A titanium–methyl group containing a covalent bridging hydrogen system: X-ray crystal structure of Ti(Me2PCH2CH2PMe2)MeCl3

1982 ◽  
pp. 1410-1411 ◽  
Author(s):  
Zain Dawoodi ◽  
Malcolm L. H. Green ◽  
Victor S. B. Mtetwa ◽  
Keith Prout
Keyword(s):  
Crystal Structure ◽  
Methyl Group ◽  
X Ray ◽  
Hydrogen System ◽  
Covalent Bridging

The crystal structure of 5-O-Acetyl-1,2 : 3,4-di-O-isopropylidene-α-D-glucoseptanose, C14H22O7, by use of X-ray and neutrondiffraction data

1983 ◽  
Vol 36 (11) ◽  
pp. 2269 ◽  
Author(s):  
RA Wood ◽  
VJ James ◽  
AD Rae ◽  
JD Stevens ◽  
FH Moore
Keyword(s):  
Crystal Structure ◽  
Neutron Diffraction ◽  
Diffraction Analysis ◽  
Chair Conformation ◽  
Asymmetric Unit ◽  
Methyl Group ◽  
Neutron Diffraction Analysis ◽  
X Ray ◽  
Acetate Methyl ◽  
Independent Molecules

The crystal structure of 5-O-acetyl-1,2:3,4-di-O-isopropylidene-α-D-glucoseptanose [P212121, Z 8, a 14.329(5), b 22.075(5), c 10.012(5) �] has been determined by X-ray and neutron diffraction analyses. For the neutron diffraction analysis, the acetate group and the trans-O-isopropylidene group were deuterated. Constrained refinement was used in the neutron diffraction analysis to counter over parameterization in the block-diagonal least-squares refinement. Final unweighted R-values were 0.038 [X-ray for 3070 reflections with [Fo > 2.58σ (Fo)] and 0.061 [neutron for 1118 reflections with Fo > 4σ ([Fo)]The neutron refinement revealed a disordering of the acetate methyl group in each of the two independent molecules in the asymmetric unit. The septanose ring in each molecule adopted the same twist-chair conformation but the dioxolan rings assumed different twist and envelope conformations.

Structure Investigations of Agonists of the Natural Neurotransmitter Acetylcholine VI [1]. X-Ray Structure Analysis of Trimethyl[2-(propionyloxy)ethyl]- ammonium-iodide (O-Propionylcholine-iodide)

1986 ◽  
Vol 41 (5-6) ◽  
pp. 641-646 ◽  
Author(s):  
Alfred Gieren ◽  
Michail Kokkinidis
Keyword(s):  
Crystal Structure ◽  
Nitrogen Atom ◽  
Formula Unit ◽  
Ammonium Iodide ◽  
Asymmetric Unit ◽  
Torsion Angles ◽  
Methyl Group ◽  
X Ray ◽  
Acetylcholine Chloride ◽  
Structure Investigations

The title compound (1) crystallizes in the orthorhombic, noncentrosymmetric space group Pna21 with a = 10.241(11), b = 12.903(12), c = 9.312(9) Å and with one formula unit per asymmetric unit. The stereochemically comparable torsion angles of the cation of 1 and of acetylcholine chloride are analogous. In the crystal structure the trimethylammonio methyl group is surrounded by three anions in the first coordination sphere. The geometry of a triangle formed by one of these counterions which occupies a special face of the N+C4 tetrahedron of the (CH3)3N+-CH2-R moiety, the nitrogen atom of the ammonium group and the oxygen atom of the carbonyl group is typical for nicotinic agonists.

Synthesis and Structure of a New Class of Fused Heterocycle with 8,9-Dihydro-pyridazino[1,2,4]triazine Skeleton

2017 ◽  
Vol 68 (6) ◽  
pp. 1159-1162
Author(s):  
Ionel Humelnicu ◽  
Violeta Vasilache
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Spectral Analysis ◽  
Heterocyclic System ◽  
Intensity Data ◽  
Methyl Group ◽  
X Ray ◽  
New Class ◽  
Out Of Plane

