Crystal and molecular structure of 2-bromo-5,6-dihydro-6-methyl-4H,8H-pyrido [3,2,1-de]phenanthridin-8-one

Crystals of the title compound, C₁₇H₁₄BrNO, are monoclinic, with space groupP2₁/a,a = 14.314(5),b = 15.009(11),c = 6.596(3) Å, and = 102.39(3) °. Diffraction data were collected with CuK radiation to a Bragg angle of 77 °. The structure was solved by the heavy-atom method and refined to anR index of 0.059 for 2129 reflections. In agreement with NMR results, the C=O group is orientedanti to the benzene ring, and the methyl group at C(6) is axial. Unlike 1-(p-bromobenzoyl)-2-methyl-1,2,3,4-tetrahydroquinoline, the heterocyclic ring assumes a well defined half-chair conformation. Except for C(5) and the methyl group at C(6), the whole molecule is very nearly planar.     

The pseudoguaianolide isoconfertiflorin

The sesquiterpene lactone isoconfertiflorin, C₁₇H₂₂O₅, 1, crystallizes in trigonal space group P3₁ with a = 10.4498(5), c = 12.7516(8) Å, V = 1205.9(2) ų, and Z = 3. It differs from confertiflorin in having an endocyclic C=C bond in the lactone ring, which carries an exocyclic methyl group. The seven-membered ring adopts an approximate twist-chair conformation with C10 lying in the local two-fold axis, and asymmetry parameter C₂ = 5.8°. The cyclopentanone ring has the half-chair conformation with C4 on the local two-fold axis, and C₂ = 0.9°. The lactone ring is almost planar with maximum deviation 0.014(2) Å. Both methyl groups on the 7-membered ring are –oriented. The acetyl group at C8 has an orientation.     

Crystal and molecular structure of 2,5-dimethyl-3,4-diacetylfuran

The crystal and molecular structure of 2,5-dimethyl-3,4-diacetylfuran has been determined by direct methods using CuK. photographic data. Refinement by full-matrix least-squares methods gave a finalR factor of 0·097. The crystals are monoclinic: space groupP2₁/c,a =14·92(2),b = 4·09(1),c =16·68(3) Å and = 109·7(5) °;Z = 4. The furan ring of the molecule is planar, and the exocyclic atoms bound to the atoms of the ring lie close to the ring plane. The planes of the acetyl groups are tilted by 16 ° and 47 ° with respect to the ring plane. The exocyclic bond angles of this compound are significantly different from the equivalent angles in furan.     

Structure of 1,2,3,4,9,9-hexachloro-6,7-tetrahydro-l,4-methano-naphthalene: a facially differentiated, annulated 1,3-cyclohexadiene

The X-ray crystal structure of the title compound is reported. Crystal data: T = 100 K, monoclinic, P2₁/n, a = 8.2990(17), b = 13.2300(26), c = 12.0350(24) Å, = 93.676(30)°, V = 1318.7 (5) ų, and R = 0.0368. The methylene carbon atoms in the cyclohexadiene ring are disordered over two positions above and below the ring plane. The chlorine substituted endocyclic double bond deviates from planarity with an angle of 8.10(13)° toward the endo-face. The facially differentiated 1,3-cyclohexadiene moiety is only slightly pyramidalized, deviating 1.75(20)° also toward the endo-face of the tricyclic system.     

Guayulin B

The sesquiterpene guayulin B, C₂₃H₃₀O₃, 1, crystallizes with two independent molecules in monoclinic space group P2₁ with a = 18.099 (1), b = 6.0649(6), c = 19.126(1) Å, = 100.82(1)°, V = 2062.1(5) ų, and Z = 4. The double bonds of the cyclodecadiene ring are E, both methyl groups on the 10-membered ring are -oriented. The cyclopropane ring at C6 and C7 also has the orientation, while the anisoyloxy group is oriented . The 10-membered rings of the two independent molecules have the same conformation as that of guayulin A.     

Studies on the conformation of α-arylcinnamic acids and their esters: Crystal structures of methyl (E)-2,3-bis(3,4-dimethoxyphenyl)propenoate and methyl (Z)-2,3-bis(3,4-dimethoxyphenyl)propenoate

