Crystal and molecular structure of (±)-1-phenyl-2-amino-1-propanol,C9H13NO

The crystal structure of (±)-phenylpropanolamine has been determined by single-crystal X-ray diffraction methods. The structure was solved by direct methods and refined by least-squares toR=0.055 andR _w=0.045 for 2000 reflections (I2 (I)). The molecule was found to adoptgauche geometry. Inter- and intramolecular N-HO and O-HN hydrogen bonds were observed in the crystal structure.     

Crystal structure of a nucleoside analog: 2′,3′-dideoxy-3′-fluoro-5-bromocytidine

The title compound crystallizes in the orthorhombic space groupP2₁2₁2₁ witha=5.084(1),b=14.322(3),c=16.065(2)Å,Z=4. The structure was solved by the heavy atom method and refined by full-matrix least-squares calculations to a finalR value of 0.033 for 1106 unique observed reflections. The N-glycosidic torsion anglex has a value of –153.7(4)°, in the anti-range. The sugar pucker is²T₃ withP=175(1)° and=30(1)°. The C4-C5 conformation is + sc with =46.7(7)°. The structure is stabilized by N-HN, N-HO and O-HO hydrogen bonds and C-HO close contacts.     

Crystal structure of a nucleoside analogue, 2′,3′-dideoxy-3′-fluoro-5-chlorocytidine

The title compound, 1-(2,3-dideoxy-3-fluoro--d-erythro pentofuranos-1-yl)-5-chlorocytosine, crystallises in the orthorhombic space groupP2₁2₁2₁ witha=5.142(1),b=14.177(2),c=15.721(2) Å,Z=4. The crystal structure was solved by the heavy atom method and refined by full-matrix least-squares method to a finalR value of 0.031 for 1629 unique observed reflections. The N-glycosidic torsion angle is –156.1(2)° and the sugar moiety is anti to the cytosine base. The sugar pucker is ₂ ³ T withP=178.2(1)° and=31(1)°. The atom 05 is in a +sc conformation with respect to the furanose ring. The molecular packing in the crystal is stabilized by N-HN, N-HO, O-HO hydrogen bonds and C-HO close contacts.     

Polymorphs of nitrofurantoin. I. Preparation and X-ray crystal structures of two monohydrated forms of nitrofurantoin

The preparation and X-ray crystal structures of two monohydrates of the antibacterial drug nitro furantoin are reported. MonohydrateI crystallizes in the monoclinic space groupP2₁ n and monohydrateII in the orthorhombic space group Pbca. The nitrofurantoin molecule maintains the same, planar conformation in both crystals. The molecular packing arrangements inI andII are distinctly different,I possessing a layer structure while inII the packing is based on a herring bone motif. Hydrogen bonds of the type O-HO, N-HO, O-HN and C-HO stabilize the crystal structures.     

Molecular structure and some reactivity aspects of 2,6-diamino-4(3H)-pyrimidinone monohydrate

Crystals of C₄H₆N₄O·H₂O are orthorhombic:Pbca,a=16.721(2),b=4.242(1),c=18.293(2)Å,Z=8. The structure has been solved by direct methods and refined by full-matrix least-squares techniques toR=0.046 for 1252 unique reflections. The structure consists of approximately planar molecules of the 3(H)4-one tautomer. Delocalization of the ring and the C=O-electrons, and conjugation of the lone-pair electrons of the amine groups with the pyrimidinone nucleus are observed. The molecules are connected by O-HO, N-HN, and N-HO hydrogen bonds. The molecular structure clarifies the chemical properties of the compound.     

Crystal structure of a nucleoside analog, 2′,3′-dideoxy-3′-azido-5-chlorocytidine

The title compound, l-(2,3-dideoxy-3-azido--D-erythro pentofuranos-1-yl)-5-chlorocytosine, crystallizes in the orthorhombic space groupP2₁2₁2₁ witha=5.840(1),b=13.780(1),c=15.396(2)Å,Z=4. The structure was solved by direct methods and refined by full-matrix least-squares calculations to a finalR value of 0.033 for 1688 unique observed reflections. The N-glycosidic torsion angle has a value of –160.8(1)°, in the and range. The sugar pucker is ₂ ³ T withP=180(1)° and=34(1)°. The C4–C5 conformation is +sc with =50.8(2)°. The azido group is nonlinear and oriented trans to the C3–C4 bond. The molecular packing in the crystalline space is stabilized by N-HN, N-HO, O-HO hydrogen bonds and C-HO close contacts.     

