The crystal structure of 2-nitroresorcinol

2-Nitroresorcinol is triclinic, space group P; at –100°Ca=7.083(2),b=7.696(2),c=6.607(2) Å, =74.61(2), =77.81(2), =68.64(2)°,V=320.8(2) ų,D _x=1.606(1) g cm^–3,Z=2. The two hydroxyl groups form symmetric intramolecular hydrogen bonds to the nitro group. The molecules pack in stacks held together by - interaction with adjacent molecules in a head-to-tail arrangement.     

Low-temperature,high-resolution crystal structure study of tricyclo[3.3.1.13,7]decan-2-ol (adamantanol-2)

The structure of the title compound (C₁₀H₁₅OH) was determined by X-ray diffraction at liquid nitrogen temperature. The crystals are triclinic, spacegroupP¯1 witha=11.3686(5),b=11.3990(5),c=11.4353(6) Å,=82.193(4),=70.211(4) and =62.279(4)°,V _c =1233.9(1) ų,Z=6,F(000)=504,D _x =1.229 g cm^–3; MoK radiation, =0.71073 Å,(MoK)=0.7 cm^–1. FinalR factor=0.046 andwR=0.062 for 8162 reflections withI>2.5(I). The asymmetric unit consists of three independent adamantanol-2 molecules which together with the three symmetry-related molecules form a cluster having pseudo ¯3 symmetry. The six molecules in the cluster are connected by six O-HO hydrogen bonds, the oxygens of which constitute an almost ideal chair conformation.     

Crystal structure of tylophorine methiodide monohydrate,C25H30NO 4 + I−·H2O

The crystal structure of tylophorine (Chemical name 2,3,6,7 tetramethoxy phenanthro [9,10:6, 7] indolizidine. Contribution No. 0871.) methiodide monohydrate has been determined. C₂₅H₃₀NO ₄ ⁺ I^–·H₂0, triclinic, P,a=8.831(1)Å, b=10.842(2),c=13.902(2), =105.0(1)^o, =104.7(1), =97.3(1),V=1210.22ų, Z=2,D _x =1.428 g./cm^–3, (CuK)=1.54184Å, (CUK)=107.2 cm^–1, F(000)=544,T=295^oK,R=0.038,Rw=0.046, for 2331 observed reflections withI2(I). Apart from van der Waals forces, the structure is stabilized by two hydrogen bonds of the type Ow(H) ... O and Ow(H) ... I^– involving the water molecule as the donor and atom O4 of the methoxy group and I^– as acceptors.     

Crystal and molecular structure of 3-(4-chlorobenzoylimino)-5,6-dihydro-3H-imidazo[2,1-c]-1,2,4-dithiazole

Crystal structure of the title compound belonging to the group of-acylimino derivatives of sulfur(II) compounds has been determined by X-ray structure analysis. The crystals are monoclinic, P2₁/c,a=11.210(2),b=8.197(1),c=13.659(2) Å,=102.36(2)°,V=1226.0(3) ų,Z=4,D _x =1.61 g cm^–3, (MoK)=0.71069 Å,=6.3 cm^–1. The structure has been refined to a finalR value of 0.035 for 1401 observed reflexions.The molecule is nearly planar with symmetrym. The title compound contains a very short intramolecular C=OS contact of 2.328(3) Å, suggesting a bond-non-bond resonance interaction.     

Crystal and molecular structures of quinazolines: A ring conformational study

The solid state structures of two dihydropyrimidines (DHPM) viz, 2-[(4-dimethylamino)phenyl]-1-phenethyl-2,3-dihydro-1H-quinazolin-4-one (compound 1) and 1-phenethyl-2p-tolyl-2,3-dihydro-1H-quinazolin-4-one (compound 2) are reported here. The compound 1 belongs to triclinic (P-1) space group with cell parameters a = 7.4314(12) Å, b = 9.9747(16) Å, c = 14.658(2) Å, = 104.142(3), = 102.584(3), = 98.188(3). The compound 2 also belongs to triclinic (P-1) space group with cell parameters a = 9.8707(11) Å, b = 9.9225(11) Å, c = 10.7425(13) Å, = 79.227(2), = 80.568(2), = 63.649(2). The structures show that the substituent at 2-position will play a key role in defining the pyrimidine ring conformation. The central dihydropyrimidine ring in both the structures are affected by conjugation. The sum of the valence angles around all the nitrogens is very close to 360, indicating that the state of hybridization of these atoms is sp². The DHP ring is puckered in such a manner that the atoms N1, C3, C4, C5, and N2 are coplanar and the sixth atom C2 is displaced 0.605 Å (0.18 Å for compound 2) above the least squares plane. The conformation of dihydropyrimidine ring can be described as a sofa with asymmetric parameters C_s[C2] = 6.09 (compound 1) and 4.73 (compound 2), respectively. The phenethyl group has a fully extended conformation with respect to the central pyrimidine ring (N2–C16–C17–C18 174.8(2) and 179.1(6) for compounds 1 and 2, respectively). The substituents on the DHPM ring, dimethylamino-phenyl/p-tolyl groups of compound 1/2 occupy equatorial/axial positions at C2. In the crystal packing, six membered rings form through dimerization using N–HO hydrogen bonding.     