The conformations of stereoisomers of -arylcinnamic acids and their esters are discussed based on crystal structures of the E and Z forms of 2,3-bis(3,4-dimethoxyphenyl)propenoic acid and its methyl ester. In the E forms of the cinnamic acid and the cinnamic acid ester, the plane of the -aryl substituent is approximately perpendicular to that of the rest of the molecule. In the Z forms the plane of the carboxyl or methoxycarbonyl group is approximately perpendicular to that of the ethylenic group, and both the aromatic group planes are significantly twisted out of the ethylenic group plane. Crystal structures of methyl (E)-2,3-bis(3,4-dimethoxyphenyl)propenoate (space group P2₁/n with a = 8.1697(5), b = 11.3882(9), c = 19.7766(9) Å, = 90.058(4)°, V = 1840.0(2) ų, and Z = 4), monoclinic methyl (Z)-2,3-bis(3,4-dimethoxyphenyl)propenoate (space group P2₁/n with a = 11.183(2), b = 5.640(2), c = 29.737(7) Å, = 99.19(2)°, V = 1851.4(9) ų, and Z = 4), and orthorhombic methyl (Z)-2,3-bis(3,4-dimethoxyphenyl)propenoate (space group P2₁2₁2₁ with a = 8.849(4), b = 24.288(9), c = 8.734(3) Å, V = 1877(1) ų, and Z = 4) are reported.     

Crystal and molecular structure of 2,5-dimethyl-3,4-diacetylpyrrole

An X-ray crystallographic study of 2,5-dimethyl-3,4-diacetylpyrrole showed that the crystals are monoclinic, space groupP2₁/n,a = 10·01(3),b = 12·93(3),c = 7·41(2) Å and = 91·5(5) °. The crystal structure was solved by direct methods and refined by least squares to a finalR factor of 0·13. The values determined for the bond distances and angles of the pyrrole ring are in good agreement with the values reported in the literature. However, there are significant changes in the exocyclic bond angles of the atoms of the ring. The planes of the acetyl groups are tilted with respect to the ring plane, forming dihedral angles of 22 ° and 40 °.     

Crystal structure and conformation of the antimalarial drug 5,7-methoxy-8-(3-methyl-1-buten-3-ol)-coumarin

The crystal and molecular structure of the antimalarial compound 5,7-methoxy-8-(3-methyl-1-buten-3-ol)-coumarin, C₁₆H₁₈O₅, M _r = 290.3 Da, has been determined from X-ray diffraction data. The material crystallizes in the monoclinic space group P2₁/c with 4 molecules per unit cell of dimensions a = 8.9044(9), b = 17.623(1), c = 10.175(1) Å, = 113.97(1)°, crystal density D _c = 1.322 g/cm³. The structure was determined using direct methods and refined by full-matrix least squares to a conventional R index of 0.066 for 2416 measured reflections and 206 parameters.The coumarin ring system is almost planar with the methoxy C atoms rotated slightly out of the coumarin mean plane. Apart from the terminal CH₃ groups C(12) and C(13), which are 1.184(3) Å above and –1.315(3) Å below the plane, the 3-methyl-1-buten-3-ol substituent is planar (rms deviation 0.009 Å) making an angle of 6.31(7)° with the phenyl ring. One intermolecular hydrogen bond is present in the crystal structure between O(5)–HO(5) and the symmetry related O(2) oxygen, generated by the symmetry operation (x, 1/2 – y, –1/2 + z).     

Crystal and molecular structure of 1-(p-bromobenzoyl)-2-methyl-1,2,3,4-tetrahydroquinoline

Crystals of the title compound, C₁₇H₁₆BrNO, are monoclinic, space groupP2₁/n, unit-cell parametersa = 14.48,b = 6.20,c = 16.72 Å, and = 97.35 °. Three-dimensional data were collected with CuK radiation using an automatic diffractometer. The structure was solved by the heavy-atom method and refined by block diagonal least squares to anR index of 0.088 for 2210 reflections. The main features obtained from our studies are (i) the C=O group is orientedanti to the benzene ring, in agreement with the nmr studies; (ii) the C(2) proton is equatorial while the methyl group at C(2) is in an axial position, also in agreement with nmr data. The bromobenzoyl ring and the benzene ring are at 64 ° to each other, while the carbonyl >C=O and the bromobenzoyl groupsBr are at 42 ° to each other.     

Synthesis and X-ray structure of 5′-methoxy-2,4,6-trimethyl-2′-nitrosobiphenyl

The synthesis and X-ray crystal structure of 5-methoxy-2,4,6-trimethyl-2-nitrosobiphenyl is reported. The compound (C₁₆H₁₇NO₂) is monoclinic, with a = 11.080(4), b = 16.899(6), c = 15.410(5) Å, = 108.329(5)°, and space group P2₁/n. There are two independent molecules within the crystal. In each of these molecules the two phenyl rings are mutually orthogonal, with interplanar dihedral angles of 85.09 and 89.43° respectively. The nitroso substituents are essentially coplanar with the phenyl ring, with torsional angles of only 3.5 and 2.2°, respectively, while the methoxy groups make angles of 5.2 and 10.0°, respectively, with the phenyl ring.     

