Hydrogen bonding in 2-hydroxy((di)thio)benzoates. I. X-ray structures of 2,6-dimethylpiperidinium salts

X-ray structural data are reported for 2,6-dimethyl-piperidinium-2-hydroxybenzoate (C₁₄H₂₁NO₃, orthorhombic,P2₁2₁,2₁, (19);a=7.983(1)Å,b=12.680(2)Å,c=13.838(2)Å;Z=4;R=0.042) and for two polymorphs of 2,6-dimethylpiperidinium-2-hydroxythiobenzoate (C₁₄H₂₁NO₂S), an-form (monoclinic,P2₁/n (14);a=8.005(4)Å,b=22.150(2)Å,c=8.672(4)Å,=101.91(6)°;Z=4;R=0.059) with an intramolecular O-HS hydrogen bond, and a-form (orthorhombic,P2₁2₁2₁ (19);a=8.188(1)Å,b=14.781(2)Å,c=24.163(4)Å;Z=8;R=0.15) with an intramolecular O-HO hydrogen bond. The intra-and intermolecular hydrogen bond patterns are discussed, including the literature data of 2,6-dimethylpiperidinium-2-hydroxydithiobenzoate.     

A comparison of the coordination preferences of Zn, Co, and Cd(II) with the heteroscorpionate ligand (2-hydroxy-3-t-butyl-methylphenyl)bis (3,5-dimethylpyrazolyl)methane

Reaction of the Zn, Cd, or Co nitrate salts with the deprotonated ligand (2-hydroxy-3-t-butyl-methylphenyl)bis(3,5-dimethylpyrazolyl)methane (L1O^–) in methanol produced the following complexes: [(L1OH)Zn(NO₃)₂] in two isomorphs, a = 40.983(8) Å, b = 9.571(2) Å, c = 15.667(8) Å, = 90, = 106.38(1), = 90, C2/c, and a = 13.027(3) Å, b = 14.781(4) Å, c = 16.107(3) Å, = 90, = 105.30(1), = 90, P2₁/n; [(L1OH)Cd(pz)(NO₃)₂] a = 14.7476(2) Å, b = 13.5411(2) Å, c = 16.7223(2) Å, = 90, = 110.3840(10), = 90, P2₁/c; and [(L1O)Co(pz)(NO₃)] a = 11.4240(2) Å, b = 13.4498(2) Å, c = 13.8056(2) Å, = 105.2080(10), = 105.8130(10), = 112.7470(10), P . The Zn adopts a pseudotetrahedral four-coordinate geometry where the potentially tridentate ligand is actually bidentate with a protonated and uncoordinated phenoxy arm. The Co complex is pseudooctahedral six-coordinate where the phenoxy arm is deprotonated and coordinated. Finally the Cd complex is seven-coordinate but the metal is not coordinated through the phenoxy group that is again protonated.     

Reaction of trimethylaluminum and trimethylgallium with bifunctional amines: Syntheses and molecular structures of [Me2Al−N(CH2CH2)2−C−(OCH2)2]2 and [Me2Ga−N(Si(H)Me2)2]2

The crystalline products [Me₂Al–N(CH₂CH₂)₂–C–(OCH₂)₂]₂ (I) and [Me₂Ga–N(Si(H)Me₂)₂]₂ (II) were prepared from reactions of trimethylaluminum and trimethylgallium with 1,4-dioxa-8-azaspiro[4.5]-decane and 1,1,3,3-tetramethyldisilazane, respectively, in toluene. The organoaluminum dimer crystallizes in the monoclinic space groupP2₁/c with unit cell parametersa=8.970(2) ,b=9.683(2) ,c=12.833(3) , =103.18(2)°,V=1085.3(3) ³, andD _calcd=1.22 g cm^–3 forZ=2. Least-squares refinement based on 935 observed reflectionsI>3(I) in the range 3.5°<2<45.0° led to a finalR factor of 0.033 (R _w =0.041). The dimeric organosilazagallium crystallizes in the triclinic space group with unit cell parametersa=7.636(2) ,b=9.168(2) ,c=9.466(3), =72.81(2)°, =87.94(2)°, =69.90(2)°,V=593.0(3) ³, andD _calcd=1.30 g cm^–3 forZ=1. Least-squares refinement based on 1661 observed reflectionsI>3(I) in the range 3.5°<2<48.0° led to a finalR factor of 0.055 (R _w =0.070). Both compoundsI andII reside about a crystallographic center of symmetry and contain a planar M₂N₂ (M=Al forI, Ga forII) four-membered ring withI having an Al...Al contact of 2.801 .     

