STUDIES ON THE CRYSTAL STRUCTURE OF Al-(D-TRYPTOPHAN) INSULIN

We have determined the crystal structure of Al-(D-Trp) insulin and discovered that it belongs to the trigonal system with space group R3. The parameters of the unit cell are a=b=78.6, c=50.0. A set of data for half a sphere reciprocal space to a spacing of 2.2 were collected. The model was adjusted and refined by using a step-by-step approach and a stereochemically-restrained least squares program, assisted by manual revision based on the difference Fourier maps, to a final R-factor of 0.218. The main and side chains of both Al-D-Trp residues in the asymmetric unit are well ordered. The packing of Al-(D-Trp) insulin in the unit cell, the conformational differences with other insulin structures and its structure and function relationship bave also been discussed.     

STUDIES ON THE CRYSTAL STRUCTURE OF CHALCONE DERIVATIVES Ⅰ. Crystal Structure of 4-Brom-4'''' -Methoxyl-Chalcone(BMC)

<正> BrC6H4C2H2COC6H4OCH3, Mr = 317. 19, is monoclinic, space group PC with unit cell of a = 15. 869(3), b = 7. 146(2), c=5. 991(1) (?); β=82.85 (1)°; Z = 2, Dc=1. 56g/cm3; V = 674. 1(?)3; λ(MoKa) = 0. 71073A, μ= 30. 1 cm-1, F(000) = 320e, final R = 0. 040, Rw = 0. 041 for 993 observed reflections with I>3σ(I). As the two phenyl planes and the C2H2CO group are non-coplanar, the conjugated system was disturbed. This will produce a large hypsochromic shift of cutoff wavelength of transmission.     

STUDIES ON THE STRUCTURE OF FORKED CONJUGATIVE SYSTEMS——THE CRYSTAL STRUCTURE AND CONFORMATION OF 2-BENZOYLTHIOPHENE

The crystal structure and the conformational properties of the title compound have been investigated by means of X-ray single diffraction and the PCILO methods. C_(11)H_8OS belongs to the orthorhombic system, the space group is P2_12_12_1, a=11.945(4), b 10.236(7), c=7.649(4), Z=4, D_c-1.37g/cm~3. The molecule is not planar structure because of steric hindrance. The thiophene ring and the phenyl ring make dihedral angles of 21°(θ_1) and 32°(θ_2) with the carbonyl frame plane, respectively. The lowestenergy conformation obtained by PCILO calculation is in agreement with the crystallinestatc conformation. In this paper, the molecular structure, the influence of steric hindrance and the groups' abilities to conjugate upon the conformation and the variations of the potential energy of the isolated molecule in the whole conformational space are discussed.     

STUDIES ON THE CRYSTAL STRUCTURE OF Al-(L-TRYPTOPHAN) INSULIN AT 2.1RESOLUTION

In order to study the biological effect of alterations to the N-terminus of the insulin A-chain, we have determined the crystal structure of Al-(L-Trp) insulin and discovered that it belongs to the trigohal system with space group R3. The parameters oof the unit cell are a=b=80.3A, c=37.5A. The model was adjusted and refined by using a stereochemically-restrained least squares program, assisted by manual revision of the model based on the difference Fourier map, to a final R-factor of 0.195. The main and side chains of both Al-(L-Trp) residues in the asymmetric unit are well ordered. It was found that the Al-Trp residue of molecule I occupied two distinct positions. We have proposed from the results of the three-dimensional structure that the 4-zinc insulin hexameric form is a stored state of insulin molecules in a conformation of low activity. The structural details of the insulin molecule and its structure and function relationship have also been discussed.     

STUDIES ON THE SYNTHESIS OF THE SPIROKETAL FRAGMENT OF AZADIRACHTIN(Ⅰ)

The stereoselective synthesis of substituted [2,2,1]-bicyclo-heptan-2-one 12,a supposed intermediate to the spiroketal fragment of azadi-rachtin was described.When 12 was treated with mCPBA in CH_2Cl_2 in the pres-ence of excess amount of solid sodium bicarbonate,only 13 was obtained.Thespiroketal intermediate 20 was converted from 9 through 5 steps by an alterna-tive route.     

