Crystal and molecular structure of p-chlorothymols. II: 4-chloro-3-methyl-5-isopropylphenol (PCMT)

The crystal and molecular structure of the title compound: C₁₀H₁₃OCl, determined by single-crystal X-ray diffraction is reported. Crystals are monoclinic, space group P2₁/a (N_o14),a=18.435(7),b=24.642(6),c=9.116(6)Å,=103.23(5)°,Z=16,D _x =1.216 Mg m^–3,F(000)=1568,V=4031(1)ų. The structure was solved by direct methods and the finalR value is 8.5%. The four molecules in asymmetric unit are linked by hydrogen bonds and form an infinite chain parallel to the (bc) plane. Different chains are held together by van der Waals forces.     

Synthesis and crystal structure of 5-amino-4-cyano-1-[(5-methyl-1-t-butyl-4-pyrazolyl)carbonyl]-3-methylthio-1H-pyrazole

The title compound, 5-amino-4-cyano-1-[(5-methyl-1-t-butyl-4-pyrazolyl)carbonyl]-3-methylthio-1H-pyrazole 5, was synthesized by the treatment of 4 (5-methyl-1-t-butylpyrazole-4-carbohydrazide) with 2-cyano-3, 3-dimethylthio-acrylonitrile, and its crystal structure was determined by X-ray diffraction method. The crystal belongs to monoclinic, space group P2₁/c with unit cell parameters a = 13.566(4) Å, b = 10.833(3) Å, c = 11.202(3) Å, α = 90°, β = 98.073(5)°, γ = 90°, V = 1629.9(8) ų, Z = 4, D _c = 1.298, M _r = 318.40, μ = 0.210 mm⁻¹, F(000) = 672, R ₁ = 0.0488 and wR ₂ = 0.1250.     

Crystal structures of two isomeric oximes. (EE)-2-methyl-3-phenyl-3-thiocyanatopropenaldoxime and (Z)-5-methyl-6-phenyl-1,3-thiazin-2-one oxime

The crystal structure of two isomeric oximes, C₁₁N₁₀N₂OS have been studied by X-ray diffraction. The open-chain thiocyanato derivative is somewhat'less dense and crystallizes with the orthorhombic space group Pbcn;a,b,c=18.718(1), 10.601(3), 11.528(1) Å,Z=8. The heterocyclic isomer occurs as pseudo-orthorhombic (Cmma)twinned crystals of space group P2₁/n, a, b, c, =12.11(1), 7.46(1), 12.12(1) Å, 100.09(1)^o,Z=4. Twinning occurs as a result of the near-equality of the monoclinica andc cell constants.     

Synthesis, crystal structure, and molecular modeling (AM1) of Methyl 6-chloro-4-(2-chlorophenyl)-5-formyl-2-methyl-1, 4-dihydropyridine-3-carboxylate

The synthesis and structural characterization of Methyl 6-chloro-4-(2-chlorophenyl)-5-formyl-2-methyl-1,4-dihydropyridine-3-carboxylate is described. The structure was refined to R₁ = 0.0470 for 2665 reflections (with I > 2(I)). Crystal data: C₁₅H₁₃C₁₂NO₃, monoclinic,space group P2₁/c, a = 11.163(9), b = 14.484(8), c = 9.422(7) Å, V = 1512.9(19) ų, Z = 4. The results of crystallographic and molecular modeling (AM1) were compared. The Cl atom attached to the phenyl group has two possible orientations, having 75% (sp) and 25% (ap) occupancy, respectively. The molecules in the crystal are held together by means of intermolecular hydrogen bonds of the type N=H...O and by C=H...O interactions.     

Crystal structure of 1β-methyl-4α-isopropylcyclohexyl-spiro-5′-hydantoin

The crystal structure of 1-methyl-4-isopropylcyclohexyl-spiro-5-hydantoin has been determined by single-crystal X-ray diffraction techniques, and refined by full-matrix least-squares methods. The molecule C₁₂H₂₀N₂O₂·H₂O crystallizes with one molecule of water in the orthorombicP2₁2₁2₁ space group, witha=15.869(5),b=14.043(4),c=6.240(2) Å, andZ=4; the finalR factor was 0.032. The X-ray results showed that both substituents (methyl and isopropyl) in the cyclohexyl ring are in thetrans configuration. The configuration of the molecule is in agreement with suggestions of organic chemists.     

