Synthesis and crystal structure investigation of pyridine‐2‐(3′‐mercaptopropanoic acid)‐N ‐oxide

Pyridine‐2‐(3′‐mercaptopropanoic acid)‐N ‐oxide (I), is a higher homologue of 1‐oxopyridinium‐2‐thioacetic acid (II) [1]. It crystallizes in monoclinic space group P2₁ with a = 9.2168(2) Å, b = 4.1423(2) Å, c = 11.3904(4) Å, β = 98.65(2)°, V = 429.93(3) ų and Z = 2. The least‐squares refinement gave residual index R = 0.024 for 1070 observed reflections. The introduction of an additional methylene group in (II) causes a flip in the carboxylic acid group of (I) that facilitates the molecules to align infinite antiparallel chains through strong C–H···O interactions. The molecules are interlinked by O–H···O hydrogen bonding across the chains and forming an infinite screw chain along y‐direction. The molecular packing is stabilized by O–H···O and C–H···O hydrogen bonding and π‐π electron interactions. This is an important facet of the crystal packing. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Synthesis and structural conformation of N‐substituted 1,4‐dihyropyridine derivatives

N‐(Phenyl)‐3,5‐dicarbethoxy‐2,6‐dimethyl‐4‐(phenyl)‐1,4‐dihydropyridine (A) and N‐(4‐methoxy phenyl)‐‐3,5 dicarbethoxy‐2,6 dimethyl‐4‐(3‐nitro phenyl)‐1,4‐dihydropyridine (B) has been synthesized as per scheme and characterized by the X‐ray diffraction method. The compound A crystallizes in monoclinic space group P21/c with cell parameters a = 9.2770(11)Å, b = 8.6410(5)Å, c = 27.601(3)Å, β = 97.724(3)°, Z = 4. The compound B crystallizes in monoclinic space group P21/c with cell parameters a = 11.229(6), b = 12.746(7)Å, c =17.606(6)Å, β = 104.531(3)°, Z = 4. The structures exhibit both intra and intermolecular hydrogen bonds. Dihydropyridine ring of both the compounds adopt a flat boat conformation. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Structural studies of crystalline oligosaccharides VI: Crystal structure and conformation of benzyl‐4,6‐O‐benzylidene‐3‐O‐benzoyl‐β‐D‐galactoside

Monsaccharides are the building blocks of polysaccharides and hence are the simplest sugar molecules to study the conformation and molecular structures of sugars. Benzyl‐4,6‐O‐benzylidene‐3‐O‐benzoyl‐β‐D‐galactoside is a key intermediate in the synthesis of polysaccharides. Crystal structural investigation of the title compound was undertaken to establish their chemical structure as well as to study their solid state conformation. Crystals of the title compound, obtained from water/methanol, are orthorhombic, space group P2₁2₁2₁, with cell dimensions a=11.290 (4), b=9.941 (1), c= 21.442(2)Å, V= 2406ų, Z=4, D_obs= 1.42 gm/cm³, D_calc=1.423 g/cm³, 2886 reflections were collected on a CAD‐4 diffractometer. The structure was solved by direct methods and refined to a final reliability index of 4.7%. The galactoside sugar has the chair conformation with C2' and C5' deviating from the mean plane of the other atoms of the sugar. The 4,6‐O‐benzylidene ring also has a chair conformation with the benzoyl group proximal to O6'. The crystal structure is stabilized by O‐H…O hydrogen bonds involving O2' as donor and three C‐H…O hydrogen bond interactions. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Crystal structure of 3‐(3‐nitrophenylhydrazonocarbonyl)‐(1H)‐1,2,4‐triazole