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 and molecular structure of 1,6-dimethyl-3,6-dimethoxy-3-[(N-methylindol-3-yl)methyl] piperazine-2,5-dione,C18H23N3O4

The structure of the title compound, C₁₈H₂₃N₃O₄, was determined by X-rays.M _r =344.40, triclinic, space groupP¯1,a=8.163(4),b=9.230(2),c=13.297(2) Å,=102.70(2),=103.58(3)°,=102.50(3)°,V=911.3 ų,Z=2,D _c =1.26 Mg m^–3. CuK radiation (graphite crystal monochromator,=1.54178 Å),(CuK)=7.50 cm^–1,T=290 K. Final conventionalR-factor=0.068,R _w =0.079 for 1912 unique reflections and 295 variables. The structure was solved usingMultan andDirdif. The title compound is the first example of a 3,6-tetrasubstituted dioxopiperazine adopting a folded conformation, owing to a direct interaction between the dioxopiperazine ring and the aromatic side chain.     

Thermal decomposition of energetic materials. 45. Fast thermolysis patterns of energetic oxamides

Fast thermal decomposition (dT/dt=70-80°C sec^–1) of four energetic oxamides [N,N-bis(2-nitratoethyl) oxamide, N,N-bis(3-nitratopropyl)oxamide, N,N-bis(2-nitratopropyl)oxamide, and N,N-bis(2-azidoethyl)oxamide] in Ar is described by FTIR/temperature profiling. The product sequence and temperatures are used to analyze how the alkyl chain length, the position of the nitrate ester group, and the nature of the energetic group affect the thermolysis process. The crystal structure of N,N-bis(3-nitratopropyl)oxamide was determined: monoclinic,P2₁/c,a=5.125(2),b=6.906(2),c=18.441(8) Å,=94.91(3)°,V=650.3(4) ų,Z=2,D=1.502 g cm^–3,R(F)=0.036,R(wF)=0.044.     

Syntheses and structures of dihydrocalix[4]arenes bearing O-benzonitrile and O-acetonyl substituents

Three 25,27-dihydrocalix[4]arene derivatives, bearing benzonitrile and acetone groups on the oxygens, were prepared and structurally characterized. All three structures crystallize in , with cell dimensions: bis(benzonitrile)calix[4]arene·toluene, a = 11.530(2) Å, b = 12.013(2) Å, c = 14.089(4) Å, = 103.555(18)°, = 94.341(18)°, = 104.704(16)°, and V = 1815.9(7) ų; anti-bis-acetone-calix[4]arene, a = 7.5847(8) Å, b = 12.0948(17) Å, c = 15.3375(16) Å, = 78.982(10)°, = 76.932(9)°, = 73.129(10)°, and V = 1299.6(3) ų; syn-bis-acetone-calix[4]arene, a = 9.080(3) Å, b = 10.391(3) Å, c = 14.816(3) Å, = 96.998(19)°, = 100.02(2)°, = 103.93(3)°, and V = 1299.6(3) ų.     

Synthesis and structural characterization of 2,6-bis-(N-methylenemorpholino)-4-ter-butylphenol

The crystal and molecular structure of the title compound, C₂₀H₃₂N₂O₃, has been determined from X-ray diffraction data using CuK radiation (=1.5418 Å). The compound crystallizes in triclinic space groupP1^¯ with a=8.828(1),b=18.680(1),c=6.272(2)Å, =93.42(1), =0.24(2), =77.93(1)°,V=1009.4(2)ų, andZ=2. The structure was solved by direct methods and the full-matrix least-squares refinement leads the finalR-factor to 0.065 for 3481 observed reflections withI3(I). The phenyl ring is planar and the morpholino rings assume perfect chair conformation. The molecules are held together by van der Waals forces.DCB Contribution No. 810.     

