBr₂(hbt)(PPh₃)] and the UV–Vis spectra of these complexes have been discussed on this basis.     

(1R,2R)-(+)-(1,2)-DPEN-Bonded Sulfonic Acid Resin: A Trifunctional Heterogeneous Catalyst for Asymmetric Michael Additions of Acetone to Nitroolefins

Based on (1R,2R)-(+)-(1,2)-DPEN skeleton, a series of primary amine–sulfamide bifunctional catalysts were synthesized, which exhibited excellent catalytic performance in the Michael addition of acetone to β-nitrostyrene. Therefore, a trifunctional heterogeneous catalyst was designed and prepared by simple N-sulfonyl reaction of (1R,2R)-(+)-(1,2)-DPEN and sulfonyl chloride resin. It was employed for the aforementioned addition without any additive and satisfactory results (80.5% conversion; 84.3% ee) were obtained. Meanwhile, the structural and textural properties of the catalyst were characterized by infrared spectroscopy (FT-IR), elemental analysis, SEM, and N₂ adsorption and desorption experiments. Finally, the generality of the catalyst was investigated.     

Physicochemical characterization of the dimeric lanthanide complexes [en{Ln(DO3A)(H2O)}2] and [pi{Ln(DTTA)(H2O)}2]2-: a variable-temperature 17O NMR study

The Gd(III) complexes of the two dimeric ligands [en(DO3A)2] {N,N'-bis[1,4,7-tris(carboxymethyl)-1,4,7,10-tetraazacyclododecan-10-yl-methylcarbonyl]-N,N'-ethylenediamine} and [pi(DTTA)2]8- [bisdiethylenetriaminepentaacetic acid (trans-1,2-cyclohexanediamine)] were synthesized and characterized. The 17O NMR chemical shift of H2O induced by [en{Dy(DO3A)}2] and [pi{Dy(DTTA)}2]2- at pH 6.80 proved the presence of 2.1 and 2.2 inner-sphere water molecules, respectively. Water proton spin-lattice relaxation rates for [en{Gd(DO3A)(H2O)}2] and [pi{Gd(DTTA)(H2O)}2]2- at 37.0 +/- 0.1 degrees C and 20 MHz are 3.60 +/- 0.05 and 5.25 +/- 0.05 mM(-1) s(-1) per Gd, respectively. The EPR transverse electronic relaxation rate and 17O NMR transverse relaxation time for the exchange lifetime of the coordinated H2O molecule and the 2H NMR longitudinal relaxation rate of the deuterated diamagnetic lanthanum complex for the rotational correlation time were thoroughly investigated, and the results were compared with those reported previously for other lanthanide(III) complexes. The exchange lifetimes for [en{Gd(DO3A)(H2O)}2] (769 +/- 10 ns) and [pi{Gd(DTTA)(H2O)}2]2- (910 +/- 10 ns) are significantly higher than those of [Gd(DOTA)(H2O)]- (243 ns) and [Gd(DTPA)(H2O)]2- (303 ns) complexes. The rotational correlation times for [en{Gd(DO3A)(H2O)}2] (150 +/- 11 ps) and [pi{Gd(DTTA)(H2O)}2]2- (130 +/- 12 ps) are slightly greater than those of [Gd(DOTA)(H2O)]- (77 ps) and [Gd(DTPA)(H2O)]2- (58 ps) complexes. The marked increase in relaxivity (r1) of [en{Gd(DO3A)(H2O)}2] and [pi{Gd(DTTA)(H2O)}2]2- result mainly from their longer rotational correlation time and higher molecular weight.     

Ferrocene Compounds. XXVII. Synthesis and Structure of 2-(Ferrocenylmethyl)propane-1,3-diol

The title compound was obtained by reduction of diethyl (ferrocenylmethyl)malonate with lithium aluminium hydride in diethyl ether. The structure of this novel ferrocene derivative was assigned by means of elemental analysis, IR, [¹H]NMR, and [¹³C]NMR spectroscopy. The structure was also confirmed by a single crystal X-ray study. The compound crystallizes in monoclinic P2₁/a space group with unit cell dimensions: a = 9.7360(6), b = 27.040(5), c = 14.767(3) Å, = 103.835(6)°, V = 3774.8(11) ų, Z = 12. The asymmetric unit contains three crystallographically independent molecules. In the ferrocenyl moieties, the Fe–C bond distance values are in the range 2.006(5)—2.051(3) Å and C–C distances in the range 1.366(7)–1.425(4) Å. The cyclopentadienyl rings in each of the molecules are mutually twisted by about 13° from the eclipsed conformation. The hydroxyl groups are involved in the intermolecular O–H...O hydrogen bond formation with O-O distances in the range 2.686(3)–2.801(4) Å forming infinite two-dimensional network in a [0 0 1] plane. The crystal structure is additionally stabilized by C–H-O weak intermolecular hydrogen bonds.     

New oxorhenium complexes with 2-(2′-hydroxyphenyl)-2-benzoxazolinato ligand. X-ray structure and DFT calculations for [ReOX2(hbo)(AsPh3)] and [ReOX2(hbo)(PPh3)] complexes

The reactions of [ReOX₃(AsPh₃)₂] and [ReOX₃(PPh₃)₂] with 2-(2′-hydroxyphenyl)-2-benzoxazoline (Hhbo) have been examined and [ReOX₂(hbo)(AsPh₃)] and [ReOX₂(hbo)(PPh₃)] (X = Cl, Br) complexes have been obtained. The crystal and molecular structures of [ReOCl₂(hbo)(AsPh₃)] (1) and [ReOBr₂(hbo)(PPh₃)] (4) have been determined. The electronic structures of 1 and 4 have been calculated with the density functional theory (DFT) method. The spin-allowed electronic transitions of 1 and 4 have been calculated with the time-dependent DFT method, and the UV–Vis spectra of these complexes have been discussed.     

(+)-安五脂素的分离与结构(英文)

从长梗南五味子中分得一种木脂素新化合物——(+)-安五脂素(1),它在体外对 H~+,K~+-ATP 酶和 P-388细胞有明显抑制作用;对人血清中的 HBsAg 也有弱抑制作用。经与绝对构型已知物(3)对照,证明1的结构为(2R,3S)-1-(3,4-次甲二氧苯基)-2,3-二甲基-4-(4-羟基-3-甲氧苯基)-丁烷。     

Synthesis of 2-[2-(5-phenyl-1,2,4-oxadiazol-3-yl)-ethyl]benzimidazole and its x-ray analysis

Cyclization of O-benzoyl-2-(benzimidazol-1-yl)propioamidoxime under different temperature conditions gave 2-[2-(5-phenyl-1,2,4-oxadiazol-3-yl)ethyl]benzimidazole whose structure has been determined by X-ray analysis. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1057–1061, July, 2006.