STUDIES ON THE CRYSTAL STRUCTURE OF (D-Ala)-B0 PORCINE INSULIN AT 1.9 RESOLUTION

The crystal structure of (D-Ala)-B0 porcine insulin has been determined, using data to 1.9 and atomic parameters of 2 Zn porcine insulin as a starting model, and through the use of the difference method and the restrained least square method, to a final R-factor of 0.211 and r. m. s. deviation of 0.057 for the bond lengths. The electron densities of B0 residues were very clear. Introduction of B0 residues into the molecules had reduced the thermal vibration of the N-terminus of B-chain for both molecules Ⅰ and Ⅱ and made the molecules pack closer in the crystal The obvious differences between the crystal structures of 2 Zn and (D-Ala)-B0 porciue insulin were the conformations of partial polar groups around the possible receptor binding surface and the assembly mode of two helixes of A-chain in molecule I. In the local environment of the N-terminus of Bchain there were great differences between the crystal structures of(D-Ala)-B0 porcine insulin, (Trp)-B1 porcine insulin and Des B1(Phe) bovine insulin.     

STUDIES ON TRANSITION-METAL PERHALOPHENYL COMPOUNDS.VI.CRYSTAL STRUCTURE OF TRANS-BROMO-BIS(METHYLDIPHENYLPHOSPHINE) (σ-PENTABROMOPHENYL)NICKEL(II)

<正> M= 1010.62, D24-P212121, a=11.654(3), b=15.812(9), c=18.556(8) A, V=3419.5A3, Z=4, Dc=1.963 g·cm-3. Final R=0.066 for 2187 reflections. The central nickel(II) atom of the title compound is in slightly distorted square-planar coordination.     

INTERCONVERSION OF COMPOUNDS WITH PENTA-AND HEXACOORDINATE PHOSPHORUS. CRYSTAL AND MOLECULAR STRUCTURE OF THE TRIALKYLAMMONIUM HEXAOXYPHOSPHORIDE, [(PO6)(C6H5)2(C6H4)(CF3C˭CCF3)]−[(C2H5)3NH]+

Abstract

The structure of triethylammonium diphenoxy-o-phenylenedioxy-1,2-bistrifluoromethylethenylenedioxyphosphoride, a compound with hexacoordinate phosphorus obtained by addition of triethylammonium phenoxide to the pentacoordinate phosphorus precursor, has been determined by x-ray crystallographic methods. The compound crystallizes from ether in space group P2_1/n of the monoclinic system. There are four formula units, (C₂₂H₁₄O₆P)-(NC₆H₁₅)⁺ in the unit cell (Z=4), with one ion-pair constituting the asymmetric unit of the crystal. The cell dimensions are a=10.787(5), b=16.604(6), c=16.668(4) Å; β=102.84°(3); D _ctlc=1.415 g cm^?3, D _meas=1.412 g cm^?3 (25°). Data were obtained on a CAD4 automatic diffractometer; 5310 unique non-zero reflections were collected with θ≤ 75° using (θ-2θ) scan, with a scan width of 1.0°. The phosphorus and oxygen atoms were located using the MULTAN program. All other non-hydrogen atoms were found in subsequent iterations of partial-structure phased Fourier maps. The structure was refined by full-matrix least-squares techniques to a final R _w value of 7.5% on F based on 4855 independent reflections. The phosphorus atom is hexacoordinate and at the center of a nearly regular octahedron, with the two phenoxy groups cis to each other. The two P–O (exocyclic) bonds are shorter (ave. 1.656(4) Å) than the four P–O (endocyclic) bonds (ave. 1.711(4) Å). The positively charged nitrogen is closer to two of the uncharged oxygen ligands (3.000 and 3.108(6) Å) than to the negatively charged phosphorus (4.063(6) Å) within the formula unit. The changes in molecular parameters when an oxyphosphoride is derived from an oxyphosphorane by addition of a sixth oxy-ligand are discussed.     

