Synthesis and Structural Studies of Novel Taxoids Derived from 1-DeoxybaccatinVI

Abstract  

Three novel taxoids were synthesized from 1-deoxybaccatinVI and their crystal structures were determined by X-ray crystallographic techniques. The influence of C(7), C(10) and C(4) substituents of the tetracyclic moiety on molecular conformations were investigated. The result shows that 4-acetyl moiety plays an important role in the conformation of the diterpenoid core. All of these 1-deoxybaccatinVI derivatives crystallize in orthorhombic system, space group P2₁2₁2₁. In the structures, the six-membered A ring exhibits the 1,4-di-planar conformation, the eight-membered B ring adopts boat–chair conformation and the six-membered C ring exhibits slightly distorted half-chair conformation.     

Three-Six-Membered Rings with Diverse Conformations in the Structure of 9-(4-Methoxyphenyl)-3,3-Dimethyl-10-(4-Methylphenyl)-1,2,3,4,5,6,7,8,9,10-Decahydroacridin-1,8-Dione

Abstract  

The crystal structure of 9-(4-methoxyphenyl)-3,3-dimethyl-10-(4-methylphenyl)-1,2,3,4,5,6,7,8,9,10- decahydroacridin-1,8-dione is determined by X-ray diffraction at 153(2) K. The title compound 1, C₂₂H₂₁N₅O₆, is triclinic, space group P-1, a = 9.6382(15) ?, b = 11.5847(15) ?, c = 12.4722(11) ?, α = 66.075(9)°, β = 70.176(9)°, γ = 85.800(13)°, Z = 2, V = 1194.1(3) ?³. It is interesting that the central pyridine ring of the acridine moiety is slightly distorted and adopts a boat conformation. The outer six-membered ring with two methyl groups adopts half-chair conformation, while another outer partially saturated six-membered ring adopts distorted boat form. In addition, the un-classical hydrogen bonds of C–H···O link the molecules forming polymers in the crystals.     

Synthesis and Crystal Structure of 1-Propionyl-3,6-bis (4-trifluoromethyl-phenyl)-1,4-dihydro-1,2,4,5-tetrazine

Abstract  

1-Propionyl-3,6-bis(4-trifluoromethyl-phenyl)-1,4-dihydro-1,2,4,5-tetrazine was prepared and its structure was determined by X-ray diffraction. Crystallization occurs in the monoclinic space group P2₁/c with a = 9.570 (2) ?, b = 12.273 (2) ?, c = 16.641 (3) ?; β = 103.75 (1)°; and Z = 4. The structure was solved by direct methods and refined to an R value of 0.0318. The central six-membered ring of the title compound has a boat conformation and is not homoaromatic.     

The Crystal Structure of 1-[2-(furan-2-yl)-6-methyl-1,2,3,4-tetrahydroquinolin-4-yl]Pyrrolidin-2-one

Abstract  

The title compound, C₁₈H₂₀N₂O₂, a potential pharmaceutical agent, crystallizes in the monoclinic P2₁/n space group with unit cell parameters a = 11.157 (7) ?, b = 8.776 (6) ?, c = 16.460 (11) ?, β = 103.08 (3)°. The tetrahydroquinoline ring system formed by the fusion of the benzene ring and the piperidine ring via two carbon atoms is coplanar, with the later adopting a sofa conformation. The pyrrolidine group in position 4 adopts an envelope conformation. Dimers related by inversion centers and linked by hydrogen bonds of the type N–H···O form cycles described by the graph set R₂²(16). Additionally, the dimers connect through weak hydrogen bonds of the type C–H···O with graph set C(10) to form chains extending along [001].     

