scholarly journals Expected and Unexpected Products in Half Curcuminoid Synthesis: Crystal Structures of But-3-en-2-ones and 3-Methylcyclohex-2-enones

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 404
Author(s):  
Marco A. Obregón-Mendoza ◽  
Imilla I. Arias-Olguín ◽  
William Meza-Morales ◽  
Yair Alvarez-Ricardo ◽  
María Isabel Chávez ◽  
...  
Keyword(s):  
Solid Solution ◽  
Crystal Packing ◽  
Chiral Discrimination ◽  
Strong Hydrogen Bond ◽  
Racemic Mixture ◽  
Compound I ◽  
Trans Conformation ◽  
Michael Type Addition ◽  
New Perspective ◽  
Robinson Annulation

The expected (E)-but-3-en-2-ones compounds I and II (half curcuminoids) were obtained by the Claisen–Schmidt reaction between aldehydes 3,4-dimethoxybenzaldehyde or 4-nitrobenzaldehyde with acetone. Concomitantly, 3-methylcyclohex-2-enones compounds III and IV arose from an unexpected reaction of but-3-en-2-ones in the cascade reaction of a Michael-type addition of a second molecule of acetone followed by Robinson annulation under strong basic conditions. Both enones exhibit the (E)-configuration, compound I displays s-trans conformation, whereas compound II exhibits conformational disorder as solid solution of s-cis and s-trans conformations. The related 3-methylcyclohex-2-enones exhibit envelope conformation. Compound III constitutes an example of the rarest case of racemic solid solution (pseudoracemate), where a lack of chiral discrimination with respect to the two enantiomers leads to an enantiomeric disorder of a racemic mixture with different occupancies at the reference site. Due to the lack of strong hydrogen-bond donors in all compounds, the crystal packing is mainly stabilized by weak intermolecular C-H···O interactions between the molecules. The present work provides a new perspective on the search for by-products normally overlooked in Claisen–Schmidt condensations.

scholarly journals Tetrahydroberberine, a pharmacologically active naturally occurring alkaloid

2015 ◽  
Vol 71 (4) ◽  
pp. 262-265 ◽  
Author(s):  
Subramanya Pingali ◽  
James P. Donahue ◽  
Florastina Payton-Stewart
Keyword(s):  
Hydrogen Bonds ◽  
Crystal Packing ◽  
Racemic Mixture ◽  
Inversion Center ◽  
Intermolecular Hydrogen Bonds ◽  
Naturally Occurring ◽  
Pharmacologically Active

Tetrahydroberberine (systematic name: 9,10-dimethoxy-5,8,13,13a-tetrahydro-6H-benzo[g][1,3]benzodioxolo[5,6-a]quinolizine), C20H21NO4, a widely distributed naturally occurring alkaloid, has been crystallized as a racemic mixture about an inversion center. A bent conformation of the molecule is observed, with an angle of 24.72 (5)° between the arene rings at the two ends of the reduced quinolizinium core. The intermolecular hydrogen bonds that play an apparent role in crystal packing are 1,3-benzodioxole –CH2...OCH3and –OCH3...OCH3interactions between neighboring molecules.

scholarly journals Crystal structures and conformations of two Diels–Alder adduct derivatives: 1,8-bis(thiophen-2-yl)-14-oxatetracyclo[6.5.1.02,7.09,13]tetradeca-2(7),3,5-trien-10-one and 1,8-diphenyl-14-oxatetracyclo[6.5.1.02,7.09,13] tetradeca-2,4,6-trien-10-one

2015 ◽  
Vol 71 (2) ◽  
pp. 213-216
Author(s):  
S. Gopinath ◽  
P. Narayanan ◽  
K. Sethusankar ◽  
Meganathan Nandakumar ◽  
Arasambattu K. Mohanakrishnan
Keyword(s):  
Crystal Packing ◽  
Rotation Axis ◽  
Alder Reaction ◽  
Ring System ◽  
Diels Alder ◽  
Compound I ◽  
Diels Alder Reaction ◽  
Phenyl Rings ◽  
Axis Parallel ◽  
Alder Adduct

