X-ray mapping in heterocyclic design: XV. Tricyclic heterocycles based on 2-oxo-2,5,6,7-tetrahydro-1<Emphasis Type="Italic">H</Emphasis>-cyclopenta[<Emphasis Type="Italic">b</Emphasis>]pyridine-3-carbonitrile

The structures of five compounds are studied using single-crystal X-ray diffraction: 2-oxo-2,5,6,7-tetrahydro-1H-cyclopenta[b]pyridine-3-carbonitrile [a = 15.641(8) Å, b = 9.373(5) Å, c = 7.387(4) Å, β = 92.91(5)°, Z = 4, space group P2₁/c]; 1-[2-(4-chlorophenyl)-2-oxoethyl]-2-oxo-2,5,6,7-tetrahydro-1H-cyclopenta[b]pyridine-3-carbonitrile [a = 4.728(4) Å, b = 28.035(11) Å, c = 11.184(3) Å, Z = 4, space group P2₁2₁2₁]; 2-[2-(4-chlorophenyl)-2-oxoethoxy]-6,7-dihydro-5H-cyclopenta[b]pyridine-3-carbonitrile [a = 10.1202(13) Å, b = 11.2484(18) Å, c = 13.4323(19) Å, β = 102.05(1)°, Z = 4, space group P2₁/c]; 2-(4-chlorophenyl)-3a, 6,7,8-tetrahydrocyclopenta[e][1.3]oxazolo[3.2-a]pyridine-4-carboxamide perchlorate [a = 7.702(2) Å, b = 9.599(3) Å, c = 23.798(5) Å, β = 93.44(2)°, Z = 4, space group P2₁/c]; and (3-amino-6,7-dihydro-5H-cyclopenta[b]furo[3.2-e]pyridin-2-yl)(4-chlorophenyl)methanone [a = 7.3273(2) Å, b = 13.390(3) Å, c = 28.792(8) Å, Z = 8, space group Pbca]. The structures are solved using direct methods and refined by the full-matrix least-squares procedure in the anisotropic approximation to R = 0.0580, 0.0724, 0.0469, 0.0477, and 0.0418, respectively.     

Crystal Structure of 2-(4,5-Bis(4-methoxyphenyl)-5<Emphasis Type="Italic">H</Emphasis>-chromeno[4,3-<Emphasis Type="Italic">b</Emphasis>]pyridin-2-yl)phenol

Abstract  

The title compound 2-(4,5-bis(4-methoxyphenyl)-5H-chromeno[4,3-b]pyridin-2-yl)- phenol (C₃₂H₂₅NO₄, Mr = 487.53) was synthesized and crystallized. The crystal belongs to monoclinic, space group P2(1)/c with a = 12.4170 (11), b = 18.313 (2), c = 11.7103 (10) ?, β = 111.569(2)°, V = 2476.4(4) ?³, Mr = 487.53, Z = 4, Dc = 1.308 g/cm³, μ(MoK _α ) = 0.086 mm⁻¹, F(000) = 1024, the final R ₁ = 0.0632 and wR ₂ = 0.1454. X-ray analysis reveals that the atoms of C(1), C(2), C(3), C(4), C(5) and N(1) form a planar six-membered ring, while the atoms of C(1), C(2), C(6), C(7), C(12) and O(1) form a six-membered ring of envelope conformation.     

Synthesis and Crystal Structure of 7,8,9,10-Tetrahydro-2-bromo-cyclohepta[<Emphasis Type="Italic">b</Emphasis>]indol-6(5<Emphasis Type="Italic">H</Emphasis>)-one

The title compound, C₁₃H₁₂BrNO, was synthesized and characterised by IR, ¹H and ¹³C NMR spectroscopy. The proposed structure was confirmed by single crystal X-ray diffraction. The single crystal data revealed that the compound crystallizes in the triclinic system, sp. gr. P1, with Z = 2. The sevenmembered ring exhibits a slightly distorted envelope conformation. N–H···O hydrogen bonds form a centrosymmetric dimer, these interactions create a stair-like chain of molecules that interacts only loosely with neighbouring chains via van der Waals interactions, and C–H···π contacts are found in the crystal structure.     

