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.     

Structures of 1,2,3,4-tetrahydro-6H-pyrimido[2,1-b]-quinazolin-6-one and its hydrochloride

C₁₁H₁₁N₃O, m.p. 243°C, P2/n,Z=4,a=5.843(2),b=14.241(3),c=11.102(1) Å, =93.30(2)°,R=0.046; C₁₁H₁₁N₃O·HCl·H₂O, Pca2₁,Z=8,a=18.640(2),b=8.894(2),c=14.404(2)Å,R=0.062. The molecules of the free base are in 1H-tautomeric form. N(1)-H...N(11) hydrogen bonds join molecules of the free base into dimers, which enable tautomeric rearrangement (not observed in this study) also in the solid state without any changes in molecular packing. The quinazoline system deviates slightly from planarity and benzene electrons are partially localized at C(7)–C(8) and C(9)–C(10) bonds as seen from their lengths of about 1.375 Å, while other bonds in the benzene ring are at least 0.02 Å longer.     

Crystal and molecular structure of diazoxide,an antihypertensive agent

Diazoxide, C₈H₇ClN₂O₂S, is monoclinic:P2₁/c,a = 7.209(8),b = 6.610(8),c = 19.263(11) Å, = 91.01(6) °,Z = 4. The structure was solved by Patterson and Fourier methods and refined to anR of 4.2% by the use of 1174 independent observed reflections which were collected on a computer-controlled, four-circle Philips diffractometer (MoK radiation). The molecular structure shows that the 4H form of 1,2,4-benzothiadiazine-7-chloro-3-methyl-1,1-dioxide is the predominant tautomer. The benzothiadiazine ring is roughly planar with the sulfonyl group perpendicular to the ring. The bond lengths and angles are in good agreement with the average values observed in related structures. There is substantial evidence for double-bond character in the two N(2)–C(3) and C(3)–(4) bonds and for delocalization of electrons. Short N(4)O(2) and N(2)Cl intermolecular distances (2.92 and 3.19 Å, respectively), with appropriate geometries, indicate the presence of hydrogen bonds.     

Crystal structures of 3-(4-pyridinyl)-5,6,7,8-tetrahydro-1,2,4-triazolo[4,3-a]pyrimidine and its 6-hydroxy derivative

(1): C₁₀H₁₁N₅,M _r=201.23, from water, P ,a=6.913(1),b=8.198(2),c=9.212(2) Å, =72.36(2), =109.03(2) and =88.13(1)^o,D _x=1.436 g/cm³,Z=2. FinalR=0.043 for 1477 observed reflections. (2): C₁₀H₁₁N₅O,M _r=217.23, from methanol/water solution. P2₁/c,a=9.291(2),b=11.263(3),c=10.454(3) Å, and =114.05(1)^o,D _x=1.444, g/cm³,Z=4. FinalR 0.056 for 1587 observed reflections. The data were collected on a diffractometer at room temperature. Structures were solved by direct methods and refined by anisotropic full-matrix least-squares method. In the solid state both molecules have the same conformation and are packed in similar manner. The planarity of the condensed triazole ring and its electrons conjugation with a lone pair at N8 impose C6 sofa conformation of the saturated diazine rings. Hydroxy group in2 is in an energetically unfavorable axial position. Both in1 and2, N8–H ... N34 hydrogen bonds join molecules into infinite chains, and O6–H ... N1 hydrogen bonds in2 span the chains into two-dimensional net. The molecules in hydrogen bonded chains and sheets have the same chirality.     

Investigation of 2-(3,4-dimethoxyphenyl)-5,6-dimethoxy-1H-indene by X-ray crystallography and NMR spectroscopy

2-(3,4-Dimethoxyphenyl)-5,6-dimethoxy-1H-indene (obtained by acid treatment of 1,2-bis(3,4-dimethoxyphenyl)-1,3-propanediol) crystallizes in space groupP2₁/c witha=6.836(6),b=28.631(9),c=16.344(6) Å, =95.73(5)°, andZ=8. There are two molecules in the asymmetric unit; the conformations of these molecules exhibit minor differences. In the crystals the double bond in the five-membered ring of the compound is disordered over two positions. The nature of the bonds in the five-membered ring could be ensured by¹H-NMR and¹³C-NMR spectral examinations.     