Crystal and molecular structure of 4,17a-methy1-4, 17a-diaza-5α-androstane (HS353): An intermediate in the design of azasteroid neuromuscular blocking agents

The crystal and molecular structure of 4, 17a-methyl-4, 17a-diaza-5-androstane (HS353), C₂₀N₂H₃₆ has been determined by direct methods and successive electron density calculations. The crystals are triclinic,a=7.419(2),b=20.300(4),c=12.866(2)Å,=105.91(2),=76.33(2),=99.32(2)°, space groupP1,Z=4. Block-matrix least-squares refinement converged toR=0.0660 for 3243 reflections withI3I (CuK radiation). The four independent molecules show only minor conformational variations, all rings being trans-connected chairs. Introduction of N at positions 4 and 17a of ringsA andD creates asymmetry in both conformation and bond angles, producing outward bending of the C-N side groups at both ends of all four molecules.Steroids and related studies, Part 83.     

Crystal and molecular structure of 3-methoxy-6-nor-6,7-secooestra-1,3,5(10),9(11), 14-penten-17-one-8β-ethyl carboxylate

C₂₀H₂₂O₄,M _r =326.39, triclinic,P¯1,a=10.365(2),b=11.383(2),c=8.461(1) Å, =103.60(1),=104.44(1), =105.23(1)°,Z=2, (CuK)=1.54178 Å;R=0.0633 for 1940 reflections. The results of the X-ray analysis have shown that the ethyl carboxylate substituent is oriented. The geometry of the main skeleton of the molecule has not revealed any significant differences in the present compound and in the case of the epimeric molecule.     

Anticancer agent development. 5. X-ray structure and1H nmr spectral analysis of (1α,2α,5α,6α)-2,6-bis(3,4-methylenedioxyphenyl)-3,7-dioxabicyclo[3.3.0]octane-4,8-dione

The title compound, C₂₀H₁₄O₈, Mr=382.3, crystallized from chloroform in the centric space group P¯1 witha=6.516(4),b=6.798(3),c=9.545(7) Å,=85.31(5),=73.87(5), =79.59(4)°,V=399.2 ų, and D_calc=1.59 g cm^–3 forZ=1. Least-squares refinement of 1035 observed [F_o5(F_o)] reflections led to the final agreement index ofR=0.074. The molecule resides on a crystallographic center of inversion and is disordered into two different conformations. This manifests itself as a 50/50 disorder at O(4), C(2), and C(3). The observed structure reveals acis relationship between the bridgehead hydrogen atoms and the aryl rings. The 90 MHz¹H nmr spectrum of the title compound exhibits an AAXX spin system with a H(1)C(2) to H(1)C(3) and H(1)C(2) to H(1)C(3) coupling constant of 2.8 Hz. Computer spectral simulation and Karplus equation analysis are utilized to illustrate a relaxation of the torsion angles between H(1)C(2) and H(1)C(3), and H(1)C(2) and H(1)C(3) is solution.     

Low-temperature,high-resolution crystal structure study of tricyclo[3.3.1.13,7]decan-2-ol (adamantanol-2)

The structure of the title compound (C₁₀H₁₅OH) was determined by X-ray diffraction at liquid nitrogen temperature. The crystals are triclinic, spacegroupP¯1 witha=11.3686(5),b=11.3990(5),c=11.4353(6) Å,=82.193(4),=70.211(4) and =62.279(4)°,V _c =1233.9(1) ų,Z=6,F(000)=504,D _x =1.229 g cm^–3; MoK radiation, =0.71073 Å,(MoK)=0.7 cm^–1. FinalR factor=0.046 andwR=0.062 for 8162 reflections withI>2.5(I). The asymmetric unit consists of three independent adamantanol-2 molecules which together with the three symmetry-related molecules form a cluster having pseudo ¯3 symmetry. The six molecules in the cluster are connected by six O-HO hydrogen bonds, the oxygens of which constitute an almost ideal chair conformation.     