Synthesis and crystal structures of two potential gem-di(pyrazolyl)cycloalkane ligands, 1,1-di(pyrazol-1-yl)cyclohexane [C6H10(C3N2H3)2] and 1,1-di(pyrazol-1-yl)cyclopentane [C5H8(C3N2H3)2]

The species 1,1-di(pyrazol-1-yl)cyclohexane, C₁₂H₁₆N₄, crystallizes in the monoclinic space group P2₁/c with a = 8.340(2), b = 14.281(5), c = 10.153(3) Å, = 106.86(2)°, and Z = 4. The cyclohexane moiety has the chair conformation. The congener, 1,1-di(pyrazol-1-yl)cyclopentane, C₁₁H₁₄N₄, while not isomorphous, also crystallizes in space group P2₁/c with a = 14.350(2), b = 6.776(1), c = 11.043(2) Å, = 100.68(1)°, and Z = 4. The cyclopentane ring has a conformation in which four carbon atoms are essentially coplanar, while the fifth (that with the two pyrazolyl substituents) lies 0.63 Å from this plane, resulting in a bend of 41.3° across the C(2)···C(5) vector. The hydrogen atoms in each structure were located directly and their coordinates refined.     

Studies of systemic acylanilide fungicides. Part II. Crystal structure and molecular conformation ofdl-methylN-(2,6-dimethylphenyl)-N-(2-furoyl)alaninate

A crystalline modification of the title compound (C₁₇H₁₉NO₄) was determined by three-dimensional X-ray analysis from diffractometer data. Crystal data: monoclinic,Cc,a=15.997(12) Å,b=7.929(7) Å,c=14.664(11) Å,=118.70(5)°,Z=4;D_x=1.227 Mg m^–3,(MoK)=0.094 mm^–1. FinalR=0.068 for 852 observed reflections. The dimethylphenyl ring is strongly twisted (94.9°) with respect to the amidic plane of the molecule, which almost coincides with the furan ring (6.9°).     

Crystal structure of trismorpholino phosphiniminocyclotrithiazene

The title compound (OC₄H₈N)₃P=N–S₃N₃ crystallizes in a monoclinic crystal system with unit cell parameters a = 8.9996(3), b = 17.2895(7), and c = 12.3648(9) Å, = 90.63(5)°, Z = 4, and space group P2₁/n. Strikingly the exocylic S1–N4 bond length is 1.545(3) ÅR and is accompanied by the largest angle at P–N4–S1 as 131.2(2)°. The tricoordinated sulfur atom of the cyclotrithiazene ring deviates from the mean plane of other five atoms by 0.654(1) Å.     

Crystal structure and conformation of frentizole, [1-(6-methoxy-2-benzothiazolyl)-3-phenylurea, an antiviral agent and an immunosuppressive drug

Crystals of Frentizole (from ethanol/water) are monoclinic, space group P2₁/c, with a = 11.187(4), b = 7.392(2), c = 32.727(6) Å, = 92.77(2)°, Z = 8, D _o = 1.47 g/cm³, and D _c = 1.472 g/cm³. There are two independent molecules in the crystallographic asymmetric unit with very different conformations. In molecule A the urea group is in the plane of the benzothiazole ring (0.9°) whereas in molecule B the dihedral angle between them is 4.4°. The dihedral angle between the planes of the phenyl group and the benzothiazole ring are ±157° and ±12°, respectively, in the two molecules. The molecules are linked by a pair of N–H···N hydrogen bonds involving the urea nitrogen and two other N–H···N bonds involving the urea nitrogen and the nitrogen of the benzothiazole group.     

Crystal structure of 1,4-dihydro-1-methyl-3′-methylsulfinyl-4-oxo-6-nitro-3,4′-diquinolinyl sulfide complex with DMF

The title compound crystallized as a complex with N,N-dimethylformamide (DMF) in a monoclinic space group P2 ₁ /c with a = 9.469(2), b = 25.168(5), c = 9.860(3) Å, and = 97.48(3)°. The two quinoline moieties are nearly perpendicular. The sulfoxide oxygen is pointed toward the H-2 proton. The S-methyl group is perpendicular to the parent pyridine ring plane.     

