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.     

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.     

Crystal and molecular structure of 1,N6-ethenoadenosine hydrochloride

The X-ray structure of 1,N ⁶-ethenoadenosine hydrochloride, C₁₂H₁₄N₅O₄Cl, has been determined from three-dimensional diffractometer data and refined by full-matrix least-squares techniques. The crystals are monoclinic:P2₁ No. 14,a=6.1540(5),b=18.511(1),c=6.7412(4) Å,=112.602(5)°,andZ=2; finalR=0.045 for 2662 observed reflections. The crystal and molecular structure of Ado·HC1 is very similar to that of Ado·HC1. On the other hand, the dimensions and conformation of the Ado·H⁺ cation are drastically different from those of Et Ado·H⁺. The adenosine·H⁺ moiety is not planar but has an S shape. The ribose is 2-endo-3-exo puckered, with ag ⁺ side chain; the glycosidic torsion angle is in theanti region. The structure contains a three-dimensional network of H bonds in which also C-HA interactions seem to play an important role. There is no base stacking in the structure.     

Structure of bis(2-pyridine-N-oxide) diselenide and its formation from tetraphenylantimony(V)selenopyridine-N-oxide

The structure of bis(2-pyridine-N-oxide) diselenide was determined by single crystal X-ray diffraction. The compound crystallized in the triclinic system and the structure was solved in the space group . The lattice constants were determined to bea=7.174(2),b=7.176(2),c=11.070(2) , =87.67(2)°, =73.68(2)°, and =89.57(2)°;Z=2,D _x=1.906 Mg m^–3. The final least squares refinement based on 1942 independent observed reflections yieldedR=0.033,wR=0.044. The Se–Se bond length is 2.326(1) and each Se is coordinated to the O atom of the corresponding N-oxide moiety at a distance of about 2.6 .     

Stable crystalline adducts of 1,6-bis(o-hydroxyanilino)-1,5-hexadiene-3,4-dione withN,N-dimethyl carboxamides and urea derivatives

The red colored and poorly soluble 1,6-bis(o-hydroxyanilino)-1,5-hexadiene-3,4-dione (3f) forms stable adducts5 and7 of exact stoichiometric ratios withN,N-dimethyl carboxamides4 and ureas6. The adducts are yellow colored and easily soluble in organic solvents. The crystal structure of3f (monoclinic space groupP2 ₁/c witha=7.903(2),b=10.941(2),c=8.976(3) Å, =90.13(2)°) indicates planarity with extensive delocalization of the -electrons. The poor solubility is referred to the formation of strong intermolecular hydrogen bonds (H(O)...O3 andH(O)...O3=1.79 Å). The crystal structure of the 12 DMF adduct5a (monoclinic space groupP2 ₁/c witha=6.068(1),b=19.668(2),c=10.645(1) Å, =107.791(8)°) shows a less pronounced delocalization of the -electrons which might be the explanation for the color change from red to yellow. In5a the intermolecular hydrogen bonds of3f are interrupted by forming new hydrogen bonds from the hydroxyl group to the carbonyl group of DMF (H(O)...O(L) andH(O)...O(L)=1.86 Å), whereby the solubility is markedly changed. The thermal stability of the addition products5 and7 was determined by thermogravimetry.     

C−Cl...π(Ar)...Cl−C,Cl...Cl and other interactions in the structures of two 6-substituted-2,4-bis(trichloromethyl)-1,3-benzdioxin's: (I) 6-carboxymethyl; (II) 6-propionyl,an antimethanogenesis food additive

C₁₂H₃Cl₆O₄, (I),M _r=428.91, triclinic, ,a=9.197(1),b=9.336(2),c=9.830(1) Å, =79.29(1), =83.33(1), =85.38(1)°,V=822.16,Z=2,D _x=1.73 Mg m^–3,F(000)=428, (MoK)=0.71069 Å, =10.62 cm^–1, room temperature, finalR=0.033 for 2573 unique counter reflections withF _o>4(F _o). C₁₃H₁₀Cl₆O₃, (II),M _r=426.94, triclinic, ,a=9.374(2),b=9.503(1),c=9.888(4) Å, =79.26(2), =82.10(3), =84.43(1)°,V=854.88,Z=2,D _c=1.66 Mg m^–3,F(000)=428, =0.71069 Å, =10.17 cm^–1, room temperature, finalR=0.030 for 2609 unique counter reflections withF _o>4(F _o). Compounds I and II are isostructural. Centrosymmetric dimers are formed by hydrogen bonds from the two methine hydrogen atoms to the carbonyl oxygen atom. The dimers are linked by Cl...(Ar)...Cl, Cl...O and Cl...Cl interactions to form a three-dimensional pattern. The geometry associated with these interactions is discussed in terms of the electrophile: nucleophile model.     

