Geometry of lidocaine-like molecules: 2. Crystal structures of 2-benzyl-2-(1-piperidinyl)-N-(2,6-dimethylphenyl) acetamide and its hydrochloride hemihydrate

The title compounds both crystallize in the monoclinic space group P2₁ (Z = 4), with a = 12.574(1), b = 9.653(1) c = 16.483(1) Å, and = 91.84(1)° for the free base and a = 10.991(2), b = 16.864(3), c = 12.030(2) Å, = 99.35(3)° for the hydrochloride. The most important factors affecting conformation of the molecules are: ortho-substitution of the benzene ring in the acetanilide system and substitution of the C atom. Surprisingly, the conformation does not depend on the protonation state of the amine nitrogen atom, which greatly affects packing and hydrogen bonding patterns in the crystalline state. The conformation in which the H atom of the charged amine group is in a trans position to the main backbone of the molecule, is probably responsible for the antiarrhythmic activity, while a gauche conformation promotes local anaesthetic action. The separation of the lipophilic (xylidine) and amine groups, being two important pharmacophores, equals about 4.7 Å in the studied compounds and other structures comprising the amino-2,6-dimethyl-acetanilide system.     

The Synthesis and Crystal Determination of 3-Hydroxy-4-(4-methoxyphenyl)-5-(2-nitrophenyl)furan-2(5H)-one

Abstract  

The title compound, C₁₇H₁₃NO₆, was synthesized and structurally characterized by elemental analysis, MS, ¹H NMR and single crystal X-ray diffraction. It crystallizes in monoclinic system space group C 2/c with a = 27.981(6) ?, b = 12.996(3) ?, c = 8.0900(16) ?, β = 91.06(3)°, V = 2941.4(10) ?³, Z = 8, R ₁ = 0.0675, wR ₂ = 0.1626, and T = 298(2) K. The X-ray structure determination revealed that the center furanone ring is nearly coplanar with p-methoxybenzene ring and forms a dihedral angle of 87.2(1)° with the nitrobenzene ring. O–H···O Intermolecular hydrogen bonds link pairs of molecules into centrosymmetric dimers, making a graph set motif of R ₂²(10). The dimers are further assembled into a chain of edge-fused R ₄⁴(34) rings running along the [001] direction. The final three-dimensional supramolecular architecture is stabilized by weak π–π interactions.     

Synthesis and Crystal Structure of 1,7-Bis(4-methoxyphenyl)-4-(1,3-dithiolan-2-ylidene)-1,6-heptadiene-3,5-dione

Abstract  

The synthesis and crystal structure of 1,7-bis(4-methoxyphenyl)-4-(1,3-dithiolan-2-ylidene)-1,6-heptadiene-3,5-dione is described. This compound crystallizes in the space group P2₁ with unit cell parameters a = 14.207 ?, b = 7.752(1) ?, c = 19.473(1) ?, β = 91.00(3)°, with two molecules in the asymmetric unit. The ketenedithioacetal functionality present between the carbonyl groups prevents the possibility of keto-enol tautomerization in this compound. The cinnamoyl groups are organized parallel to each other due to the push–pull nature of the ketenedithioacetal functionality.     

Crystal and molecular structures of 2-amino-5-(m-nitrophenyl)-1,3,4-Thiadiazole

2-Amino-5-(m-nitrophenyl)-1,3,4-thiadiazole (C₈H₆N₄O₂S) is studied using IR and ¹H NMR spectroscopy and X-ray diffraction (CAD4 automated diffractometer, λMoK _α, graphite monochromator, 957 unique reflections, Patterson method, R = 0.0326). The crystals are monoclinic, a = 11.832 Å, b = 9.862 Å, c = 8.353 Å, β = 110.40(3)°, V = 913.6(3) ų, d _calcd = 1.212 g cm^?3, μ(MoK _α) = 0.253 mm^?1, Z = 4, and space group P2₁/c. In the crystal, the C₈H₆N₄O₂S molecules form infinite layers parallel to the xz plane. Each layer contains aromatic rings with nitro groups that deviate from the layer plane on either side of the layer. In the packing, the aromatic rings with nitro groups of one layer fill spaces between aromatic rings with nitro groups of the adjacent layers.     