Crystal structure analysis of 4-phenylquinolin-2-(1<Emphasis Type="Italic">H</Emphasis>)-one

The crystal structure of 4-phenylquinolin-2-(1H)-one (C₁₅H₁₁NO) is determined by X-ray diffraction. The compound crystallizes in the orthorhombic crystal system (space group Pbca) with the unit cell parameters a = 7.382(2) Å, b = 21.795(3) Å, c = 14.066(5) Å, and Z = 8. The structure is solved by direct methods and refined to an R-value of 0.0398 for 1360 observed reflections [F₀ > 4σ (F₀)]. The quinoline moiety and the substituted phenyl ring are nearly planar. The dihedral angle between these two moieties is 64.65(6)°. The crystal structure is stabilized by two intermolecular N-H?O and C-H?O interactions.     

Synthesis and Crystal Structures of Methyl 3-(Benzoylamino)-6-methyl-2-oxo-2<Emphasis Type="Italic">H</Emphasis>-pyran-5-carboxylate and <Emphasis Type="Italic">N</Emphasis>-[5-(3,4-Dimethoxyphenyl)-6-methyl-2-oxo-2<Emphasis Type="Italic">H</Emphasis>-pyran-3-yl]benzamide

Abstract  

The compounds methyl 3-(benzoylamino)-6-methyl-2-oxo-2H-pyran-5-carboxylate (1), C₁₅H₁₃NO₅, and N-[5-(3,4-dimethoxyphenyl)-6-methyl-2-oxo-2H-pyran-3-yl]benzamide (2), C₂₁H₁₉NO₅, crystallize as a centrosymmetric hydrogen-bonded dimer facilitated by N–H···O interactions involving the amide and carbonyl moiety of the lactone group of adjacent molecules. Supramolecular aggregation in 1 is controlled by a combination of π–π interactions [centroid–centroid distance = 4.0745(11) ?] and weak C–H···O hydrogen bonding between the phenyl ring of the benzoylamino group and the carbonyl atom of the methoxycarbonyl group and in 2 by a combination of π–π interactions [centroid–centroid distance = 4.0699(8) and 4.1556(10) ?], weak C–H···O interactions between the methoxy substituents of the adjacent dimethoxyphenyl group and weak C–H··· π interactions.     

Synthesis and Crystal Structure of (5-Methyl-3-phenyl-1<Emphasis Type="Italic">H</Emphasis>-pyrazol-1-yl)-[5-(<Emphasis Type="Italic">p</Emphasis>-tolylamino)-2<Emphasis Type="Italic">H</Emphasis>-1,2,3-triazol-4-yl]methanone

Abstract  

(5-Methyl-3-phenyl-1H-pyrazol-1-yl)-[5-(p-tolylamino)-2H-1,2,3-triazol-4-yl]methanone was synthesized and characterized by ¹H NMR, MS and IR spectra data. The structure of title compound was identified by X-ray diffraction. Compound, C₂₀H₁₈N₆O, Mr = 358.40, crystallizes in the triclinic space group P-1 with unit cell parameters a = 10.303(6), b = 12.489(7), c = 15.305(9) ?, α = 108.489(12), β = 101.920(11), γ = 96.971(13)°, V = 1790.0(17) ?³, Z = 4, Dx = 1.330 mg/cm³. The final R was 0.0520.     

Electron diffraction study of 1<Emphasis Type="Italic">M</Emphasis> illites with interstratified <Emphasis Type="Italic">trans</Emphasis>- and <Emphasis Type="Italic">cis</Emphasis>-vacant 2 : 1 layers

Illites from the volcanogenic Zn-Au-Ag sulfide deposit Galkinskoe (Northern Urals) have been investigated using oblique-texture electron diffraction patterns in combination with the simulation of diffraction effects. Along with single-phase tv/cv1M illites, the structures of which are formed by statistically interstratified dioctahedral 2: 1 layers with vacant trans- or cis-octahedra, illites in the form of a mixture of two interstratified tv/cv1M phases, with the dominance of tv- or cv layers, are identified. It is shown that in the latter case the diffraction pattern can also be interpreted within the single-phase tv/cv model, provided that the tv- and cv layers are distributed with some tendency to segregate. The structural features indicating the preference of the two-phase model are analyzed.     

