scholarly journals Synthesis and X-Ray Crystal Structure of Two Acridinedione Derivatives

2014 ◽  
Vol 2014 ◽  
pp. 1-8
Author(s):  
Dalbir Kour ◽  
D. R. Patil ◽  
M. B. Deshmukh ◽  
Vivek K. Gupta ◽  
Rajni Kant
Keyword(s):  
Crystal Structure ◽  
Crystal Structures ◽  
Crystal Packing ◽  
Direct Methods ◽  
Boat Conformation ◽  
Asymmetric Unit ◽  
X Ray ◽  
Independent Molecules

The two acridinedione derivatives 1 [3,3,6,6-tetramethyl-9-(4-methoxyphenyl)-3,4,6,7,9,10-hexahydro-2H,5H-acridine-1,8-dione (C24H29NO3)] and 2 [3,3,6,6-tetramethyl-9-(4-methylphenyl)-3,4,6,7,9,10-hexa-hydro-2H,5H-acridine-1,8-dione (C24H29NO2)] were synthesized and their crystal structures were determined by direct methods. The asymmetric unit of compound 1 contains two independent molecules. The 1,4-dihydropyridine (DHP) ring adopts boat conformation in both 1 and 2. In 1 the dione rings exist in sofa conformation (for both the crystallographically independent molecules) while the corresponding rings in 2 adopt half chair and sofa conformations, respectively. The crystal packing is stabilized by intermolecular N–H⋯O and C–H⋯O interactions in compound 1 and N–H⋯O interactions in compound 2.

Crystal structure of cis-Tetracarbonylbis(chloromercury)iron

1976 ◽  
Vol 29 (9) ◽  
pp. 1905 ◽  
Author(s):  
CL Raston ◽  
AH White ◽  
SB Wild
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Diffraction Data ◽  
Title Compound ◽  
Direct Methods ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
X Ray ◽  
Independent Molecules

The crystal structure of the title compound has been determined by direct methods from X-ray diffraction data and refined by least squares to a residual of 0.071 for 2647 'observed' reflections. Crystals are monoclinic, C2/c, a = 36.81(1), b = 11.181(2), c = 20.369(5) �, β = 95.28(3)�, Z = 32. There are four independent molecules in the asymmetric unit, all with the cis disposition of ligands (<Fe-Hg), 2.498 �; <Hg-Fe-Hg), 80.9�); in one of the molecules one of the carbonyl sites is occupied by a more substantial moiety, possibly a result of partial occupancy of HgCl as a result of disorder or decomposition.

Synthesis and crystal structures of two structurally related kryptoracemates

2017 ◽  
Vol 73 (7) ◽  
pp. 575-581 ◽  
Author(s):  
Philipp Kramer ◽  
Michael Bolte
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Crystal Packing ◽  
Symmetry Element ◽  
Inversion Symmetry ◽  
Asymmetric Unit ◽  
Chiral Molecules ◽  
Space Groups ◽  
Independent Molecules

Kryptoracemates are racemic compounds (pairs of enantiomers) that crystallize in Sohnke space groups (space groups that contain neither inversion centres nor mirror or glide planes nor rotoinversion axes). Thus, the two symmetry-independent molecules cannot be transformed into one another by any symmetry element present in the crystal structure. Usually, the conformation of the two enantiomers is rather similar if not identical. Sometimes, the two enantiomers are related by a pseudosymmetry element, which is often a pseudocentre of inversion, because inversion symmetry is thought to be favourable for crystal packing. We obtained crystals of two kryptoracemates of two very similar compounds differing in just one residue, namely rac-N-[(1S,2R,3S)-2-methyl-3-(5-methylfuran-2-yl)-1-phenyl-3-(pivalamido)propyl]benzamide, C27H32N2O3, (I), and rac-N-[(1S,2S,3R)-2-methyl-3-(5-methylfuran-2-yl)-1-phenyl-3-(propionamido)propyl]benzamide dichloromethane hemisolvate, C25H28N2O3·0.5CH2Cl2, (II). The crystals of both compounds contain both enantiomers of these chiral molecules. However, since the space groups [P212121 for (I) and P1 for (II)] contain neither inversion centres nor mirror or glide planes nor rotoinversion axes, there are both enantiomers in the asymmetric unit, which is a rather uncommon phenomenon. In addition, it is remarkable that (II) contains two pairs of enantiomers in the asymmetric unit. In the crystal, molecules are connected by intermolecular N—H...O hydrogen bonds to form chains or layered structures.