The title compounds, C21H16O2S2(I) and C25H20O2(II), are products of a tandem `pincer' Diels–Alder reaction consisting of [2 + 2] cycloadditions between benzo[c]furan and cyclopentanone. Each comprises a fused tetracyclic ring system containing two five-membered rings (inenvelopeconformations with the O atom as the flap) and six-membered rings (inboatconformations). In addition, two thiophene rings in (I) and two phenyl rings in (II) are attached to the tetracyclic ring system. The cyclopentanone ring adopts atwistedconformation in (I) and anenvelopeconformation in (II). In (I), the thiophene rings are positionally disordered over two sets of sites, with occupancy ratios of 0.901 (2):0.099 (2) and 0.666 (2):0.334 (2). In (II), the oxygen atom of the cyclopentanone ring is rotationally disordered over two sites with an occupancy ratio of 0.579 (4):0.421 (4). The molecular structure of (I) is stabilized by an intramolecular C—H...O hydrogen bond, which generates anS(7) ring motif. In the crystal, the molecules are linkedviaweak C—H...O hydrogen bonds, which generateR22(16) ring motifs in (I) andC(8) chains in (II). In both structures, the crystal packing also features C—H...π interactions. The crystal studied of compound (I) was twinned by non-merohedry. The twin component is related by the twin law [−1 0 0 −0.101 1 −0.484 0 0 −1] operated by a twofold rotation axis parallel to thebaxis. The structure of (I) was refined with a twin scale factor of 0.275 (2).

scholarly journals The solid solution (Fe0.81Al0.19)(H2PO4)3with a strong hydrogen bond

2010 ◽  
Vol 66 (3) ◽  
pp. i33-i36
Author(s):  
Nadia Belfguira ◽  
Siwar Walha ◽  
Abdelhamid Ben Salah ◽  
André Mathieu Fransolet ◽  
Ahlem Kabadou
Keyword(s):  
Solid Solution ◽  
Hydrogen Bond ◽  
Strong Hydrogen Bond

scholarly journals Hirshfeld analysis and molecular docking with the RDR enzyme of 2-(5-chloro-2-oxoindolin-3-ylidene)-N-methylhydrazinecarbothioamide

2017 ◽  
Vol 73 (5) ◽  
pp. 702-707
Author(s):  
Jecika Maciel Velasques ◽  
Vanessa Carratu Gervini ◽  
Lisliane Kickofel ◽  
Renan Lira de Farias ◽  
Adriano Bof de Oliveira
Keyword(s):  
Molecular Docking ◽  
Hydrogen Bonds ◽  
Title Compound ◽  
Crystal Packing ◽  
Three Dimensional ◽  
Resonant Scattering ◽  
Maximum Deviation ◽  
Compound I ◽  
Acta Cryst ◽  
Compound C

The acetic acid-catalyzed reaction between 5-chloroisatin and 4-methylthiosemicarbazide yields the title compound, C10H9ClN4OS (I) (common name: 5-chloroisatin-4-methylthiosemicarbazone). The molecule is nearly planar (r.m.s. deviation = 0.047 Å for all non-H atoms), with a maximum deviation of 0.089 (1) Å for the O atom. AnS(6) ring motif formed by an intramolecular N—H...O hydrogen bond is observed. In the crystal, molecules are linked by N—H...O hydrogen bonds, forming chains propagating along thea-axis direction. The chains are linked by N—H...S hydrogen bonds, forming a three-dimensional supramolecular structure. The three-dimensional framework is reinforced by C—H...π interactions. The absolute structure of the molecule in the crystal was determined by resonant scattering [Flack parameter = 0.006 (9)]. The crystal structure of the same compound, measured at 100 K, has been reported on previously [Qasem Aliet al.(2012).Acta Cryst.E68, o964–o965]. The Hirshfeld surface analysis indicates that the most important contributions for the crystal packing are the H...H (23.1%), H...C (18.4%), H...Cl (13.7%), H...S (12.0%) and H...O (11.3%) interactions. A molecular docking evaluation of the title compound with the ribonucleoside diphosphate reductase (RDR) enzyme was carried out. The title compound (I) and the active site of the selected enzyme show Cl...H—C(LYS140),Cg(aromatic ring)...H—C(SER71), H...O—C(GLU200)and FeIII...O...FeIIIintermolecular interactions, which suggests a solid theoretical structure–activity relationship.

Comparative study of two oxalate isomers with different dimensionalities

2014 ◽  
Vol 70 (a1) ◽  
pp. C656-C656
Author(s):  
Hamza Kherfi ◽  
Malika Hamadène ◽  
Achoura Guehria-Laidoudi ◽  
Slimane Dahaoui ◽  
Claude Lecomte
Keyword(s):  
Water Molecule ◽  
Three Dimensional ◽  
Organic Ligand ◽  
Compound I ◽  
Hydrothermal Conditions ◽  
Trans Conformation ◽  
Metal Centers ◽  
Space Group ◽  
Oxalate Ligand ◽  
Compound Ii