Crystal structure of 1,3-di-2-[(4-methoxyphenyl)-1-diazenyl]imidazolidine

The crystal and molecular structure of 1,3-di-2-[(4-methoxyphenyl)-1-diazenyl]imidazolidine (1) has been determined by single crystal X-ray diffraction analysis. This novel bis-triazene assumes a close-to planar structure with the aryltriazene moieties aligned in diametrically opposed directions, unlike many other previously reported bis-triazenes, which assume a folded structure. The structure of 1 is compared with the closely related, non-cyclic bis-triazene analogue (2), and also compared with the structure of the simple mono-triazene (3). Crystal data: 1 C₁₇H₂₀N₆O₂, monoclinic, space group C2/c, a = 34.948(3), b = 5.925(5), c = 8.1225(6) Å, = 100.8420(10)°, and V = 1652.0(2) ų, for Z = 4.     

Crystal structures of anhydro-bases of 1- and 2-(ethoxycarbonylmethylo)-4-hydroxycinnolinium hydroxides

C₁₂H₁₂N₂O₃,M _r=232.24. (1): C2/c,Z=8,a=14.658(1),b=4.9375(4),c=31.859(4) Å, =91.710(6)°. (2): P2₁/c,Z=4,a=11.422(2),b=4.8864(2),c=21.176(3)Å, =103.29(3)°. The study confirms significant contribution of quinoid diazine ring form in anhydrobase of 1-substituted 4-hydroxycinnolinium hydroxides. The phenomenon corresponds with a negative net charge at formerly positively charged N(1) atom, with fewer hydrogen contacts of less negatively charged O(4) and with increased stacking in 1-substituted derivative, in comparison with 2-substituted structure.     

Crystal structures of difluoro[2-(4-methoxyphenyl)-3-oxo-3-phenylpropanalato]boron(III), [BF2(C16H13O3)], and bis[2-(4-methoxyphenyl)-3-oxo-3-phenylpropanalato]copper(II), [Cu(C16H13O3)2]

The crystal structures of difluoro[2-(4-methoxyphenyl)-3-oxo-3-phenylpropanalato]boron(III), [BF₂(C₁₆H₁₃O₃)], and bis[2-(4-methoxyphenyl)-3-oxo-3-phenylpropanalato]copper(II), [Cu(C₁₆H₁₃O₃)₂], have been determined by single-crystal X-ray diffraction methods. The structures were solved by direct methods and electron density calculations and were refined by the full-matrix least-squares method. Difluoro[2-(4-methoxyphenyl)-3-oxo-3-phenylpropanalato]-boron(III) crystallizes as yellow rhombs in the monoclinic space groupP2₁/c witha=11.429(3),b=11.364(4),c=11.412(4) Å,=92.19(2)°,V=1481.0(8) ų andZ=4. A total of 2754 unique reflections were collected. Of these 1342 were considered observed [I>3(I)] leading to a finalR-value of 0.045. Boron is tetrahedrally coordinated to the two fluorine atoms and to two oxygen atoms of the bidentate 2-(4-methoxyphenyl)-3-oxo-3-phenylpropanalato ligand, C₁₆H₁₃O ₃ ^– . Average bond distances: C-C (aromatic) 1.378(10) Å, B-O 1.473(7) Å and B-F 1.343(4) Å. bis[2-(4-Methoxyphenyl)-3-oxo-3-phenylpropanalato]copper(II) crystallizes as dark yellow-green plates in the monoclinic space groupC2/c witha=23.410(7),b=13.856(3),c=8.039(3) Å,=101.79(2)°,V=2553(1) ų andZ=4. Of the unique set of 3076 scanned reflections 2401 hadI>3(I) for whichR became 0.040. Copper is coordinated to four oxygen atoms, two from each of the two bidentate 2-(4-methoxyphenyl)-3-oxo-3-phenylpropanalato ligands, in a distorted square planar manner. The molecule hasC ₂ symmetry. Average bond distances: C-C (aromatic) 1.383(6) Å and Cu-O 1.896(8) Å. The crystals of both compounds consist of monomeric molecular complexes held together by van der Waals forces.     

Crystal structures of two azo compounds, 2-methyl-2-(4-bromphenylazo)-1,3-indandione and 2-methyl-2-(4-ethoxyphenylazo)-1,3-indandione

In the two title compounds, the 2-methyl-1,3-dioxoindan-2-yl and 4-(brom; ethoxy) phenyl groups aretrans with respect to one another. The phenyl ring and the azo group are not coplanar in the two molecules. The five-membered rings of the two compounds adopt an envelope conformation. The crystallographic parameters are as follows: 2-Methyl-2-(4-bromphenylazo)-1,3-indandione (I): monoclinic, P2₁/a witha=8.098(2),b=14.442(2),c=12.554(1)Å, =100.55(2)^o, andD _calc=1.58 g cm^–3 forZ=4; 2-methyl-2-(4-ethoxyphenylazo)-1, 3-indandione (II): monoclinic, P2₁/a witha=8.258(2),b=14.449(1),c=13.559(2)Å, =101.19(1)^o, andD _calc=1.29 g cm^–3 forZ=4.     