Molecular structure of Lantadene-B&C,triterpenoids ofantana camara,red variety: Lantadene-B, 22β-angeloyloxy-3-oxoolean-12-en-28-oic acid; Lantadene-C, 22 β-(S)-2′-methyl butanoyloxy-3-oxoolean-12-en-28-oic acid

(I)Lantadene-B: C₃₅H₅₂O₅,M _r =552.80, MonoclinicC2,a=25.65(1),b=6.819(9),c=18.75(1) Å,=100.61(9),V=3223(5) ų,Z=4,D _x =1.14 g cm^–3 CuK (=1.5418A),=5.5 cm^–1,F(000)=1208,R=0.118,wR=0.132 for 1527 observed reflections withF _o 2(F _o ). (II)Lantadene-C: C₃₅H₅₄O₅·CH₃OH,Mr=586.85, Monoclinic,P2₁,a=9.822(3),b=10.909(3),c=16.120(8)Å,=99.82(4),V=1702(1)ų,Z=2,D _x =1.145 g cm^–3, MoK (=0.7107Å), =0.708 cm^–1 F(000)=644,R=0.098, wR=0.094 for 1073 observed reflections. The rings A, B, C, D, and E aretrans, trans, trans, cis fused and are in chair, chair, sofa, half-chair, chair conformations, respectively, in both the structures. In the unit cell the molecules are stabilized by O-HO hydrogen bonds in both the structures, however an additional C-HO interaction is observed in the case of Lantadene-C.DCB Contribution No 809.     

Investigation of lignin models of the biphenyl type by X-ray crystallography and NMR spectroscopy

Lignin models of the biphenyl type have been synthesized and crystal structures of two of them have been determined. The tetraacetate of 5,5-bis(hydroxymethyl)-3,3-dimethoxy-2,2-biphenyldiol crystallizes in space group witha=11.319(2),b=12.232(6),c=9.242(3) Å, =101.66(3)°, =108.14(2)°, =79.08(2)° andZ=2.R=0.036 (2720 observed [I>3(I)] reflections). The acetate of 5,5-di-tert-butyl-2,3,3-trimethoxy-2-biphenylol crystallizes in space group witha=11.972(2),b=21.621(3),c=9.834(1) Å, =91.18(1)°, =113.13(1)°. =98.42(1)°, andZ=4.R=0.050 (8129 observed [I>3(I)] reflections).¹H NMR and¹³C NMR data for the above-mentioned compounds and a third model, the diacetate of 5,5-bis(1-hydroxyethyl)-2,2,3,3-tetramethoxybiphenyl, are reported. Observed signal positions are compared with those calculated on the basis of crystal structure data. The possibilities to obtain structural information about biphenyl structures in lignins from NMR spectra are discussed.     

Crystal structure of 8-(3,4-dimethylphenoxy)-16H dinaphtho[2,1-d:1′,2′-g] dioxaphosphocin 8-oxide

The title compound, C₂₉H₂₃O₄P crystallizes in the triclinic space group witha=9.636(1),b=10.327(1),c=13.406(1) Å, =102.22(1), =100.59(1), =109.84(1)^o.V=1178.1(2) ų,Z=2,D _cal=1.32 M gm^–3, (CuK)=6.16 cm^–1, (CuK)=1.5418 Å andT=295K. The structure was solved by direct methods and refined by full-matrix least-squares method to a finalR=0.052 andwR=0.063 for 2708 reflections withl3(l). The napthalene ring A lies perpendicular to the best plane of the phenyl ring [91.6(1)^o] and the ring B orients at an angle of 55.7(1)^o with this plane and is inclined at an angle of 77.8(1)^o with ring A. The heterocyclic phosphorous eight-membered ring assumes a distorted boat conformation.DCB Contribution No. 822.     

Crystal and molecular structure of 3-methoxy-6-nor-6,7-secooestra-1,3,5(10),9(11), 14-penten-17-one-8β-ethyl carboxylate

C₂₀H₂₂O₄,M _r =326.39, triclinic,P¯1,a=10.365(2),b=11.383(2),c=8.461(1) Å, =103.60(1),=104.44(1), =105.23(1)°,Z=2, (CuK)=1.54178 Å;R=0.0633 for 1940 reflections. The results of the X-ray analysis have shown that the ethyl carboxylate substituent is oriented. The geometry of the main skeleton of the molecule has not revealed any significant differences in the present compound and in the case of the epimeric molecule.     

