scholarly journals β-Ketophosphonates with Pentalenofuran Scaffolds Linked to the Ketone Group for the Synthesis of Prostaglandin Analogs

2021 ◽  
Vol 22 (13) ◽  
pp. 6787
Author(s):  
Constantin I. Tănase ◽  
Constantin Drăghici ◽  
Miron Teodor Căproiu ◽  
Anamaria Hanganu ◽  
Gheorghe Borodi ◽  
...  
Keyword(s):  
Lithium Salt ◽  
Methyl Esters ◽  
Secondary Compounds ◽  
Molecular Structures ◽  
Keto Group ◽  
High Yield ◽  
Oxidation Reactions ◽  
Prostaglandin Analogues ◽  
X Ray ◽  
Oxidation Of Alcohols

β-Ketophosphonates with pentalenofurane fragments linked to the keto group were synthesized. The bulky pentalenofurane skeleton is expected to introduce more hindrance in the prostaglandin analogues of type III, greater than that obtained with the bicyclo[3.3.0]oct(a)ene fragments of prostaglandin analogues I and II, to slow down (retard) the inactivation of the prostaglandin analogues by oxidation of 15α-OH to the 15-keto group via the 15-PGDH pathway. Their synthesis was performed by a sequence of three high yield reactions, starting from the pentalenofurane alcohols 2, oxidation of alcohols to acids 3, esterification of acids 3 to methyl esters 4 and reaction of the esters 4 with lithium salt of dimethyl methanephosphonate at low temperature. The secondary compounds 6b and 6c were formed in small amounts in the oxidation reactions of 2b and 2c, and the NMR spectroscopy showed that their structure is that of an ester of the acid with the starting alcohol. Their molecular structures were confirmed by single crystal X-ray determination method for 6c and XRPD powder method for 6b.

1,2-Di(silyl)benzene and 1,4-Dibromo-2,5-di(silyl)benzene

1994 ◽  
Vol 49 (8) ◽  
pp. 1036-1040 ◽  
Author(s):  
Robert Schröck ◽  
Alexander Sladek ◽  
Hubert Schmidbaur
Keyword(s):  
Methanesulfonic Acid ◽  
Intermediate Compound ◽  
Molecular Structures ◽  
High Yield ◽  
Electronic Effects ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Yields ◽  
Experimental Findings ◽  
Silylation Reaction

1,2-Di(silyl)benzene (3), has been prepared in a three-step process starting with the reac­tion of 1,2-dibromobenzene and p-tolyl(chloro)silane with magnesium in tetrahydrofuran. which affords 1,2-bis(p-tolylsilyl)benzene (1) as a stable high-yield intermediate. Compound 1 has been converted into 1,2-bis(trifluoromethanesulfonatosilyl)benzene (2) with trifluoro- methanesulfonic acid, and finally into 3 by reduction with lithiumaluminiumhydride, both again in high yields. - In an attempt to prepare 1,2,4,5-tetra(silyl)benzene in an analogous way. only the bis-silylated species could be obtained (from 1,2,4,5-C6H2Br4. p-MeC6H4SiClH2 and Mg powder: 1,4-dibromo-2,5-bis(p-tolylsilyl)benzene. 4, and 1,4-dibromo-2,5-di(silyl)- benzene, 6, via 1,4-dibromo-2,5-bis(trifluoromethanesulfonatosilyl)benzene, 5). The crystal structures of compounds 4 and 6 have been determined by X-ray diffraction. The results indicate no steric hindrance in these molecules and it is thus not obvious from the molecular structures why the silylation reaction does not proceed any further to give the tetrasilylated benzene derivatives. Electronic effects have to be invoked to rationalize the experimental findings.

Contribution to the Chemistry of 2,2,6,6-Tetramethylpiperidino Aluminium Compounds

2005 ◽  
Vol 60 (10) ◽  
pp. 1027-1035 ◽  
Author(s):  
Klaus Knabel ◽  
Heinrich Nöth
Keyword(s):  
Nmr Spectroscopy ◽  
Elevated Temperatures ◽  
Molecular Structures ◽  
High Yield ◽  
Dry Ice ◽  
X Ray ◽  
Unexpected Reaction

