Synthesis, conformational analysis, and molecular structure of 5-ethyl-5,6-dihydro-11H-dibenzo[b,e]azepine-6-thione

1994 ◽  
Vol 72 (2) ◽  
pp. 334-338 ◽  
Author(s):  
J. Irurre ◽  
F. Marquillas ◽  
A. Alvarez-Larena ◽  
J.F. Piniella
Keyword(s):  
Molecular Structure ◽  
Solid State ◽  
Conformational Analysis ◽  
Activation Barrier ◽  
Direct Methods ◽  
Membered Ring ◽  
Boat Conformation ◽  
X Ray Diffraction ◽  
X Ray ◽  
R Value

5-Ethyl-5,6-dihydro-11H-dibenzo[b,e]azepine-6-thione has been synthesized and studied in the solid state and in solution by X-ray diffraction and 1H DNMR, respectively. The crystals are monoclinic, P21/n, a = 9.642(1), b = 13.757(2), c = 9.889((2) Å, β = 98.57(1)°, Z = 4. The structure has been solved by direct methods and refined to an R value of 0.040 for 1771 reflections with I > 2.5σ(I). The seven-membered ring has a slightly deformed boat conformation. The activation barrier associated with the inversion ring has been determined, being ΔG≠ = 21.6 kcal/mol.

scholarly journals Approaches to the synthesis of triterpenoids. IV. The ABC + E ring approach to the pentacyclic triterpene skeleton. Synthesis of a pentacyclic compound suitable for triterpene synthesis

1978 ◽  
Vol 56 (16) ◽  
pp. 2139-2149 ◽  
Author(s):  
John W. Apsimon ◽  
Satyanand Badripersaud ◽  
John W. Hooper ◽  
Richard Pike ◽  
George I. Birnbaum ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Least Squares ◽  
Direct Methods ◽  
Unit Cell ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Pentacyclic Triterpene ◽  
X Ray ◽  
R Value ◽  
Triterpene Synthesis

Studies on the ABC + E ring construction of the pentacyclic triterpene skeleton are described. Acid-catalysed cyclisation of the mixture of diastereoisomers 11 led to preferential cyclisation of one isomer to 10-methoxy-2,2,4aβ,6aβ, 12bβ -pentamethyl-1,2,3,4,4a,5,6,6a, 6bα,7,8,12b,13,14-tetradecahydro-1-picenone (12). An X-ray analysis was performed on this compound which crystallizes in the monoclinic space group P2/c. There are four molecules in the unit cell which has dimensions a = 6.456(2), b = 42.518(6), c = 8.519(2) Å, β = 100.92(3)°. The structure was solved by direct methods and refined by block-diagonal least-squares to a final R value of 0.042 for all 3234 observed reflections. The molecular structure found by X-ray diffraction confirms the stereochemical reasoning used in the synthetic steps.

The preparation and the crystal and molecular structure of S3N2NH2+BF4−; a molecular orbital study of the protonation of the trisulphur trinitride anion

1984 ◽  
Vol 62 (9) ◽  
pp. 1822-1827 ◽  
Author(s):  
Clifford G. Marcellus ◽  
Richard T. Oakley ◽  
A. Wallace Cordes ◽  
William T. Pennington
Keyword(s):  
Molecular Structure ◽  
Molecular Orbital ◽  
Crystal And Molecular Structure ◽  
Direct Methods ◽  
Membered Ring ◽  
Molecular Orbital Calculations ◽  
X Ray Diffraction ◽  
Triclinic Space Group ◽  
X Ray ◽  
Molecular Orbital Study

Protonation of the trisulphur trinitride ion, S3N3−, with tetrafluoroboric acid yields the ring-contracted S-amino thiodithiazyl salt, S3N2NH2+BF4−. The crystal and molecular structure of this salt has been determined by X-ray diffraction. The crystals are triclinic, space group P1, with a = 5.445(2), b = 7.346(3), c = 9.473(5) Å, α = 85.89(4), β = 83.92(3), γ = 82.13(3)°, V = 372.6(4) Å3, Dc = 2.02 g cm−3, and Z = 2. The structure was solved by direct methods and refined by full-matrix least-squares procedures to give a final R = 0.060. The structure of the five-membered ring with a single exocyclic NH2 group bonded to sulphur is discussed in relation to other S3N2NR derivatives. The reasons for the instability of six-membered rings of the type S3N3R are discussed in the light of MNDO molecular orbital calculations on an S3N3H model.