C-H⋯π(Ar)⋯Cl-C,C-Cl⋯π(Ar), Cl⋯Cl and other interactions in the crystal structure of 6-benzoyl-2,4-bis(trichloromethyl)-1,3-benzdioxin

The title compound is monoclinic,P2₁/n,Z=4,a=9.934(1),b=18.399(2),c=11.098(2)Å, =111.08(1)°. The molecule can conveniently be visualized as a benzophenone molecule with one of the aromatic rings fused to a 1,3-dioxin ring which adopts a distorted envelope conformation withcis-trichloromethyl groups substituted at positions 2 and 4. An interaction, observed for the first time, involves a hydrogen atom and a chlorine atom from opposite sides of the same aromatic ring to give C-H-(Ar)Cl-C. The parameters are Hring-centroid 2.63 A, Clring centroid 3.41 Å, Hring-centroidCl 167°, C-Hring centroid 159°, C-Clring centroid 150.2°. The (Ar) system is that of the unfused aromatic ring. A second (Ar) Cl-C interaction occurs but this time with the (Ar) system of the fused aromatic ring. The ClCl and ClO(=C) interactions form the familiar zig-zag pattern which has been noted for many chloroaromatic compounds.     

Two acetylamino derivatives of 2,4-bis(trichloromethyl)-1,3-benzdioxin showing different types of hydrogen bonding: (a) (C13C)CH⋯O=C and (b) N-H⋯O=C

8-Acetylamino-6-methyl-2,4-bis(trichloromethyl)-1,3-benzdioxin, (I), is monoclinic,P2₁/c,a=15.174(4),b=11.977(7),c=9.911(3)Å,=99.72(2)°. 6-Acetylamino-2,4-bis(trichloromethyl)-1,3-benzdioxin, (II), is monoclinic,P2₁/_n,a=5.927(4),b=40.623(1),c =7.120(3)Å,=91.39(4)°. In compound (I) the imino hydrogen atom is locked in an intramolecular hydrogen bond to the proximate oxygen atom of the heterocyclic ring and is not available for intermolecular hydrogen bonding. Instead the weakly acidic hydrogen atom [Cl₃C-C(2)]H takes part in a hydrogen bond to the carbonyl oxygen atom in another molecule. In compound (II) a normal intermolecular hydrogen bond of the type N-HO=C occurs. The 6-acetylam-ino group is twisted about the (C_Ar-N) bond such that the angles NHO=C, C_ArH_ArO=C, NHOH_ArC_Ar, at the carbonyl oxygen group total 360° (where NH is in the related molecule). The packing in both compounds takes the form of infinite chains and in compound (II) partial overlap of the aromatic ring and the acetylamino group, with very little offset, also occurs.     

Polymorphs of nitrofurantoin. 2. Preparation and X-ray crystal structures of two anhydrous forms of nitrofurantoin

The preparation and X-ray crystal structures of two polymorphs of the antibacterial drug nitrofurantoin are reported. The -polymorph is triclinic, space groupP¯1 witha=6.774(1),b=7.795(1),c=9.803(2)Å, =106.68(1),=104.09(2), =92.29(1)°,Z=2. The-polymorph is monoclinic, space groupP2₁/n witha=7.840(5),b=6.486(1),c=18.911(6)Å,=93.17(3)°,Z=4. The nitrofurantoin molecules adopt the same, planar conformation in both polymorphs. Both crystal structures are built up from layers held together by van der Waals forces. In each polymorph, intralayer cohesion is effected by N-HO and C-HO hydrogen bonds, but their arrangements differ in the two crystals. The significance of the C-HO hydrogen bond, now known to occur in four modifications of nitrofurantoin, is discussed.     

Cl⋯π(Ar), Cl⋯Cl,and other intermolecular interactions in the crystal structure of 8-nitro-6-methyl-2-trichloromethyl-4-dichloromethylene-1,3-benzodioxin

Crystals of the title compound are monoclinic,P2₁,a=9.791(4),b=7.129(3),c=10.428(3)Å,=91.84(3)°,V=727.50ų,Z=2. The structure was solved by direct methods, from data collected at room temperature on an Enraf-Nonius CAD4 diffractometer, and refined by full matrix least squares to a finalR value of 0.045 using 2466 reflections. The molecules form stacks along theb axis of the formA, B, A, B(A=dichloromethylene group; B=aromatic ring in the molecule at –x, 1/2+y, –z to the molecule atx, y, z containing A). Cl(Ar),, ClCl, ClO(N), (Cl₃C)HO intermolecular interactions are also present. An inverse correlation between the (C)ClCl(C) distance and the difference in the corresponding pairs of C-ClCl angles is observed and is interpreted in terms of incipient nucleophile: electrophile attack.     