tmpAlBr2 (tmp = 2,2,6,6-tetramethylpiperidino) was prepared from AlBr3 and tmp2AlBr at 90 °C in the absence of a solvent, but could not be crystallised from toluene or hexane because it reacted with the solvents to form tmpH·AlBr3 in high yield. tmpH·AlMeCl2, obtained from the components, decomposes at elevated temperatures but no tmpAlCl2 could be isolated. Attempts to generate the cation [tmp-Al-tmp]+ from tmp2AlBr or tmp2AlCl by halide abstraction with B(C6F5)3, Ph3C(SnCl5) or SbCl5 or from tmp2AlR (R = Me, Ph) and B(C6F5)3 have failed. An unexpected reaction occurred on treatment of tmp-B=P(tBu)AlBr3 with BH3 in THF which led to the formation of [AlBr2(thf)4][AlBr4]. The attempted synthesis of tBu2Al(tmp) from tBu2AlBr and Li(tmp) gave a product which, on exposure to CO2 at dry ice temperature, yielded the salt [(tBuAl)2(O2C(tmp))3][tBu3Al-Br-AltBu3] in low yield. All isolated products were characterized by NMR spectroscopy and by X-ray determination of their molecular structures.

scholarly journals Peroxidative Oxidation of Alkanes and Alcohols under Mild Conditions by Di- and Tetranuclear Copper (II) Complexes of Bis (2-Hydroxybenzylidene) Isophthalohydrazide

Molecules ◽  
2018 ◽  
Vol 23 (10) ◽  
pp. 2699 ◽  
Author(s):  
Manas Sutradhar ◽  
Elisabete Alegria ◽  
M. Guedes da Silva ◽  
Cai-Ming Liu ◽  
Armando Pombeiro
Keyword(s):  
Variable Temperature ◽  
Product Yield ◽  
Antiferromagnetic Coupling ◽  
Oxidation Reactions ◽  
X Ray ◽  
X Ray Crystallography ◽  
Mild Conditions ◽  
Microwave Assisted ◽  
Oxidation Of Alcohols ◽  
Cyclohexyl Hydroperoxide

Bis(2-hydroxybenzylidene)isophthalohydrazide (H4L) has been used to synthesize the dinuclear [Cu2(1κNO2:2κN′O′2-H2L)(NO3)2(H2O)2] (1) and the tetranuclear [Cu4(μ-1κNO2:2κN′O2-H2L)2(μ-NO3)2(H2O)4]·2C2H5OH (2) complexes. The solvent plays an important role in determining the ligand behaviour in the syntheses of the complexes. An ethanol-acetonitrile mixture of solvents favours partials enolization in the case of 2. Both complexes have been characterized by elemental analysis, infrared radiation (IR), single crystal X-ray crystallography and electrochemical methods. The variable temperature magnetic susceptibility measurements of 2 show strong antiferromagnetic coupling between the central nitrato-bridged Cu (II) ions. The catalytic activity of both 1 and 2 has been screened toward the solvent-free microwave-assisted oxidation of alcohols and the peroxidative oxidation of alkanes under mild conditions. Complex 1 exhibits the highest activity for both oxidation reactions, leading selectively to a maximum product yield of 99% (for the 1-phenylethanol oxidation after 1 h without any additive) and 13% (for the cyclohexane oxidation to cyclohexyl hydroperoxide, cyclohexanol and cyclohexanone after 3 h).

scholarly journals Ethynylthioamide Complexes: Synthesis, Reactivity and an Unusual Coupling Reaction with Diethylaminopropyne

2007 ◽  
Vol 62 (3) ◽  
pp. 346-356 ◽  
Author(s):  
Normen Szesni ◽  
Matthias Drexler ◽  
Bernhard Weibert ◽  
Helmut Fischer
Keyword(s):  
Solid State ◽  
Lithium Salt ◽  
Coupling Reaction ◽  
High Yield ◽  
X Ray ◽  
Solid State Structures ◽  
Three Component Coupling

The reaction of [(CO)5Cr(THF)] with propynethioic acid amides, R-C≡C-C(=S)NMe2 (R = H, SiMe3), yields the thioamide complexes [(CO)5Cr-S=C(NMe2)C≡C-H] (1a) and [(CO)5Cr- S=C(NMe2)C≡C-SiMe3] (1b). Treatment of solutions of 1a or 1b with methyllithium generates, via deprotonation or desilylation, the lithium salt Li[(CO)5Cr-S=C(NMe2)C≡C] (2). On filtration over silica, 2 is readily reprotonated. Complex 1a is inert towards methanol, however, adds diethylamine across the C≡C bond to give the thioacrylamide complex [(CO)5Cr-S=C(NMe2)C(H)=C(H)NMe2] (3). Thiourea displaces the thioamide ligand to give [(CO)5Cr-S=C(NH2)2] (4). Complex 1a reacts with half an equivalent of diethylaminopropyne in a three-component coupling to form the homobinuclear complex [(CO)5Cr-S=C(NEt2)-C(CH3)=C(H)-C(H)=C(NMe2)-C≡C-C(NMe2)=S- Cr(CO)5] (5) in high yield. The solid state structures of complexes 1a and 5 were established by X-ray structural analyses.