Crystal and molecular structure of 3-methoxy-B-nor-5,7-seco-1,3,5(10), 9(11)-estrapent-14-en-17-one-8-β-ethyl carboxylate

The crystal structure of the title compound has been determined by X-ray analysis. Crystal data: triclinic,P¯1, C₂₀H₂₂O₄,M _r =326,39,a=8.296(1),b=10.704(2),c=11.186(1) Å,=112.58(1),=100.81(1), =95.79(1)°,V _c =884.38(8) ų,D _x =1.225 g·cm^–1, (CuK)=1.54178 Å,=6.05 cm^–1,F(000)=384, room temperature,R=0.082 for 2410 unique reflections withF4 F. The conformation of the 3-methoxy-B-nor-5,7-seco-1,3,5(10), 9(11)-estrapent-14-en-17-one-8--ethyl carboxylate (1a) molecule is similar to that of the estranes. Since theB ring is not closed, the rotation around the C(9)-C(10) bond is possible and torsion of the molecule is observed.     

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.     

Structure of two 1,3-dioxane derivatives from 4′, 5′-dimethylfurocoumarins: 4a, 11a-dihydro-4a, 11a-dimethyl-8H-pyrano[3′,2′∶5,6]benzofuro[3,2-e]-1, 3-dioxan-8-one and 7a,11a-dihydro-7a,11a-dimethyl-2H-pyrano[2′, 3′∶4,5]benzofuro[3,2-d] (1,3) dioxan-2-one

Treatment of dimethylated psoralen and angelicin in the 4, 5-position leads to the formation of 1,3-dioxane derivatives, resulting from the condensation of an 1,3-dioxane ring to the 4, 5-positions of the dihydrofurocoumarin moiety. The structures of these new compounds, 4a, 1 1a-dihydro-4a, 11a-dimethyl-8H-pyrano [3, 25,6]benzofuro[3,2-e]-1, 3-dioxan-8-one (C₁₅H₁₄O₅) (1) and 7a, 11a-dihydro-7a, 11a-dimethyl-2H-pyrano[2, 34, 5]benzofuro[3, 2-d](1, 3)dioxan-2-one (C₁₅H₁₄O₅) (2) have been assigned by¹H and¹³C NMR measurements, mass spectrometry results, and X-ray analysis. Compound (1): triclinic,P¯1,a=9.847(2),b=8.927(2),c=8.334(2) Å,=95.98(2),=108.81(3), =106.73(3)°; compound (2): triclinic,P¯1,a=7.296(4),b=7.481(2),c=11.812(4) Å,=91.67(2),=95.97(4), =94.20(3)°. The structures were solved by direct methods and refined by full-matrix least squares toR=0.050 (1) and 0.056 (2). In both compounds the coumarin rings can be regarded as coplanar, while the five-membered ring adopts an envelope conformation and the 1,3-dioxane ring a chair conformation.     

Structures of 8α-(2′-methylbutyryloxy)-9α-hydroxymontahibisciolide,a new skeletal type of sesquiterpene lactone,and of its precursor 8α-isobutyryloxy-9-oxo-germacra-4E, 1(10)Z-dien-6β,12-olide

The structures of a new skeletal type of sesquiterpene lactone, containing a seven, five, fivering system, and of its putative precursor, a 9-oxo-melampolide, have been confirmed by single crystal X-ray structure determination. The central 5-membered ring of the new skeleton istrans-fused to the cycloheptene ring andcis-fused to the lactone ring. Transannular interactions and the geometry of thetrans carbon-carbon double bond of the oxo-melampolide and the keto-group at C9, suggest that the new seven, five, five tricyclic skeleton-type of montahibisciolide can easily be reached by a transannular cyclization process. The isobutyrloxy group of the oxo-melampolide is disordered into two partially populated conformations. 8-(2-Methylbutyryloxy)-9-hydroxymontahibisciolide,3, C₂₀H₂₈O₅, crystallizes in orthorhombic space groupP2₁2₁2₁ witha=8.294(2),b=9.740(2),c=22.675(1) Å,V=1832(1)ų,Z=4. The structure was refined toR=0.043 andR _w=0.048 for 2898 observed reflections with CuK radiation. 8-isobutyryloxy-9-oxo-germacra-4E, 1(10)Z-dien-6, 12-olide,4, C₁₉H₂₄O₅, crystallizes in monoclinic space groupC2 witha=32.879(7),b=5.793(2),c=9.884(4)Å, =99.01(3)°,V=1859.5(9)å³,Z=4. The structure was refined toR=0.054 andR _w=0.064 for 1010 observed reflections with MoK radiation.     

