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.     

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 ofendo-5-acetoxy-4-(p-tolylsulfonyl)methyl-exo-10-oxatricyclo-[5,2,1,02,6]deca-3,8-diene,C19H20O5S

The structure of the title compound, C₁₉H₂₀O₅S, was determined by X-rays.M _r =360.42, monoclinic, space groupP2₁/c, a=8.517(2),b=31.107(2),c=20.517(4) Å,=96.205(18)°,V _c =5403.9 ų,Z=12,D _x =1.45 Mg m^–3. CuK radiation (graphite crystal monochromator, =1.54178 Å),(CuK)=1.777 mm^–1,F(000)=2280T=295 K. Final conventionalR-factor=0.058,R _w =0.060 for 3476 observed reflections and 552 variables. The structure was solved usingMultan andDirdif (direct methods applied to difference structures). The configurations of three crystallographically independent molecules in the asymmetric unit of the crystal are reported.     

Hydrogen bonding in labdane diterpenoids, labda-7,12(E),14-triene-17-oic acid and labda-12(Z),14,17-triene-18-oic acid

Two labdane diterpenoids, labda-7,12(E),14-triene-17-oic acid (1) and labda-12(Z),14,17-triene-18-oic acid (2), C₂₀H₃₀O₂, have been isolated from Croton oblongifolius. Both 1 and 2 crystallized in the monoclinic system, space group C2, with cell dimensions of a = 21.912(1) Å, b = 7.4002(4) Å, c = 11.5079(7) Å, = 101.999(1)^o and a = 21.308(2) Å, b = 11.9067(9) Å, c = 7.5606(6) Å, = 100.763(1)^o, respectively. Compound 1, a rare example of carboxylic group bound to a cyclohexene ring, forms an infinite intermolecular hydrogen-bonded polymer [O1 O2(–x + 1/2, y + 1/2, –z + 2) 2.697(2) Å], whereas molecules of compound 2 are linked to form an asymmetric hydrogen-bonded dimer [O1 O2(–x, y, –z) 2.657(3) Å].     

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.     

The crystal structure of 2,2′-bis-1,3-dithiole and dimethyl dicyanofumarate CT complex

The crystal structure of 2,2-bis-1,3-dithiole dimethyl dicyanofumarate has been determined from a single-crystal X-ray study. The compound crystallizes in the monoclinic space groupP2₁/c with two complexes per unit cell of dimensionsa=11.075(2)Å,b=11.615(3)Å,c=6.623(4)Å, ==90.0°,=95.7(16)°, andV=847.6(9)ų. The observed and calculated densities are 1.56 and 1.57 g cm^–3 respectively. Full-matrix least-squares refinement using 404 reflections having 4°250° andI3(I) converged atR=0.0492 andR _w =0.0614. Structural parameters in bond lengths and bond angles do not change to any observable extent when comparing the parent molecules to the complexed state. AnOrtep view along thec-axis shows the units to be arranged in segregated parallel stacks with a distance of 3.31 Å between layers.We are indebted to the US Army Research Office, Grant DAAG-29-77-G-0231, for support of the research and to Dr. J. H. Enemark and Dr. W. Setzer for their professional advice.     

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.     

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.     

On the organoaluminum chemistry of multidentate phosphine ligands. Reaction of trimethylaluminum with bis(diphenylphosphino)methane: Synthesis and molecular structure of [Al(CH3)3]2[(C6H5)2PCH2P(C6H5)2]

Reaction of an excess of trimethylaluminum with bis(diphenylphosphino)-methane in heptane affords the crystalline complex [A1(CH₃)₃]₂[(C₆H₅)₂PCH₂P(C₆H₅)₂]. The title compound crystallizes in the triclinic space group P¯1 with unit cell parametersa=10.053(6),b=11.017(6),c=15.908(8) Å,=85.58(4),=71.80(4), =77.49(4)°,V=1634(1) ų, andD _c=1.07 g cm^–3 forZ=2. Least-squares refinement based on 2924 observed reflection with intensitiesI3I) in the range 2.00245.0° converged atR=0.050 (R _w=0.067). The Al-P distances are 2.585(2) and 2.521(2) Å, and the P-C-P angle is 121.4(2)°.     

Synthesis and characterization of ternary L-histidine complexes. Crystal structure of (2,2′-dipyridyl)-(L-histidinato-N,N′,O)copper(II) perchlorate 1.5 hydrate

A series of ternary complexes of copper(II), cobalt(II) and zinc(II) with L-histidine, 1,10-phenanthroline, 2,2-dipyridyl or imidazole having perchlorate or acetate as counterions were synthesized and characterized by conventional methods and for [Cu(bipy)(L-hist)]ClO₄·1.5H₂O and X-ray crystal structure was determined. The crystals belong to the monoclinic space groupC2 witha=18.843(3),b=10.582(2),c=11.020(2), =115.20(10)°,Z=4,R=0.0535. The structure is consistent of [Cu(bipy)(L-hist)]⁺ cations, perchlorate ions and water molecules. The geometry around copper is trigonal bipyramidal with one N,N,O tridentate L-histidine molecule and one 2,2-dipyridyl ligand, the apical sites are occupied by the -amino nitrogen [Cu–N(71) 1.995(8)] and by N(11) of 2,2-dipyridyl [Cu–N(11) 1.983(7)], the equatorial plane is formed by the N(3) imidazole -nitrogen [Cu–N(3) 2.140(6)], O(82) carboxylic oxygen [Cu–O(82) 2.009(5)] and N(22) [Cu–N(22) 2.010(7)].     