The Synthesis and Crystal Structure of (4α,8β,13β,16β)-13-Methyl-16,18-diol-17-Norkaurane: A Simultaneous Reduction Product of Isosteviol

Abstract  

(4α,8β,13β,16β)-13-methyl-16,18-diol-17-norkaurane was synthesized by esterification and reduction of isosteviol, respectively. The structure of the title compound was established by spectral analysis and X-ray diffraction studies. The compound crystallizes in the orthorhombic space group P2₁2₁2₁ with unit cell parameters: a = 7.3705 (14) ?, b = 13.508 (3) ?, c = 20.139 (4) ?, V = 2005.1 (7) ?³, Z = 4. The conformation of rings A and B is chair, whereas the conformation of ring C is unsymmetrical distorted chair. The stereochemistry of the A/B and B/C ring junctions is trans, while the five-membered ring D adopts an envelope conformation.     

Synthesis, characterization, and crystal structure of an iron(II) 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane macrocyclic complex

The synthesis and detailed characterization of the macrocyclic complex [Fe(meso)(CH₃CN)₂](ClO₄)₂·2CH₃CN (meso: 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane) based on analytical, spectrometric, spectroscopic and X-ray diffraction methods are reported herein. This is the first single crystal structure of an iron-meso complex ever reported in the literature. The molecular structure revealed a tetragonally distorted octahedral geometry with the iron(II) bound to four amine nitrogens in the equatorial plane, while the apical positions are occupied by acetonitrile molecules. The macrocycle adopts the most stable conformation with the six-membered rings in chair form, while the gauche conformation is seen for the five-membered rings. The compound crystallizes in the space group P2₁/n, with cell parameters a=10.139(1), b=12.237(1), c=13.311(1) ?, β=99.542(2)° and Z=2.Supplementary material CCDC-239983 contains the supplementary crystallographic data for this paper. These data can be obtained free of charge at [or from the Cambridge Crystallographic Data Centre (CCDC), 12 Union Road, Cambridge CB2 1EZ, UK; fax: +44(0)1223–336033; email: deposit@ccdc.cam.ac.uk].”     

X-Ray Crystal Structure of Phyllostin,a Metabolite Produced by <Emphasis Type="Italic">Phyllosticta cirsii</Emphasis>, a Potential Mycoherbicide of <Emphasis Type="Italic">Cirsium arvense</Emphasis>

Abstract  

The X-ray crystal structure of phyllostin (8-hydroxy-3-methyl-2-oxo-2,3,4a,5,8,8a-hexahydro-benzo[1,4]dioxine-6-carboxylic acid methyl ester) is reported. Phyllostin was recently and for the first time isolated, together with phytotoxin phyllostoxin and the phyllostictines A–D, from the culture filtrates of Phyllosticta cirsii, a fungal pathogen isolated from diseased Cirsium arvense leaves and evaluated as biocontrol agent of this noxious perennial weed. Phyllostin crystallizes in the monoclinic space group P2₁ with unit cell parameters: a = 8.371(2), b = 7.026(1), c = 9.918(1) ?, β = 92.013(8)°, Z = 2. The final refinement converged to R1 = 0.0530 for 1026 observed reflections having I > 2σ(I). In the molecule two trans joined six-membered rings are present. The cyclohexene ring adopts a half-chair conformation. The 2-oxo-1,4-dioxan ring adopts a distorted half-chair conformation. The relative stereochemistry of the four chiral centers turns out to be 3R,4aS,8R,8aS. In the crystal packing molecules form infinite chains through O–H···O intermolecular hydrogen bonds. Chains run along the crystallographic a axis forming layers of molecules stacking in the [0 1 0] direction.     

Crystal Structure of 2-(4,5-Bis(4-methoxyphenyl)-5<Emphasis Type="Italic">H</Emphasis>-chromeno[4,3-<Emphasis Type="Italic">b</Emphasis>]pyridin-2-yl)phenol

Abstract  

The title compound 2-(4,5-bis(4-methoxyphenyl)-5H-chromeno[4,3-b]pyridin-2-yl)- phenol (C₃₂H₂₅NO₄, Mr = 487.53) was synthesized and crystallized. The crystal belongs to monoclinic, space group P2(1)/c with a = 12.4170 (11), b = 18.313 (2), c = 11.7103 (10) ?, β = 111.569(2)°, V = 2476.4(4) ?³, Mr = 487.53, Z = 4, Dc = 1.308 g/cm³, μ(MoK _α ) = 0.086 mm⁻¹, F(000) = 1024, the final R ₁ = 0.0632 and wR ₂ = 0.1454. X-ray analysis reveals that the atoms of C(1), C(2), C(3), C(4), C(5) and N(1) form a planar six-membered ring, while the atoms of C(1), C(2), C(6), C(7), C(12) and O(1) form a six-membered ring of envelope conformation.     