Crystal and molecular structure of (endo)-1-methoxycarbonyl-5-ethoxycarbonyl-4,5,6,11b-tetrahydroisoxazolidino-[2,3-a]-β-carboline,C18H20N205

The structure of the title compound, C₁₈H₂₀N₂O₅, was determined by X-rays atT=290 K.M _r =344.366, monoclinic, space groupP2₁/c,a=11.4266(5),b=7.9563(15),c=18.9075(7) Å, =101.851(3)°,V=1682.3 ų,Z=4,D _x =1.360 Mg m^–3. CuK radiation (graphite crystal monochromator, X=1.54178 Å),(CuK)=7.91 cm^–1. Final conventionalR-factor=0.054,R _w =0.073 for 2787 observed reflections and 286 variables. The structure was solved usingMultan.     

Crystal and molecular structure of 5-ethoxy-4-methylene-exo-10-oxatricyclo[5.2.1.02,6]-deca-8-ene-3-ol,C12H16O3

The structure of the title compound, C₁₂H₁₆O₃, was determined by X-rays.M _r =208.26, triclinic, space groupP¯1,a=7.802(2),b=8.449(2),c=9.069(1) Å,=90.79(1)°,=105.57(1)°, =106.07(1)°,Z=2,D _x =1.26 Mg m^–3; MoK radiation (graphite crystal monochromator, =0.71069 Å),(MoK)=0.96 cm^–1,T=290 K. Final conventionalR-factor=0.046,R _w =0.067 for 3009 observed reflections and 184 variables. The structure was solved using Patterson methods andDirdif, and the resulting all cis-endo configuration of the alcohol group on C(3) and the ethoxy group on C(5) shows that the stereochemistry of the metal-mediated addition reaction involved is solely determined by steric factors.     

3,3′-di[1,3-thiazolidin-4-one] system. Structural and conformational studies on configurational isomers with anti-inflammatory activity

3,3(1,2-Ethanediyl)bis(2-halophenyl-thiazolidin-4-one) derivatives display different pharmacological activities depending on the configuration of the 2,2 centers and on the oxidation state of the sulfur atoms. Quantum-chemical calculations on the 3-fluorophenyl-substituted configurational isomers are reported here, together with the X-ray structure of the 11 dioxide derivative. This crystallizes in the monoclinic space group P2₁/c, with four molecules per unit cell and cell dimensions:a=18.917(3),b=9.003(2),c=12.062(2)Å, =96.20(3)°. The compound, which has an approximate center of symmetry in the middle of the ethylene chain and two asymmetric carbon atoms of opposite chiralities, is the (2R,2S-meso) (or 2S,2R-meso) stereoisomer.     

Conformations of cyclic disulfides: The crystal structure of (1RS,2RS,7RS,8RS)-1,2,7,8-tetrahydroxy-4,5,10,11-tetrathiacyclododecane

The racemic form of the title compound C₈H₁₈O₄S₄ (TTCD), a twelve-membered cyclic disulfide, has been synthesized and studied by X-ray diffraction. TTCD·H₂O crystallizes in a multiply twinned pseudo-monoclinicC-centered lattice. For convenience aC-centered triclinic unit cell was chosen of dimensionsa=33.855(3),b=5.534(1),c=14.836(2) Å, =90.05(1),=94.76(1), =89.22(1)°,V=2769(1) ų,Z=8, space groupC¯1. The structure, solved by direct methods, was refined to anR of 0.063, using 2769 observed reflections. The two crystallographically independent TTCD molecules in the unit cell have very similar conformations. The distortion from the pseudomonoclinic symmetry is discussed in relation to the hydrogen bonding network.     

Dinuclear complex of rhodium(III) with an amine-phenol ligand: synthesis and X-ray crystal structure

A new rhodium(III) complex of an amine-phenol ligand N,NN-bis-(2-hydroxybenzyl)1,3-diaminopropane was synthesized and characterized by X-ray diffraction studies. Diffraction data were collected by the-2 scan method using MoK. radiation. The structure was solved by conventional methods resulting in a final R factor of 0.037 for 1954 independent reflections (F _o >2(F _o )). The structure consists of a dinuclear complex with two -hydroxy bridges between the two Rh atoms. The overall charge of the molecule is neutral due to deprotonation of all phenolic groups. Crystal data: triclinic, space groupP¯1,a=7.308(3)Å;b=9.586(3)Å,c=12.686(5)Å, =87.51(2), =88.28(2), =71.70(3)°,V=866.6(6)ų;Z=2.     

