Crystal structures of 3-methyl-1,2,4-benzotriazine 1-oxide and 2-oxide

The compound 3-methyl 1,2,4-benzotriazine 1,4-dioxide (1) belongs to a new class of clinically promising, bioreductively-activated antitumor drugs. Reductive metabolism of these triazine di-N-oxides typically produces mixtures of mono-N-oxide analogues. As part of our efforts toward characterization of the in vitro metabolism of 1, we synthesized the 1-oxide (2) and 2-oxide (3) analogues and characterized these compounds using X-ray crystallography. Compounds 2 and 3 (C₈H₇N₃O) crystallized in the monoclinic space group P2₁/c. Unit cell parameters for 2: a = 9.0466(7), b = 10.5959(8), c = 7.8981(6) ?, β = 98.4940(10), and z = 4. Unit cell parameters for 3: a = 5.7193(4), b = 9.3774(7), c = 13.8427(11) ?, β = 101.6370(10), and z = 4.Supplementary material X-ray crystallographic data reported in this paper is deposited with the Cambridge Crystallographic Data Center as supplementary publication numbers CCDC 294738 (compound 2) and CCDC 294739 (compound 3). Copies of available material can be obtained, free of charge, on application to the Director, CCDC, 12 Union Road, Cambridge CB21EZ, UK.     

Synthesis of 1,2-dimethoxy-1,2-di(pyridin-2-yl)-1,2-ethanediol: Crystal and molecular structure determination

The compound, 2-hydroxy-[1,2-di(pyridin-2-yl)]ethane-1-one, 1, was isolated from the reaction of 2-pyridinecarboxaldehyde and 2-pyridinemethanol at 140°C without catalyst or solvent and characterized by¹H-NMR and IR spectral data. The compound 1 was treated with ethyl acetate to produce the 1,2-di(pyridin-2-yl)ethane-1,2-dione, 2. When 2 was dissolved in an excess of CH₃OH, crystals of 1,2-dimethoxy-1,2-di(pyridin-2-yl)-1,2-ethanediol, 3, were obtained. The molecular and crystal structure of 3 was determined by single crystal X-ray diffraction. The compound crystallizes in the monoclinic system belonging to the P2₁/n space group with a = 6.867(2) ?, b=9.546(4) ?, c=10.522(5) ?, α=90°, β=98.48(4)°, γ=90°. The asymmetric unit comprises two molecules of 3. Although the di-hemiketal was obtained in crystal form, it was found to be unstable, because its IR spectrum changed after a short time, indicating that it had been converted back to the original diketone, 2. The IR showed signals at 1713, and 1690 due to νC =O assigned to di-ketone group.     

New sulfur derivatives of 2,3-dichloropyrrolo[1,2-a] benzimidazol-1-one. Demonstration of regioselective thiolate addition and X-ray diffraction structures of 2-chloro-3-methylthiopyrrolo[1,2-a]benzimidazol-1-one and 2,3-di(benzylthio)pyrrolo[1,2-a]benzimidazol-1-one

The reaction of thiols with the heterocyclic compound 2,3-dichloropyrrolo[1,2-a] benzimidazol-1-one (1) has been investigated as a route to new redox-active, bidentate sulfur ligands. Treatment of 1 with either methylthiol or benzylthiol in the presence of pyridine affords monosulfide compounds 2-chloro-3-methylthiopyrrolo[1,2-a] benzimidazol-1-one (2) and 2-chloro-3-benzylthiopyrrolo[1,2-a]benzimidazol-1-one (3) and the disulfide derivatives 2,3-di(methylthio)pyrrolo[1,2-a]benzimidazol-1-one (4) and 2,3-di(benzylthio)pyrrolo[1,2-a]benzimidazol-1-one (5). The substitution of the first chlorine group in 2,3-dichloropyrrolo[1,2-a]benzimidazol-1-one (1) occurs regioselectively at C-3 to produce 2-chloro-3-methylthiopyrrolo[1,2-a]benzimidazol-1-one (2) and 2-chloro-3-benzylthiopyrrolo[1,2-a]benzimidazol-1-one (3), followed by replacement of the remaining chlorine group to furnish the disulfide compounds 4 and 5. The new thiols have been isolated by column chromatography and characterized in solution by spectroscopic methods. The molecular structures of 2-chloro-3-methylthiopyrrolo[1,2-a]benzimidazol-1-one and 2,3-di(benzylthio)pyrrolo[1,2-a]benzimidazol-1-one have been determined by X-ray crystallography. Compound 2 crystallizes as two independent molecules in the monoclinic space group P2₁/c, a = 13.221(2) Å, b = 18.478(2) Å, c = 8.948(1) Å, = 100.088(3)°, V = 2152.3(5) ų, Z = 8, and d_calc = 1.547 Mg/m³; R = 0.0354, R_w = 0.0739 for 2820 reflections with I > 2(I). Compound 5 crystallizes in the triclinic space group P-1, a = 5.180(1) Å, b = 11.494(2) Å, c = 17.243(3) Å, = 86.024(3)°, = 88.606(4)°, = 81.235(3)°, V = 1012.1(4) ų, Z = 2, and d_calc = 1.360 Mg/m³; R = 0.0354, R_w = 0.0692 for 2655 reflections with I > 2(I). The redox properties of the disulfide compounds 4 and 5 have been explored by cyclic voltammetry, where a one-electron reduction at ca. –1.10 V has been observed for each compound. The site of electron accession in has been established by carrying out molecular orbital calculations at the extended Hüuckel level on the model compound 2,3-di(thio)pyrrolo[1,2-a]benzimidazol-1-one.     