Crystal structures of five policyclic compounds related to the natural product forskolin

(3(Z),4,6a,9a,9b)-(±)-3a,4,6a,7,8,9,9a,9b-octahydro-4,7,7, 9b-tetramethyl-3a-[3-(methoxymethyloxy)-3-methyl-1-butenyl]-5H-naphto[1,8-de]-1,3-dioxin-6-one (I), C₂₂H₃₆O₅,M _r=378.51, monoclinic,P2₁/n,a=6.330(1),b=14.576(2),c=22.837(2)Å,=93.04(1)°,V=2104.1(2)ų,Z=4,D _c=1.19 Mg/m³, (MoK)=0.71069Å,=0.8 cm^–1,F(000)=832,T=298 K,R=0.054 for 1971 observed reflections; (7a,10a,10b,12)-(±)-7a,9, 10,10a,10b,11,12,12a-octahydro-2,2,10,10,10b,12a-hexamethyl-2H,8H-1-benzopyrano[4a,5,6,-de][1,3,2]-benzodioxin-11-one (II), C₂₀H₂₉O₄,M _r=334.5, triclinic,P-1,a=10.595(2),b=12.152(1),c=8.073(1)Å,=106.53(1),=105.65(1), =66.29(1)°,V=897.9(2)ų,Z=2,D _c=1.24 Mg/m³, (MoK)=0.71069Å,=0.8 cm^–1,F(000)=362,T=298 K,R=0.046 for 2848 observed reflections; (7a,10a,10b,12, 12a)-(±)-7a,9,10,10a,10b,11,12,12a-octahydro-2,2,10,10,10b,12a-hexamethyl-2H,8H-1-benzopyrano[4a,5,6-de][1,3,2]-benzodioxin-11, 12-diol (III), C₂₀H₃₂O₅ (two molecules in the asymmetric unit),M _r=352.2, triclinic,P-1,a=12.948(3),b=13.615(3),c=12.197(4)Å,=101.16(2),=111.88(2), =69.48(2)°,V=1863.8(9)ų,Z=2,D _C=1.26 Mg/m³,(MoK)=0.71069 Å,=0.8 cm^–1,F(000)=768,T=298 K,R=0.060 for 4570 observed reflections; 4-acetoxy-4-[[(4a,5,8a)-(±)-hexahydro-4a,6,6-trimethyl-4H-1,3-benzodioxin-4-one]-5-yl]butan-2-one (IV), C₁₇H₂₆O₆,M _r=326.4, monoclinic,P2₁/c,a=10.495(2),b=12.050(2),c=14.216(2)Å,=108.51(1)°,V=1704.8(5)ų,Z=4,D _c=1.27 Mg/m³,(MoK)=0.71069 Å,=0.9 cm^–1,F(000)=704,T=298 K,R=0.049 for2455 observed reflections; (3a,4,5,6,6a,9a,9b)-(±)-4,5-epoxy-decahydro-3, 3a-dihydroxy-2-ethoxy-4,7,7,9b-tetramethyl-naphto-[1,8-bc]-pyran-6-ol-acetate (V), C₂₀H₃₂O₇,M _r=383.5, monoclinic,C2/c,a=10.353(2),b=17.975(3),c=21.188(3)Å,=91.29(1)°,V=3942(1)ų,Z=8,D _c=1.29 Mg/m³,(MoK)=0.71069 Å,=0.8 cm^–1,F(000)=1664,T=298 K,R=0.051 for 2120 observed reflections. We report here the complete structures of four decalin derivatives (compoundsI, II, III, V) and one related compound (compoundIV) synthetized in order to find an efficient synthetic approach for the natural productforskolin.     

Crystal and molecular structure of (exo)-1-carboxymethyl-5-ethoxycarbonyl-4,5,6,11b-tetrahydroisoxazolidmo-[2,3-a]-β-carboline,C18H20N2O5

The structure of the title compound C₁₈H₂₀N₂O₅, was determined by X-rays atT=290 K.M _r =344.366, monoclinic, space groupP2₁/c,a=15.589(4),b=7.619(1),c=16.792(4) Å, =111.47(2)°,V=1856.1 ų,Z=4,D _x =1.23 Mg m^–3. CuK radiation (graphite crystal monochromator, =1.54178 Å),(CuK)=7.17 cm^–1,F(000)=728. Final conventionalR-factor=0.075,R _w =0.106 for 2266 observed reflections and 274 variables. The structure was solved usingMultan.     