The title compound, C₁₀H₈N₆O₃, was synthesized by the reaction of 3‐(1H)‐1,2,4‐triazole hydrazine with 3‐nitrobenzaldehyde in ethanol. The single crystal structure has been determined by X‐ray analysis. The crystal belongs to monoclinic system, space group p2₁/c with cell constant, a = 8.0214(17) Å, b = 17.334(4) Å, c = 8.9070(18) Å, V= 1179.4(4) ų. An intramolecular N—H...O and N—H…N hydrogen bond are observed between the ‐NH group with O atom of the carbonyl group and the ‐NH group with N atom. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Crystal structure of N‐[(1Z)‐1‐(3‐methyl‐3‐phenylcyclobutyl)‐2‐thiomorpholin‐4‐ylethylidene] thiourea

The crystal structure of N‐[(1Z)‐1‐(3‐methyl‐3‐phenylcyclobutyl)‐2‐thiomorpholin‐4‐ylethylidene] thiourea (C₁₈H₂₆N₄S₂) has been determined by X‐ray crystallographic techniques. The compound crystallizes in the orthorhombic space group Pbca, with unit cell parameters: a = 15.692(3), b = 20.803(8), c = 11.979(6)Å, Z = 8, V = 3911(7)ų. The crystal structure was solved by direct methods and refined by full‐matrix least squares to a final R‐value of 0.084 for 1447 observed reflections [I > 2σ ( I ) ]. In the thiosemicarbazide moiety, the S = C bond length is 1.656(6), N‐C‐N angle is 115.6(5)°. The crystal structure is stabilized by the intermolecular N‐H...S hydrogen bonds. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Synthesis and crystal structure determination of 6,7‐dihydro‐2‐methoxy‐4‐(substituted)‐5H ‐benzo[6,7]cyclohepta[1,2‐b ]pyridine‐3‐carbonitrile

The compounds 6,7‐dihydro‐2‐methoxy‐4‐(4‐methylphenyl)‐5H ‐benzo[6.7]cyclohepta[1,2‐b ]pyridine‐3‐carbonitrile (compound IIIa) and 4‐(4‐chlorophenyl)‐6,7‐dihydro‐2‐methoxy‐5H ‐benzo[6,7]cyclohepta[1,2‐b ]pyridine‐3‐carbonitrile (compound IIIb) were synthesized and their structures have been determined from three dimensional X‐ray data using direct method and refined by full matrix least squares with anisotropic thermal parameters for non‐hydrogen atoms to conventional R(gt) of 0.036 and 0.038 for the two compounds respectively. For compound (IIIa) the crystals are monoclinic, space group C_c, with a=11.2909 (5) Å, b=17.7755(8) Å, c=9.1437(4) Å and β=95.428(3)°, while the crystals of the second compound (IIIb) are triclinic, space group P1, with a=8.7465(3)Å, b=10.3958(3)Å, c=10.9011(4)Å, α= 108.3870(10)°, β=101.3741(12)°, γ=97.9594(12)°. The molecular structure of the two compounds have nearly the same configuration, where the cyclohepta ring takes the boat shape and the methoxy and the carbonitrile groups are attached at the same position C₂ and C₈. The difference occurs only at the position C₄, where the substituent is methylphenyl for compound (IIIa) and chlorophenyl for the other. The bond lengths, valency angles and the hydrogen bonding were calculated and fully discussed. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Crystal structure of 4‐(1‐methyl‐1‐mesitylcyclobutane‐3‐yl)‐2‐aminothiazole

The crystal structure of 4‐(1‐methyl‐1‐mesitylcyclobutane‐3‐yl)‐2‐aminothiazole (C₁₇H₂₂N₂S₁) has been determined by X‐ray crystallographic techniques. The compound crystallizes in the triclinic space group P‐1 with Z = 6. The crystal structure was solved by direct methods and refined by full‐matrix least squares to a final R‐value of 0.052 for 2298 observed reflections [I > 2σ ( I ) ]. There are three crystallographically independent molecules, I, II and III. These molecules are held together by intermolecular N‐H...N hydrogen bonds. © 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim     

Crystal structure analysis of 5‐amino‐7‐(pyrrolidin‐1‐yl)‐2,4,4‐trimethyl‐1,4‐dihydro‐1,6‐naphthyridine‐8‐carbonitrile

