Structure and conformation of 6-nitro-2,4-bis(trichloromethyl)-1,3-benzdioxin: X-ray crystallographic determination

6-Nitro-2,4-bis(trichloromethyl)-1,3-benzdioxin is triclinic,P¯1;a=6.604(2),b=7.678(6),c=15.201(4) Å; =91.57(5),=99.39(2), =90.50(5)°;Z=2. The structure was solved by direct methods from data collected at room temperature on an Enraf-Nonius CAD4 diffractometer and refined by least squares to a finalR value of 0.035 using 2092 reflections.The molecule consists of a heterocycle in a distorted screw boat conformation fused to a significantly nonplanar aromatic ring. One-CCl₃ group is pseudoequatorial while the (Ar-C)CCl₃ group is pseudoaxial. The C_Ar-C-O-C side of the ring is much flatter than the C_Ar-C_Ar-O-C side, the distortion being caused by the necessity of the-C_axCl₃ group to bend away from the heterocycle. C-C_eq 1.532(4) Å; C-C_ax 1.550(4) Å; C-C(C_ax)-O 113.0(3)°; C(C_ax)-O-C(C_eq) 115.5(2)°.     

Structure and conformation of 6-nitro-2,4-bis(dichloromethyl)-1,3-benzdioxin

6-Nitro-2,4-bis(dichloromethyl)-1,3-benzdioxin is monoclinic,P2₁/c, witha=8.514(1),b=22.187(3),c=7.931(1) Å,=117.96(1)°,Z=4. The structure was solved, from data collected with MoK radiation on an Enraf-Nonius CAD4 diffractometer, by direct methods and refined by full-matrix least squares using 2170 unique reflections to give a finalR factor of 0.032. The heterocyclic ring in the title compound has an envelope conformation with thecis-dichloromethyl groups in pseudoequatorial positions. The average C-C(HCl₂) distance is 1.516(4) Å. A comparison is given with the structure of the analogous compound 6-nitro-2,4-bis(trichloromethyl)-1,3-benzdioxin (Irving, A., and Irving, H. M. N. H. (1986)J. Crystallogr. Spectrosc. Res. 16, 703) which also containscis-halogenoalkyl groups but in which the –CCl₃ group at the 4-position occupies a pseudoaxial position.     

Structure and conformation of 6,8-dinitro-2,4-bis(trichloromethyl)-1,3-benzdioxin: X-ray crystallographic determination

6,8-dinitro-2,4-bis(trichloromethyl)-1,3-benzdioxin is monoclinic,P2₁/c,Z=4,a=12.348(2),b=11.575(3),c=12.183(4) Å,=107.48(2)°. The structure was solved by direct methods, from data collected at room temperature on an Enraf-Nonius CAD4 diffractometer, and refined by least-squares to a finalR value of 0.032 using 2192 reflections. The heterocyclic ring is an envelope structure, the dihedral angle between the plane of the aromatic ring and that containing five of the atoms of the heterocycle being 4.98(6)°. One -CCl₃ group is pseudoequatorial while the (Ar-C)CCl₃ group is pseudoaxial. C-C_eq 1.526(3) Å; C-C_ax 1.537(3) Å; C-C(C_ax)-O 112.4(2)°; C(C_ax)-O-C(C_eq) 115.2(2)°.     

Crystal and molecular structure of 6-nitro-1,3-benzdioxin: Comparison with the molecular structures of the 2,4-bis(dichloromethyl) and 2,4-bis(trichloromethyl) derivatives

6-Nitro-1,3-benzdioxin is orthorhombic,Pbca,a=7.278(4),b=19.292(3),c=10.978(1) Å,Z=8. The structure was solved by direct methods from data collected at room temperature on an Enraf-Nonius CAD4 diffractometer and refined by least squares to a finalR value of 0.041 using 725 reflections. Some parameters associated with the heterocycle are torsion angle (C_Ar)O-C-O-C(C_Ar) 69.1(4)°; bond lengths C_Ar-O 1.362(3), (C_Ar)O-C 1.434(5), (C_Ar.O)C-O 1.377(5), O-C(C_Ar) 1.431(5), C-C_Ar 1.501(5) Å; bond angles C_Ar-O-C 113.5(3), O-C-O 111.5(3), C-O-C(C_Ar) 110.3(3), O-C-C_Ar 109.9(3)°;H_axH_ax 2.52(5) Å.     