The crystal and molecular structure of syn-2,11-diselena[3,3]metacyclophane and comparison with the dithia-analogue

1982 ◽  
Vol 60 (3) ◽  
pp. 362-367 ◽  
Author(s):  
Gordon W. Bushnell ◽  
Reginald H. Mitchell
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Solid State ◽  
Crystal And Molecular Structure ◽  
State Structure ◽  
X Ray Diffraction ◽  
Hydrogen Atoms ◽  
X Ray ◽  
Anti Conformer ◽  
R Value

The crystal structure of syn-2,11-diselena[3,3]metacyclophane, 1a, has been determined by single crystal X-ray diffraction and refined to an R-value of 0.039. The crystal structure is monoclinic with a = 1926(1), b = 801.4(3), c = 924(1) pm, β = 98.9(1)°, and is isomorphous with that of the analogous sulphur compound. The space group is P21/n with 4 molecules per cell, D(meas) = 1.733 g cm−3, D(calcd) = 1.726 g cm−3. The molecule has the syn-conformation with the largest possible Se—Se distance of 721.8 pm. The benzenoid rings form a dihedral angle of 19.1°. The distance between the internal aryl hydrogen atoms on rings 1 and 2 is 285.1 pm. The internal aryl C atoms are 314.6 pm apart. The 1Hmr solution spectra of 1a are consistent with the solid state structure, and can be explained without involving equilibration with an anti-conformer.

Crystal structures of medium ring compounds. Part III. The crystal and molecular structure of trans-anti-trans-4,5:9,10-biscyclohexano-1,3,6,8-tetraoxecane

1979 ◽  
Vol 57 (16) ◽  
pp. 2154-2158 ◽  
Author(s):  
Aris Terzis ◽  
T. Bruce Grindley
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Crystal And Molecular Structure ◽  
Chair Conformation ◽  
Membered Ring ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ring Compounds ◽  
R Value ◽  
Medium Ring

The crystal structure of trans-anti-trans-4,5:9,10-biscyclohexano-1,3,6,8-tetraoxecane (3) has been determined by X-ray diffraction. The crystals are monoclinic, a = 11.919(3), b = 17.330(7), c = 7.019(2) Å, β = 98.91(1)°, P21/c, with Z = 4. The structure was solved by application of the tangent formula and refined by large block least squares to a final R value of 0.060 (Rw = 0.058).The ten-membered ring is present in the crystal in a twist-chair-boat-chair conformation — one which has been calculated to be relatively unstable for cyclodecane. Possible reasons why 3 adopts this conformation are discussed.

The conformation of a ten-membered ring: the crystal and molecular structure of trans-syn-trans-4,5:9,10-biscyclohexano-1,3,6,8-tetraoxecane

1977 ◽  
Vol 55 (14) ◽  
pp. 2692-2699 ◽  
Author(s):  
Aris Terzis ◽  
T. Bruce Grindley ◽  
J. Brian Faught
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Crystal And Molecular Structure ◽  
Membered Ring ◽  
Thermal Parameters ◽  
X Ray Diffraction ◽  
X Ray ◽  
R Value

The crystal structure of trans-sys-trans-4,5:9,10-biscyclohexano-1,3,6,8-tetraoxecane (1) has been determined by X-ray diffraction. The crystals are monoclinic, a = 10.995(2), b = 5.291(1), c = 12.241(2) Å, β = 114.68(1)°, P21/c, with Z = 2. The structure was solved by the application of symbolic addition procedures and refined with anisotropic thermal parameters for all atoms to a final R value of 0.039 (Rw 0.062) for 1135 independent reflections.The ten-membered tetraoxecane ring is present in the crystal in a boat-chair-boat (BCB) conformation, which is somewhat different in geometry than the BCB conformations observed for cyclodecane derivatives. The causes of these differences are discussed. Intramolecular non-bonded interactions cause one CH2 group to be significantly distorted from local C2v symmetry.