The title compound [CCDC 199359], C₁₆H₂₀N₅ crystallized in Monoclinic system with the space group C2/c. The unit cell parameters are: a = 16.554(6), b = 12.145(4), c = 16.221(5)Å and β = 102.67(1)°. The molecular structure is stabilized by an intramolecular C‐H…N type hydrogen bond and the molecular packing by the intermolecular C‐H…N and N‐H…N type hydrogen bonds. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

3 β ‐Acetoxy‐5 α ‐cholestan‐6‐one: A Steroid

The crystal and molecular structure of 3 β ‐Acetoxy‐5 α ‐cholestan‐6‐one has been determined by X‐ray crystallographic techniques. The compound crystallizes in the space group P2₁ with cell parameters : a = 13.060(3), b=6.299(2), c=17.152(6)Å; β =96.47(3)o, V = 1402.02ų, Z = 2, R = 0.072 for 1921 observed reflections. The six‐membered rings (A, B and C) exist in the chair conformations while the five‐membered ring‐d assumes half‐chair. All rings of the steroid skeleton are trans connected.     

Crystallographic Investigations of 3β‐acetoxy‐5α‐cholestan‐6‐one‐semicarbazone ‐ A Steroid

The crystal structure of 3b‐acetoxy‐5a‐cholestan‐6‐one‐semicarbazone (C₃₀H₅₁O₃N₃) has been determined by X‐ray diffraction methods. It crystallizes in the orthorhombic space group P2₁2₁2₁ with cell parameters a = 11.641(1), b = 16.552(1) c = 31.181(4) Å and Z = 8. The structure has been refined to an R‐value of 0.050 for 4407 observed reflections. Two molecules in the asymmetric unit have been observed. In both the crystallographically independent molecules, all the three six‐membered rings (A, B and C ) of steroid nucleus exist in chair conformation, while the five‐ membered ring D exists in 13β distorted‐envelope in molecule‐I and 13β, 14α half‐chair conformation in molecule‐II. Three intermolecular N‐H … O hydrogen bonds have been observed.     

Crystal Structure Analysis of 3'5' (dichloro phenyl)‐3‐ethyl‐5‐phenyl thio indalo [1,2‐e] imidazolidine

The title compound crystallizes in monoclinic system with space group P2₁ /n. The cell parameters are a = 12.3824(3) Å, b = 8.9255(1) Å, c = 19.9188(4) Å, V = 2181.75(7) ų , α = γ = 90.0° and β = 97.663(1)°. The structure has an indole moiety and an imidazolidine ring connected together. The phenyl sulfonyl group is attached to the indole moiety and the dichlorophenyl ring to the imidazolidine ring. The structure has a C‐H … Cl intra molecular hydrogen bond and C‐H … π type intermolecular interactions.     

The Crystal Structures of O,O‐Dimethylalpinumisoflavone and 5‐O‐Methyl‐4'‐O‐(3‐methyl‐but‐2‐en‐1‐yl)alpinumisoflavone

The petrol extract of the rootbark of Milletia Thonningii obtained by column chromatography afforded sixteen different crystalline samples to be isolated. The crystal structures of two of these compounds, O,O‐Dimethylalpinumisoflavone (I) and 5‐O‐Methyl‐4'‐O‐(3‐methyl‐but‐2‐en‐1‐yl)alpinumisoflavone (II) are being reported here. (II) has two independent molecules in the asymmetric unit and differs from (I) in a longer side chain attached to C(15) of the phenyl ring. The structural features of the three molecules in the title compounds are reported and compared. The derivatives, being subject of this article are the first reported crystal structures where the isoflavone fragment is fused to a further six membered ring that results in a tricyclic ring system. The benzopyrone fragments are planar. The dihedral angles between the benzopyrone fragment and the phenyl ring being 55.38(6)° for (I) and 44.75(15)° /44.64(15)° for the respective independent molecules of (II) are within the range of values observed for similar structures.     