Convenient synthesis, X-ray crystal structure, and Raman spectrum of the heptasulphide dianion, S72−, in [PPN]2S7•2EtOH

1986 ◽  
Vol 64 (8) ◽  
pp. 1509-1513 ◽  
Author(s):  
Tristram Chivers ◽  
Frank Edelmann ◽  
John F. Richardson ◽  
Kenneth J. Schmidt
Keyword(s):  
Crystal Structure ◽  
Raman Spectrum ◽  
Molecular Structures ◽  
High Yield ◽  
Torsion Angles ◽  
X Ray ◽  
X Ray Crystallography ◽  
Crystal And Molecular Structures ◽  
Convenient Synthesis ◽  
Stretching Vibrations

The S72− ion is readily prepared in high yield by the reaction of [PPN]SH with cyclo-S8 in ethanol. The crystal and molecular structures of [PPN]2S7•2EtOH have been determined by X-ray crystallography. The crystals are monoclinic and belong to the space group P21, a = 13.199(2), b = 19.414(2), c = 14.046(2) Å, β = 94.027(6)°, V = 3590.3(7) Å3, Z = 2. The final R and Rw values were 0.064 and 0.060, respectively. The S72− ion is an unbranched chain of sulphur atoms in the cis,trans,cis-configuration with torsion angles of 89.99(18), 71.84(16), 76.54(16), and 94.19(18)°. The S—S distances (in Å) become progressively smaller in the sequence d(S—S central) [2.072(3) and 2.070(3)] > d(S—S internal) [2.050(2) and 2.037(3)] > d(S—S) terminal [2.044(3) and 2.026(4)]. The Raman spectrum of the S72− ion in [PPN]2S7•2EtOH exhibits characteristic S—S stretching vibrations at 503, 453, 419, and 395 cm−1.

One-pot Synthesis of Pyrazolone Sulfones by Iodine-catalyzed Sulfenylation of Pyrazolones with Aryl Sulfonyl Hydrazides Followed by Oxidation in Water

2018 ◽  
Vol 15 (3) ◽  
pp. 380-387
Author(s):  
Xia Zhao ◽  
Xiaoyu Lu ◽  
Lipeng Zhang ◽  
Tianjiao Li ◽  
Kui Lu
Keyword(s):  
Double Bond ◽  
Efficient Method ◽  
Room Temperature ◽  
Sulfonyl Chloride ◽  
Antibacterial Activities ◽  
Oxidation Reactions ◽  
Reaction Conditions ◽  
One Pot ◽  
X Ray ◽  
Amide Form

Aim and Objective: Pyrazolone sulfones have been reported to exhibit herbicidal and antibacterial activities. In spite of their good bioactivities, only a few methods have been developed to prepare pyrazolone sulfones. However, the substrate scope of these methods is limited. Moreover, the direct sulfonylation of pyrazolone by aryl sulfonyl chloride failed to give pyrazolone sulfones. Thus, developing a more efficient method to synthesize pyrazolone sulfones is very important. Materials and Method: Pyrazolone, aryl sulphonyl hydrazide, iodine, p-toluenesulphonic acid and water were mixed in a sealed tube, which was heated to 100°C for 12 hours. The mixture was cooled to 0°C and m-CPBA was added in batches. The mixture was allowed to stir for 30 min at room temperature. The crude product was purified by silica gel column chromatography to afford sulfuryl pyrazolone. Results: In all cases, the sulfenylation products were formed smoothly under the optimized reaction conditions, and were then oxidized to the corresponding sulfones in good yields by 3-chloroperoxybenzoic acid (m-CPBA) in water. Single crystal X-ray analysis of pyrazolone sulfone 4aa showed that the major tautomer of pyrazolone sulfones was the amide form instead of the enol form observed for pyrazolone thioethers. Moreover, the C=N double bond isomerized to form an α,β-unsaturated C=C double bond. Conclusion: An efficient method to synthesize pyrazolone thioethers by iodine-catalyzed sulfenylation of pyrazolones with aryl sulfonyl hydrazides in water was developed. Moreover, this method was employed to synthesize pyrazolone sulfones in one-pot by subsequent sulfenylation and oxidation reactions.