Ethyl 1,2,3,4-tetra-O-acetyl-β-D-glucopyranuronate

The crystal structure, at 120 K, and solution ¹H and ¹³C NMR spectra of ethyl 1,2,3,4-tetra-O-acetyl--D-glucopyranuronate, (8) have been determined. Compound 8 crystallizes in the triclinic space group, P1 (Z = 1) with a = 6.0209(3) Å, b = 8.9698(5) Å, c = 9.9818(8) Å, = 104.965(2)°, = 98.522(3)°, = 106.790(5)°. The Cremer and Pople puckering parameters [Q = 0.602(4) Å, = 7.1(4)°, = 325(3)°] for the pyranose ring in the solid state indicate a near ideal ⁴C₁ chair conformation with a slight distortion in the direction towards ⁰H₅. A number of weak, soft intermolecular C–H O hydrogen bonds set up a 3D array. NMR spectra and FAB and EIMS data have been obtained. Solution NMR parameters suggest that the solid state conformation is maintained in solution in chloroform.     

Synthesis and X-ray structure analysis of 2-acetylamino-benzoic acid

The title compound crystallizes in the orthorhombic space group Fdd2 with unit cell parameters a = 10.848(1) Å, b = 30.264(1) Å and c = 10.577(1) Å, V = 3472.47(2) ų, and Z = 4. The final reliability index is 0.030 for 700 observed reflections. Nitrogen of the amide group and carbon atom of the acid group deviate significantly below and above the plane of the phenyl ring. The crystal cohesion is accentuated by N—HO and O—HO hydrogen bonds.     

Hydrogen bonding in 2-hydroxy((di)thio)benzoates. I. X-ray structures of 2,6-dimethylpiperidinium salts

X-ray structural data are reported for 2,6-dimethyl-piperidinium-2-hydroxybenzoate (C₁₄H₂₁NO₃, orthorhombic,P2₁2₁,2₁, (19);a=7.983(1)Å,b=12.680(2)Å,c=13.838(2)Å;Z=4;R=0.042) and for two polymorphs of 2,6-dimethylpiperidinium-2-hydroxythiobenzoate (C₁₄H₂₁NO₂S), an-form (monoclinic,P2₁/n (14);a=8.005(4)Å,b=22.150(2)Å,c=8.672(4)Å,=101.91(6)°;Z=4;R=0.059) with an intramolecular O-HS hydrogen bond, and a-form (orthorhombic,P2₁2₁2₁ (19);a=8.188(1)Å,b=14.781(2)Å,c=24.163(4)Å;Z=8;R=0.15) with an intramolecular O-HO hydrogen bond. The intra-and intermolecular hydrogen bond patterns are discussed, including the literature data of 2,6-dimethylpiperidinium-2-hydroxydithiobenzoate.     

Structural characterization of 2,6-bis(N-methylenepiperidino)-4-nitrophenol (MPN) and 2,6-bis-(N-methylenemorpholino)-4-nitrophenol (MMN)3

MPN: C₁₈H₂₇N₃O₃,M _r=333.43, monoclinic,P2₁/n. a=6.207(2),b=21.893(6),c=13.693(3) Å; =96.12(2)^o,V=1850.1(8) ų.,Z=4,D _cal=1.20 mg/m³,F(000)=720, (CuK)=1.5418 Å, andT=298K.R=0.042 andwR=0.049 for 1675 observed reflections. MMN: C₁₆H₂₃N₃O₅,M _r=337.38, triclinic,P,a=9.642(1) Å,b=10.123(5) Å,c=9.341(2) Å, =93.00(3)^o, =90.96(1)^o, =110.46(1)^o, V=852.5(5) ų,D _cal=1.31 mg m^–3.F(000)=360,Z=2, (CuK)=1.5418 Å,R=0.054 andwR=0.074 for 2804 observed reflections. The piperidine and morpholino rings assumechair conformation and orient each other at an angle of 44.8(1)^o (MPN) and 47.1(1)^o (MMN), respectively.Contribution No. 827 from DCB.