We report here two bimetallic oxalate isomers with the same chemical formula [RbCr(C2O4)2(H2O)2], which have been synthesized respectively by a slow evaporation method at room temperature (compound I) [1], and under hydrothermal conditions (compound II) [2] with the same starting salts. Their structures show a several discrepancies, due probably to the synthetic conditions. Indeed, the compound I crystallizes in space group C2/m with the Cr, Rb atoms and one oxygen from water molecule lying on special positions. Moreover, the unique oxalate ligand forms a bridge between metal centers. The Cr atom is coordinated to 2 bidentate-chelating oxalates and 2 aqua ligands in a trans-conformation and any water molecule has been found around the 8-coordinated Rb atom, leading to a layered structure consists of alternating Rb and Cr polyhedra connected via the unique organic ligand. Whereas, the compound II crystallizes in space group P21/n, with all atoms located on general positions. Furthermore, two independent oxalato ligands exhibit different configurations, which one is pentadentate and the other is hexadentate with two different chelating modes. The very slightly distorted Cr octahedra consists of 2 bidentate-chelating oxalato ligands and 2 water molecules in a cis-conformation, while the alkali metal is surrounded by seven O atoms from oxalate groups, completed with two H2O molecules which are bridging the Cr and Rb polyhedra by one common edge. This results in the formation of three different chains of alternating edge- and vertex-shared polyhedra through oxalates groups and aqua ligands, running along the three space directions to build a three dimensional framework. These two compounds can be considered as supramolecular isomers [3].

scholarly journals Crystal structure determination of two pyridine derivatives: 4-[(E)-2-(4-methoxyphenyl)ethenyl]-1-methylpyridin-1-ium hexafluoro-λ6-phosphane and 4-[(E)-2-[4-(dimethylamino)phenyl]ethenyl]-1-phenyl-1λ5-pyridin-1-ylium hexafluoro-λ6-phosphane

2019 ◽  
Vol 75 (2) ◽  
pp. 288-291
Author(s):  
J. Arul Martin Mani ◽  
M. Mercina ◽  
S. Antony Inglebert ◽  
P. Narayanan ◽  
V. Joseph ◽  
...  
Keyword(s):  
Double Bond ◽  
Benzene Ring ◽  
Pyridine Ring ◽  
Crystal Packing ◽  
Pyridine Derivatives ◽  
Compound I ◽  
Π Interactions ◽  
Molecular Salts ◽  
Compound Ii

The title molecular salts, C16H16NO+·PF6 −, (I), and C21H21N2 +·PF6 −, (II), are pyridine derivatives. In compound (I), the cation comprises a methyl N-substituted pyridine ring and a methoxy-substituted benzene ring connected by a C=C double bond. The F atoms of the PF6 − anion are disordered over two sets of sites with refined occupancy factors of 0.614 (7):0.386 (7). In compound (II), the cation comprises a pyridine ring attached to unsubstituted phenyl ring and a dimethylaniline ring, which are connected by a C=C double bond. The anion is PF6 −. In both salts, the cation adopts an E configuration with respect to the C=C bond. The pyridine ring makes a dihedral angle of 9.86 (12)° with the methoxy-substituted benzene ring in compound (I) and 11.2 (3)° with the dimethylamine-substituted benzene ring in compound (II). In compound (I), the crystal packing is stabilized by weak C—H...F intermolecular interactions which result in R 4 3(14) ring motifs, forming molecular sheets running parallel to (\overline{1}03). These are further stabilized by weak P—F...π interactions. In compound (II), the crystal packing is stabilized by C—H...F interactions, which result in R 6 6(40) ring motifs, forming molecular sheets running parallel to (101) and these are further connected by π–π interactions.

scholarly journals Crystal structure, spectroscopic characterization and Hirshfeld surface analysis of aquadichlorido{N-[(pyridin-2-yl)methylidene]aniline}copper(II) monohydrate

2020 ◽  
Vol 76 (2) ◽  
pp. 148-154 ◽  
Author(s):  
Miguel F. Molano ◽  
Vaneza P. Lorett Velasquez ◽  
Mauricio F. Erben ◽  
Diana L. Nossa González ◽  
Alix E. Loaiza ◽  
...  
Keyword(s):  
Water Molecule ◽  
Surface Analysis ◽  
Crystal Packing ◽  
Copper Chloride ◽  
Spectroscopic Characterization ◽  
Hirshfeld Surface ◽  
Hirshfeld Surface Analysis ◽  
Strong Hydrogen Bond ◽  
Chloride Dihydrate ◽  
Pyramidal Geometry