The crystallographic structure of 4-hydroxy-3-methylene-4-(p-nitrophenyl)butan-2-one

The crystallographic structure of 4-hydroxy-3-methylene-4-(p-nitrophenyl)butan-2-one 1 is disclosed by x-ray analysis. It crystallized in the space group C2/c (#15) with a = 19.958(4), b = 10.486(3), c = 15.009(3) Å, = 137.553(6)°, V = 2120.0(9) Å,³ Dcalc = 1.386 g/cm³, and Z = 8.     

Crystal and molecular structure of palladium(II), copper(II) and zinc(II) complexes of 1-methyl-3-(4-methyl)phenyltriazen-1-oxide

The structures of palladium(II), copper(II) and zinc(II) bis(chelates) of 1-methyl-3-(4-methyl)phenyltriazen-1-oxide have been determined by single-crystal X-ray methods. The crystals of [Pd(OMeN₃C₆H₄Me-4)₂] (I) are triclinic witha=7.410(3),b=7.806(3),c=8.371(2) Å, =65.80(2), =88.73(3), =81.04(3)°,Z=1, space group . The crystals of [Cu(OMeN₃C₆H₄Me-4)₂] (II) are monoclinic,a=14.934(5),b=10.111(4),c=11.762(3) Å, =96.00(2)°,Z=4, space group P2₁/c. The crystals of [Zn(OMeN₃C₆H₄Me-4)₂] (III) are triclinic witha=7.912(2),b=10.056(2),c=11.600(2) Å, =87.31(3), =74.96(3), =74.02(3)°,Z=2, space group . The structures of (I), (II), and (III) were solved to final values ofR=0.029, 0.043 and 0.034, respectively. A planar structure has been found for (I), (II) exhibits a tetrahedrally distorted square planar structure, whereas (III) is tetrahedral. The crystals of all three complexes are held by networks of stacking interactions.     

Crystal structure of 1,2;5,6-di-O-isopropylidene-3-O-(phenylacetyl)-D-glucofuranose

The synthesis and X-ray crystal structure of 1,2;5,6-di-O-isopropylidene-3-O-(phenylacetyl)-D-glucofuranose is reported. It crystallizes in the orthorhombic system with space group P2₁2₁2₁ (No. 19); a = 9.9313(12) Å, b = 10.0657(12) Å, c = 20.343(2) Å, and Z = 4. The solid state structure is discussed in terms of the use of the title compound for further chemistry.     

Crystal structure oftrans-tetrachlorobis[2-(2-1H-imidazolyl)-1H-imidazolium]cadmium(II), [Cd(H3biim)2Cl4]

The reaction between cadmium(II) chloride and 2,2'-bi-1H-imidazole (H₂biim) in an acidic solution affords [Cd(H₃biim)₂Cl₄] (H₃biim=2-(2-1H-imidazolyl)-1H-imidazolium) in 63% yield. The compound crystallizes in the triclinic space groupP1, wherea=8.072(2),b=8.100(2),c=8.593(2) Å, =75.89(2), =62.94(2), =63.29(1)°,V=446.4(2) ų, andZ=1. The central Cd atom exhibits an octahedral geometry composed of a Cl₄N₂ core. The Cd-N bond distance is 2.392(2) Å. Cd–Cl distances are 2.5919(9) and 2.671(1) Å.     