Co-crystal Structure of 11-Hydroxy-2,3,9-trimethoxy-6<Emphasis Type="Italic">H</Emphasis>-chromeno[3,4-<Emphasis Type="Italic">b</Emphasis>]chromen-12-one and 11-Hydroxy-2,3,9-trimethoxy-chromeno[3,4-<Emphasis Type="Italic">b</Emphasis>]chromene-6,12-dione

Abstract  

A 1:1 co-crystal structure of 11-hydroxy-2,3,9-trimethoxy-6H-chromeno[3,4-b]chromen-12-one and 11-hydroxy-2,3,9-trimethoxy-chromeno[3,4-b]chromene-6,12-dione (stemonone) was crystallized from the reaction mixture of 6-deoxyclitoriacetal and methanesulfonyl chloride, and its structure was characterized by X-ray diffraction. This co-crystal crystallizes in a triclinic crystal system, space group P(−1) with unit cell parameters of a = 8.1317(3) Å, b = 9.8224(4) Å, c = 10.7268(3) Å, α = 78.116(1)°, β = 77.463(1)°, γ = 77.140(1)°, Z = 2 and V = 804.11(3) Å³. The crystal structure was solved by direct methods and refined by full-matrix least-squares on F ² to final values of R ₁ = 0.0501 and wR ₂ = 0.1520.     

Synthesis and structure of 7-methyl-5-phenyl-1<Emphasis Type="Italic">H</Emphasis>-pyrazolo[4,3-<Emphasis Type="Italic">e</Emphasis>]tetrazolo[4,5-<Emphasis Type="Italic">b</Emphasis>][1,2,4]triazine<Superscript>(1)</Superscript>

The synthesis of 5-azido-3-methyl-1-phenyl-1H-pyrazolo[4,3-e][1,2,4]triazine 2 and 7-methyl-5-phenyl-1H-pyrazolo[4,3-e]tetrazolo[4,5-b][1,2,4]triazine 3 is described and the crystal and molecular structure of the latter is reported. This compound crystallizes in the monoclinic system, space group P2₁/n, with cell constants a = 11.607(2) Å, b = 7.982(1) Å, c = 13.147(2) Å, = 110.60(1), Z = 4, T = 293 K and D_cal = 1.470 g cm^–3. The structure was solved by direct methods and refined to R value of 0.0368 for 1906 reflections. The X-ray analysis revealed that the linear form of the tetrazolo-fused ring system of 3 exists in the crystal. The molecule as a whole has an almost planar conformation stabilized by the short intramolecular NsH interaction. The molecular packing in the crystal is determined by the van der Waals forces only.Part 26 in 1,2,4-triazines in organic synthesis. For part 25 see Mojzych et al.¹     

Synthesis,redox properties,and X-ray diffraction structure of 2,3-<Emphasis Type="Italic">bis</Emphasis>(ethylthio)-<Emphasis Type="Italic">N</Emphasis>-(<Emphasis Type="Italic">p</Emphasis>-MeOC<Subscript>6</Subscript>H<Subscript>4</Subscript>)maleimide

Refluxing 2,3-dichloromaleic anhydride with p-anisidine in benzene with water removal gives the condensation product 2,3-dichloro-N-(p-MeOC₆H₄)maleimide (1) 75% yield. This new maleimide compound reacts with added ethanethiol in the presence of Et₃N or DBU to furnish the bidentate sulfide ligand 2,3-bis(ethylthio)-N-(p-MeOC₆H₄)maleimide (2) in 85% yield. Each product has been characterized in solution by IR, NMR, and UV-vis spectroscopies, and the solid-state structure of 2,3-bis(ethylthio)-N-(p-MeOC₆H₄)maleimide was unequivocally established by single-crystal X-ray diffraction analysis. 2,3-bis(Ethylthio)-N-(p-MeOC₆H₄)maleimide crystallizes in the monoclinic space group C2/c, a = 20.035(3)Å, b = 9.188(1)Å, c = 16.887(2)Å, = 93.696(2)°, V = 3102.3(8)ų, Z = 8, and D_calcd = 1.385 mg/m³; R = 0.0268, R_w = 0.0676 for 2025 reflections with I > 2 (I). The nature of the LUMO in 2,3-bis(ethylthio)-N-(p-MeOC₆H₄)maleimide (2) has been determined by extended Hückel molecular orbital calculations, and these data are discussed relative to the cyclic voltammetry results and other structurally relevant compounds prepared in our labs.     