The N,N-diacetylaminobenzene group in the structure of 6-methyl-8-N,N-diacetylamino-2,4-bis(trichloromethyl)-1,3-benzdioxin

Crystals of 6-methyl-8-N,N-diacetylamino-2,4-bis(trichloromethyl)-1,3-benzdioxin are triclinic, P¯1,Z=2,a=9.586(3),b=9.914(2),c=12.308(5) Å,=67.19(3),=71.95(3), =74.14(2)°. The structure was solved by direct methods, from data collected at room temperature on an Enraf-Nonius CAD4 difFractometer, and refined by least squares to a finalR value of 0.039 using 3038 reflections. The heterocyclic ring has an envelope conformation. Of thecis-CCl₃ groups one CC1₃ group is pseudoequatorial while the –(C_Ar·C)CCl₃ group is pseudoaxial. (C_Ar)O-C 1.405(4); (C_Ar·O)C-O 1.387(4) Å; C_Ar-C(C_ax)-0 112.3(3); C(C_ax)-O-C(C_eq) 116.1(2)°; (C_Ar)O-C-O-C(C_Ar)58.2(3)°. The configuration of the diacetylamino group (DAA) issyn-anti. The -systems of the DAA and of the aromatic ring are approximately orthogonal, the deviations from orthogonality probably being caused by an intermolecular bifurcated hydrogen bond, each such interaction involving two molecules only, between thesyn O(=C) of the DAA and both hydrogen atoms bonded to the heterocyclic ring in a molecule of the enantiomer. The geometry of the DAA-benzene fragment is compared with those found in the other three published X-ray structures containing this group.     

Structure ofcis-2,4-bis (trichloromethyl)-1,3,5,-trioxane

cis-2,4-Bis(trichloromethyl)-1,3,5-trioxane is monoclinic,C2/c, a=19.432(4),b=5.895(1),c=20.721(6) Å,=100.66(2)°,Z=8. The structure was solved by direct methods, from data collected at room temperature on an Enraf-Nonius CAD4 diffractometer, and refined by least-squares to a finalR value of 0.034 using 1786 reflections. The molecule is in the chair conformation with the –CCl₃ groups located equatorially [at C(2) and C(6) in the numbering scheme used in the paper]. Endocyclic parameters quoted cyclically are O(1)-C(2) 1.418(3), C(2)-O(3) 1.387(3), O(3)-C(4) 1.419(3), C(4)-O(5) 1.416(3), O(5)-C(6) 1.391(4), C(6)-O(1) 1.415(3) Å; and angles at O(1) 108.7(2), C(2) 110.5(2), O(3) 110.1(2), C(4) 109.5(2), O(5) 109.9(2), C(6) 110.5(2)°. The average endocyclic torsion angle is 59.1(5)°.     

Structure and conformation of 6,8-dinitro-2-trichloromethyl-4-dichloromethylene-1,3-benzdioxin

6,8-Dinitro-2-trichloromethyl-4-dichloromethylene-1,3-benzdioxin is orthorhombic,Pccn,a=18.850(3),b=18.404(3),c=8.849(2) Å,Z=8. The structure was solved by direct methods, from data collected at room temperature on an Enraf-Nonius CAD4 diffractometer, and refined by least squares to a finalR value of 0.036 using 1889 reflections. The heterocyclic ring has an envelope conformation and is substituted pseudo-equatorially by a trichloromethyl group. The molecular parameters and conformation of the title compound are discussed with reference to the 6-nitro analog and with reference to 6-nitro and 6,8-dinitro-2, 4-bis(trichloromethyl)-1,3-benzdioxin.     

Structure and conformation of 6-nitro-2-trichloromethyl-4-dichloromethylene-1,3-benzdioxin: X-ray crystallographic determination

6-Nitro-trichloromethy1-4-dichloromethylene-1,3-benzdioxin is monoclinic,C2/c,a=12.906(2) Å,b=19.957(2) Å,c=19.992(2) Å,=99.05(1)°,Z=8. The structure was solved by direct methods, from data collected at room temperature on an Enraf-Nonius CAD4 diffractometer, and refined by least squares to a finalR value of 0.032 using 1838 reflections.The compound exhibits a distorted envelope structure in the dioxin ring, and the trichloromethyl group is in the equatorial position. The angle between the planes each containing a group of three atoms from either end of the double bond of the:C(ring)=CCl₂ moiety is 3.8(2)°: a short discussion of deformations found in other compounds which contain:C(ring)=CC1₂ in light atom structures is given. The benzene ring is slightly puckered and planarity has been retained about the carbon atoms which are common to both rings.     