Crystal Structure of N,N'‐Bis(3‐(o‐dimethylaminoimino‐ethyl) ‐2‐hydroxy‐5‐methyl)‐benzylpiperazine

The structure of the synthesized title compound, C₃₀H₄₆N₆O₂ , was solved by using X‐ray diffraction techniques. The compound crystallized in monoclinic space group P2₁/n with cell dimensions a = 14.0629(7), b = 6.5696(3), c = 17.7948(8)Å, β = 111.35(2)°, V = 1531.2(1)ų, Z = 2, D_cal = 1.134 Mgm^‐3 and T = 293(2)K. The molecule possesses a center of symmetry, and hence, there is half a molecule in the asymmetric unit. The piperazine ring adopts chair conformation with the substituents at the equatorial position, subtending a dihedral angle of 88.87(1)° with the phenyl ring. The phenyloxy hydrogen is involved in an intramolecular O‐H...N type of hydrogen bond.     

Crystal and molecular structure of 3‐phenyl‐4‐(p‐chlorobenzylamino)‐4,5‐dihydro‐1‐H‐1,2,4‐triazol‐5‐on

The structure of the title compound, C₁₅H₁₃N₄OCl was determined by single crystal X‐ray diffraction technique. The structure consists of a p‐chlorobenzylamino moiety and triazol and phenyl rings. The title compound crystallizes in the monoclinic space group P2₁/c with a = 14.368(3), b = 6.255(3), c = 17.631(3) Å, β = 113.24(3)°, Z = 4, V = 1455.8(8) ų and D_x = 1.372 gcm^‐3. The structure was solved by direct methods and refined by full‐matrix least‐squares method (R=0.0477). The dihedral angle between the triazole moiety and the phenyl ring is 28.8(3)°. The molecular packing is stabilized by N‐H…N and N‐H…O types of inter molecular hydrogen bonds. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Crystal Structure of 6, 6' ‐ Dihydroxy ‐ 2, 2' ‐ biphenyl ‐ 19 ‐ crown ‐ 5 ; Comparison of Some Structural Features among Related Ligands and Compounds

It has been determined the crystal structure of 6,6'‐dihydroxy‐2,2'‐biphenyl‐19‐crown‐5, C₂₂H₂₈O₇ (1a). Likewise, it has been set up a comparison between the results and some features of this structure obtained by molecular mechanics calculations. Due the presence of a hydrogen bond, the crown oxygens have not a geometrical disposition to lead its electronic pairs into the cavity and therefore the system complexation constant decreases, compared to some related ligands and compounds.     

Crystal structure analysis of {bis‐2,6‐(3,5‐dimethylprazolyl) pyridine‐dicyanato}copper(II)monohydrate

A mononuclear copper(II) complex, [Cu(dmpp)(OCN)₂(H₂O)], was synthesized using 2,6‐bis (3,5‐dimethylpyrazolyl) pyridine (dmpp) and cyanate anion (OCN), and characterized by single crystal X‐ray diffraction. The coordination around the Cu atom is a distorted square‐pyramid involving three N atoms from the dmpp ligand and one N atom from OCN at the basal plane. The O atom of the OCN group is located at the apical position. The Cu atom is located 0.2782(1) Å above the basal plane. The Cu atom is coordinated by different donor atoms of the OCN groups. The complex crystalizes in monoclinic space group P2₁/n, with unit cell dimensions a= 12.4413(12), b=11.1457(13), c=14.2203(12) Å, β=108.817(3)°, V= 1866.5(3) ų. The cell containes 4 molecules. In the crystal, there are three intermolcular and three intramolecular hydrogen bonds interactions. The Cu atom and crystal water O interactions is 5.574 Å. © 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim     