Crystal and molecular structure of bis(8-phenylmenthyl) 2-(2-methyl-5-oxo-3-cyclohexen-1-yl)propandioate, C42H54O5· CH3CN

The X-ray crystal structure of the title compound, as crystallized from acetonitrile-water was determined. The relative stereochemistry of the cyclohexenone ring with respect to the 8-phenylmenthyl esters was determined. The title compound crystallizes in the noncentrosymmetric space group P2₁, with a=8.9850(10) ?, b=15.575(3) ?, c=14.478(2) ?, β=94.61(2)°, and D _calc=1.118 g cm⁻³ for Z=2.     

Crystal structure of 3β-acetoxy-pregna-5,16-dien-20-one (16 DPA)

The title compound, 3β-acetoxy-pregna-5,16-dien-20-one, C₂₃H₃₂O₃, has been synthesized by acetylation followed by oxidation of diosgenin and its crystal structure has been solved from single crystal X-ray diffraction data. The compound crystallizes into orthorhombic space group P2₁2₁2₁ with unit cell parameters: a = 6.031(4) ?, b = 12.481(2) ?, c = 27.162(5) ?, Z = 4. The crystal structure has been refined to R = 0.0597 for 1291 observed reflections. Rings A and C of the compound are in chair conformation whereas ring B is in half-chair conformation. Ring D is in envelop conformation. The A/B ring junction is quasi-trans, while ring systems B/C and C/D are trans fused about the C8–C9 and C13–C14 bonds, respectively. The steroid nucleus has a small twist, as shown by the C19–C10⋅C13–C18 pseudo-torsion angle of 9.5°. The crystal packing is determined by a pair of weak C–H⋅O hydrogen bonds in addition to van der Waals interactions.     

X-ray structural and spectroscopic investigation of 1-piperidine-2,4-dinitrobenzene

The crystal structure of the title compound (C₁₁H₁₃N₃O₄) has been determined by single-crystal X-ray diffraction. The compound is monoclinic, space group P2₁/n, witha=9.968(2),b=9.156(2),c=13.249(2)Å, =102.05(2)°, andD _x=1.563 gcm^–3 forZ=4. The aromatic ring shows a slight boat deformation. Theo- andp-NO₂ groups are twisted out of the plane of the phenyl ring by 39.0(2)° and 4.4(1)°, respectively. The piperidine ring exhibits a slightly deformed chair conformation. Short C–H...O intermolecular contacts stabilize the three dimensional structure. UV and NMR data indicate that the molecule in solution presents a conformation similar to that of the the solid state.     

Synthesis and Crystal Structure of 5-Chloro-3-Methyl-1-Phenyl-1H-Pyrazole-4-Carbaldehyde

Abstract  

The title compound, 5-chloro-3-methyl-1-phenyl-1H-pyrazole-4-carbaldehyde 2, was prepared in a series of syntheses to produce new pyrazole derivatives, and its crystal structure was determined by X-ray diffraction method. The crystal belongs to monoclinic, space group P2₁/c with unit cell parameters a = 6.7637(4) ?, b = 6.8712(3) ?, c = 22.4188(10) ?, β = 93.8458(14)o, V = 1039.56(9) ?³ and Z = 4. X-Ray reveals that the aldehydic fragment is almost coplanar with the adjacent pyrazole ring, but the two ring planes are inclined at 72.8(1)o. The molecule is linked to its neighbor by two directionally specific C–H···O interactions.     