Crystal structure of 4,6-dinitro-1-(5-tetrazolyl)-1H-indazole trihydrate

The title compound, C₈H₄N₈O₄·3H₂O, crystallizes in space groupP¯1 with cell constantsa=7.022(1),b=9.507(2),c=10.906(2) Å,=84.99(1),=71.89(1),=72.56(1)°,Z=2, andV _c =660.2 ų. The structure was solved by direct methods using diffractometer data and was refined by full-matrix least-squares methods to anR value of 0.060 for 2112 observed reflections. The molecule, consisting of a phenyl ring fused to a pyrazole ring with a tetrazole ring connected to it equatorially, is planar except for the N(7) nitro-group oxygen atoms. The structure is stabilized by a three-dimensional network of O-HO, O-HN, and N-HO hydrogen bonds through the water molecules.     

Structure of fruticuline B: A new natural anthracene quinodimethide of abietanoid origin

The title compound is C₁₉H₁₈O₄·1/2 CH₃OH, triclinic,P¯1,a=9.891(2),b=13.273(4),c=13.860(4) Å,a=66.47(2),=86.91(2), and =85.59(2)°. The structure was solved by direct methods and refined by least-squares techniques to anR factor of 0.082 for 2282 observed reflections. The X-ray structure uniquely resolves the one remaining ambiguity, namely the assignment of the correct structure4. There are two crystallographically independent molecules (A and B) and one disordered methanol molecule. Both molecular skeletons show small distortions from planarity with inclinations of 1.7 and 4.0° between the outermost rings A/C in molecules A and B, respectively. Intramolecular hydrogen bonds of the form O(3A)-HO(2A) and O(3B)-HO(2B) are observed in molecules A and B, respectively. The molecules are linked by pairs of O(3A)-HO(2B) and O(3B)-HO(2A) hydrogen bonds. The dimerlike structures are stabilized by intermolecular C-HO interactions and van der Waals forces.     

Molecular complexes of sulfonamides. 2.1:1 complexes between drug molecules: sulfadimidine-acetylsalicylic acid and sulfadimidine-4-aminosalicylic acid

The preparation and crystal structures of the 1:1 complexes sulfadimidine-acetylsalicylic acid (I) and sulfadimidine-4-aminosalicylic acid (II) are described. Each complex unit is maintained by two intermolecular hydrogen bonds, namely N-HO=C and NH-O, involving the N atom of the sulfonamide group and one pyrimidine N atom of the sulfonamide and the carboxylic group of the acid. Molecular parameters for protonated complexed aspirin, as found in I, are reported for the first time and reveal a significantly different conformation from that of the uncomplexed aspirin molecule. The structure of the 4-aminosalicylic acid molecule does not change significantly on complexation with sulfadimidine. Variation in the hydrogen bonded NO distances in these complexes and their analogs is discussed.     

Structure and spectroscopic properties of the 1∶2 complex of 3,5-dimethylpyridine with 3,5-dinitrobenzoic acid and its deuterated analog

The structure of the nondeuterated and deuterated complexes of 3,5-dimethylpyridine with 3,5-dinitrobenzoic acid in a stoichiometric ratio 12 have been determined by X-ray diffraction methods. The crystals of the nondeuterated complex are triclinic, space groupP¯1 witha=9.409(9),b=10.813(7),c=12.310(7)Å,a=95.75(5),=108.17(7), =91.46(7)° andZ=2. The crystals of the deuterated complex are monoclinic, space groupP2₁/c, witha=11.680(6),b=8.451(4),c=24.382(9)Å,=102.94(4)° andZ=4. Both structures have been solved by direct methods and refined toR=0.035 for 2235 and toR=0.044 for 1938 independent reflections for nondeuterated and deuterated crystal, respectively. The structures consist of 3,5-dimethylpyridinium cations and hydrogen (or deuterium) bis(3,5-dinitrobenzoate) anions. The N(1)⁺-H(N1)O(1)^–, O(7)-H(7)O(2), N(1)⁺-D(1)O(l)^– and O(7)-D(7)O(2) bond lengths are 2.644(4), 2.499(3), 2.739(5), and 2.526(5)Å, respectively. The IR spectra of both complexes within the proton (or deuteron) absorption range have been studied.     

Crystal structure of 5-fluoro-1-(2,3,6-trideoxy-α-l-glycero-hex-2-enopyranos-4-ulosyl)uracil

The present compound crystallizes in the space groupP2₁2₁2₁ withZ=4 and cell parametersa=21.687(2),b=8.155(3),c=5.883(2)Å. The structure was solved by direct methods and refined by full-matrix least-squares to a finalR value of 0.045 for 1153 observed reflections. The N-glycosidic torsion angle _CN is in the anti-range and the pyranosyl ring adopts a distorted half-chair conformation with ₂=142.7(4)°, ₂=124.4(3)° andQ=0.456(2)Å. In the crystal packing the molecules are linked together by N-HO hydrogen bonds and C-HO contacts.     