Crystal structure of (diphenyl)(morpholino)phosphiniminocyclotrithiazene

The title compound (C₆H₅)₂(OC₄H₈N)P=N–S₃N₃ crystallizes in the space group with unit cell parametersa=9.3900(2),b=9.4747(1),c=11.3850(3) Å, =95.73(4), =96.85(6), =104.26(2)^o, and Z=2. The tricoordinated sulfur of the cyclotrithiazene ring deviates from the mean plane of other skeletal atoms by 0.683(4) Å. The angle at this atom is the smallest in the ring and is enclosed by the longest S–N bonds observed in the ring.     

Structure of a rearrangement product: 1-methyl-3-(5-amino-1-benzylimidazol-4-yl)-1,2,4-triazole,C13H14N6

The title compound was prepared during the course of an attempt to synthesize 8-amino-3-benzyl-6-methylimidazo[4,5-e][1,2,4]triazepine. The crystals are monoclinic, space groupP2₁/c,a=6.2375(5),b=9.1070(8),c=22.182(2) Å,=91.797(7)°,Z=4. The structure was solved by direct methods and refined by least squares toR=0.063 on all 2142 measured reflections. The imidazol-4-yl-triazole system is planar, conjugated, and aromatic. One hydrogen atom of the exocyclic amino group is involved in a bifurcated hydrogen bond, of which one branch is an intramolecular attraction to a triazole ring nitrogen atom, while the other branch is intermolecular. The crystal is held together by two N-HN hydrogen bonds between molecules related by translation along thea axis and by- stacking interactions of the imidazol-4-yl-triazole ring systems and the phenyl rings across centers of inversion.Visiting scientist, The Institute for Cancer Research.     

Structure of 4-amino-3-butyl-1,2,4-triazole-5-thione: Relation to derivatives with H, Me, Et, and Pr in the 3-position

The compound 4-amino-3-butyl-1,2,4-triazole-5-thione [crystal data: C₆H₁₂N₄S, triclinic, P , Z = 2, a = 7.546(2), b = 11.217(3), c = 5.681(1) ?, α = 103.12(2), β = 91.33(2), γ = 72.41(2)°, V = 445.9(2) ?³] contains an essentially planar triazole ring with the butyl group rotated out of the plane by approximately 104°. The molecules form hydrogen-bonded dimers through intermolecular N–HS interactions involving the thione sulfur atom and the protonated nitrogen atom on the ring. These units are then linked into columns through N–HN hydrogen bonds between the amine group and the unsubstituted ring N atom of adjacent molecules. The structural features of this compound are compared with those of the corresponding triazoles with H, methyl, ethyl and propyl groups on the 3-carbon.     

Crystal structure of 5-benzoylamino-5-isopropyl-4-oxo-1,3-dioxane

C₁₄H₁₇NO₄ crystallizes in the monoclinic space groupP2₁/n (Z=4) witha=10.208(2),b=10.888(2),c=11.909(2) Å, and=90.89(2)°. The structure was solved by direct methods and refined by full-matrix LSQ to anR factor of 0.036. The 4-oxo-1,3-dioxane ring is in a slightly distorted O(1)-sofa conformation flattened at the C(4) end with the 5-isopropyl substituent in a pseudoaxial position and planar lactone group. The molecules form dimers by means of intermolecular N-HO(4) hydrogen bonds of 3.091(2) Å. The¹H NMR spectrum of the title compound shows unusual features.     

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 and conformation of the monohydrate of N-t-boctyrosyl-proline (Boc-Tyr-Pro·H2O)

The structure and conformation of the monohydrate of N-t-boc-tyrosyl-proline (Boc-Tyr-Pro·H₂O) (C₁₉H₂₆O₆N₂·H₂O) has been investigated with X-ray crystallographic and spectroscopic methods. Boc-Tyr-Pro crystallized in an extendedtrans conformation in the space group P2₁2₁2₁ with cell dimensionsa=8.566(1),b=9.996(1),c=24.734(1). The conformation of Boc-Tyr-Pro reflex -helix type prolines. Three intermolecular hydrogen bonds are observed. Crystal water is involved in two hydrogen bonds (to the hydroxyl group of the C-terminal of the proline residue; to the carbonyl group of the t-Boc functionality) while the hydroxyl group of the tyrosyl residue (to the carbonyl group of the amide bond) is involved in one hydrogen bond. The puckering mode of the pyrrolidine ring of the proline residue is similar to what has been previously observed for other proline-containing peptides.Cis-trans isomerism is observed in the NMR spectra of Boc-Tyr-Pro with a predominance for the extended side chain for the tyrosyl residue.     