Synthesis, Crystal Structure and ab initio Studies of Cyclohexyl N-Phenylcarbamate

Abstract  

Cyclohexyl N-phenylcarbamate, C₁₃H₁₇NO₂ (I), which is a useful target for biotransformations by fungi, has been synthesized and the structure has been solved by X-ray diffraction. The crystals are triclinic, space group P [`1] \bar{1} , with a = 5.2581 (2) ?, b = 9.5080 (3) ?, c = 12.6165 (4) ?, α = 70.544 (2)°, β = 89.075 (2)°, γ = 80.447 (2)°, M _r = 219.28, V = 585.96 (3) ?³, Z = 2 and R = 0.065. In the title compound the phenyl ring makes a dihedral angle of 30.68(7)° with the carbamate group The molecules are linked into infinite chains via N–H···O hydrogen bonds along the a axis. These hydrogen-bonded chains are further linked by weaker C–H···π interactions. Quantum-mechanical ab initio calculations for the free molecule reproduce well the observed bond lengths and valency angles but show that the crystal packing might be responsible for the rotation of the phenyl ring out of the carbamate plane in the solid state conformation.     

3-Methyl-3a,4-Dihydro-3H-Thiochromeno[4,3-c]isoxazol

Abstract  The crystal structure of the title compound, C₁₁H₁₁NOS, was determined by an X-ray diffraction analysis. The compound crystallizes in the monoclinic space group P2₁/c with cell parameters a = 10.533(2) ?, b = 12.7826(19) ?, c = 7.6491(17) ?, β = 107.997(17)^°, V = 979.5(3) ?³ and Z = 4. The S containing heterocycle adopts a sofa conformation, whereas the 5-membered ring adopts an envelope conformation. The crystal packing is characterized by weak C–H···N contacts and π-stacking interactions. Graphical Abstract  The title compound, 3-methyl-3a,4-dihydro-3H-thiochromeno[4,3-c]isoxazol was synthesized by an 1,3 dipolar cycloaddition reaction and its crystal structure determined. Single crystal X-ray diffraction analysis reveals that the aromatic 6-membered ring is planar, whereas the ring containing the S atom adopts a sofa conformation and the 5-membered ring an envelope conformation. The methyl group is in an equatorial position.      

Synthesis and Structural Conformation Studies of a Potent Unsymmetrical 1,4-Dihydropyridine

Abstract 2,6-Dimethyl-5-(phenylcarbamoyl)-4-(3-nitrophenyl)-1,4-dihydropyridine-2-carboxylate was synthesized in two steps and was characterized spectroscopically and confirmed by X-ray diffraction studies. The molecule crystallizes in the monoclinic crystal class in the spacegroup P2₁/c with cell parameters a = 10.5960(6) ?, b = 10.2450(7) ?, c = 19.5790(11) ?, β = 107.448(3)° and Z = 4. The 1,4-dihydropyridine ring in the structure adopts a flattened boat conformation. Graphical Abstract 2,6-Dimethyl-5-(phenylcarbamoyl)-4-(3-nitrophenyl)-1,4-dihydropyridine-2-carboxylate was synthesized in two steps and was characterized spectroscopically and confirmed by X-ray diffraction studies. The molecule crystallizes in the monoclinic crystal class in the spacegroup P2₁/c with cell parameters a = 10.5960(6) ?, b = 10.2450(7) ?, c = 19.5790(11) ?, β = 107.448(3)° and Z = 4. The 1,4-dihydropyridine ring in the structure adopts a flattened boat conformation.      

Synthesis, Structural Characterization and Spectroscopic Properties of 1,2-Bis[4-(3,5-dimethyl-1H-pyrazol-1-yl)-2-oxobutyl]benzene

Abstract  

The crystal structure of the title compound C₂₂H₃₀N₄O₂·H₂O (L), has been determined using X-ray diffraction at 293 K. The crystal of 1,2-bis[4-(3,5-dimethyl-1H-pyrazol-1-yl)-2-oxobutyl]benzene is in triclinic crystal system with space group P(−1) (Z = 2), lattice parameters a = 8.225(6) ?, b = 10.967(6) ?, c = 12.903(6) ?, V = 1119.1(11) ?³. Analyses of single crystals of L, crystallized from dichloromethane/diethyl ether (1:1), revealed that the molecules are arranged in couples, which adopt a pseudo chair conformation, by means of intermolecular O–H···N hydrogen bonding interactions. Moreover, the extended structure revealed a 1D chain caused by several C–H···N intermolecular interactions.     