Synthesis and crystal structure of 2-anilino-6<Emphasis Type="Italic">H</Emphasis>-5-(1-phenyl-3-methyl-5-pyrazolone-4-ylene)-1,3,4-thiadiazine

A novel pyrazolone derivative 2-anilino-6H-5-(1-phenyl-3-methyl-5-pyrazolone-4-ylene)-1,3,4-thiadiazine (PMCP-PTSC) containing NNS hexa-atomic heterocycle has been obtained and characterized by means of single crystal X-ray diffraction, IR and ¹H NMR spectroscopies. It is interesting that when grown from two different solvents, two different crystalline structures are formed. The monoclinic crystal A belongs to a P2₁/c space group. The unit cell parameters are a = 16.414(4) Å, b = 12.530(3) Å, c = 8.432(1) Å, = 91.75(2) Å, and Z = 4. The triclinic crystal B belongs to a P space group. The unit cell parameters are a = 11.386(2) Å, b = 12.326(2) Å, c = 12.411(3) Å, = 83.07(1)°, = 87.76(2)°, = 86.52(2)°, and Z = 4. The structure analyses show the title compound is the keto-form. Dimers in crystal packing of A and supramolecular one-dimensional (B) concatenate structures were assembled by the intermolecular hydrogen bonds.     

Synthesis and structure of 4-methyl-1-N-(p-tolyl)imidazole as organic corrosion inhibitor

Heterocyclic organic compounds containing nitrogen, sulfur or oxygen atoms are often used to protect metals from corrosion acting as organic corrosion inhibitors. Their inhibiting role is based on excellent ligand abilities and formation of stabile metal complex. Two requirements are essential for using selected class of organic inhibitors: (a) ligand capacity in the conditions of corrosion such as atmospheric conditions, acid or neutral corrosion, etc., and (b) nontoxicity, i.e., environmentally friendly inhibitors. Imidazole derivatives are capable to fulfil both requirements and they are, from that point of view, very promising and profound class of ligands. Synthesis and X-ray diffraction molecular and crystal structure of 4-methyl-1-N-(p-tolyl)imidazole has been reported, since it exhibits the most prominent corrosion inhibiting role. The synthesis, starting from 4-methylimidazole and 4-bromotoluene, is based on Ullmann-type coupling reaction by applying modifications of N-arylation by arylhalogenides and Cu₂O as an efficient catalyst.

The molecular and crystal structure of prepared N-substituted imidazole derivative reveals non-planar molecular conformation and the supramolecular assembling of the molecules via C-H···N intermolecular hydrogen bonds between C_sp2-H proton donor groups and basic imidazole nitrogen atom. The molecules are related by a 2₁ screw axis parallel to [0 1 0] in the form of infinite C(4) zig-zag 1D chains via C-H···N intermolecular hydrogen bonds. Such alignment produces additional weak stacking interaction between imidazole and phenyl ring of related chains.     

Structure of 5-methyl-7-methoxy-isoflavone

The structure of 5-methyl-7-methoxy-isoflavone was determined by X-ray diffraction. The compound crystallizes in the monoclinic space group P2₁/c, with cell dimensions of a = 10.321(3) Å; b = 11.290(5) Å; c = 11.979(8) Å; = 107.00(5)°; V = 1334.9(11) ų and D_calc. = 1.325 Mg/m³ for Z = 4. The structure was solved by direct methods and refined to an R value of 0.0409. As expected ring A and ring B in 5-methyl-7-methoxy-isoflavone are coplanar, while ring C is rotated to a dihedral angle of 59.42 (7)°. Intermolecular C–HO hydrogen bonds link molecules related by the screw axis and glide-planes to form a loosely connected layer structure.     