Structures of 2-, 3-, and 4-methyl-9-oxothioxanthenes

The structures of 2-, 3-, and 4-methyl-9-oxothioxanthenes (2-, 3-, and 4-TX, respectively) were determined by single crystal x-ray methods. The molecules are folded by 2–3° about their SC=O lines. Bond distances and angles vary only slightly as a function of the methyl substitution position, and reveal no inherent structural reason for the long-range nmr couplings observed between the ring and methyl protons. The molecular packings exhibit interesting similarities as well as subtle differences that result from variation of the methyl position. Crystals of 2-TX are orthorhombic, space groupPn2₁ a,a=10.807(1),b=4.024(2),c=24.827(3) Å,Z=4,R=0.059 for 715 observed reflections. Crystals of 3-TX are orthorhombic, space groupPbc2₁,a=3.999(1),b=25.051(2),c=10.758(1)Å,Z=4,R=0.041 for 1382 observed reflections. Crystals of 4-TX are triclinic, space groupP¯1,a=7.118(1),b=7.907(2),c=10.415(2) Å,=77.74(1),=74.35(1), =73.96(1)°,Z=2,R=0.043 for 1542 observed reflections.Deceased.     

Crystal and molecular structure of (exo)-1-methoxycarbonyl-5-ethoxycarbonyl-4, 5,6,11b-tetrahydroisoxazolidino-[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, orthprombic, space groupP2₁2₁2₁,a=9.350(5),b=11.954(2),c=15.455(3) Å,V _c =1727.3 ų,Z=4,D _c =1.324 Mg m^–3. CuK. radiation (graphite crystal monochromator, =1.54178 Å),(CuK)=7.70 cm^–1. Final conventionalR-factor=0.065,R _w =0.086 for 2887 observed reflections and 265 variables. The structure was solved usingMultan.     

Crystal structure,physical and photophysical properties of a platinum(II) complex coordinated to the biphenyl dianion and cyclooctadiene

The complex, Pt(bph)(COD), where bph is the biphenyl dianion and COD is 1,5-cyclooctadiene, crystallizes in the orthorhombic space groupPbca witha=12.178(4) Å,b=9.693(3) Å andc=25.344(9) Å andZ=8. The Pt–C distances to the olefinic carbon atoms that result from the electron donation of the COD ligand are in the range 2.20(3)–2.27(3) Å and the Pt–C distances to the bonded bph ligand are shorter at 2.01(3)–2.03(2) Å. The lowest energy absorption of the complex is at 383 nm (=1.2×10³). The emission spectrum is structured in fluid solution at room temperature with the emission energy maximum at 537 nm, _cm, and =1.93 s. Temperature dependent emission lifetime measurements result in ak _o value of 2.69×10⁴, a preexponential factor of 2.47×10⁶ and a E₁ value of 324 cm^–1.     

Structural and spectral studies of binuclear copper(II) 2-acetylpyridine 3-azacyclothiosemicarbazones with sulfato bridges

Structures of two binuclear copper(II) complexes with sulfato bridges and tridentate 2-acetylpyridine 3-azacyclothiosemicarbazone ligands have been solved. The complex-sulfato-bis{(2-acetylpyridine 3-hexamethyleneiminyl-thiosemicarbazonato)copper(II)} N,N-dimethylformamide, [Cu(Achexim)]₂SO₄·DMF, has the following structural properties: triclinic, P1¯(#2), a = 12.314(4), b = 15.885(4), c = 10.959(4) Å, = 103.25(2), = 103.60(2), = 109.94(2)°, V = 1843(2) ų, and Z = 2; for -sulfato-bis{(2-acetylpyridine 3-piperidylthiosemicarbazonato)copper(II)}chloroform, [Cu(Acpip)]₂SO₄·CHCl₃: triclinic, P1¯(#2), a = 11.657(1), b = 17.101(2), c = 10.338(1) Å, = 98.51(1), = 109.294(7), = 107.016(9)°, V = 1790.3(4) ų, and Z = 2. The size of the azacyclo ring significantly affects the stereochemistry of these binuclear complexes.     

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.