Crystal and molecular structure of bis(quinoxaline)-2,2′,3,3′-disulfide,C16H8N4S2

The crystal and molecular structure of bis(quinoxaline)-2,23,3-disulfide, C₁₆H₈N₄S₂, was determined by direct methods and refined by least-squares methods, using 823 reflections collected with a two-circle Weissenberg diffractometer, including anisotropic temperature factors for nonhydrogen atoms to a finalR of 0.104. The crystals are monoclinic prismatic: space groupP2₁/a,a = 18.98(2),b = 9.27(2),c = 3.89(1) Å, = 100.3 °(1),Z = 2. The structure consists of layers of molecules staggered along thec axis. The molecule is centrosymmetric, and makes an acute angle of 36.9 ° with theab plane; it is planar within an rms atom deviation of 0.02 Å. The S-C (1.752–1.760 Å) distances are normal for a S-C (sp²) bond. The N-C bonds (1.372–1.381 Å) adjacent to the benzene ring are longer than the N-C bonds (1.318–1.322 Å) adjacent to the central C₄S₂ ring.     

X-ray crystal structure of the 1:1 dimethylpicric acid–acenaphthene complex

The dimethylpicric acid–acenaphthene complex is orthorhombic, space group P2₁2₁2₁; at 24° a = 7.3685(1), b = 15.4159(1), c = 16.1296(3) Å, D _x = 1.491(2) g cm^–3, V = 1832.19(4) ų, Z = 4. The phenolic OH group in the dimethylpicric acid is intramolecularly hydrogen bonded to one of the ortho nitro groups with an OO distance of 2.500(2) Å. This nitro group is twisted out of the plane of the benzene ring by 8.2°; the twist angles of the other nitro groups are 52.6 and 83.5°. The acenaphthene molecule deviates slightly from planarity as a consequence of the torsion angle at CH ₂-CH ₂ being 1.8 rather then 0°. The molecules pack in stacks of alternating picric acid and acenaphthene molecules. Each stack is surrounded by a close-packed arrangement of six other stacks. The acenaphthene molecules are 2.7° away from being parallel to the benzene ring in the picric acid. The distances from the benzene ring to the acenaphthene carbon atoms range from 3.26 to 3.49 Å on one side of the ring and from 3.30 to 3.54 Å on the other.     

Crystal and molecular structure of 2,2-diphenyl-5-dichloromethylene-3-oxazoline-4-ethylcarboxylate

The structure of an oxazoline compound: 2,2-diphenyl-5-dichloromethylene-3-oxazoline-4-ethylcarboxylate has been established uniquely by X-ray crystallography. C₁₉H₁₅Cl₂NO₃ is monoclinic, space groupP2₁/n, with the cell dimensionsa=8.170(1),b=23.559(2),c=9.962(1) Å,=105.53(1)°,V=1847.5(3) ų,Z=4,M _r=376.2,D _x=1.35,D _o=1.36 g cm^–3,F(000)=776,T=293 K,=33.2 cm^–1, finalR=0.062 for 2321 observed reflections. Two phenyl rings make a dihedral angle of 83.3(4)° and are equally inclined to oxazoline ring plane. The ethylcarboxylate group is planar and is at an angle of 76.1(4)° with respect to oxazoline ring plane.N.C.L. Communication No. 5360.     

Crystal structure of 3-phenyl-7-bromoisoxazolo[4,5-d]pyridazin-4(5H)-one

The crystal and molecular structure of 3-phenyl-7-bromoisoxazolo[4,5-d]-pyridazin-4(5H-one, C₁₁H₆BrN₃O₂, has been determined from two- and three-dimensional X-ray data and refined by Fourier and least-squares methods toR = 0·101 for 1187 observed reflexions. Crystals of 3-phenyl-7-bromoisoxazolo-[4, 5-d]pyridazin-4(5H)-one are monoclinic:a = 7·67,b = 6·84,c = 20·52 Å, = 91·5 °,Z = 4, space groupP2₁/c. The benzene ring makes an angle of 4·5 ° with the plane of the isoxazole ring, and the other part of the molecule is slightly non-planar. The bond distances and angles compare well with those of other similar molecules. Two N-H...O hydrogen bonds join the two molecules related by a centre of symmetry. Close molecular packing is found in layers parallel to (100).     

Crystal structure of the charge transfer complex 9-cyclohexyladenine-iodine

The crystal structure of the charge-transfer complex of iodine with 9-cyclohexyladenine, C₁₁H₁₅I₂N₅, has been determined, and refined by three-dimensional least-squares techniques. The crystals are monoclinic:P2₁/c,Z = 4,a = 9·1728(7),b = 12·289(1),c = 13·596(1) Å, = 99·564 °(6). The finalR value for 3629 reflexions is 0·039. The iodine forms a charge-transfer bond with N(1) of the adeninering, with an N—I bond length of 2·520(3) Å. The I—I—N(1) arrangement is approximately linear (bond angle, 177·1 °). The I—I molecule makes an angle of 21·5 ° with the plane of the adenine ring.Supported by N. I. H. Development Award 5-K4-GM-42572.