NMR-Spectra and Solution Structures of Some Piperazine-2,5-Diones. X-Ray Crystal-Structure of Threo-1-Acetyl-3-(Alpha-Bromobenzyl)-3-Methoxy-Piperazine-2,5-Dione

1986 ◽  
Vol 39 (7) ◽  
pp. 1141 ◽  
Author(s):  
JA Elix ◽  
GD Fallon ◽  
SM Marcuccio ◽  
ID Rae
Keyword(s):  
Crystal Structure ◽  
Heterocyclic Ring ◽  
Ring System ◽  
Side Chain ◽  
Boat Conformation ◽  
Methyl Derivative ◽  
X Ray ◽  
Solution Structures ◽  
Cdcl3 Solution ◽  
Substituted Piperazine

3-(α- Bromobenzyl )-3-methoxypiperazine-2,5-diones are prepared by the reaction of 3-benzylidenepiperazine-2,5-diones with N- bromosuccinimide in methanol. The crystal structure of the threo-1-acetyl compound shows the side chain in the EN conformation, with the bromine above the heterocyclic ring, the latter ring system being almost planar. This conformer predominates in CDCl3 solution also, but in (CD3)2SO the piperazine-2,5-dione ring adopts a boat conformation. Both the erythro isomer and an N(4)-methyl derivative exist in solution predominantly as folded conformers. The importance of repulsive interactions in predicting the conformation of substituted piperazine-2,5-diones is discussed.

Synthesis and X-ray crystal structure determination of 3,4-diphenyl-6-(diphenylmethyl)-1,5-dioxa-2-thiane-2-oxide

1991 ◽  
Vol 69 (2) ◽  
pp. 185-188 ◽  
Author(s):  
L. Breau ◽  
N. K. Sharma ◽  
I. R. Butler ◽  
T Durst
Keyword(s):  
Crystal Structure ◽  
Key Words ◽  
Structure Determination ◽  
Title Compound ◽  
Heterocyclic Ring ◽  
Ring System ◽  
Sulfuryl Chloride ◽  
Similar Treatment ◽  
X Ray

Erythro and threo-1,2-diphenyl-2-tert-butylsulfinylethanols 5 and 8 were prepared from the condensation of the α-lithio derivative of benzyl-tert-butyl sulfoxide with benzaldehyde. Reaction of 5 with sulfuryl chloride gave the title compound, (2R*,3S*,4R*,6R*)-3,4-diphenyl-6-(diphenylmethyl)-1,5-dioxa-2-thiane-2-oxide 6, the first representative of a new heterocyclic ring system. Similar treatment of 8 resulted in the formation of 7, a stereoisomer of 6. This same compound was also obtained by photolysis of 6. In both 6 and 7 the S=O bond is in an axial orientation. Key words: sulfuryl chloride, reaction with β-hydroxy sulfoxides; 1,2-diphenyl-tert-butylsulfinylethanol; β-hydroxysulfoxides; β-sultines; N-chlorosuccinimide, reaction with β-hydroxysulfoxides.

scholarly journals 3-Hydroxy-3-methylisochroman-1-one–2-(carboxymethyl)benzoic acid (1/1)

IUCrData ◽  
2018 ◽  
Vol 3 (11) ◽  
Author(s):  
Akoun Abou ◽  
Ludovic Akonan ◽  
Frédérica Koblavi-Mansilla ◽  
Aka Joseph N'gouan ◽  
Konan René Kambo
Keyword(s):  
Three Dimensional ◽  
Heterocyclic Ring ◽  
Ring System ◽  
Boat Conformation ◽  
Acid Molecule ◽  
Crystalline Compound ◽  
X Ray Diffraction ◽  
X Ray ◽  
Compound C ◽  
Dimensional Network

The title co-crystalline compound, C10H10O3·C9H8O4, has been synthesized and characterized in a single-crystal X-ray diffraction study. In the 3-hydroxy-3-methylisochroman-1-one molecule, the six-membered heterocyclic ring lies between an envelope and a screw-boat conformation. In the 2-carboxymethylbenzoic acid, molecule, the 2-carboxymethyl substituent is almost planar (r.m.s deviation = 0.048 Å) and makes a dihedral angle of 79.59 (7)° with the planar benzene ring. In this molecule, intramolecular C—H...O contacts generate five- and six-membered rings, forming a tricyclic ring system. In the crystal, classical O—H...O and C—H...O hydrogen bonds combine with C—H...π(ring) and unusual C=O...π(ring) contacts to generate a three-dimensional network.

Tele-Substitution Reactions in the Synthesis of a Promising Class of Antimalarials

2020 ◽  
Author(s):  
Marat Korsik ◽  
Edwin Tse ◽  
David Smith ◽  
William Lewis ◽  
Peter J. Rutledge ◽  
...  
Keyword(s):  
Heterocyclic Ring ◽  
Ring System ◽  
Substitution Reactions ◽  
Laboratory Notebook ◽  
Polar Solvents ◽  
X Ray ◽  
X Ray Crystallography ◽  
The Core ◽  
Nmr Data