Crystal structure of 3-pheny1-5-chloro-7-bromoisoxazolo[4,5-d]pyrimidine

The crystal and molecular structure of 3-phenyl-5-chloro-7-bromoisoxazolo-[4,5-d] pyrimidine, C₁₁H₅BrClN₃O, has been determined by X-ray techniques, and refined by Fourier and least-squares methods toR = 0·102 for 689 observed reflexions. The compound crystallizes in the orthorombic system:a = 15·72(4),b = 10·65(3),c = 6·72(3) Å,Z = 4, space groupPnam. The molecules lie on mirror planes, and all interatomic distances and angles within the molecule have reasonable values.Close molecular packing exists in layers (corresponding to crystallographic mirror planes) stacked normal toc.     

Crystal and molecular structure of acetamidrazone derivatives

N ¹-acetylacetamidrazones and N ¹-benzoylacetamidrazones (1a–d) were characterized by ¹H and ¹³C NMR spectroscopy. The actual tautomeric form present has been shown to be the amide hydrazone. NMR spectra of N ¹-acetylacetamidrazones (1a,b) showed the existence of Z and E isomers in solution, while N ¹-benzoylacetamidrazones (1c,d) were present as Z isomers. The crystal structures of the amidrazones have been determined at 173 and 293 K, respectively. The amidrazones 1c and 1d crystallize in the monoclinic system: in particular for 1c space group P2₁/c, with a = 11.016(5), b = 20.594(14), c = 13.657(7) Å = 98.29(3)° V = 3066(3) ų and D _c = 1.243 g/cm³ for Z = 4; for 1d space group P2₁/a, with a = 9.410(5), b = 10.449(3), c = 14.295(11) Å = 101.04(5)° V = 1380(1) ų and D _c = 1.220 g/cm³ for Z = 4. The X-ray diffraction analysis carried out on 1c has shown the presence of three molecules in the asymmetric unit which differ for the orientation of the phenyl ring.     

Crystal structure and conformation of the antimalarial drug 5,7-methoxy-8-(3-methyl-1-buten-3-ol)-coumarin

The crystal and molecular structure of the antimalarial compound 5,7-methoxy-8-(3-methyl-1-buten-3-ol)-coumarin, C₁₆H₁₈O₅, M _r = 290.3 Da, has been determined from X-ray diffraction data. The material crystallizes in the monoclinic space group P2₁/c with 4 molecules per unit cell of dimensions a = 8.9044(9), b = 17.623(1), c = 10.175(1) Å, = 113.97(1)°, crystal density D _c = 1.322 g/cm³. The structure was determined using direct methods and refined by full-matrix least squares to a conventional R index of 0.066 for 2416 measured reflections and 206 parameters.The coumarin ring system is almost planar with the methoxy C atoms rotated slightly out of the coumarin mean plane. Apart from the terminal CH₃ groups C(12) and C(13), which are 1.184(3) Å above and –1.315(3) Å below the plane, the 3-methyl-1-buten-3-ol substituent is planar (rms deviation 0.009 Å) making an angle of 6.31(7)° with the phenyl ring. One intermolecular hydrogen bond is present in the crystal structure between O(5)–HO(5) and the symmetry related O(2) oxygen, generated by the symmetry operation (x, 1/2 – y, –1/2 + z).     

Crystal and molecular structure oftrans-1-isopropyl-1-methyl-4-acetyl-4-phenylpiperidinium iodide

The crystal structure oftrans-1-isopropyl-1-methyl-4-acetyl-4-phenylpiperidinium iodide has been determined from single-crystal X-ray data and refined by least-squares methods toR=0.052. The orthorhombic crystals have unit-cell dimensions ofa=10.792(6),b=11.594(8),c=13.746(9) Å, space groupP2₁2₁2₁, andZ=4. The piperidine ring is in the chair form with the bulky substituents, the isopropyl and the phenyl groups, respectively in equatorial and axial positions.     