THE SYNTHESIS AND X-RAY CRYSTAL STRUCTURE STUDIES OF (DI-3-INDOL YL )M ETH YLFERROCENE

<正> A novel anhydrous zinc chloride catalyzed condensation reaction of ferrocenealdehyde with indole in solid state gave the title compound (Di-3-indolyl) methylferrocene ((C8H6N)2CHC5H4FeC5H5) selectively, and its crystal structure has been determined by X-ray diffraction analysis. The crystal belongs to triclinic system, space group P1, with cell parameters a = 9. 624(2), b = 9. 957(2), c=11. 295 (4)A,α=92. 17(2), β=92. 23(2), γ=111. 30(1)°, V=985. 4A3, Mr = 430. 33, Z = 2, Dx = 1. 44g/cm3,μ= 7. 8cm-1, F(000) = 444. The final R = 0. 056 for 3027 observed reflections.     

THE CRYSTAL STRUCTURE OF AgCu(SC(NH_2)_2)_4Cl_2

<正> INTRODUCTION. By mixing aqueous solutions of AgNO_3-Tu(mol ratio 1:1, Tu==SC(NH_2)2) with CuCI-Tu(mol ratio 1:3) we obtained a colourless crystalcompound. Its crystal and molecular structure was determined by X-raydiffraction and shortly reported in this paper.     

CRYSTAL STRUCTURE OF GdCl_3(DIMETHOXYETHANK)_2

<正> C8H2oCl3GdO4,Mr=443.80,monoclinic, space group P21/c, a=11.442 (3),b= 8.849(2), c= 15.575(5)A,β=104.8l(2)° ,V=1521.9(7)A3,Z= 4, DC = 1.94 g/cm3,λ(MoKα) =0.71069A,F(000)=860. The structure was solved by Patterson and Fourier techniques and refined by least-squares nethod to a final conventional lvalue of 0.051 (Rw=0.054). The central ion Gd(III) is bonded to three chlorine atoms and four oxygen atoms froa two dimethoxye-thane molecules to form a distorted pentagonal bipyramid. The Qd-Cl distances are in the range of 2.460-2.628A (average 2.571A). The Gd-O distances are in the range of 2.408-2.493A (average 2.458A).     

STUDIES ON SCHIFF BASE COMPLEXES——Ⅳ. SYNTHESIS AND CRYSTAL STRUCTURE OF Fe (SALDPT) SAL

制备了Fe(saldpt)sal单晶并作了晶体结构分析。晶体数据:单斜,空间群P2_1/C(#14),a=12.486(5),b=18.502(8),c=10.870(5)A,β=104.23(3)°,V=2434(2)A~3,Z=4,D_c=1.40g/cm~3     

STUDIES ON THE WITTIG REACTION(XIII): KINETICS OF THE PTC-WITTIG REACTIONS OF 2-BUTENYL METHYL-DIPHENYLPHOSPHONIUM SALT WITH SUBSTITUTED BEN2ALDEHYDES

The kinetics of PTC-Wittig reaction between substitutedaromatic aldehydes and 2-butenyl methyldiphenylphosphonium salthas been studied. The low reaction constant (ρ=0. 30) impliesthat these PTC-Wittig reactions take place through low polarintermediate.     

STUDIES ON THE SYNTHESIS OF(±)-CEMBRENE-A

A precursor 2 of cembrene-A(a termite trail pheromone)was prepared fromgeraniol through 7 steps.     

DETERMINATION OF CRYSTAL STRUCTURE OF C6H5GdCl2（THF）4

<正> By X-ray (λ=0. 71069A) diffraction of single crystal,we have determined the crystal structure of C6H5GdCl2 (THF)4,C22H37Cl2O4Gd, MT=593. 2,or-thorhombic space group Ccm2;with lattice parameters a=12. 776(6),b=12. 954(6), c=15. 802(3)A ;V=2615. 4(1. 8)A3;Z=4,Dc=2. 43gcm-3,μ=29. 3cm-1,F(000) = 1120. The structure was solved by heavy-atom method and Fourier techniques and refined by least-squares to a final R=0. 051 ,Rw = 0. 049 for 839 reflections with I≥1. 5σ (I). The results revealed that the bond length of Gd-C is 2. 437(22) A ,the average bond lengths of Gd-Cl 2. 678(6) A ,Gd-O 2. 499(12) A, C-C from phenyl group 1. 376(40)A. This crystal structure is the first organolanthanide complex with only one Ln-C bond in the molecule.     