Variable Ag—O bonding patterns in silver cyclic amide tri-aryl-phosphine complexes

The solid-state structures of five new tri-arylphosphine silver cyclic amide complexes having a systematic variation in the ring structures have been resolved. Normal Ag—N bonding and variable, weaker Ag—O bonding interactions, which can be attributed to the ring modifications, form the basis of the bonding patterns. Reported here are the solid-state structures of silver complexes of tri-arylphosphine derivatives of silver 1(2H)-phthalazinone, silver phthalimide, silver 1,2,3-benzotriazin-4(3H)-one, silver 2H-1,3-benzoxazine-2,4(3H)-dione and silver 2,3-dihydro-1,4-phthalazine- dione. The unit cell parameters are: P-1, a = 11.179(2) ?, b = 15.508(3) ?, c = 22.636(5) ?, α = 104.30(3)°, β = 95.39(3)°, γ = 94.62(3)°; C2/c, a = 17.3600(8) ?, b = 15.4930(8) ?, c = 15.0760(7) ?, β = 113.911(2)°; P-1, a = 11.0656(2) ?, b = 11.9447(2) ?, c = 17.4764(3) ?, α = 79.5254(9)°, β = 80.2877(9)°, γ = 68.9136(7)°; P-1, a = 10.5743(4) ?, b = 11.8439(4) ?, c = 19.0110(8) ?, α = 102.4280(13)°, β = 104.0330(12)°, γ = 100.2520(18)°, P-1, a = 13.6908(3) ?, b = 16.2230(4) ?, c = 18.3678(7) ?, α = 86.8920(10)°, β = 69.5290(10)°, γ = 70.7840(10)°, respectively. Four of the complexes include ligand chelation by Ag—O bonding to the adjacent carbonyl in addition to the main Ag—N connection.     

Structure of tetrahydro-2-naphthyl-4H-1,3,6,2-dioxazaboracine

Intramolecular B-N coordination occurs in tetrahydro-2-naphthyl-4H-1,3,6,2-dioxazaboracine, 2: (R = 2-naphthyl; R = H) both in the solid state and in CDCl₃ solution. Compound 2: (R = 2-naphthyl; R = H) crystallizes in the orthorhombic space group P2₁2₁2₁ (Z = 4), with a = 9.266(6), b = 11.034(8), c = 12.0635(10) Å. Molecules are linked, in the solid state, into spiral chains. As only one of the two oxygen atoms present in each molecule is involved in H-bonding, the boron and nitrogen centres are chiral. The intramolecular B-N bond length is 1.671(4) Å; other geometric parameters are B-O bond lengths of 1.448(4) and 1.464(4) Å, a B-C bond length of 1.598(4) Å, and bond angles at B between 100.6(3) and 115.4(3)°. The ¹¹B value for 2 (R = 2-naphthyl, R = H) at 25°C in CDCl₃ solution is 10.7 ppm.     

Crystal structures of substituted imidazolidine derivatives

The crystal structures of isoxazole, 3-[[dihydro-2-[(Z)-2-oxohyrazono]-1H-imidazol-1-(3H)-yl]methyl-5-phenyl-,N-oxide] (C₁₃H₁₃N₅O₃) (I), isoxazole,3-[[dihydro-2-[(Z)-2-oxohyrazono]-1H-imidazol-1-(3H)-yl]-methyl-5-(4-methylphenyl)-,N-oxide] (C₁₄H₁₅N₅O₃) (II) and isoxazole, 3-[[dihydro-2-[(Z)-2-oxohyrazono]-1H-imidazol-1-(3H)-yl]-methyl-5-(2-methoxyphenyl)-,N-oxide] (C₁₄H₁₅N₅O₄) (III) have been determined by X-ray diffraction studies. The compound I, crystallized in triclinic space group with unit cell dimensions a = 7.2405(7) ?, b = 7.9936(8) ?, c = 11.6573(11) ?, α = 97.801(2)°, β = 90.884(2)°, γ = 96.250(2)° and Z = 2. Compound II crystallized in orthorhombic space group Pna2₁ with unit cell dimensions a = 10.1778(10) ?, b = 28.228(3) ?, c = 5.1206(5) ?, and Z = 4. Compound III crystallized in monoclinic space group P2₁/n with unit cell dimensions a = 7.8439(9) ?, b = 7.8544(9) ?, c = 23.534(3) ?, β = 99.464(2)° and Z = 4. For all three compounds, the five-membered imidazolidine ring adopts an envelope conformation. The crystal structures are stabilized by both the intramolecular N–H···O and intermolecular N–H···N hydrogen bonding.     