A twist boat: Structure and conformation oftrans-2,4,6-tris(trichloromethyl)-1,3,5-trithian

Trans-2,4,6-tris(trichloromethyl)-1,3,5-trithian, (CCl₃·CHS)₃, has been prepared free from persistent impurification bycis-trans-2,4,6-tris(trichloromethyl)-1,3,5-oxadithian and its conformation determined by single crystal x-ray crystallography. The title compound is orthorhombic,Pbca, a=10.479(10),b=27.957(14),c=11.093(3) Å,V=3250 ų,Z=8. The structure was solved by direct methods, from data collected at room temperature on an Enraf-Nonius CAD4 diffractometer, and refined by full-matrix least squares to a finalR value at 0.074 using 1186 reflections. The molecule exhibits a twist boat conformation with the –CCl₃ groups occupying pseudoequatorial positions. The torsion angles in the trithian ring are successively 29(1), –79(1), 41(1), 41(1), –84(1), 39(1)°. Average values are: S-C 1.82(2), C(ring)-C(Cl₃) 1.56(4), C-Cl 1.76(2) Å, S-C-S 112.7(2)°. The C-S-C angles are 97.4(7), 101.4(7), 97.3(7)°.     

Conformational analysis and X-ray structure of 1-(2,4-dichlorobenzyl)-1H-indazole-3-carboxylic acid

The results of a X-ray structure determination and of a quantum-chemical Conformational analysis on the title compound are reported. The crystals belong to the triclinic system, space groupP¯1 (after structure determination), with two molecules in the unit cell, whose parameters are:a=11.966(2),b=8.118(2),c=7.693(2)Å,=97.03(2),=92.98(2), =106.15(2)°: observed density (by flotation) 1.49, calculated 1.503 g cm^–3. The structure was solved from 1815 diffractometer-measured intensities, withI2.5(I) and refined by full-matrix least-squares to a final conventional indexR=0.035 (R _w =0.043). The most relevant feature of the molecular structure is the orientation of the dichlorophenyl ring with respect to the planar indazole group, the dihedral angle being 83.1(1)°. A very close conformation corresponds to one of the minima calculated by the semiempirical AMI method.     

Crystallographic and conformational analysis of 1,3-bis(2,4-dimethoxyphenyl)imidazolidine-2-thione

The molecular and crystal structures of the title compound, C₁₉H₂₂N₂O₄S, were determined by single crystal X-ray diffraction technique. The title compound crystallizes in space group F d d 2, with a = 30.785(3) ?, b = 10.6455(9) ?, c = 11.0036(8) ?, Z = 8, D _calc = 1.379(2) g cm⁻³, μ(Mo-K_α) = 0.207 mm⁻¹, and its crystal system is orthorhombic. The structure was solved by direct methods and refined to a final R = 0.042 for 1530 reflections with I > 2σ (I). There is a half-independent molecule in the asymmetric unit. The title molecule has twofold rotational symmetry along with the C–S bond. Classically no hydrogen bond is found in the crystal structure. The crystal structure is stabilized by π–π stacking and edge to face (C–H…π-ring) interactions. To elucidate conformational features and steric hindrances of the title molecule, selected torsion angle is varied from −180° to +180° in every 10° and thus molecular energy profile is calculated by PM3 semi-empirical method.Supplementary materials CCDC 261789 contains the supplementary crystallographic data for this paper. These data can be obtained free of charge via www.ccdc.cam.ac.uk/data_request/cif, by emailing data_request@ccdc.cam.ac.uk, or by contacting The Cambridge Crystallographic Data Centre, 12, Union Road, Cambridge CB2 1EZ, UK; fax: $+$44 1223 336033.     

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.     

Knoevenagel condensation of the diphosphine ligand 4,5-bis(diphenylphosphino)-4-cyclopentene-1,3-dione with 9-anthracenecarboxaldehyde: Synthesis of the second-generation ligand 2-(anthracen-9-ylidene)-4,5-bis(diphenylphosphino)-4-cyclopentene-1,3-dione

The Knoevenangel condensation between 9-anthracenecarboxaldehyde and the diphosphine ligand 4,5-bis(diphenylphosphino)-4-cyclopentene-1,3-dione (bpcd) takes place rapidly in CH₂Cl₂/MeOH solution in the presence of molecular sieves (4 ?) to produce the functionalized ligand 2-(anthracen-9-ylidene)-4,5-bis(diphenylphosphino)-4-cyclopentene-1,3-dione. The title compound has been isolated and characterized in solution by IR, NMR, and UV-vis spectroscopies, and the solid-state structure has been established by X-ray diffraction analysis. 2-(anthracen-9-ylidene)-4,5-bis(diphenylphosphino)-4-cyclopentene-1,3-dione crystallizes in the triclinic space group P−1, a=10.227(2) ?, b=13.865(2) ?, c=15.905(2) ?, α=112.157(2)°, β=101.424(2)°, γ=100.065(3)°, V=1968.5(5) ?³, Z=2, and d _calc=1.101 Mg/m³; R=0.0873, R _w=0.2604 for 7452 reflections with I>2σ(I). The cyclic voltammetric behavior for 2-(anthracen-9-ylidene)-4,5-bis(diphenylphosphino)-4-cyclopentene-1,3-dione has been studied, and the observed redox data and results from extended Hückel MO calculations are discussed relative to the parent ligand bpcd.