Crystal structures of 1-(2-hydroxyphenyl)-3-phenyl-1,3-propanedione and 1-(1,3-benzodioxol-5-yl)-3-(2,4-dimethoxyphenyl)-1,3-propanedione

1-(2-Hydroxyphenyl)-3-phenyl-1,3-propanedione crystallizes in the triclinic space group (a=5.4233(5),b=13.910(1),c=17.036(1) Å, =68.311(6), =80.854(7), =78.760(8)°) as two independent enolic tautomers in which the hydroxyl and phenolic protons are hydrogen bonded to the ketonic oxygen atom. The structure was refined toR=0.039 for 2085I3(I) reflections. 1-(1,3-Benzodioxol-5-yl)-3-(2,4-dimethoxyphenyl)-1,3-propanedione, which belongs to the triclinic space group (a=7.3990(7),b=8.1239(5),c=14.004(1) Å, =86.673(6). =88.574(7), =64.885(7)°) also exists in the enolic form. The structure was refined toR=0.040 for 1564I3(I) reflections.     

The crystal structure of 2-(α-hydroxy-βββ-trichloroethyl)-4-methylphenol and its relevance to the condensation of chloral hydrate and parasubstituted phenols

The product formed by the condensation ofp-cresol and chloral hydrate in the presence of anhydrous potassium carbonate is shown by single crystal X-ray crystallography to be 2-(-hydroxy--trichloroethyl)-4-methylphenol and its failure to cyclize to form a 1,3-benzdioxin is explained. The title compound is monoclinic, P2₁,/c,Z=4,a=12.316(1),b=8.8668(9),c=10.275(2) Å,=107.90(1)°     

Synthesis,structural, and spectroscopic study of rhenium(III) and rhenium(V) 4,6-dimethylpyrimidine-2-thiolate/triphenylphosphine mixed complexes: Crystal and molecular structure of ∥ReCl2(pymS)(PPh3)2∥·C3H6O and ∥ReOCl2(pymS)(PPh3)∥

4,6-dimethylpyrimidine-2(1H)-thione reacts with rhenium(V) precursorstrans-ReOX₃(PPh₃)₂ (X=Cl, Br) in acetone, to afford two classes of crystalline pyrimidinethiolate/triphenylphosphine mixed complexes:trans-Re^IIIX₂(C₆H₇N₂S)(PPh₃)₂·C₃H₆O and Re^vOX₂(C₆H₇N₂S)(PPh₃) (X=Cl, Br). The crystal structures oftrans-ReCl₂(C₆H₇N₂S)(PPh₃)₂·C₃H₆O (I) and ReOCl₂(C₆H₇N₂S)(PPh₃) (II) have been determined from single-crystal diffractometer data and refined toR factors of 0.0496 and 0.0365, respectively. (I) crystallizes in the triclinic space group P¯1 witha=16.875(4),b=13.969(7),c=9.510(2) Å;=81.78(2)°,=85.15(12)°, =107.97(8)° andZ=2. The coordination geometry around the rhenium center exhibit mutuallytrans phosphine groups and chloride ligands disposedtrans to the nitrogen and sulfur donors of the pyrimidinethiolate ligand which form a four-membered chelate ring with the metal. (II) crystallizes in the monoclinic space group P2₁/c witha=12.554(3),b=10.501(1),c=19.200(5) Å;=106.54(2)° andZ=4. The rhenium atom presents a very distorted octahedral configuration with a chlorine atomtrans to phosphine ligand in the axial position and the N,S-chelate ligand in the equatorial plane with the sulfur donor atomtrans the Re=O_oxo group. The compounds were characterized also by means of ir and nmr spectroscopic measurements; reaction pathways are discussed on the basis of structural data.     

Molecular structure of 3-(3-oxo-bicyclo[2.2.1]hept-5-en-2-yl)-oxirane-2-carboxylic acid methyl ester

The crystal and molecular structure of an epoxy ester is described. The structure has been solved by vector search methods and refined by least squares methods toR ₁=0.0372 [I>2(I)]. The structure consists of two independent molecules in the asymmetric unit. These molecules are chemically the same. Crystal data: C₁₁H₁₂O₄, triclinic, space group ,a=10.324(3),b=10.553(7),c=10.869(5)Å, =61.77(4), =88.64(4), =88.16(6)°,V=1042.7(9)ų,Z=4.     