The synthesis and X-ray crystal structure of a new class of fused heterocycle with 8,9-dihydro-pyridazino[1,2,4]triazine type 2 is reported. The synthesis is facile and efficient and, the structure of compounds was proven by elemental and spectral analysis, the X-ray spectra including (for 2b). The compound crystallizes in the space group P21/N (monoclinic) with a = 9.0077(2) �, b = 10.20019(18) �, c = 14.0099(3) �, a= 90�, b = 89.768(2)�, g= 90�, V= 1287.22(5) and Z = 4. Accurate molecular parameters for the heterocyclic system were obtained from intensity data collected at 200(14) K. The molecule 8,9-dihydro-pyridazino[1,2,4]triazine type 2 is a noncoplanar bicyclic fused system, with an envelope shape onto the triazine moiety, the C12 carbon being out of plane. The methyl group from the C12 carbon it is almost perpendicular on the triazine plane. We also notice a rather powerful hydrogen bond between hydrogen atom from N1 and the oxygen from the C11=O1 carbonyl group.

Novel synthesis and crystal structure of Rac-N,N-dimethyl-1-ferrocenylethylamine hydrochloride

2005 ◽  
Vol 2005 (10) ◽  
pp. 651-653
Author(s):  
Yu-Mei Zhang ◽  
Zhi-Ming Zhou ◽  
Cong-Xuan Yu
Keyword(s):  
Crystal Structure ◽  
Title Compound ◽  
Substrate Molecule ◽  
Synthesis And Crystal Structure ◽  
Methyl Group ◽  
X Ray ◽  
Novel Synthesis

The title compound N, N-dimethyl-1-ferrocenylethylaminehydrochloride [Fe(C5H5)(C5H4CHCH3N+H(CH3)2)Cl-] was synthesised by esterification of the corresponding alcohol, followed by substitution with HN(CH3)2 and by extracting HCl from CH2Cl2 probably associated with Fe in the substrate molecule. Its structure was first elucidated by X-ray analysis. By analysis of the crystal structure of, it is proposed that diastereoselective ortho-deprotonation directed by Ugi's amine may be ascribed to the different hindrance exerted by methyl group at chiral C.

Crystal structure and absolute configuration of (+)-scandine hydrobromide

1982 ◽  
Vol 35 (8) ◽  
pp. 1655 ◽  
Author(s):  
JR Cannon ◽  
KD Croft ◽  
Y Matsuki ◽  
VA Patrick ◽  
RF Toia ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Absolute Configuration ◽  
Steric Effect ◽  
X Ray Diffraction ◽  
Methyl Group ◽  
X Ray ◽  
Block Diagonal

The major alkaloid of a Fijian Melodinus sp. (family Apocynaceae) has been identified as (+)-scandine (1). The crystal structure and absolute configuration of the acetone solvate of (+)-scandine hydrobromide have been determined by X-ray diffraction; diffractometer data at 295 K were refined by block diagonal least squares to a residual of 0.037 (2657 'observed' reflections). Crystals of the hydrobromide are monoclinic, P21, a 9.496(3), b 14.561(5), c 9.339(3) �, β 115.39(2)�, Z 2. Although the cations of (+)-scandine hydrobromide and (+)-N-methylmeloscine bromide have the same skeleton and the same absolute configuration, they have different conformations; this appears to be due to the steric effect of the N-methyl group in the latter cation.

Crystal structure of cesium methylsulfonate, CsCH3SO3

1967 ◽  
Vol 45 (12) ◽  
pp. 1385-1390 ◽  
Author(s):  
J. K. Brandon ◽  
I. D. Brown
Keyword(s):  
Crystal Structure ◽  
Diffraction Data ◽  
Barium Sulfate ◽  
Three Dimensional ◽  
Thermal Motion ◽  
X Ray Diffraction ◽  
Methyl Group ◽  
Space Group ◽  
X Ray ◽  
Cesium Ion

Cesium methylsulfonate, CsCH3SO3, crystallizes in space group Pnma with a = 9.526, b = 6.264, and c = 8.692 Å. Three-dimensional X-ray diffraction data have been collected photographically and refined to give a weighted agreement index (R) of 0.12. The structure is related to, but is not identical with, that of the isoelectronic compound barium sulfate. The CH3SO3− ion has C3v symmetry within the accuracy of this analysis, with S—O = 1.47 ± 0.02, S—C = 1.85 ± 0.04 Å (corrected for thermal motion), O—S—O = 112 ± 1°, and O—S—C = 107 ± 2°. The cesium ion is surrounded by nine oxygen atoms (Cs—O between 3.12 and 3.35 Å) and one methyl group (Cs—C = 3.77 Å).