Crystal structure of a butyllithium 1,2-dipiperidinoethane dimer complex

The crystal structure of butyllithium solvated by 1,2-dipiperidinoethane, BuLi·DPE-6, which has been used as an initiator for a number of important commercial anionic polymerization reactions, is reported. The complex crystallizes from pentane as a centrosymmetric dimer in the monoclinic space group P2₁/n with a = 9.8619(12), b = 17.963(2), c = 10.3655(12) ?, β = 114.090(2)° and Z = 2. The dimer is located on a crystallographic inversion center. The crystal under investigation was found to be non-merohedrally twinned. In contrast to the two other dimeric BuLi complexes previously structurally characterized in the solid state, BuLi·DPE-6 has a planar central Li₂C₂ core. Semi-empirical (PM3) calculations were used to determine the lowest energy conformations of the dimer and also identified three structural motifs that affect Li₂C₂ dimer ring planarity.     

Synthesis and crystal structure of Bi(mpo)3 (Hmpo = 2-mercaptopyridine N-oxide)

The synthesis as well as crystal and molecular structure of [Bi(C₅H₄NOS)₃] are reported. The complex crystallizes in the monoclinic system, space group P2₁/n with lattice parameters a = 9.6521(3) Å, b = 10.0659(4) Å, c = 18.4484(7) Å, = 102.13(6)°, and D _calc = 2.227 Mg · m^–3 for Z = 4. It is clear from the packing diagram that the title compound is a dimer via the secondary coordination. Surrounding Bi atom, three five-membered ring planes (Bi,O,N,C,S) make a dihedral angle of 55.91, 54.72, and 26.13° respectively. The whole crystal presents a three-dimensional network structure as each molecule produces four weak C–H O hydrogen bonds and a weak C–H S hydrogen bond.     

Crystal structure of N,N-bis(2,5-dioxopyrrolidin-1-ylmethyl)glycine

The preparation and molecular and crystal structures of the title compound are reported. The compound crystallizes in the triclinic space group (No. 2) with unit cell dimensions of a = 7.2493(3) Å, b = 8.9287(4) Å, c = 10.6594(4) Å, = 90.419(3)°, = 91.287(3)°, = 103.153(3)°, V = 671.62(5) ų, and Z = 2. The molecular structure of the title compound consists of three sections, the glycine chain and the two 2,5-dioxopyrrolidin-1-ylmethyl groups. Every molecule is linked with three adjacent molecules through three hydrogen-bonding patterns which are 8-membered or 20-membered rings. The chain of rings appears periodically, which makes the molecule form a layer structure in the crystal.     

Crystal structure of 1,5,8-trihydroxyl-3-methoxy xanthone from Swertia chirayita

In order to study the relationship between biological and pharmacological activities with their structures, a series of tri-, tetra-oxygenated xanthones including 1-hydroxyl-2,3,4,7-tetramethoxy xanthone 1, 1-hydroxyl-2,3,4,5-tetramethoxyl xanthone 2, 1-hydroxyl-3,5-dimethoxy xanthone 3, 1,8-dihydroxyl-3,5-dimethoxyl xanthone 4, 1,5,8-trihydroxyl-3-methoxy xanthone 5 has been isolated from Swertia chirayita. Their structures were established on the basis of spectral and chemical evidence. The crystal structure of 5 was also investigated by single crystal X-ray diffraction analysis. It crystallizes in the triclinic system, space group P , with a = 7.1540(10) Å, b = 7.520(2) Å, c = 10.671(2) Å, V = 562.7(2) ų, = 86.50(3), = 80.06(3), = 85.00(3), Z = 2, D_c = 1.618 g m^–3, R_int = 0.0230, wR(F²) = 0.1028, F(000) = 284. The molecular structure is nearly plane and four substituents are much closer to the plane of the molecule. Compound 5 also shows three intermolecular hydrogen bonds. A recent study shows that phenolic hydroxyls in xanthones are the main active groups capable of scavenging OH and O₂.     