Crystal structures of five policyclic compounds related to the natural product forskolin

(3(Z),4,6a,9a,9b)-(±)-3a,4,6a,7,8,9,9a,9b-octahydro-4,7,7, 9b-tetramethyl-3a-[3-(methoxymethyloxy)-3-methyl-1-butenyl]-5H-naphto[1,8-de]-1,3-dioxin-6-one (I), C₂₂H₃₆O₅,M _r=378.51, monoclinic,P2₁/n,a=6.330(1),b=14.576(2),c=22.837(2)Å,=93.04(1)°,V=2104.1(2)ų,Z=4,D _c=1.19 Mg/m³, (MoK)=0.71069Å,=0.8 cm^–1,F(000)=832,T=298 K,R=0.054 for 1971 observed reflections; (7a,10a,10b,12)-(±)-7a,9, 10,10a,10b,11,12,12a-octahydro-2,2,10,10,10b,12a-hexamethyl-2H,8H-1-benzopyrano[4a,5,6,-de][1,3,2]-benzodioxin-11-one (II), C₂₀H₂₉O₄,M _r=334.5, triclinic,P-1,a=10.595(2),b=12.152(1),c=8.073(1)Å,=106.53(1),=105.65(1), =66.29(1)°,V=897.9(2)ų,Z=2,D _c=1.24 Mg/m³, (MoK)=0.71069Å,=0.8 cm^–1,F(000)=362,T=298 K,R=0.046 for 2848 observed reflections; (7a,10a,10b,12, 12a)-(±)-7a,9,10,10a,10b,11,12,12a-octahydro-2,2,10,10,10b,12a-hexamethyl-2H,8H-1-benzopyrano[4a,5,6-de][1,3,2]-benzodioxin-11, 12-diol (III), C₂₀H₃₂O₅ (two molecules in the asymmetric unit),M _r=352.2, triclinic,P-1,a=12.948(3),b=13.615(3),c=12.197(4)Å,=101.16(2),=111.88(2), =69.48(2)°,V=1863.8(9)ų,Z=2,D _C=1.26 Mg/m³,(MoK)=0.71069 Å,=0.8 cm^–1,F(000)=768,T=298 K,R=0.060 for 4570 observed reflections; 4-acetoxy-4-[[(4a,5,8a)-(±)-hexahydro-4a,6,6-trimethyl-4H-1,3-benzodioxin-4-one]-5-yl]butan-2-one (IV), C₁₇H₂₆O₆,M _r=326.4, monoclinic,P2₁/c,a=10.495(2),b=12.050(2),c=14.216(2)Å,=108.51(1)°,V=1704.8(5)ų,Z=4,D _c=1.27 Mg/m³,(MoK)=0.71069 Å,=0.9 cm^–1,F(000)=704,T=298 K,R=0.049 for2455 observed reflections; (3a,4,5,6,6a,9a,9b)-(±)-4,5-epoxy-decahydro-3, 3a-dihydroxy-2-ethoxy-4,7,7,9b-tetramethyl-naphto-[1,8-bc]-pyran-6-ol-acetate (V), C₂₀H₃₂O₇,M _r=383.5, monoclinic,C2/c,a=10.353(2),b=17.975(3),c=21.188(3)Å,=91.29(1)°,V=3942(1)ų,Z=8,D _c=1.29 Mg/m³,(MoK)=0.71069 Å,=0.8 cm^–1,F(000)=1664,T=298 K,R=0.051 for 2120 observed reflections. We report here the complete structures of four decalin derivatives (compoundsI, II, III, V) and one related compound (compoundIV) synthetized in order to find an efficient synthetic approach for the natural productforskolin.     