An X-ray Crystallographic Study of the Related Triazenes, 1,4-Di[(<Emphasis Type="Italic">E</Emphasis>)-2-(2-nitrophenyl)-1-diazenyl]piperazine and Methyl 4-{(E)-2-(4-methylpiperazino)-1-diazenyl}benzoate

Abstract The crystal structures of methyl 4-{(E)-2-(4-methylpiperazino)-1-diazenyl}benzoate (2a) and 1,4-di[(E)-2-(2-nitrophenyl)-1-diazenyl]piperazine (3a) have been determined by single crystal X-ray diffraction analysis. The bis-triazene (3a) adopts an unusual pseudo-boat conformation in the piperazine ring, with a dihedral angle of 52.20(0.06)° between the two planes defined within the piperazine ring. The crystal structures of 2a and 3a are compared with the structure of the triazene (4) and the closely related bis-triazene (5). The piperazine ring of 2a adopts a typical chair conformation, whereas the piperazine ring of 3a adopts an unusual boat conformation. Crystal data: 2a C₁₃H₁₈N₄O₂, monoclinic, space group P2₁ /n, a = 13.849(3) ?, b = 6.577(1) ?, c = 14.904(3) ?, α = 90°, β = 96.098(3)°, γ = 90° and V = 1,349.8(4) ?³, for Z = 4. 3a C₁₆H₁₆N₈O₄, triclinic, space group P-1, a = 7.6066(6) ?, b = 8.3741(7) ?, c = 14.507(1) ?, α = 78.673(1)°, β = 81.877(1)°, γ = 73.445(1)° and V = 865.0(1) ?³, for Z = 2. Index abstract The crystal structures of methyl 4-{(E)-2-(4-methylpiperazino)-1-diazenyl}benzoate (2a) and 1,4-di[(E)-2-(2-nitrophenyl)-1-diazenyl]piperazine (3a) have been determined by single crystal X-ray diffraction analysis.     

Crystal Structure of bis(18-Crown-6)-bis(formato-O) dicaesium dihydrate

Abstract  The crystal structure of the title compound, [2Cs⁺(C₁₂H₂₄O₆)₂(CHO₂ ⁻)₂(H₂O)₂], was determined by an X-ray diffraction analysis. The compound crystallizes in the monoclinic space group P2₁ /n with cell parameters a = 10.4278(7) ?, b = 10.0183(5) ?, c = 18.2383(12) ?, β = 93.723(5)°, V = 1910.3(2) ?³ and Z = 2. The Cs cations are bonded to each of the six O atoms of a crown ether ring, two water molecules, and one O atom of a formato anion. As a result of that, a centrosymmetric dimeric dinuclear complex is formed. The two halves of the dimer are connected by a ring of formato anions and water molecules which are linked by O–H···O hydrogen bonds. Index Abstract  The title compound, bis(18-crown-6)-bis(formato-O), caesium dihydrate, features a centrosymmetric dimeric dinuclear complex where two Cs cations are coordinated by six O atoms of a crown ether ring. The two halves of this complex are held together by a ring of formato anions and water molecules which are linked by hydrogen bonds.      

Crystal Structure and Characterization of Iridoid Related Compound Isoeucommiol

Abstract  

A single crystal of iridoid related compound isoeucommiol was obtained through NaBH₄ reduction of aucubigenin which was formed by enzymatic hydrolysis of aucubin. Its structure and stereochemistry were determined by X-ray diffraction. The crystal adopts an envelope conformation, presenting a triclinic system, space group P1 with Z = 1, unit cell dimensions a = 5.4158(13) ?, b = 6.5251(15) ?, and c = 7.1555(17) ?. Moreover, extensive network of intermolecular O–H···O hydrogen bonds in crystal lattices can be observed.     