Crystal structure of two lipophilic antifolates: 2,4-diamino-5-(n-hexyl)-6-methylpyrimidine and 2,4-diamino-5-(n-heptyl)-6-methylpyrimidine ethanesulfonate

The 5-hexyl (I) and the 5-heptyl (II) analogs of 2,4-diamino-6-methylpyrimidine both crystallize in the space groupP2₁/c withZ=4. Unit cell parameters of I are C₁₁H₂₀N₄·H₂O,a=17.204(3),b=4.609(9),c=16.765(2)Å,= 91.53(2)°; those of II are C₁₂H₂₃N₄ ⁺·C₂H₅SO₃ ^–,a=12.489(1),b=16.702(2),c=8.9558(7)Å,=99.208(8)°. The molecular packing of I contains one water, while II forms a salt with ethanesulfonic acid. The alkyl chain of I adopts an alltrans conformation; in contrast, II has onegauche orientation between carbons 2 and 3 of heptyl. These are the first structural data on two alkyl lipophilic antifolates with antineoplastic activity.     

Crystal structure of 1,1-diphenyl-2,4-dimethyl-5-(N-benzamide)-1,3-pentadiene

Crystals of the title compound are monoclinic (C₂₆H₂₅NO): space groupP2₁/c,a=16.565(3),b=10.328(2),c=12.621(3) Å,=104.02(3)°. The structure was solved by direct methods and refined by block-matrix least-squares to giveR=0.056 andR _w =0.061 for 1613 reflections above 2(I). The amide moiety is tilted by 19.3(2)° with respect to the mean aromatic ring plane. The two othergem phenyl rings subtend a dihedral angle of 112.2(4)° to each other. The molecules are joined in the solid by N-HO hydrogen bonds.     

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 of 5,5'-(Furan-2-ylmethylene)bis(6-amino-1,3-dimethylpyrimidine-2,4(1H,3H)-dione)

Crystallography Reports - The crystal structure of the title compound is determined by single crystal X-ray structure analysis. The compound C17H20N6O5, crystallizes in the monoclinic crystal...     

Crystal Structures of 1,7-Bis(furyl)-4-(1,3-dithiolan-2-ylidene)-1,6-heptadiene-3,5-dione and 1,7-bis(thienyl)-4-(1,3-dithiolan-2-ylidene)-1,6-heptadiene-3,5-dione

Abstract  

The title compounds (bis(alkenoyl) ketene dithioacetals) were prepared starting from the cyclic acyl ketene dithioacetal and aromatic aldehydes. These compounds were characterized by IR, ¹H NMR, mass spectral studies and X-ray crystal structure analysis. The bis(furyl) ketene dithioacetal crystallized in the space group P[`\text1] P{\bar{\text{1}}} with unit cell dimensions a = 7.7626(12) ?, b = 9.0217(13) ?, c = 26.827(5) ?, α = 86.271(14)°, β = 87.643(14)°, γ = 66.286(11)° and the structure was refined to an R-factor of 0.0528 while bis(thienyl) ketene dithioacetal crystallized in the space group P2₁/c with unit cell dimensions a = 10.2433(9) ?, b = 10.4142(6) ?, c = 18.0973(18) ?, β = 106.0° and the structure was refined to an R-factor of 0.0446. The ketenedithioacetal functionality present between the carbonyl groups prevents the possibility of keto-enol tautomerization in these compounds. In both the crystal structures, the crystal packing is stabilized by C–H···O hydrogen bonds as well as van der Waals interactions.     

4-(2,3-Dichlorophenyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-bis(methoxycarbonyl), 4-(2,4-dichlorophenyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-bis(methoxycarbonyl), and 4-(2,3,5-trichlorophenyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-bis(methoxycarbonyl): conformational observations in the crystalline state

Hydrogen bonding interactions displayed by three crystalline chloro-substituted 4-phenyl-1,4-dihydropyridine molecules 4-(2,3-Dichlorophenyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-bis(methoxycarbonyl), 4-(2,4-dichlorophenyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-bis (methoxycarbonyl) and 4-(2,3,5-trichlorophenyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-bis (methoxycarbonyl), suggests that, in contrast to previous observation, sp orientation of the 3 or 5 substituted carbonyl group accomodates hydrogen bonding to the carbonyl oxygen atom when polar orthosubstituents exist on the phenyl ring.