STUDIES ON SCHIFF BASE COMPLEXES——Ⅳ. SYNTHESIS AND CRYSTAL STRUCTURE OF Fe (SALDPT) SAL

制备了Fe(saldpt)sal单晶并作了晶体结构分析。晶体数据:单斜,空间群P2₁/C(#14),a=12.486(5),b=18.502(8),c=10.870(5)Å,β=104.23(3)°,V=2434(2)ų,Z=4,D_c=1.40g/cm³.     

STUDIES ON THE RELATIONSHIP BETWEEN THE HELICAL STRUCTURE AND OPTICAL ACTIVITIES OF SOME CHIRAL CYCLICESTERS Ⅰ

ＳＴＵＤＩＥＳＯＮＴＨＥＲＥＬＡＴＩＯＮＳＨＩＰＢＥＴＷＥＥＮＴＨＥＨＥＬＩＣＡＬＳＴＲＵＣＴＵＲＥＡＮＤＯＰＴＩＣＡＬＡＣＴＩＶＩＴＩＥＳＯＦＳＯＭＥＣＨＩＲＡＬＣＹＣＬＩＣＥＳＴＥＲＳⅠ￥ＢｉｎｇＤＥＮＧ（ＤｅｐａｒｔｍｅｎｔｏｆＣｈｅｍｉｓｔｒ...     

THE CRYSTAL AND MOLECULAR STRUCTURE OF THE VIOLET ISOMER OF (⊘P)2[(CF3)2C2S2] RuCO

Abstract

The crystal structure and the details of the molecular configuration of the violet isomer of (?₃ P)₂ [(CF₃)₂ C₂ S₂] -RuCO were established from three dimensional, single crystal, X-ray diffraction data. This isomer crystallizes in the orthorhombic system, space group D¹⁵ ₂h-Pbca, in a cell whose dimensions are: a = 22.394(8), b = 19.107(6) and c = 17.480(5)Å. The measured and calculated densities are 1.56(2) and 1.56 gm-cm^?3 and z = 8 molecules/ unit cell. The shape of the polyhedron of ligands around the central Ru atom is a square pyramid distorted principally by the fact that the Ru—C bond length is shorter than the four bonds to the nearly equidistant phosphorus and sulfur ligands. The dithiolene sulfur atoms occupy adjacent positions in the basal plane; the two triphenylphosphine ligands occupy a basal plane site and the unique axial position while the carbonyl carbon occupies the fourth basal plane site.

The two Ru—S bond lengths are 2.298(3) and 2.287(3) Å, while the two Ru—P distances are 2.353(3) and 2.274(3) A in length, the latter being the basal plane Ru—P bond. The Ru—C and C—O bond lengths are 1.849(11) and 1.133(11) Å, respectively. The bonds within the triphenylphosphines are normal and the phenyl rings are planar, nearly equilateral hexagons. The dithiolene ligand has C—S and (ethylene C)—(ethylene C) distances of 1.719(10) and 1.358(12) Å, respectively, which conform more closely to values expected from an unsaturated cis-dithiol than a dithioketone. The closest inter or intramolecular contact between the Ru atom and the phenyl hydrogens is 3.08 A, which is about 0.5 Å longer than the sum of van der Waals' radii. When refinement was complete, the unweighted and weighted R(F) factors, for 2386 observed reflections, were 0.060 and 0.055, with an error of fit of 1.16.     

INVESTIGATIONS ON THE CRYSTAL STRUCTURE OF 2-(m-CYANOPHENYL)-5-CYANOBENZOTHIAZOLE AND CONFORMATIONS OF ITS ISOMERS

The crystal structure of 2-(m-cyanophenyl)-5-cyanobenzothiazole has been determined by X-ray single crystal diffraction method and its conformational analysis and its two isomers have been carried out by employing the PCILO method. The crystal of title compound belongs to the monoclinic system, space group P2_1/c, a=23.793(7), b=3.852(1), c=27.004(11), β=98.40°(3), Z=8, D_(calc). =1.42g/cm~3, F(000)=1072, the final β=0.048. The crystals of this molecule and its two isomers belong to a same space group, but the packing schemes of the molecules in the unit cell, the separations and the mutual orientation of-C≡N bonds are not same. From the detailed analysis and comparison of their packing schemes in crystal, it can be considered that they may be possible to polymerize to different extent in the solid state by appropriate energy stimulation.