The crystal and molecular structure of syn-[4.4.3]propella-2,4,12-trien-11-ol 3,5-dinitrobenzoate

1985 ◽  
Vol 63 (4) ◽  
pp. 862-865 ◽  
Author(s):  
Judith C. Gallucci ◽  
Katsuo Ohkata ◽  
Leo A. Paquette
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Crystal And Molecular Structure ◽  
Molecular Geometry ◽  
Chair Conformation ◽  
Membered Ring ◽  
Aqueous Acetone ◽  
X Ray Diffraction ◽  
X Ray ◽  
R Value

The crystal structure of syn-[4.4.3]propella-2,4,12-trien-11-ol 3,5-dinitrobenzoate, 2, has been determined by single crystal X-ray diffraction and refined to an R value of 0.051. The crystal structure is triclinic with a = 10.208(2), b = 13.355(2), c = 7.068(1) Å, α = 99.35(1)°, β = 100.63(1)°, γ = 100.79(1)°, and the space group is [Formula: see text] with two molecules per cell, D(calcd) = 1.39 g cm−3. The unsaturated five-membered ring resides in an envelope conformation with C6—C11—C12—C13 lying essentially in a plane. The fifth atom, C1, is positioned 0.47 Å out of this plane on the side opposite O1. The latter is situated 1.38 Å away and projects the 3,5-dinitrobenzoate group above the central portion of the cyclohexadiene unit. Four contiguous carbon atoms in the latter ring are mutually coplanar and the fused cyclohexane ring adopts a chair conformation. The overall molecular geometry is reconcilable with its solvolytic behavior in aqueous acetone.

Crystal structure determination of the conformation of two bicyclo[3.3.1]nonan-ones

1985 ◽  
Vol 63 (6) ◽  
pp. 1166-1169 ◽  
Author(s):  
John F. Richardson ◽  
Ted S. Sorensen
Keyword(s):  
Crystal Structure ◽  
Direct Methods ◽  
Chair Conformation ◽  
Molecular Structures ◽  
Boat Conformation ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Final Agreement

The molecular structures of exo-7-methylbicyclo[3.3.1]nonan-3-one, 3, and the endo-7-methyl isomer, 4, have been determined using X-ray-diffraction techniques. Compound 3 crystallizes in the space group [Formula: see text] with a = 15.115(1), c = 7.677(2) Å, and Z = 8 while 4 crystallizes in the space group P21 with a = 6.446(1), b = 7.831(1), c = 8.414(2) Å, β = 94.42(2)°, and Z = 2. The structures were solved by direct methods and refined to final agreement factors of R = 0.041 and R = 0.034 for 3 and 4 respectively. Compound 3 exists in a chair–chair conformation and there is no significant flattening of the chair rings. However, in 4, the non-ketone ring is forced into a boat conformation. These results are significant in interpreting what conformations may be present in the related sp2-hybridized carbocations.

The X-Ray Crystal Structure of 1,2-3,4-Di-O-isopropylidene-4-C-methylthiomethoxy-β-L-arabino-hexoseptanos-5-ulose

1990 ◽  
Vol 43 (12) ◽  
pp. 2083 ◽  
Author(s):  
DC Craig ◽  
VJ James ◽  
JD Stevens
Keyword(s):  
Crystal Structure ◽  
Title Compound ◽  
Membered Ring ◽  
Boat Conformation ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
X Ray

The crystal structure of the title compound (1) has been determined by X-ray diffraction. Crystals of (1) are orthorhombic, space group P21212 with a 11.425(1), b 24.916(1), c 5.8952(3)Ǻ, Z 4. Refinement on 1675 observed reflections measured with Cu Kα radiation converged at R 0.034. The seven- membered ring adopts a boat conformation in which the pseudo plane of symmetry passes through the ring oxygen.