Structures of transition and alkaline earth metal salts of 5-aminonaphthalene-2-sulfonate and 6-aminonaphthalene-1, 3-disulfonate: Some unusual coordination behaviors

Salts of 5-aminonaphthalene-2-sulfonate with divalent Mg, Mn, Co, and Ni cations have been crystallized and their structures determined by single crystal X-ray methods. The Mg, Mn, and Co salts are isostructural. Crystal data for hexaaquamagnesium(II) 5-aminonaphthalene-2-sulfonate hexahydrate, [Mg(H₂O)₆](H₂NC₁₀H₆SO₃)₂·6H₂O: monoclinic, P2₁/c, Z=2, a=14.1329(18) ?, b=8.5789(11) ?, c=12.4880(17) ?, β=93.374(3)°, V=1511.5(3) ?³; hexaaquamanganese(II) 5-aminonaphthalene-2-sulfonate hexahydrate, [Mn(H₂O)₆](H₂NC₁₀H₆SO₃)₂·6H₂O: monoclinic, P2₁/c, Z=2, a=14.249(3) ?, b=8.5940(17) ?, c=12.505(3) ?, β=93.30(3)°, V=1528.8(6) ?³; hexaaquacobalt(II) 5-aminonaphthalene-2-sulfonate hexahydrate, [Co(H₂O)₆](H₂NC₁₀H₆SO₃)₂·6H₂O: monoclinic, P2₁/c, Z=2, a=14.1406(18) ?, b=8.5674(11) ?, c=12.4960(16) ?, β=93.297(2)°, V=1511.4(3) ?³. The structures are composed of alternating layers of octahedral metal–aqua complexes and sulfonate anions linked by hydrogen bonds. The three water molecules of crystallization are associated with the hexaaquametal cations and sulfonate O atoms. The repeat unit along the a-axis is a single layer. The Ni salt [crystal data for tetraaquabis(5-aminonaphthalene-2-sulfonato-N)nickel(II) dihydrate, [Ni(H₂O)₄(H₂NC₁₀H₆SO₃)₂]·2H₂O: triclinic, , Z=1, a=6.8524(10) ?, b=8.3094(12) ?, c=11.4832(17) ?, α=69.003(2)°, β=76.570(3)°, γ=83.952(2)°, V=593.56(15) ?³] has a very different structure with direct coordination of the amine N atom to Ni, a modified stacking pattern, and fewer free water molecules. Ag and Ni salts of an amine-substituted naphthalenedisulfonate have also been characterized. Crystal data for diaqua(6-ammonionaphthalene-1,3-disulfonato-O)silver(I) hydrate,[Ag(H₂O)₂(H₃NC₁₀H₅(SO₃)₂)]·0.42H₂O: monoclinic, P2₁/c, Z=2, a=9.099(3) ?, b=21.406(6) ?, c=7.629(2) ?, β=110.178(4)°, V=1394.9(7) ?³; tetraaquabis (6-ammonionaphthalene-1,3-disulfonato-O)nickel(II)tetrahydrate, [Ni(H₂O)₄(H₂NC₁₀H₅ (SO₃)₂)₂]·4H₂O: triclinic,, Z=1, a=6.7971(17) ?, b=10.661(3) ?, c=11.165(3) ?, α=68.308(4)°, β=88.292(5)°, γ=84.896(5)°, V=748.8(3) ?³. The silver salt contains six coordinate metal centers each of which bonds to four sulfonate O atoms from three different anions and two water molecules. The nickel salt contains octahedral cations with four water molecules and two trans sulfonate O atoms. Both structures are layered, but differently from each other and from those of the monofunctional naphthalenesulfonate salts.Unusual coordination of a sulfonate group to a transition metal and coordination of an amine group to nickel but not to cobalt or manganese have been observed in a series of metal aminonaphthalenesulfonate salts