X-ray structures of two methoxybenzo[b]thiophenes

The crystal and molecular structures of two methoxybenzo[b]thiophenes have been determined by three-dimensional, single-crystal X-ray diffractometry. Both 3-(4-hydroxy-3, 5-dimethoxybenzoyl)-2-(4-methoxyphenyl)-6-methoxybenzo[b]thiophene and 3-(2,6-dimethoxybenzoyl)-2-(4-methoxyphenyl)-6-methoxybenzo[b]thiophene (hereafter referred to asI andII, respectively) crystallize in the monoclinic centrosymmetric space groupP2₁/n (No. 14, C _2h ⁵ ) with four formula units-per cell witha=6.866(1),b=28.638(2),c=11.830(2) Å, and =105.52(1)° anda=9.328(1),b=7.977(1),c=29.650(4) Å, and =97.87(1)°, respectively. The phase problems were solved by direct methods and the respective final full-matrix least-squares refinements converged toR=0.046 and 0.031. The structures differ in the positioning of the dimethoxy groups of the benzoyl ligands and the addition of a hydroxyl group inI. The molecules in the crystal lattice are held together by van der Waals forces plus the addition of hydrogen bonding in compoundI. Selected bond distances and angles and torsion angles are tabularized.     

Crystal and molecular structure of (exo)-2-methoxycarbonyl-5-ethoxycarbonyl-4,5,6,11b-tetrahydroisoxazolidino-[2,3-a]-β-carboline,C18H20N2O5

The structure of the title compound, C₁₈H₂₀N₂O₅, was determined by X-rays atT=290 K.M _r =344.366, monoclinic, space groupP2₁/c,a=13.7850(8),b=8.8951(7),c=15.1603(11) Å, =111.410(6)°,V _c =1730.7 ų,Z=4,D _x =1.322 Mgm^–3. Cu K radiation (graphite crystal monochromator, =1.54178 Å),(Cu K)=7.69 cm^–1. Final conventionalR-factor=0.057,R _w =0.076 for 2160 observed reflections and 271 variables. The structure was solved usingMultan.     

Two acetylamino derivatives of 2,4-bis(trichloromethyl)-1,3-benzdioxin showing different types of hydrogen bonding: (a) (C13C)CH⋯O=C and (b) N-H⋯O=C

8-Acetylamino-6-methyl-2,4-bis(trichloromethyl)-1,3-benzdioxin, (I), is monoclinic,P2₁/c,a=15.174(4),b=11.977(7),c=9.911(3)Å,=99.72(2)°. 6-Acetylamino-2,4-bis(trichloromethyl)-1,3-benzdioxin, (II), is monoclinic,P2₁/_n,a=5.927(4),b=40.623(1),c =7.120(3)Å,=91.39(4)°. In compound (I) the imino hydrogen atom is locked in an intramolecular hydrogen bond to the proximate oxygen atom of the heterocyclic ring and is not available for intermolecular hydrogen bonding. Instead the weakly acidic hydrogen atom [Cl₃C-C(2)]H takes part in a hydrogen bond to the carbonyl oxygen atom in another molecule. In compound (II) a normal intermolecular hydrogen bond of the type N-HO=C occurs. The 6-acetylam-ino group is twisted about the (C_Ar-N) bond such that the angles NHO=C, C_ArH_ArO=C, NHOH_ArC_Ar, at the carbonyl oxygen group total 360° (where NH is in the related molecule). The packing in both compounds takes the form of infinite chains and in compound (II) partial overlap of the aromatic ring and the acetylamino group, with very little offset, also occurs.     

Conformational study on aryl ketones: The structure of 2,6-dimethyl-1,5-di-(2-methyl)-propanoylnaphthalene

C₂₀H₂₄O₂ (M _r =296.4) crystallizes in the monoclinic system, space groupC2/c witha=24.154(4),b=8.001(2),c=12.751(3) Å;=136.8(1)°;V=1686.9 ų,Z=4,D _c =1.17 g cm^–3,(Cu-)=5.4 cm^–1,=1.5418 Å,F(000)=640. The molecule in the solid state adopts a centrosymmetric geometry with the molecular center of symmetry coincident with a crystallographic center of symmetry. This fact forces the molecule to themeso conformation.     