Molecular structure of isopropyl 1-phenyl-4-phenylhydrazono-5-oxo-3-pyrazolecarboxylate

The new azopyrazolone dye has been synthesized and its crystal structure has been investigated. Crystals of C₁₉H₁₈N₄O₃ are triclinic: ,a=7.484(1),b=10.646 (1),c=11.897(1) Å, =82.28(1), =72.86(1), =86.83(1)°,Z=2. The structure has been solved by direct methods and refined by full-matrix least-squares techniques toR=0.050 for 2622 unique reflections. The tautomeric form of the molecules has been determined as a hydrazo form. Delocalization of the C5=O3 and C4=N3 -electrons and delocalization of the lone-pair electrons of N1, N3, and N4 atoms has been observed. The intramolecular N–H...O hydrogen bond forms the six-membered ring C₂N₂H...O condensed with the pyrazolone ring. The molecules are connected by intramolecular C–H...O hydrogen bonds.     

Molecular assembly in an inclusion crystal of tris(2-benzimidazylmethyl)amine with 4-nitrobenzoic acid

A 1:2 inclusion compound of tris(2-benzimidazylmethyl)amine with 4-nitrobenzoic acid [(C₂₄H₂₁N₇) · (C₇H₅NO₂)₂] has been prepared and the molecular assembly in solid state has been determined by X-ray crystal structural analysis. The crystal structure (C 2/c, a = 25.488(5), b = 13.304(3), c = 21.479(4) Å, = 93.35 (3)°, Z = 8, R = 0.065) consists of discrete dimeric inclusion compounds joined together by N(5)...N(6) intermolecular hydrogen bonds between pairs of centrosymmetrically related benzimidazole rings of the hosts. There are two types of guest molecules in the crystal, one is incorporated within the cavity of the host via three intramolecular N—H···O hydrogen bonds while the other is situated outside the cavity and connected with the host through one O—H···N hydrogen bond. The – stacking interactions between guests and benzimidazole rings result in one-dimensional columns. The aromatic face–face interactions between neighbouring columns facilitate the assembly of those columns into two-dimensional layers.     

Crystal and molecular structure of (2-amino-4-methyl-1-pyridinio) cyanoborane

The crystal structure of the title compound, C₇H₁₀N₃B, has been determined by X-ray diffraction using CuK radiation. The crystals are monoclinic,P2₁/c witha=6.941(2),b=15.961(3),c=7.739(2) Å,=90.5(2)° andZ=4. The structure was solved by direct methods, and refined by full matrix least squares to a finalR-value of 056 with 833 observed reflections. The molecule is in the elongated form, but is not planar; the torsion angle C(2)-N(1)-B-C(8) is 82.9(4)°. The bond distances N(1)-B=1.587(5) Å; B-C(8)=1.586(6) Å; C(8)N(3)=1.134(5) Å. The B-C-N moiety is slightly [176.9(4)°] nonlinear. The molecules are linked by weak hydrogen bonds N(2)-H(1N)N(3), N(2)-N(3)=3.055(5) Å and N(2)-H(2N)N(3), N(2)-N(3)=3.165 Å.     

Annulated bicyclo[2.2.2]octenones: 9-hydroxy-9-chloromethyl-endo-tricyclo[5.2.2.02,6]undeca-4,10-diene-3-spiro(1′-cyclopropane)-8-one and 12-hydroxy-12-chloromethyl-endo-tricyclo [8.2.2.02,9]tetradeca-13-en-11-one

A single crystal X-ray diffraction study of two annulated bicyclo[2.2.2]octenones has been carried out to establish their precise stereostructures. The compounds, with their crystal data, are:1, 9-hydroxy-9-chloromethyl-endo-tricyclo[5.2.2.0^2,6]undeca-4,10-diene-3-spiro(1-cyclopropane)-8-one, C₁₄H₁₅O₂Cl, space group P2₁/c,a=10.540(2),b=9.668(1),c=11.841(4)Å, =95.67(2)°,Z=4, and2, 12-hydroxy-12-chloromethyl-endo-tricyclo[8.2.2.0^2,9]tetradeca-13-en-11-one, C₁₅H₂₁O₂Cl, space group C2/c,a=20.747(8),b=6.498(1),c=20.525(3)Å, =93.04(3)°,Z=8. The molecule of1 has endo stereochemistry at the ring junction and the spirocyclopropane ring is proximal to the hydroxyl group. In2, the eight membered ring deviates from a chair conformation and one ring atom is disordered. Crystals of1 and2 contain centrosymmetric dimers formed by C=O...O–H hydrogen bonds.     