The Chlorination of Some Substituted 2,4-Dimethylphenols

1994 ◽  
Vol 47 (2) ◽  
pp. 289 ◽  
Author(s):  
JLM Gordon ◽  
MP Hartshorn ◽  
RJ Martyn ◽  
AJ Morgan ◽  
WT Robinson ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Acetic Acid ◽  
Carbon Tetrachloride ◽  
Acetic Anhydride ◽  
Methyl Group ◽  
X Ray

Chlorination reactions of 2-chloro-3,4,6-trimethylphenol (4), 2-chloro-4,6-dimethylphenol (5) and 3-chloro-2,4,6-trimethylphenol (6) are described. In acetic acid or acetic anhydride solution, chlorinations yield predominantly the corresponding 4-chlorocyclohexa-2,5-dienones (8), (17a) and (29), but in carbon tetrachloride containing pyridine products are formed which result from the modification of the 4-methyl group in each substrate. X-Ray crystal structure analyses are reported for compounds (7), (14), (28) and (31).

Syntheses in the group of Nuphar alkaloids. IV. Crystal structure and stereochemistry of synthetic (±)-3-epinupharamine

1977 ◽  
Vol 55 (17) ◽  
pp. 3111-3117 ◽  
Author(s):  
Mlchał Sabat ◽  
Tadeusz Głowiak ◽  
Jerzy Szychowski ◽  
Jerzy T. Wrôbel ◽  
Andrzej Leniewski
Keyword(s):  
Crystal Structure ◽  
Total Synthesis ◽  
Chemical Shifts ◽  
Monoclinic Space Group ◽  
Equatorial Orientation ◽  
Methyl Group ◽  
Space Group ◽  
X Ray ◽  
Empirical Criterion ◽  
Structural Identity

Racemic 3-epinupharamine hydrobromide (C15H26BrNO2) crystals are monoclinic, space group C2/c, with a = 18.163(3), b = 13.346(2), c = 13.847(2) Å, β = 100.36(1)°, Z = 8. The X-ray analysis proved the structural identity of the compound obtained by the total synthesis with the natural 3-epinupharamine. The empirical criterion indicating the axial or equatorial orientation of the C-methyl group on the basis of the direction of changes of the chemical shifts recorded in benzene solutions does not hold for the piperidine system investigated.Les cristaux du bromhydrate d'épi-3 nupharamine racémique (C15H26BrNO2) sont monocliniques, groupe d'espace C2/c avec a = 18.163(3), b = 13.346(2), c = 13.847(2) Å, β = 100.36(1)°, Z = 8. L'analyse par rayons-X a démontré l'identité structurale du composé obtenu par synthèse totale avec l'épi-3 nupharamine naturel. Les critères empiriques permettant de déterminer l'orientation axiale ou équatoriale des groupes C-méthyles en se basant sur la direction des changements dans les déplacements chimiques enregistrés en solutions benzéniques ne peuvent être utilisés dans le système pipéridine étudié. [Traduit par le journal]

The nitration of some substituted 4-methylphenols; X-ray crystal structure of (Z)-3-Bromo-5-(bromonitromethylene)furan-2(5H)-one

1984 ◽  
Vol 37 (1) ◽  
pp. 55 ◽  
Author(s):  
MJ Gray ◽  
MP Hartshorn ◽  
BR Penfold ◽  
J Vaughan
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Similar Reaction ◽  
Methyl Group ◽  
X Ray

The nitrations of 2-substituted 4-methyl-6-nitrophenols (1a),(l1b) and (1c) give 6-substituted 3-methyl-2-nitro-1,4-benzoquinones (2a), (2b) and (2c). Similar reaction of 2,3-dibromo-4-methyl- 6-nitrophenol (5) gives 2,3-dibromo-5-methyl-6-nitro-1,4-benzoquinone (7) and the 4-nitratocyclo- hexa-2,5-dienone (12). In contrast, 2,3,6-tribromo-(4a) and 2,6-dibromo-(4b) 4-methylphenols give 1,4-benzoquinones with loss of the methyl group. Lactone (18) was formed in the nitration of the 2,6-dibromophenol (4b) and its structure was determined by single-crystal X-ray analysis.

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