X-ray crystallography of methyl (6-amino-5-cyano-2-methyl-4-(2-nitrophenyl)-4<Emphasis Type="Italic">H</Emphasis>-pyran)-3-carboxylate

The organic carbonitrile namely methyl (6-amino-5-cyano-2-methyl-4-(2-nitrophenyl)-4H-pyran)- 3-carboxylate is synthesized via one-pot multi-component reaction at room temperature using commercially available urea as inexpensive and environmentally benign organo-catalyst and its crystal structure is determined by X-ray technique. The crystals are monoclinic, sp. gr. C2/c, a = 12.3069(8) Å, b = 9.7023(7) Å, c = 24.812(2) Å, β = 94.862(6)°, Z = 8. The dihedral angle between pyran and phenyl rings is 87.8(1)°; the pyran ring is almost planar The dihedral angle between the mean planes of phenyl ring and nitro group is 44.4(2)°. The crystal structure is stabilized by N?H···N and N?H···O hydrogen bonds. In addition, C?H···π interactions are also observed in the crystal structure.     

Synthesis and Crystal Structure Determination of 3-Phenyl-2-(2-phenylhydrazino)-4<Emphasis Type="Italic">H</Emphasis>-1-benzothiopyran-4-one

Abstract  

A new type of substituted benzothiopyranone, 3-phenyl-2-(2-phenylhydrazino)-4H-1-benzothiopyran-4-one, has been prepared by the condensation-acid cyclization of polylithiated phenylacetic acid phenylhydrazide with lithiated methyl thiosalicylate. Absorption spectra, especially ¹³C NMR, provided good indication of its structure, which was conclusively established with X-ray crystal structure analysis. In comparison to the few benzothiopyran X-ray reports documented, the benzothiopyranone ring of the molecule was found to be essentially planar, with the 3-phenyl ring nearly perpendicular to the benzothiopyranone fused-ring system. Crystals of C₂₁H₁₆N₂OS are orthorhombic, P2₁2₁2₁, a = 10.140(4) ?, b = 10.432(4) ?, c = 16.228(7) ?, Z = 4, V = 1717(1) ?³, R ₁ = 0.0267 and wR ₂ = 0.0725 for reflections with I > 2σ(I). The molecular packing in the crystal is the result of N–H···O hydrogen bonding.     

Synthesis and X-ray structural analysis of (2<Emphasis Type="Italic">Z</Emphasis>)-3(4-hydroxyphenyl)-2-pyridin-4-ylacrylonitrile and (2<Emphasis Type="Italic">Z</Emphasis>)-3-(3,5-di-<Emphasis Type="Italic">tert</Emphasis>-butyl-4-hydroxyphenyl)2-pyridin-4-ylacrylonitrile

Synthesis and X-ray structural investigations have been carried out for the two title compounds C₁₄H₁₀N₂O (3a) and C₂₂H₂₆N₂O (3b). Compound 3a crystallizes in the monoclinic space group P2₁/c, with a = 3.843(1) Å, b = 24.618(5) Å, c = 11.318(2) Å, = 92.61(3), V = 1069.7(4) Å,³ and Z = 4. Compound 3b crystallizes in the triclinic space group P-1, with a = 9.004(2) Å, b = 9.447(2) Å, c = 11.713(2) Å, = 76.70(3), = 83.12(3), = 82.16(3), V = 956.5(3) Å,³ and Z = 2. Both stilbazole derivatives have Z-geometry about the ethylene bridge which links the heterocyclic and aromatic rings. The molecular skeleton of 3a is slightly non-planar: the dihedral angles between the acrylonitrile linkage and the pyridine ring, and between this linkage and the p-hydroxyphenyl ring are 7.2(2) and 4.1(2), respectively. The molecular skeleton of 3b is less planar: the values of similar dihedral angles are 17.0(2) and 20.8(2), respectively. In the crystal of 3a, the molecules are packed in stacks along the a axis with head-to-head orientation. Intermolecular hydrogen bonds O=H s N and C=H s N link molecules into sheets parallel to (100) plane. In the crystals of 3b, the molecules have a head-to-tail orientation and intermolecular hydrogen bonds O=H s N link the molecules into infinite chains along [01-1] direction.     