Crystal structure determination of the conformation of two bicyclo[3.3.1]nonan-ones

1985 ◽  
Vol 63 (6) ◽  
pp. 1166-1169 ◽  
Author(s):  
John F. Richardson ◽  
Ted S. Sorensen
Keyword(s):  
Crystal Structure ◽  
Direct Methods ◽  
Chair Conformation ◽  
Molecular Structures ◽  
Boat Conformation ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Final Agreement

The molecular structures of exo-7-methylbicyclo[3.3.1]nonan-3-one, 3, and the endo-7-methyl isomer, 4, have been determined using X-ray-diffraction techniques. Compound 3 crystallizes in the space group [Formula: see text] with a = 15.115(1), c = 7.677(2) Å, and Z = 8 while 4 crystallizes in the space group P21 with a = 6.446(1), b = 7.831(1), c = 8.414(2) Å, β = 94.42(2)°, and Z = 2. The structures were solved by direct methods and refined to final agreement factors of R = 0.041 and R = 0.034 for 3 and 4 respectively. Compound 3 exists in a chair–chair conformation and there is no significant flattening of the chair rings. However, in 4, the non-ketone ring is forced into a boat conformation. These results are significant in interpreting what conformations may be present in the related sp2-hybridized carbocations.

Influence of 3-{5-[4-(diethylamino)benzylidene]rhodanine}propionic acid on the conformation of 5-(4-chlorobenzylidene)-2-(4-methylpiperazin-1-yl)-3H-imidazol-4(5H)-one

2018 ◽  
Vol 74 (11) ◽  
pp. 1427-1433 ◽  
Author(s):  
Ewa Żesławska ◽  
Wojciech Nitek ◽  
Waldemar Tejchman ◽  
Jadwiga Handzlik
Keyword(s):  
Crystal Structures ◽  
Crystal Packing ◽  
Protonated Form ◽  
Acid Form ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
Basic Form ◽  
Piperazine Ring ◽  
X Ray ◽  
Intermolecular Contacts

The arylidene–imidazolone derivatives are a group of compounds of great interest in medicinal chemistry due to their various pharmacological actions. In order to study the possible conformations of an arylidene–imidazolone derivative, two new crystal structures were determined by X-ray diffraction, namely (Z)-5-(4-chlorobenzylidene)-2-(4-methylpiperazin-1-yl)-3H-imidazol-5(4H)-one, C15H17ClN4O, (6), and its salt 4-[5-(4-chlorobenzylidene)-5-oxo-4,5-dihydro-3H-imidazol-2-yl]-1-methylpiperazin-1-ium 3-{5-[4-(diethylamino)benzylidene]-4-oxo-2-thioxothiazolidin-3-yl}propionate, C15H18ClN4O+·C17H19N2O3S2 −, (7). Both compounds crystallize in the space group P\overline{1}. The basic form (6) crystallizes with two molecules in the asymmetric unit. In the acid form of (6), the N atom of the piperazine ring is protonated by proton transfer from the carboxyl group of the rhodanine acid derivative. The greatest difference in the conformations of (6) and its protonated form, (6c), is observed in the location of the arylidene–imidazolone substituent at the N atom. In the case of (6c), the position of this substituent is close to axial, while for (6), the corresponding position is intermediate between equatorial and axial. The crystal packing is dominated by a network of N—H...O hydrogen bonds. Furthermore, the crystal structures are stabilized by numerous intermolecular contacts of types C—H...N and C—H...Cl in (6), and C—H...O and C—H...S in (7). The geometry with respect to the location of the substituents at the N atoms of the piperazine ring was compared with other crystal structures possessing an N-methylpiperazine moiety.

Crystal Structures of Seven Terephthaldiamide Derivatives

2002 ◽  
Vol 57 (8) ◽  
pp. 914-921 ◽  
Author(s):  
P. G. Jones ◽  
J. Ossowski ◽  
P. Kus
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Layer Structure ◽  
Inversion Symmetry ◽  
Asymmetric Unit ◽  
X Ray ◽  
Layer Structures ◽  
Structure Determinations ◽  
Independent Molecules

N,N′-Dibutyl-terephthaldiamide (1), N,N′-dihexyl-terephthaldiamide (2), N,N′-di(tert-butyl)- terephthaldiamide (3), N,N,N′,N′-tetrabutyl-terephthaldiamide (4), 1,1′-terephthaloylbis- pyrrolidine (5), 1,1′-terephthaloyl-bis-piperidine (6), and 4,4′-terephthaloyl-bis-morpholine (7) have been synthesised and physicochemically characterised. The X-ray structure determinations reveal imposed inversion symmetry for compounds 1-6; compound 3 has two independent molecules with inversion symmetry in the asymmetric unit. Compounds 1-3 form classical hydrogen bonds of the type N-H···O=C, leading to a ribbon-like arrangement of molecules (1 and 2) or a layer structure (3). Compound 3 also displays a very short C-H···O interaction, a type of hydrogen bond that is also observed in compounds 4-7, which lack classical donors; thereby compounds 4-6 form layer structures and 7 a complex threedimensional network.