Ten-Vertex Polyhedral Monocarbaborane Chemistry. The Novel High-Yield Formation of the Ten-Vertex closo Compound [6-(PMe2Ph)-closo-1-CB9H9] from the Thermolysis of [8,8-(PMe2Ph)2-nido-8,7-PtCB9H11]

1993 ◽  
Vol 58 (12) ◽  
pp. 2924-2935 ◽  
Author(s):  
Jane H. Jones ◽  
Bohumil Štíbr ◽  
John D. Kennedy ◽  
Mark Thornton-Pett
Keyword(s):  
Nmr Spectroscopy ◽  
Diffraction Analysis ◽  
High Yield ◽  
Monoclinic Space Group ◽  
The Novel ◽  
X Ray Diffraction ◽  
Metal Centre ◽  
X Ray ◽  
Yield Formation ◽  
Boiling Toluene

Thermolysis of [8,8-(PMe2Ph)2-nido-8,7-PtCB9H11] in boiling toluene solution results in an elimination of the platinum centre and cluster closure to give the ten-vertex closo species [6-(PMe2Ph)-closo-1-CB9H9] in 85% yield as a colourles air stable solid. The product is characterized by NMR spectroscopy and single-crystal X-ray diffraction analysis. Crystals (from hexane-dichloromethane) are monoclinic, space group P21/c, with a = 903.20(9), b = 1 481.86(11), c = 2 320.0(2) pm, β = 97.860(7)° and Z = 8, and the structure has been refined to R(Rw) = 0.045(0.051) for 3 281 observed reflections with Fo > 2.0σ(Fo). The clean high-yield elimination of a metal centre from a polyhedral metallaborane or metallaheteroborane species is very rare.

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.

Synthesis, structural characterization and catalytic activity of chlororuthenium(II) complexes with substituted Schiff base/phosphine ancillary ligands

2020 ◽  
Vol 75 (9-10) ◽  
pp. 851-857
Author(s):  
Chong Chen ◽  
Fule Wu ◽  
Jiao Ji ◽  
Ai-Quan Jia ◽  
Qian-Feng Zhang
Keyword(s):  
Schiff Base ◽  
Catalytic Activity ◽  
Structural Characterization ◽  
Room Temperature ◽  
Molecular Structures ◽  
Cationic Complex ◽  
Neutral Complex ◽  
Ancillary Ligands ◽  
X Ray ◽  
X Ray Crystallography

AbstractTreatment of [(η6-p-cymene)RuCl2]2 with one equivalent of chlorodiphenylphosphine in tetrahydrofuran at reflux afforded a neutral complex [(η6-p-cymene)RuCl2(κ1-P-PPh2OH)] (1). Similarly, the reaction of [Ru(bpy)2Cl2·2H2O] (bpy = 2,2′-bipyridine) and chlorodiphenylphosphine in methanol gave a cationic complex [Ru(bpy)2Cl(κ1-P-PPh2OCH3)](PF6) (2), while treatment of [RuCl2(PPh3)3] with [2-(C5H4N)CH=N(CH2)2N(CH3)2] (L1) in tetrahydrofuran at room temperature afforded a ruthenium(II) complex [Ru(PPh3)Cl2(κ3-N,N,N-L1)] (3). Interaction of the chloro-bridged complex [Ru(CO)2Cl2]n with one equivalent of [Ph2P(o-C6H4)CH=N(CH2)2N(CH3)2] (L2) led to the isolation of [Ru(CO)Cl2(κ3-P,N,N-L2)] (4). The molecular structures of the ruthenium(II) complexes 1–4 have been determined by single-crystal X-ray crystallography. The properties of the ruthenium(II) complex 4 as a hydrogenation catalyst for acetophenone were also tested.

scholarly journals Near quantitative synthesis of urea macrocycles enabled by bulky N-substituent

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yingfeng Yang ◽  
Hanze Ying ◽  
Zhixia Li ◽  
Jiang Wang ◽  
Yingying Chen ◽  
...  
Keyword(s):  
High Efficiency ◽  
Molecular Structures ◽  
High Yield ◽  
Kinetic Control ◽  
High Concentration ◽  
Weak Association ◽  
Quantitative Synthesis ◽  
Thermodynamic Stabilization ◽  
Discrete Structures ◽  
Very High

AbstractMacrocycles are unique molecular structures extensively used in the design of catalysts, therapeutics and supramolecular assemblies. Among all reactions reported to date, systems that can produce macrocycles in high yield under high reaction concentrations are rare. Here we report the use of dynamic hindered urea bond (HUB) for the construction of urea macrocycles with very high efficiency. Mixing of equal molar diisocyanate and hindered diamine leads to formation of macrocycles with discrete structures in nearly quantitative yields under high concentration of reactants. The bulky N-tert-butyl plays key roles to facilitate the formation of macrocycles, providing not only the kinetic control due to the formation of the cyclization-promoting cis C = O/tert-butyl conformation, but also possibly the thermodynamic stabilization of macrocycles with weak association interactions. The bulky N-tert-butyl can be readily removed by acid to eliminate the dynamicity of HUB and stabilize the macrocycle structures.

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