Synthesis and structural studies of <Emphasis Type="Italic">tris</Emphasis>-2-chlorobenzylamine and <Emphasis Type="Italic">tris</Emphasis>-2-bromobenzylamine

The tris-2-chloro and 2-bromotribenzylamines are prepared from aqueous ammonia and 2-chlorobenzyl chloride and 2-bromobenzyl bromide, respectively, in ethanol. Recrystallization yielded colorless cubes of each product. The crystal structures are each solved in space group P , and are isostructural. The tris-2-chloro compound, 1, has a = 7.4226(5) Å, b = 9.0825(7) Å, c = 14.529(1) Å, = 78.279(1), = 82.389(1), = 84.661(1), and V = 948.41(12) ų with Z = 2, and d_calc = 1.368 Mg/m³. The tris-2-bromo analog, 2, has a = 7.6569(11) Å, b = 9.0922(13) Å, c = 14.614(2) Å, = 79.286(2), = 81.777(2), = 85.401(2), and V = 987.9(2) ų with Z = 2, and d_calc = 1.762 Mg/m³. Lithium–halogen exchange experiments conducted in tetrahydrofuran at –78C using n-butyl lithium revealed that no exchange occurred for the tris-2-chloro compound, but did occur for the tris-2-bromo analog to yield tribenzylamine upon quench and work-up.     

Crystal Structure and Conformational Analysis of 4-[(<Emphasis Type="Italic">p</Emphasis>-<Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>-Dimethylamino)Benzylidene]-2-Phenyloxazole-5-One

Abstract  

Molecular and crystal structure of 4-[(p-N,N-dimethylamino)benzylidene]-2-phenyloxazol-5-one, C₁₈H₁₆N₂O₂, have been determined by single crystal X-ray diffraction study. The title compound is monoclinic, with a = 12.1704(23) ?, b = 3.9810(5) ?, c = 30.9603(56) ?, β = 101.176(15)°, Z = 4, D _x = 1.32 g/cm³, μ(Mo Kα) = 0.087 mm⁻¹, and space group is P12₁/c1. The structure was solved by direct methods and refined to a final R = 0.047 for 3166 reflections with I > 2σ(I). The crystal structure is stabilized by C–H⋯O and C–H⋯N type intra-molecular, C–H⋯O type inter-molecular interactions. To enlighten the flexibility and the geometric isomerism (E or Z) of the title compound, the selected torsion angle is varied from −180 to 180° in every 10° separately and molecular energy profile is calculated and analyzed.     

A New <Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>-Dimethyl Purine from an Australian <Emphasis Type="Italic">Dictyoceratid Sponge</Emphasis>

Abstract  

N6-methyl mucronatine (C₈H₁₂N₅O) has been isolated from a dictyoceratid sponge collected in South East Queensland. The solid state structure of the new metabolite (I) was confirmed by X-ray crystallography, while an NMR study in d ₄-MeOH reveals the presence of a minor tautomer identified as (II).     