The reaction of N-phenyl-1-(pyridin-2-yl)methanimine with copper chloride dihydrate produced the title neutral complex, [CuCl2(C12H10N2)(H2O)]·H2O. The CuII ion is five-coordinated in a distorted square-pyramidal geometry, in which the two N atoms of the bidentate Schiff base, as well as one chloro and a water molecule, form the irregular base of the pyramidal structure. Meanwhile, the apical chloride ligand interacts through a strong hydrogen bond with a water molecule of crystallization. In the crystal, molecules are arranged in pairs, forming a stacking of symmetrical cyclic dimers that interact in turn through strong hydrogen bonds between the chloride ligands and both the coordinated and the crystallization water molecules. The molecular and electronic structures of the complex were also studied in detail using EPR (continuous and pulsed), FT–IR and Raman spectroscopy, as well as magnetization measurements. Likewise, Hirshfeld surface analysis was used to investigate the intermolecular interactions in the crystal packing.

scholarly journals Synthon robustness by C-F groups in halogen substituted N-benzylideneanilines

2014 ◽  
Vol 70 (a1) ◽  
pp. C1811-C1811
Author(s):  
Gurpreet Kaur ◽  
Angshuman Roy Choudhury
Keyword(s):  
Crystal Structure ◽  
Crystal Engineering ◽  
Crystal Packing ◽  
Weak Interactions ◽  
Topological Analysis ◽  
Strong Hydrogen Bond ◽  
Hydrogen Bond Donor ◽  
Donor And Acceptor ◽  
The Impact ◽  
Organic Fluorine

The arrangement of the molecules in their crystal structure is controlled by the non-covalent intermolecular interactions other than the effectual space filling. The role of strong hydrogen bonds in guiding the crystal packing is well-known in the literature. But, how significant are the weak interactions in the field of crystal engineering, has yet not been fully understood. Our aim is to comprehend the nature and strength of the weak interactions involving fluorine in guiding the packing of small organic molecules in their respective crystal structure. The reason being the controversies, which are involved regarding the interactions offered by "organic fluorine"[1] and also due to the importance of these interactions in the pharmaceutical industry. Some of the research groups indicate the incapability of interactions offered by fluorine in the formation of supramolecular motifs, whereas other groups have indicated that substantial role is being played by fluorine in constructing the lattice through C-H···F, C-F···F and C-F···π interactions in the presence and absence of strong hydrogen bond donor and acceptor groups. To understand more about these interactions, we have chosen a model system of halogen substituted N-benzylideneanilines[2]. In this system, we have analysed the impact of fluorine mediated interactions on the crystal packing by having fluorine as a substituent on both the phenyl rings. Then the robustness of the synthons offered by organic fluorine has been anticipated in the same system, but with one of the substituent as chlorine or bromine in either of the phenyl ring. It has been observed that the replacement of the non-interacting fluorine by its heavier analogue has not altered the supramolecular motif, which was formed by the other fluorine. But the crystal packing has been found to be completely altered in the molecules where the interacting fluorine was replaced by its heavier analogue. Salient features of our computational studies, which include the calculation of the stabilization energies of the studied dimers using MP2 method and their topological analysis using AIM2000, to support the experimental observations will also be presented to highlight the sturdiness of the synthons formed by so called "organic fluorine".

scholarly journals Synthesis, Crystal Structures, and Molecular Properties of Three Nitro-Substituted Chalcones

Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1589
Author(s):  
Alam Yair Hidalgo ◽  
Manuel Velasco ◽  
Eduardo Sánchez-Lara ◽  
Abraham Gómez-Rivera ◽  
Miguel A. Vilchis-Reyes ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Functional Groups ◽  
Direct Effect ◽  
Crystal Packing ◽  
Hirshfeld Surface ◽  
Stacking Interactions ◽  
Orthorhombic Space Group ◽  
Trans Conformation ◽  
Space Group ◽  
X Ray

Three functionalized chalcones containing combinations of nitro functional groups have been synthesized via Claisen-Schmidt condensation between 2-nitroacetophenone and nitrobenzaldehyde, and the crystal structures obtained ((E)-1,3-bis(2-nitrophenyl)prop-2-en-1-one, 1a, (E)-1-(2-nitrophenyl)-3-(3-nitrophenyl)prop-2-en-1-one, 1b and (E)-1-(2-nitrophenyl)-3-(4-nitrophenyl)prop-2-en-1-one, 1c), C15H10N2O5, are reported. Compounds 1a and 1c crystallized in the triclinic centrosymmetric space group P1¯, whereas compound 1b crystallized in the orthorhombic space group Pbca. The X-ray analysis reveals that structures 1a and 1b exhibits s-trans conformation, whereas structure 1c exists in s-cis conformation, concerning the olefinic double bonds. In addition, the results show that the position of the nitro substituent attached to the aromatic B-ring has a direct effect on the molecular coplanarity of these compounds. The Hirshfeld surface analysis suggests that the non-covalent π-π stacking interactions are the most important contributors for the crystal packing of 1a and 1b. In 1c, the crystal packing is mainly stabilized by weak intermolecular C―H···O interactions due to the planar nature of the molecule.

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