<p></p><p>We have discovered and studied a <i>tele</i>substitution reaction in a biologically important heterocyclic ring system. Conditions that favour the <i>tele</i>-substitution pathway were identified: the use of increased equivalents of the nucleophile or decreased equivalents of base, or the use of softer nucleophiles, less polar solvents and larger halogens on the electrophile. Using results from X-ray crystallography and isotope labelling experiments a mechanism for this unusual transformation is proposed. We focused on this triazolopyrazine as it is the core structure of the <i>in vivo </i>active anti-plasmodium compounds of Series 4 of the Open Source Malaria consortium.</p> <p> </p> <p>Archive of the electronic laboratory notebook with the description of all conducted experiments and raw NMR data could be accessed via following link <a href="https://ses.library.usyd.edu.au/handle/2123/21890">https://ses.library.usyd.edu.au/handle/2123/21890</a> . For navigation between entries of laboratory notebook please use file "Strings for compounds in the article.pdf" that works as a reference between article codes and notebook codes, also this file contain SMILES for these compounds. </p><br><p></p>

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.

scholarly journals Crystal structure of ethyl (2S,2′R)-1′-benzyl-3-oxo-3H-dispiro[1-benzothiophene-2,3′-pyrrolidine-2′,11′′-indeno[1,2-b]quinoxaline]-4′-carboxylate

2015 ◽  
Vol 71 (3) ◽  
pp. o195-o196
Author(s):  
J. Govindaraj ◽  
R. Raja ◽  
M. Suresh ◽  
R. Raghunathan ◽  
A. SubbiahPandi
Keyword(s):  
Crystal Structure ◽  
Three Dimensional ◽  
Ring System ◽  
Side Chain ◽  
Dihedral Angles ◽  
Pyrrolidine Ring ◽  
Compound C ◽  
Dimensional Network ◽  
Centroid Distance ◽  
Quinoxaline Ring

In the title compound, C35H27N3O3S, the spiro-linked five-membered rings both adopt twisted conformations. The pyrrolidine ring makes dihedral angles of 80.5 (1) and 77.4 (9)° with the benzothiophene ring system and the quinoxaline ring system, respectively. The S atom and C=O unit of the benzothiophene ring system are disordered over two opposite orientations in a 0.768 (4):0.232 (4) ratio. The atoms of the ethyl side chain are disordered over two sets of sites in a 0.680 (16):0.320 (16) ratio. In the crystal, molecules are linked by C—H...O, C—H...N and π–π interactions [shortest centroid–centroid distance = 3.4145 (19) Å], resulting in a three-dimensional network.

scholarly journals Unusual formation of (E)-11-(aminomethylene)-8,9,10,11-tetrahydropyrido[2′,3′:4,5]pyrimido[1,2-a]azepin-5(7H)-one and its crystal structure

2017 ◽  
Vol 73 (10) ◽  
pp. 1497-1500
Author(s):  
Khamid U. Khodjaniyazov ◽  
Utkir S. Makhmudov ◽  
Kambarali K. Turgunov ◽  
Burkhon Z. Elmuradov
Keyword(s):  
Crystal Structure ◽  
Structural Analysis ◽  
Aqueous Ammonia ◽  
Boat Conformation ◽  
X Ray ◽  
First Time ◽  
Twist Boat ◽  
Unusual Formation

Selective C-formylation of 8,9,10,11-tetrahydropyrido[2′,3′:4,5]pyrimido[1,2-a]-azepin-5(7H)-one has been studied for the first time. It was revealed that formylation proceeds by the formation of an intermediate salt, which due to the re-amination process on treatment with aqueous ammonia transformed into the corresponding (E)-11-(aminomethylene)-8,9,10,11-tetrahydropyrido[2′,3′:4,5]-pyrimido[1,2-a]azepin-5(7H)-one, C13H14N4O, as anE-isomer. Formylation was carried out by Vilsmeier–Haack reagent and the structure of the synthesized compound was confirmed by X-ray structural analysis, spectroscopic and LC–MS methods. In the molecule, the seven-membered pentamethylene ring adopts a twist-boat conformation.

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.

The Meisenheimer Rearrangement in Heterocyclic Synthesis. IV. Derivatives of the 2H,6H-1,5,4-Benzodioxazocine and 7H-1,6,5-Benzodioxazonine Ring Systems: X-Ray Crystal Structure of 10-Methoxy-5-methyl-7-phenyl-2,3,4,5-tetrahydro-7H-1,6,5-benzodioxazonine

1988 ◽  
Vol 41 (3) ◽  
pp. 293 ◽  
Author(s):  
JB Bremner ◽  
EJ Browne ◽  
LM Engelhardt ◽  
IWK Gunawardana ◽  
AH White
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Crystal And Molecular Structure ◽  
Ring System ◽  
Heterocyclic Synthesis ◽  
Rearrangement Product ◽  
Ring Systems ◽  
X Ray ◽  
Derivatives Of ◽  
Moderate Yield

Meisenheimer rearrangement of the N-oxides (4) derived from a series of 5-aryl-4-methyl-2,3,4,5-tetrahydro-1,4-benzoxazepines (3) gave rise to eight derivatives (5) of the new 2H,6H-1,5,4-benzodioxazocine ring system. Reaction of 9-methoxy-5-methyl-6-phenyl-3,4,5,6- tetrahydro-2H-1,5-benzoxazocine (6) with 3-chloroperoxybenzoic acid gave an unstable N-oxide (7). A Meisenheimer rearrangement product from (7), 10-methoxy-5-methyl-7-phenyl-2,3,4,5-tetrahydro-7 H-1,6,5- benzodioxazonine (8), the first example of this ring system, was isolated directly in moderate yield on oxidation of (6) with cooling. The crystal and molecular structure of (8) has been determined by X-ray crystallographic methods.

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