Crystal structure and conformation of N-(t-butoxycarbonyl)-L-isoleucyl-L-alanine benzylester

C₂₂N₂O₅H₃₂,M _r =404.5, monoclinic,C2,a=21.781(5),b=5.065(1),c=22.333(4)Å,=112.81(2)°,V=2271.1(9)ų,D _calc=1.148 g cm³, (CuK )=1.5418 Å,=5.89 cm^–1,F(000)=848, room temperature,R=0.058 for 2178 unique reflections [I2.5(I)]. The peptide linkage is in thetrans conformation. The molecule adopts the-sheet structure. The crystal structure is stabilized by a three-dimensional network of N-HO and C-HO hydrogen bonds.DCB Contribution No. 813.     

Crystal structure of 1,3-(N,N′-benzamide)-2-methyl-1-pentene

Crystals of the title compound are monoclinic (C20H22N2O2): space groupP2₁/n,a=11.800(3),b=13.820(2),c=11.004(3) Å,=92.74(3)°. The structure was solved by direct methods and refined by block-matrix least-squares procedure to giveR=0.078 andRw=0.076 for 1960 reflections above 3(I). The two amide groups are not coplanar with respect to their benzene rings. An intramolecular N-HO hydrogen bond was found in the molecules which are joined in chains by other strong N-HO hydrogen bonds.     

Structure of 6-aminobenzofuran-2-sulfonamide: A tropically active carbonic anhydrase inhibitor

Crystals of the title compound are triclinic. Space groupP1,a=8.652(2),b=5.184(2),c=5.050(2)Å,=100.26(3)°,=100.33(4)°, =72.82(3)°. The structure was solved by direct methods and refined by a full-matrix, least-squares procedure toR=0.033 for 1168 observed [I >2(I)] reflections. The sulfonamide group is at a right angle to the benzofuran ring and the dihedral angle between the benzene and furan ring is 2.0(1)°. In the crystal packing the molecules are linked together by N-HO and N-HN type hydrogen bonds arranging themselves in such a way that there are alternate hydrophobic and hydrophilic regions extended along the a-axis.     

Crystal and molecular structure of cesium isothiocyanatotrimethylaluminate,Cs[Al(CH3)3NCS]

The crystal structure of the title compound has been determined from three-dimensional X-ray diffraction data, and refined by full-matrix least-squares techniques. The crystals belong to the monoclinic space groupP2₁/c, witha = 8.849(4),b = 13.798(5),c = 7.943(4) Å, = 102.98(3) °, andD _x = 1.85g cm^–3 forZ = 4. The finalR factor for 1283 observed reflections is 0.046. The aluminum atom is bonded to the nitrogen atom of the thiocyanate ligand, where the Al-N bond length is 1.94(1) Å. The SCN is linear, and the CN-Al angle is 175(1) °. The cesium ion exhibits four contacts less than 3.60 Å: Cs C(thiocyanate) = 3.39(1) Å, Cs C(methyl) = 3.52(1) Å, Cs C.(methyl) = 3.56(1) Å, and Cs N = 3.575(9) Å. The closest Cs S is 3.772(3) Å.     

Crystal structure and hydrogen-bonding system of cholic acid hemihydrate,C24H40O5·1/2H2O

Crystals of the hemihydrate of this bile acid are hexagonal, space groupP6₅22, a=b=13.736(8)Å,c=85.06(6)Å,V=13,899ų. The asymmetric unit contains two independent steroid molecules and one water molecule, the latter disordered over two nonequivalent positions.Z=12[2(C₂₄H₄₀O₅)·1(H₂O)],F(000)=5496. Structure solution by direct methods; refinement by least-squares, toR=0.072. The complex hydrogen-bond system comprises: (a) three standard ordered O-HO hydrogen-bonds; (b) what is probably a symmetrically hydrogen-bonded carboxylic acid dimer, with a twofold rotation axisin the plane of the two carboxyl groups; (c) helical hydrogen-bonding chains about each 6₅ axis, disordered over four possible arrangements. In these helical chains, the six independent hydrogen-bonds can as a group be in either of two systems of nearly equivalent flip-flop arrangements: O-HO OH-O. Each helical system includes water, which can occupy either of two sites; thus, there is further disorder involving two sets of nonequivalent hydrogen-bonds with water as donor and acceptor. Many aggregation features here differ markedly from those in the crystal structures of either anhydrous cholic acid or cholic acid monohydrate.