Synthesis and Crystal Structure of Diisopropyl Hydroxy(4-methoxyphenyl)methylphosphonate

Abstract  The title compound, C₁₄H₂₃O₅P, was synthesized by the reaction of 4-methoxybenzaldehyde and diisopropyl phosphite. Its structure was determined with X-ray crystallographic, NMR, MS, and elemental analysis (EA) techniques. The crystal belongs to monoclinic, space group P 2_1/n with the following crystallographic parameters: a = 10.529 (2) ?, b = 8.424 (2) ?, c = 19.448 (4) ?, α = 90°, β = 105.2 (3)°, γ = 90°, μ = 0.180 mm⁻¹, V = 1664.1 (6) ?³, Z = 4, Dx = 1.207 mg/mm³, F (000) = 648, T = 293 (2) K, 2.00° ≤ θ ≤ 25.50°. The final residual factor is 0.049 for 1933 reflections with I > 2σ (I). Crystal packing is stabilized by interatomic hydrogen bond interactions between the doubly bonded phosphoryl O atom and the hydroxyl H atom which link the molecules into chains along the [011] plane of the unit cell. Index Abstract   The title compound, diisopropyl hydroxy(4-methoxyphenyl)methylphosphonate, was synthesized by the reaction of 4-methoxybenzaldehyde and diisopropyl phosphite. Its structure was determined with X-ray crystallographic, NMR, MS, and elemental analysis (EA) techniques. Crystal packing is stabilized by interatomic hydrogen bond interactions between the doubly bonded phosphoryl O atom and the hydroxyl H atom which link the molecules into chains along the [011] plane of the unit cell.      

Crystal and molecular structures of 2-(p-methylbenzyl)- and 2-(p-chlorobenzyl)-5-(p-bromobenzylidene)cyclopentanone. Influence of chloro and methyl substitution on solid-state reactivity

The crystal structures of the title compounds have been determined as part of an investigation into the factors which may influence the solid-state reactivity of benzylidene cyclopentanones. Thep-methyl derivative, which is photoactive in the crystalline state, in monoclinic:P2₁/c,a=18.381(2),b=11.209(2),c=8.285(2) Å,=94.46(12)°, andz=4. The chloro derivative, which is photostable, is also monoclinic:P2₁/c,a=17.522(4),b=7.906(2),c=11.888(2) Å,=91.19(14)°, andz=4. The structures were solved and developed via the heavy-atom method and refined by least-squares to finalR values of 0.062 and 0.061, respectively, using 1902 and 2356 observed reflections measured using an automatic diffractometer. The conformations of the two molecules in their crystal structures are significantly different and lead to dissimilar packing arrangements, which clearly account for the different photochemical behaviors.     

Crystal structures of N-(2-aminoethyl)-1-naphthaleneneacetamide nitrate and hydrogen tartrate dihydrate

Nitrate (1): C₁₄H₁₇N₂O⁺·NO ₃ ^– , orthorhombic, Pbca,Z=8,a=9.6924(4),b=27.664(2) andc=10.8589(6)Å.Hydrogen tartrate dihydrate (2): C₁₄H₁₇N₂O⁺·C₄H₅O ₆ ^– ·2H₂O, orthorhombic, P2₁2₁2₁,Z=4,a=7.6703(5),b=7.9368(4) andc=31.953(2)Å. In the solid state, cation conformation differ due to molecular flexibility, very different anionic environments, and resultant hydrogen bonding patterns. Despite these differences, the two structures maintain the same separations (about 7.35 Å) of the two most distant potential pharmacophoric groups, i.e., the aromatic ring and the protonated amine group.     

Crystal and molecular structure of 2-(p-tolyl)-2-dehydrosparteine

The formula of the title compound is C₂₂H₃₀N₂,M _T =322.5; monoclinic:P2₁,a=7.569(3),b=9.381(1),c=13.684(4) Å,=105.81(2)°,Z=2,V _c =933.7 ų,D _x =1.15 g cm^–3,(CuK)=5.1 cm^–1. The sparteine skeleton (bis-quinolizidine system) has atrans-trans configuration. RingA has an intermediate form between the sofa and half-chair conformations, ringsB andD-chair, and ringC-boat conformations, respectively. The double bond C(2)=C(3) is equal to 1.343(9) Å. The phenyl ring is planar and makes an angle with a plane through N(1), C(2), C(3), and C(4) atoms equal to 43.9°.     

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.     