Stereochemistry and hydrogen bonding of cytokinins: Crystal and molecular structure of 6-(4-hydroxy-3-methyl-cis-2-butenyl) aminopurine (cis-zeatin)

The title compound is C₁₀H₁₃N₅O, monoclinic,P2₁/a,a=13.829 (7),b=7.834 (7),c=20.138 (9) Å, and =100.75 (6)°. The structure was solved by direct methods and refined by least-squares techniques to anR factor of 0.079 for 1581 observed reflections. There are two crystallographically independent molecules (I andI). The N⁶-substituent is distal to the imidazole ring of the adenine moiety. It is interesting to note that the conformation of the N⁶-substituent relative to the adenine ring base in these two crystallographically independent molecules shows considerable resemblance with the preferred one usually adopted in other cytokinins. The angles between the mean planes of the adenine base and the N⁶-substituent are 65.6 and 63.3° for theI andI molecules, respectively. The molecules are linked by pairs of N(9)-H·N(3) hydrogen bonds. The dimer-like structures are stabilized by a three-dimensional network of O-H·O, O-H·N, N-H·O, and C-H·N hydrogen bonds.     

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.     

Structural studies on molecular complexes,I: Crystal and molecular structure of 9-aminoacridine-sulfamethoxypyridazine (1∶1), C13H10N2·C11H12N4O3S

The crystal structure of the molecular complex of the antiseptic 9-aminoacridme and the sulfa drug sulfamethoxypyridazine (11), C₁₃H₁₀N₂·C₁₁H₁₂N₄O₃S, has been determined by X-ray diffraction methods. The crystals are orthorhombic: Pbca (No. 61),a=16.321(1),b=16.951(1),c=16.331(1) Å,Z=8,F(000)=1984, andV _c =4518.1(5) ų. The structural parameters have been refined to a finalR value of 0.046 for 3134 observed reflections. The results of X-ray analysis show that the structure contains an acridinium-sulfanilamidate ion pair. A hydrogen atom is transferred from the sulfonamide nitrogen atom to the nitrogen atom of the acridine ring, and an N(acridinium)-HN(sulfonamide) hydrogen bond is formed. A slight folding of the acridine moiety is observed.     

Crystal and molecular structure of glycinium diphenylphosphate

The crystal and molecular structure of glycinium diphenylphosphate, C₁₄H₁₆NO₆P, has been determined by X-ray methods. The crystals are orthorhombic:Pbca (No. 61),a=11.412(3),b=24.624(7),c=10.775(3) Å,Z=8. The structure was solved by direct methods and refined to anR value of 0.043 for 1289 nonzero independent amplitudes. The molecule exists in the structure as⁺NH₃CH₂CO₂H,(C₆H₅O)₂PO ₂ ^– and is planar except for the N atom, which deviates by 0.49 Å from the plane defined by C(1), C(2), O(5), and O(6) atoms, respectively. The conformation of the diphenylphosphate anion isgauche with respect to both P-O ester bonds. There are four crystallographically independent hydrogen bonds, three of the N-HO type and one of the O-HO type.     

Crystal and molecular structure of pentachloromonoisopropylaminocyclotriphosphazatriene

Crystals of N₃P₃C1₅ (NHC₃H₇) are monoclinic:a=15.059(7),b=14.815(5),c=6.501(6) Å, =95.03(6)°, space groupP2₁/n, and Z=4. The atomic positions were determined by direct methods and refined by least-squares refinement from diffractometer X-ray intensity data toR=0.063 for 1530 reflections. In the structure, pairs of molecules mutually related by a center of symmetry are linked by N-H N hydrogen bonds. The endocyclic P-N bonds range in length from 1.556 to 1.603 Å depending on the location of the bond relative to the isopropylamino group, and the exocyclic P-N bond is only a little longer (1.617 Å). The nongeminal P-Cl bond is significantly longer (2.036 Å) than the remaining P-Cl bonds (1.988–2.013 Å). The phosphazene ring shows only a very small departure from planarity. The isopropylamino group has a symmetrical conformation, with a Cl-P-N-C torsion angle of 90.5°.