Investigation of 4-acetyl-2,6-dibenzyl-1,5-dihydroxy-2-methylcyclohexa-4,6-dien-3-one by X-ray crystallography and 1H-NMR spectroscopy

Benzylation of 3-methylphloracetophenone [1-(2,4,6-trihydroxy-3-methylphenyl)ethanone] (3) with benzyl chloride gave 4-acetyl-2,6-dibenzyl-1,5-dihydroxy-2-methylcyclohexa-4,6-dien-3-one (5). Compound 5 crystallizes in the orthorhombic space group Fdd2 with a = 17.586(2), b = 42.891(5), c = 10.279(2) Å, V = 7753(2) Å,³ and Z = 16. When crystals of 5 were dissolved in [D₆]acetone the compound underwent tautomerization and a mixture of 5 and its keto form 4 was obtained (keto form/enol form ratio 1:4).     

Separation of 4-aminobenzoic acid by cocrystallization: Crystal structure of the complex of 4-aminobenzoic acid with (2R,3R)-tartaric acid

4-Aminobenzoic acid (PABA) has been successfully separated from a mixture containing 2-aminobenzoic acid and (2R,3R)-tartaric acid. X-ray structure analysis confirms the separating result. The molecular complex formed by PABA and tartaric acid in 1:1 molar ratio crystallizes in the orthorhombic space group P2₁2₁2₁ with cell dimensions of a = 7.329(1) Å, b = 12.095(2) Å, c = 15.231(3) Å, V = 1350.1(4) ų, Z = 4. The crystal structure comprises protonated PABA, monoanion of tartaric acid, and crystalline water. The extensive H-bonding network exists in the crystal structure. H bonding between tartaric acid and both terminal groups on para position of PABA is considered as a possible reason for the successful separation.     

Molecular structure and reactivity of the 1,2-dihydrocarbazol-4(3H)-one: X-ray crystal structure of N-methyl and N-(p-methylbenzenesulfonyl) derivatives

Synthesis and reactivity analysis of the 1,2-dihydrocarbazol-4(3H)-one, and the N-methyl, N-tosyl and 2,2-dimethyl derivatives have been carried out. Molecular structures of the N-methyl and N-tosyl derivatives have been analyzed by X-ray diffraction. Crystals of the N-methyl derivative are monoclinic, space group P2₁/c,a=8.868(1),b=16.652(1),c=7.5440(4) Å, =113.657(3). Crystals of the N-tosyl derivative are monoclinic, P2₁/c,a=12.0016(3),b=8.9178(2),c=16.0485(4) Å, =104.372(2). An extended conjugation from the carbonyl group to the nitrogen atom and an envelope conformation for the common cyclohexenone fragment are evident in both cases. Oximation and Beckmann rearrangement, and etherification of the carbonyl group is reported.     

Crystal structure and characterization of 1,2-N,N-disallicydene-phenylamineato nickel(II) complex

A new complex has been synthesized and characterized by elemental analysis, IR, TGA, and single-crystal X-ray analysis. The crystal is orthorhombic and the space group is chiral (P2₁2₁2₁) with a = 6.620(3) Å, b = 17.300(4) Å,, c = 5.450(1) Å,, = 90°, = 90°, = 90°, z = 4. In the crystal lattice, the molecules create a two-dimensional network structure through hydrogen bonds. The C–HO intermolecular hydrogen bonds connect the title complex to form a supermolecular structure.     

The Synthesis and Crystal Structure of 5-(4-Bromophenylamino)-2-methylsulfanylmethyl-2<Emphasis Type="Italic">H</Emphasis>-1,2,3-triazol-4-carboxylic Acid Ethyl Ester

Abstract  The 5-(4-bromophenylamino)-2-methylsulfanylmethyl-2H-1,2,3-triazol-4-carboxylic acid ethyl ester 6 was synthesized from p-bromoaniline. The yielded product 6 was investigated with X-ray crystallographic, NMR, MS, and IR techniques. Compound 6, C₁₃H₁₅BrN₄O₂S, Mr = 371.26, crystallizes in the monoclinic space group P2₁/n with unit cell parameters a = 5.5220(1), b = 26.996(5), c = 10.596(2) ?, β = 103.83(3). V = 1533.8(5) ?³, Z = 4, Dx = 1.608 mg m⁻³. The final R ₁ was 0.0844; wR ₂ was 0.1560. H-bond is discussed. Index Abstract  The structure of 5-(4-bromophenylamino)-2-methylsulfanylmethyl-2H-1,2,3-triazol-4-carboxylic acid ethyl ester from 5-amino-1-(4-bromophenyl)-1,2,3-triazol-4-carboxylic acid ethyl ester is studied. H-bond is discussed.