The crystal structure of 5-O-Acetyl-1,2 : 3,4-di-O-isopropylidene-α-D-glucoseptanose, C14H22O7, by use of X-ray and neutrondiffraction data

1983 ◽  
Vol 36 (11) ◽  
pp. 2269 ◽  
Author(s):  
RA Wood ◽  
VJ James ◽  
AD Rae ◽  
JD Stevens ◽  
FH Moore
Keyword(s):  
Crystal Structure ◽  
Neutron Diffraction ◽  
Diffraction Analysis ◽  
Chair Conformation ◽  
Asymmetric Unit ◽  
Methyl Group ◽  
Neutron Diffraction Analysis ◽  
X Ray ◽  
Acetate Methyl ◽  
Independent Molecules

The crystal structure of 5-O-acetyl-1,2:3,4-di-O-isopropylidene-α-D-glucoseptanose [P212121, Z 8, a 14.329(5), b 22.075(5), c 10.012(5) �] has been determined by X-ray and neutron diffraction analyses. For the neutron diffraction analysis, the acetate group and the trans-O-isopropylidene group were deuterated. Constrained refinement was used in the neutron diffraction analysis to counter over parameterization in the block-diagonal least-squares refinement. Final unweighted R-values were 0.038 [X-ray for 3070 reflections with [Fo > 2.58σ (Fo)] and 0.061 [neutron for 1118 reflections with Fo > 4σ ([Fo)]The neutron refinement revealed a disordering of the acetate methyl group in each of the two independent molecules in the asymmetric unit. The septanose ring in each molecule adopted the same twist-chair conformation but the dioxolan rings assumed different twist and envelope conformations.

(1R,4S,8R,12S,13S,14R,16S,19R)-14-Hydroxy-7,7-dimethyl-17-methylene-2,9,18-trioxo-3,10-dioxapentacyclo[14.2.1.01,13.04,12.08,12]nonadec-19-yl acetate

2007 ◽  
Vol 63 (11) ◽  
pp. o4439-o4439
Author(s):  
Hao Shi
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Absolute Configuration ◽  
Title Compound ◽  
Chair Conformation ◽  
Boat Conformation ◽  
Asymmetric Unit ◽  
Compound C ◽  
Independent Molecules ◽  
The Absolute

The title compound, C22H26O8, prepared from the natural diterpenoid Macrocalyxin J, is built up from five fused rings. Cyclohenane ring A adopts a chair conformation, ring B exists in a screw-boat conformation and ring C adopts a boat conformation; the two five membered rings adopt envelope conformations. Two unique molecules are present in the asymmetric unit; both independent molecules have the same absolute configuration, the absolute configuration being deduced from the chirality of Macrocalyxin A, which was isolated from the same plant (i.e. Rabdosia macrocalyx) as Macrocalyxin J. The crystal structure displays intermolecular O—H...O hydrogen bonds.

scholarly journals Crystal structure of 5-(4-benzyloxyphenyl)-3-(4-methoxyphenyl)-6-methylcyclohex-2-en-1-one

2015 ◽  
Vol 71 (1) ◽  
pp. 16-18
Author(s):  
S. Sathya ◽  
D. Reuben Jonathan ◽  
J. Sidharthan ◽  
R. Vasanthi ◽  
G. Usha
Keyword(s):  
Crystal Structure ◽  
Benzene Ring ◽  
Title Compound ◽  
Crystal Packing ◽  
Dihedral Angles ◽  
Asymmetric Unit ◽  
Compound C ◽  
Cyclohexene Ring ◽  
Benzene Rings ◽  
Independent Molecules