Synthesis of <Emphasis Type="Italic">E</Emphasis> Isomer and Crystal Structures of <Emphasis Type="Italic">E</Emphasis> and <Emphasis Type="Italic">Z</Emphasis> Isomers of 3-(2,5-Dimethoxyphenyl)-2-(4-methoxyphenyl)acrylonitrile

Abstract Details of the synthesis of the E isomer of 3-(2,5-dimethoxyphenyl)-2-(4-methoxyphenyl)acrylonitrile, and the X-ray crystal structures of both the E and Z isomers of this compound are presented. The E isomer crystallizes in the P2₁/c space group with cell parameters, a = 8.5659(17) ?, b = 16.399(3) ?, c = 11.224(2) ?, α = 90°, β = 95.27(3)°, γ = 90°and Z = 4. The Z isomer crystallizes in the Pca2₁ space group with cell parameters, a = 4.1223(8) ?, b = 19.113(4) ?, c = 19.453(4) ?, α = 90°, β = 90°, γ = 90° and Z = 4. Index Abstract Synthesis of E isomer and X-ray crystal structure determination of both E and Z isomers of 3-(2,5-dimethoxyphenyl)-2-(4-methoxyphenyl)acrylonitrile are presented.      

Crystal Structure of 2-(2,2-Dibromovinyl)-1-methyl-1<Emphasis Type="Italic">H</Emphasis>-imidazole-4,5-dicarbonitrile

Abstract  

The crystal structure of 2-(2,2-dibromovinyl)-1-methyl-1H-imidazole-4,5-dicarbonitrile (C₈H₄Br₂N₄, Mr = 315.92) has been determined by single crystal X-ray diffraction analysis. The compound crystallizes in the monoclinic crystal system with space group P2₁/c and unit cell parameters: a = 15.144(2), b = 16.382(3), c = 8.267(1) ?, β = 95.76(2)^o and Z = 8. The final reliability index is 0.0297 for 2505 observed reflections. The two molecules of 2-(2,2-dibromovinyl)-4,5-dicyano-1-methylimidazole are localized in independent part of unit cell. The crystal packing is stabilized by C–H···N hydrogen bonds and Br···N intermolecular interactions.     

Crystal structure of (2<Emphasis Type="Italic">Z</Emphasis>)-(3,3-dimethyl-3,4-dihydroisoquinolin- 1(2<Emphasis Type="Italic">H</Emphasis>)-ylidene)nitrosoacetonitrile

The crystal structure of (2Z)-(3,3-dimethyl-3,4-dihydroisoquinolin-1(2Н)-ylidene)nitrosoacetonitrile is determined (T = 150 K, R1 = 0.0435). The compound crystallizes as the E-cis and Z-cis isomers of the nitroso tautomer. Two independent molecules differ in the rotation of the nitroso group about the С–С bond between the dihydroisoquinoline group and the substituent. Analysis of bond lengths reveals their conjugation and prevailing contribution of the zwitter-ionic structures with the positive charge located on the isoquinoline fragment and the negative charge located on the substituent. Molecules having E and Z conformations are connected by the N–H···O hydrogen bond (N···O 2.922(3) Å) into dimers. The N–H group of the other molecule forms the intramolecular N–H···O hydrogen bond (N···O 2.544(3) Å) which closes a sixmembered cycle. Electronic absorption spectra are studied, and quantum-chemical modeling of the compound is performed.     

An X-ray Crystallographic Study of 1,4-Di[(<Emphasis Type="Italic">E</Emphasis>)-2-(<Emphasis Type="Italic">p</Emphasis>-tolyl)-1-diazenyl]piperazine

Abstract  

The crystal structure of methyl 1,4-di[(E)-2-(p-tolyl)-1-diazenyl]piperazine (4) has been determined by single crystal X-ray diffraction analysis. The bis-triazene (4) adopts a normal chair conformation in the piperazine ring, with puckering parameters : φ₂ = −29(5)°, Q_T = 0.534(2) ? and θ₂ = 177.0(2)°. The crystal structure of 4 is compared with the structure of the triazene (2a) and the closely related bis-triazenes (3 and 5a). The piperazine ring of 2a and 4 adopt a typical chair conformation, whereas the piperazine ring of 3 adopts an unusual pseudo-boat conformation. Crystal data: 4 C₁₈H₂₂N₆, triclinic, space group P[`1] P\overline{1} , a = 6.8925(2) ?, b = 7.8574(3) ?, c = 16.8856(8) ?, α = 103.103(2)°, β = 90.528(2)°, γ = 101.776(2)° and V = 870.44 (6) ?³, for Z = 2.