Synthesis and structure of 4-R,5-R-[5-(hydroxy-diphenyl-methyl)-2, 2-dimethyl-[1,3]dioxolan-4-yl]-phenyl-methanone, a chiral ligand building block

A triphenyl analog of taddol, 4-R,5-R-[5-(hydroxy-diphenyl-methyl)-2,2-dimethyl-[1,3]dioxolan-4-yl]-phenyl-methanone, has been synthesized and structurally characterized. This molecule could act as a chiral ligand building block in the creation of tuned taddol analogs. Structural analysis of the title compound reveals that the hydroxyl group is involved in an intramolecular hydrogen bond and does not take part in any intermolecular interaction. Crystal packing is influenced by C–H O hydrogen bonding and phenyl phenyl interactions. Crystal data: Triclinic, P1 (No. 1), a = 5.9343(4) Å, b = 8.2367(17) Å, c = 10.987(2) Å, = 88.290(6), = 75.442(4), = 80.655(6), V = 512.86(15) ų, Z = 1, D _calc = 1.258 mg/m³. Final residual values were R ₁ = 0.0407 for 3022 observed data (I > 2s(I) ) and wR ₂ = 0.0941 for all 3524 unique data.     

Crystal structure of a 1:1 molecular adduct of hexamethylenetetramine with phenylacetic acid

A 11 crystalline adduct of hexamethylenetetramine with phenylacetic acid, (CH₂)₆N₄·C₆H₅CH₂COOH, has been isolated and characterized by X-ray analysis. The compound crystallizes in space groupI¯4 (No. 82), witha=20.576(3),c=6.907(1) Å, andZ=8. The crystal structure is composed of a packing of discrete molecular aggregates corresponding to the stoichiometric formula, each being consolidated by a NH-O hydrogen bond of length 2.643(8) Å, which has no significant effect on the regular geometry of the (CH₂)₆N₄ cage system. The C-CO₂ and phenyl groups in the C₆H₅CH₂COOH moiety make a dihedral angle of 74(1)°. The structure has been refined toR=0.071 for 1350 observed (F _o >2F _o ) MoK data.     

Investigation of lignin models of the biphenyl type by X-ray crystallography and NMR spectroscopy

Lignin models of the biphenyl type have been synthesized and crystal structures of two of them have been determined. The tetraacetate of 5,5-bis(hydroxymethyl)-3,3-dimethoxy-2,2-biphenyldiol crystallizes in space group witha=11.319(2),b=12.232(6),c=9.242(3) Å, =101.66(3)°, =108.14(2)°, =79.08(2)° andZ=2.R=0.036 (2720 observed [I>3(I)] reflections). The acetate of 5,5-di-tert-butyl-2,3,3-trimethoxy-2-biphenylol crystallizes in space group witha=11.972(2),b=21.621(3),c=9.834(1) Å, =91.18(1)°, =113.13(1)°. =98.42(1)°, andZ=4.R=0.050 (8129 observed [I>3(I)] reflections).¹H NMR and¹³C NMR data for the above-mentioned compounds and a third model, the diacetate of 5,5-bis(1-hydroxyethyl)-2,2,3,3-tetramethoxybiphenyl, are reported. Observed signal positions are compared with those calculated on the basis of crystal structure data. The possibilities to obtain structural information about biphenyl structures in lignins from NMR spectra are discussed.     

Synthesis,characterization and crystal structure of oxovanadium(IV) complex with tridentate o-van-gly and bidentate phenanthroline

A novel oxovanadium(IV) complex with tridentate schiff base and bidentate phenanthroline ligands, VO(o-van)(phen) 2H₂O[o-van-gly: o-vanillin-glycine; phen: phenanthroline], was synthesized and characterized by elemental analysis, IR and UV-vis spectra. The crystal structure was determined by X-ray single crystal diffraction analysis. The crystal of title complex (C₂₂H₂₁N₃O₇V, M_w = 490.36) belongs to triclinic, space group P-1 with the following crystallographic parameters: a = 9.247(3) Å, b = 10.125(4) Å, c = 13.100(5) Å, = 106.343(6), = 96.042(7), = 101.726(7), V = 1135.0(7) ų, Z = 2, D_c = 1.435 Mg m^–3, (MoK = 0.485 mm^–1, F(000) = 506, and final R₁ = 0.0779, wR₂ = 0.1598 for observed reflections 1606 (I > 2(I)). V(IV) is six-coordinate with three oxygen atoms and three nitrogen atoms in a distorted octahedral geometry. The complex forms a 3-D network via – stacking and hydrogen bonds.