Structure of 4-(2-chloro-4,5-dimethoxybenzylidene)-2-methyl-5-oxazolone. X-ray and NMR study

The azlactone of 6-chloroveratraldehyde 3 (4-(2-chloro-4,5-dimethoxybenzylidene)-2-methyl-5-oxazolone) was synthesized from 6-chloroveratraldehyde 2 and its structure investigated using X-ray crystallographic and nuclear magnetic resonance methods. Compound 3 crystallized in the P2₁/c (#14) space group (Z = 4) with cell dimensions a = 9.148(2), b = 22.938(2), c = 6.707(1) Å, and = 111.50(2)°. The X-ray study shows that azlactone 3 exists as the Z-isomer and crystallizes as a planar structure, i.e., both the phenyl and azlactone ring systems, as well as the functional groups attached to them, lie in the same plane. The ¹H and ¹³C NMR spectral values also support the formation of the Z-isomer only, during the synthesis of 4-(2-chloro-4,5-dimethoxybenzylidene)-2-methyl-5-oxazolone.     

Formation and crystal structure of 1-methyl-2-phenylindolizine-3-acetonitrile

1-Methyl-2-phenylindolizine-3-acetonitrile was unexpectedly obtained in the reaction of 1-methyl-2-phenylindolizine-3-thioaldehyde with cyanide ions. Its structure was determined by IR, ¹H NMR, MS, elemental analyses, and X-ray crystallography. Colorless regular prism shaped crystals of C₁₇H₁₄N₂ crystallize in the space group C2/c with cell dimensions a = 12.956(3) Å, b =10.516(2) Å, c = 20.429(4) Å, and = 90°, = 104.98(3)°, = 90°, V =2688.7(9) ų, D _calc =1.217 Mg/m³, and Z = 8.     

Crystal structure and spectroscopy of 4-N-benzylaminocoumarin

The structure of 4-N-benzylaminocoumarin (C₁₆H₁₃NO₂) has been determined by X-ray diffraction and the Ft-ir,¹H- and¹³C-nmr spectra of the compound were recorded. Crystals of the compound are monoclinic, space group P2₁/c, with cell dimensiona=8.077(2),b=14.598(4),c=10.890(3) Å, and =97.76(3)°. The Ft-ir and nmr spectra indicate that the nitrogen atom is in the amino form in solution. The crystal structure is consistent with this observation, but the C(3)–C(4) double bond is clearly delocalized to include the lone pair on the nitrogen atom.     

Crystal Structure of 5-Butoxy-4-((3-butoxyphenyl)diazenyl)-3-methyl-1-phenyl-1H-pyrazole

Crystallography Reports - New azo-pyrazolone derivative, 5-butoxy-4-((3-butoxyphenyl) diazenyl)-3-methyl-1-phenyl-1H-pyrazole, C24H30N4O2, is synthesized, and its crystal structure is determined by...     

Crystal and molecular structure of 2-chloro-4-methyl-6-[[(4-)2,2,6,6,-tetramethylpiperidinyl]amino]-3-pyridinecarbonitrile hydrochloride

The compound C₁₆H₂₄N₄Cl₂ crystallizes in the monoclinic space groupP2 ₁/c witha=16.299(2),b=7.801(1),c=14.780(2) Å,=109.89(1)° andZ=4. The structure was determined by direct methods, and refined by full-matrix least squares toR=0.046 andR _w=0.050 for 2309 reflections. The resulting structure permitted the determination of the main direction of substitution during the synthesis of this compound, and correction of a previously postulated formulae of the dyes formed. The influence of salt formation on the protonation of the N atom and on the formation of hydrogen bonds is analyzed. The influence of substituents on the geometry of pyridine and piperidine ring is discussed.     

Crystal structure of racemic 5-(p-nitrobenzoylamino)-5-methyl-4-oxo-1,3-dioxane

C₁₂H₁₂N₂O₆ crystallized from methanol in the monoclinic space group P2₁/c (Z=4) witha=13.333(4),b=10.154(3),c=9.597(2) Å and=102.37(2)°.M _r=280.24,V=1269.1(6) ų,D _x=1.466 g cm^–3,(Mo K)=0.71069 Å,=1.29 cm^–1,T=295 K. The structure was solved by direct methods and refined by full-matrix least-squares to a finalR (R _w)=0.049 (0.057) for 916 observed reflections. The molecules are linked by strong N-HO(4) hydrogen bonds with NO distance of 2.995(4) Å. The infinite racemic chains run in [001] direction.