A structural and carbon-nitrogen bond rotation study of N,N,N',N',2,2-hexamethylpropanediamide

1983 ◽  
Vol 36 (9) ◽  
pp. 1865 ◽  
Author(s):  
SF Lincoln ◽  
AM Hounslow ◽  
NJ Maeji ◽  
TW Hambley ◽  
MR Snow ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Solid State ◽  
Kinetic Parameters ◽  
Methyl Groups ◽  
X Ray Diffraction ◽  
X Ray ◽  
Bond Rotation ◽  
Nitrogen Bonds ◽  
Rotation Study ◽  
Nitrogen Bond

The molecular structure of N,N,N',N',2,2-hexamethylpropanediamide has been determined in the solid state by X-ray diffraction methods. The structure of Me2NCOCMe2CONMe2 may be broadly described as two planar Me2NCO entities intersecting at the tetrahedral -CMe2- site. The angle between the normals to the two Me2NCO planes is 104.6�, and the two oxygen atoms are disposed outwards from the molecule and away from each other. Proton (270-MHz) n.m.r. studies yield k(320 K) 32.0 � 3.2 s-1, ΔH‡ 69.5 � 0.4 kJ mol-1 and ΔS‡ 0.6 � 1.1 J K-1 mol-1 for rotation of the N-methyl groups about the carbon-nitrogen bonds in CD3NO2 solution. Similar magnitudes for the kinetic parameters characterizing this process are obtained in CDCl3, and CD3CN solutions.

scholarly journals Synthesis of Trithia-Borinane Complexes Stabilized in Diruthenium Core: [(Cp*Ru)2(η1-S)(η1-CS){(CH2)2S3BR}] (R = H or SMe)

Inorganics ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 21 ◽  
Author(s):  
Koushik Saha ◽  
Urminder Kaur ◽  
Rosmita Borthakur ◽  
Sundargopal Ghosh
Keyword(s):  
Mass Spectrometry ◽  
1H Nmr Spectroscopy ◽  
Chair Conformation ◽  
Membered Ring ◽  
Molecular Structures ◽  
Boat Conformation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Butterfly Cluster ◽  
Tellurium Powder

The thermolysis of arachno-1 [(Cp*Ru)2(B3H8)(CS2H)] in the presence of tellurium powder yielded a series of ruthenium trithia-borinane complexes: [(Cp*Ru)2(η1-S)(η1-CS){(CH2)2S3BH}] 2, [(Cp*Ru)2(η1-S)(η1-CS){(CH2)2S3B(SMe)}] 3, and [(Cp*Ru)2(η1-S)(η1-CS){(CH2)2S3BH}] 4. Compounds 2–4 were considered as ruthenium trithia-borinane complexes, where the central six-membered ring {C2BS3} adopted a boat conformation. Compounds 2–4 were similar to our recently reported ruthenium diborinane complex [(Cp*Ru){(η2-SCHS)CH2S2(BH2)2}]. Unlike diborinane, where the central six-membered ring {CB2S3} adopted a chair conformation, compounds 2–4 adopted a boat conformation. In an attempt to convert arachno-1 into a closo or nido cluster, we pyrolyzed it in toluene. Interestingly, the reaction led to the isolation of a capped butterfly cluster, [(Cp*Ru)2(B3H5)(CS2H2)] 5. All the compounds were characterized by 1H, 11B{1H}, and 13C{1H} NMR spectroscopy and mass spectrometry. The molecular structures of complexes 2, 3, and 5 were also determined by single-crystal X-ray diffraction analysis.

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