The title compound, C27H26O3, crystallized with two independent molecules (AandB) in the asymmetric unit. In moleculeA, the plane of the central benzene ring forms dihedral angles of 75.78 (14) and 52.75 (16)° with that of the terminal benzene rings, and the dihedral angle between the planes of the terminal benzene rings is 51.49 (17)°. The corresponding values for moleculeBare 75.18 (14), 58.11 (16) and 47.91 (16)°, respectively. The cyclohexene ring adopts an envelope conformation in both molecules, with the C atom to which is attached the central benzene ring as the flap. The crystal packing, is stabilized by C—H...π interactions.

scholarly journals Crystal structure of ethyl 2-[(4-bromophenyl)amino]-3,4-dimethylpent-3-enoate

2014 ◽  
Vol 70 (10) ◽  
pp. o1122-o1123
Author(s):  
Julio Zukerman-Schpector ◽  
I. Caracelli ◽  
Hélio A. Stefani ◽  
Amna N. Khan ◽  
Edward R. T. Tiekink
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Dihedral Angle ◽  
Title Compound ◽  
Crystal Packing ◽  
Dihedral Angles ◽  
Methyl Groups ◽  
Asymmetric Unit ◽  
Compound C ◽  
Independent Molecules

In the title compound, C15H20BrNO2, there are two independent molecules (AandB) comprising the asymmetric unit and these adopt very similar conformations. InA, the dihedral angle between the CO2and MeC=CMe2groups is 80.7 (3)°, and these make dihedral angles of 3.5 (3) and 84.09 (16)°, respectively, with the bromobenzene ring. The equivalent dihedral angles for moleculeBare 78.4 (3), 2.1 (3) and 78.37 (12)°, respectively. The most prominent interactions in the crystal packing are amine-N—H...O(carbonyl) hydrogen bonds between the two independent molecules, resulting in non-centrosymmetric ten-membered {...OC2NH}2synthons. Statistical disorder is noted for each of the terminal methyl groups of the ethyl residues.

scholarly journals Crystal structures of 5,12-dimethyl-1,4,8,11-tetraazacyclotetradecane cobalt(III) mono-phenylacetylide and bis-phenylacetylide

2018 ◽  
Vol 74 (4) ◽  
pp. 522-529 ◽  
Author(s):  
Benjamin M. Oxley ◽  
Brandon Mash ◽  
Matthias Zeller ◽  
Susannah Banziger ◽  
Tong Ren
Keyword(s):  
Crystal Structures ◽  
Symmetry Operator ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
Weak Base ◽  
Monoclinic Symmetry ◽  
X Ray ◽  
Independent Molecules ◽  
Solvent Molecules ◽  
Occupancy Rates

Reported in this contribution are the synthesis and crystal structures of new mono- and bis-phenylacetylides based on CoIII(DMC) (DMC is 5,12-dimethyl-1,4,8,11-tetraazacyclotetradecane). Chlorido(5,12-dimethyl-1,4,8,11-tetraazacyclotetradecane)(phenylethynyl)cobalt(III) chloride–acetonitrile–methanol (1/1/1), [Co(C8H5)Cl(C12H28N4)]Cl·CH3CN·CH3OH, 1, and (5,12-dimethyl-1,4,8,11-tetraazacyclotetradecane)bis(phenylethynyl)cobalt(III) trifluoromethanesulfonate–dichloromethane (2/1), [Co(C8H5)2(C12H28N4)]2(CF3SO3)2·CH2Cl2, 2, were prepared under weak-base conditions in satisfactory yields. Single-crystal X-ray diffraction studies revealed that both 1 and 2 adopt a pseudo-octahedral symmetry in which the Cl—Co—C angles of 1 and C—Co—C of 2 range from 177.7 (2) to 178.0 (2)° and from 177.67 (9) to 179.67 (9)°, respectively. In both structures, the CoIII metal center is coordinated in the equatorial plane by four N atoms, in which the N—Co—N angles range from 85.6 (3) to 94.4 (3)°. The structure of 1 features two crystallographically independent molecules in its triclinic cell (Z′ = 2), which are related to each other by pseudo-monoclinic symmetry. The crystal investigated was twinned by a symmetry operator of the approximate double-volume C-centered cell (180° rotation around [201] of the actual triclinic cell), with a refined twin ratio of 0.798 (3) to 0.202 (3). Both methanol solvent molecules in 1 are disordered, the major occupancy rates refined to 0.643 (16) and 0.357 (16). Compound 2 also contains two molecules in the asymmetric unit, together with two trifluoromethanesulfonate anions [of which one is disordered; occupancy values of 0.503 (16) and 0.497 (16)] and a disordered dichloromethane [occupancy values of 0.545 (12) and 0.455 (12)].

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