Crystal structure of N‐(3,4‐dichlorophenyl)‐N′‐hydroxy‐2‐oxo‐2‐phenylacetamidine

The title compound (C₁₄H₁₀N₂O₂Cl₂) crystallizes in the monoclinic space group P2₁/a with a=10.042(1) Å, b=10.317(1) Å, c=13.877(2) Å, β=97.36(2)°, V=1425.8(3) ų, Z=4, D_x=1.44 g.cm^‐3. The structure was solved by direct methods and refined by full‐matrix least‐squares method (R = 0.0457). The title molecule consists of 3,4‐dichlorophenylamino and 2‐phenyl‐1,2‐ethanedione‐1‐oxime groups. The intermolecular O‐H…N and N‐H…O hydrogen bonds [O…N 2.760(6) and 3.087(5) Å] are highly effective in forming the polymeric chains. The oxime group has an E configuration. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Different complexation behavior of a proton transfer compound obtained from 1,10‐phenanthroline and pyridine‐2,6‐dicarboxylic acid with Sn(IV), Sb(III) and Tl(I)

The different complexation methods of a proton transfer compound, (phenH)₂(pydc) (phen=1,10‐phenanthroline; pydcH₂= pyridine‐2,6‐dicarboxylic acid), are discussed and formation of [Sn(pydc)(phen)(OH)₂]·3H₂O ( 1 ), {[Sb(pydc)(phen)]₂O}·2DMSO·4H₂O( 2 ) and [(Tl(pydcH)]_n ( 3 ) complexes are reported. The characterization was performed using IR spectroscopy and X‐ray diffraction. The structures of Sn(IV) and Sb(III) complexes show that both cationic and anionic fragments of the starting proton transfer compound have been involved in the complexation. Whereas the structure of Tl(I) complex demonstrates that only the anionic fragment of (phenH)₂(pydc) is contributed to the complexation. The complexes 1‐3 show a variety of structural features including mononuclear, binuclear and polymeric structures. In compounds ( 1 ), ( 2 ) and ( 3 ) a large number of hydrogen bonds are observed. These interactions play an important role in the formation and stabilization of supramolecular systems in the crystal lattices. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Crystallographic Analysis of Acetyl β ‐boswellic acid

The crystal structure of the title compound (3 α ‐acetoxy‐urs‐12‐en‐24‐oic acid, C₃₂H₅₀O₄) has been determined by X‐ray crystallographic techniques. The compound crystallizes into orthorhombic space group P2₁2₁2₁ with unit cell parameters : a = 12.773(2), b=16.381(4), c=27.929(7)Å. The structure has been solved by direct methods and refined to R = 0.054 for 4930 observed reflections. The structure contains two crystallographically independent molecules in the asymmetric unit which are almost identical in geometry. Rings A, B, D and E have chair conformations while ring C assumes a sofa conformation in both the molecules. The molecules in the structure are linked together by intra‐ and intermolecular O‐H…= and C‐H…O hydrogen bonds.     

Presence of pseudo‐peptide bond in the crystal structure of n‐(t‐butoxycarbonyl)‐ε‐n′‐benzyloxycarbony‐l‐lysyl‐l‐isoleucine (boc‐lys(obzl)‐ile)

The dipeptide Boc‐Lys(OBzl)‐Ile crystallizes in monoclinic space group P2₁ with cell parameters a = 5.003(1), b = 19.199(3), c = 15.270(2)Å, β =93.42(1)°, V = 1464.1(3)ų, Z = 2, D_cal = 1.117 Mg/m³ at T = 293 K. The structure was solved by direct methods and refined by full‐matrix least‐squares procedure to a final R = 0.096 and wR = 0.101 using 1379 reflections. The peptide unit is in trans conformation and the molecule takes up an extended conformation. In the lysine side chain, delocalization of electrons and pseudo peptide bond formation is observed at the interaction site of benzyloxycarbonyl group. Both N‐H…O and main chain C‐H…O hydrogen bonds stabilize the molecules in the unit cell in a parallel β‐sheet fashion. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)