Crystal structures of 1,1-di(p-substituted phenyl)-2,2-dinitroethylenes

The X-ray crystal structures of 1,1-di(p-methylphenyl)-2,2-dinitroethylene (2), 1,1-di(p-methoxylphenyl)-2,2-dinitroethylene (3), 1,1-di(p-fluorophenyl)-2,2- dinitroethylene (4), 1,1-di(p-chlorophenyl)-2,2-dinitroethylene (5), and 1-phenyl-1- (p-nitrophenyl)-2,2-dinitroethylene (6) are reported and compared with that of 1,1-diphenyl-2,2-dinitroethylene (1). Owing to steric repulsion between the aryl rings, the single bond lengths between C(1) and the two ring carbons atoms are longer than the normal sp²–sp² bond distance of 1.46 Å. For 4–6 in which the aryl rings contain electron-withdrawing substituents (F, Cl, NO₂), the double bonds between C(1) and C(2) are shorter than those in 2 and 3, whose aryl rings containing electron-donating substituents. Furthermore, the steric repulsion between the aryl rings and C NO₂ fragments results in an appreciable twist about the central double bond. The two aryl rings of compounds 1–6 make dihedral angles of 77.7, 66.6, 62.8, 80.9, 82.0, and 71.2°, and the two C NO₂ fragments make dihedral angles of 68.5, 67.8, 65.9, 76.9, 73.0, and 71.9°, respectively.     

Crystal and molecular structure of 2-(1,3-benzothiazol-2-yl)-2-(4-tert-butylcyclohexylidene)ethanonitrile

The crystal and molecular structure of the title compound (C₁₉H₂₂N₂S) has been investigated by single crystal X-ray methods. The crystals are orthorhombic, space groupPbca, with cell dimensions:a=12.082(2)Å,b=11.460(2)Å,c=25.128(4)Å. The structure was solved by direct methods, and refined with 1225 independent reflections by a full-matrix, least-squares procedure, which converged toR=0.042. The benzene and thiazole planes are coplanar and the cyclohexane ring adopts a chair conformation.     

The Crystal Structures of (Z)-Ethyl 2-(4-chlorophenyl)-3-(2,4-difluorophenyl-amino)acrylate and its Analogues

Abstract  

The title compound, C₁₇H₁₄ClF₂NO₂, crystallizes in monoclinic space group P2₁/c with unit cell dimension of a = 16.276(3) ?, b = 7.5030(15) ?, c = 13.812(3) ?, α = 90°, β = 111.11(3)°, γ = 90° and Z = 4. The structure of the title compound reveals a Z configuration with respect to the C=C double bond in aminoacrylate fragment. The molecule is stabilized by intramolecular N–H···F and N–H···O hydrogen bonds. In the ethyl 2-aryl-3-arylaminoacrylates, electronic properties of the substituents in the aniline motif clearly affected the attached C–N bond length, and such effect is very little relative to Z-/E-configuration with respect to the C=C double bond.     

Crystal structures of N-phenyl-2-(1,4,7,10-tetraoxa-13-azacyclopentadecane-13-carbonyl)benzamide and N-(4-ethoxyphenyl)-2-(1,4,7,10-tetraoxa-13-azacyclopentadecane-13-carbonyl)benzamide

The crystal structures of two monoaza-15-crown-5 macrocycles substituted at the nitrogen atom are determined by X-ray diffraction. The structures of these crystals are characterized by the intramolecular and intermolecular N-H?O and C-H?O interactions. The conformation of the 15-membered rings and the specific features of the molecular packing in the crystals are discussed.     

Crystal and molecular structures of 1-(2-carboxypropan-2-ylamino)-3-(1-naphthyloxy) propan-2-ol (1) (C17H21NO4) and 1-(2-carbamoyl propan-2-ylamino)-3-(1-naphthyloxy) propan-2-ol (2) (C17H22N2O3)

The crystal structures of two new-adrenergic antagonists, derivatives of propranolol containing 2-methylalanine fragment are described in this paper. The space groups and unit-cell parameters are: compound1 (C₁₇H₂₁NO₄): monoclinic, space groupP2₁/n,a=5.787(1),b=18.703(4),c=23.526(5)Å,=96.49(2)°; compound2 (C₁₇H₂₂N₂O₃): triclinic, space groupP¯1,a=8.321(1),b=10.121(1),c=10.368(1)Å,=109.49(1)°,=90.49(1)°, =103.48(1)°. The structures were solved by direct methods and refined with full matrix least-squares techniques toR indices of 0.055 and 0.049, respectively. The molecules of compound1 exist in the crystal as dual ions. The molecules of compound2 are compact and their external chain is twisted in a characteristic way (similar to that found in peptides).