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 and molecular structure of 1R,3S,5S,7R,10R-3,6,6,10,14-Pentamethyltricyclo[10.3.0.05,7]pentadeca-11,14-diene-1, 10-dihydroxy-2,13-dione (Japodagrol), C20H28O4

A new cytotoxic macrocyclic diterpenoid named Japodagrol, C₂₀H₂₈O₄, has been isolated from the ornamental plantJatropha podagrica, family Euphorbiaceae, grown in Nigeria. The structure of the title compound, C₂₀H₂₈O₄, was solved by X-ray analysis.M _r =332.44, monoclinic space groupC2,a=23.285(4),b=6.5105(12),c=12.505(3) Å,=98.504(17),V=1874.8 ų,Z=4,D _c =1.178 Mg/m³. CuK radiation (graphite crystal monochromator, =1.54184 A), (CuK)=6.13 cm^–1,F(000)=720,T=290 K. Final conventionalR factor=0.035,R _w =0.038 for 3349 observed reflections. The structure was solved with the programDirdif. The 5-membered ring is closed to a half-chair form. The compound contains inter- and intramolecular hydrogen bonds.     

Structure of 17α-methyl-testosterone semihydrate,C20H30O2·1/2 H2O

The crystal structure of 17-methyltestosterone hemihydrate, C₂₀H₃₀O₂·1/2H₂O, has been determined:M _r =312.5, space groupP2₁2₁2₁2₁,a=6.374(2),b=12.807(2),c=43.398(5)Å,V _c =3543(2)ų,Z=8,D _x =1.172 mg^–3, CuK radiation ( = 1.54184 Å),(CuK)=5.5 cm^–1,F(000)=1376. The structure was solved usingMultan. The final conventionalR=0.053 (R _w =0.052) for 3634 reflections. The structure contains two crystallographically independent molecules in the asymmetric part of the unit cell that have almost identical geometry.     

Structure of the dipeptide L-lysine-L-leucine·Acetate, 0.5 acetic acid hemihydrate

2(C₁₂H₂₆O₃N₃·C₂H₃O₂)·C₂H₄O₂·H₂O,M _r =350.44, triclinic, P1,a=5.576,b=12.574(3),c=14.946(2) Å, =107.80(2), =96.34(2), =89.89(2)°.B=991.04(6) ų,Z=2,D _x =1.201 g/cm³, (KCu)=1.5418, Å, =7.4 cm^–1, room temperature.R=0.074 for 2645 observed reflections. In the unit cell there are two peptide molecules, three acetic acid molecules, two of them likely to be present as acetate anions, and one water molecule. Each peptide exists in zwitterionic form with the carboxylic group deprotonated, and with positive charges both in the amino terminal and -amino groups of lysine. The two peptide molecules have almost identical conformations. The dipeptide backbone is folded.     

Crystal and molecular structure of 5-bromo-pentacyclo[4.3.0.02,5.03,8.04,7]nonane-4-carboxylic acid,C10H9BrO2

The structure of the title compound, C₁₀H₉BrO₂, was determined by X-rays.M _r =241.08, triclinic, space groupP¯1,a=5.800(1),b=6.441(1),c=12.030(1) Å,=92.90(1)°,=95.65(2)°, =95.69(2)°,V _c =444.2 ų,Z=2,D _x =1.80 Mg m^–3, MoK radiation (graphite crystal monochromator, =0.71069 Å),(MoK)=48.58 cm^–1,T=290 K. Final conventionalR-factor=0.037,R _w =0.044 for 1863 observed reflections and 145 variables. The structure was solved usingMultan andDirdif. The results show that the 5-bromo substituent has a marked effect on the geometry of the homocubane skeleton. Its presence prevents a complete release of geometrical strain and induces a shortening of the bond distances to the apex carbon atom.     

Crystal and molecular structure of (exo)-2-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, monoclinic, space groupP2₁/c,a=13.7850(8),b=8.8951(7),c=15.1603(11) Å, =111.410(6)°,V _c =1730.7 ų,Z=4,D _x =1.322 Mgm^–3. Cu K radiation (graphite crystal monochromator, =1.54178 Å),(Cu K)=7.69 cm^–1. Final conventionalR-factor=0.057,R _w =0.076 for 2160 observed reflections and 271 variables. The structure was solved usingMultan.     

Crystal and molecular structure of nitrito-bis(1,3-propanediamine) nickel(II) tetraphenylborate

The title compound is orthorhombic,M _r =590.2,P2₁2₁2₁ (No. 19),a=9.865(2),b=9.924(2),c=31.202(7) Å,V=3055(2) ų,Z=4,D _x =1.283 g cm^–3, (MoK );F(000)=1256; (MoK )=6.76 cm^–1, finalR=0.052 for 1441 reflections I2.5(I). The nitrite group is chelated via the two oxygen atoms; the two six-membered rings resulting from the coordination of the 1,3-propanediamine ligands to the nickel(II) atom are in the chair conformation. The Ni-N and Ni-O distances average 2.07(1) and 2.14(2) Å respectively. The two Ni-O distances are nearly equivalent.     

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.     

Crystal structures of [(η5-C5H4COOH)W(CO)3R] (R=Me,I)

The crystal structures of [(₅-C₅H₄COOH)W(CO)₃R] (R=Me, I) have been determined. They crystallize in two different monoclinic space groups. R=Me isP2₁/c,a=10.4833(6),b=8.0144(7),c=13.0731(6) , =93.147(4)°, andD(calc)=2.374 g-cm^–3 forZ=4. R=I isP2₁/n,a=7.814(2),b=13.075(4),c=11.097(4) , =91.75(2)°, andD(calc)=2.953 g-cm^–3 forZ=4. Both possess a four-legged piano stool geometry. The methyl ligand in the R=Me complex is disordered between two positions insyn oranti relative to the substituted carbon of the cyclopentadienyl ligand. The iodo ligand in the R=I complex is, however, exclusively insyn-position.     

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.