Asymmetric induction in the Sommelet rearrangement of chiral benzyl sulfonium salts

1976 ◽  
Vol 54 (2) ◽  
pp. 193-201 ◽  
Author(s):  
Stewart John Campbell ◽  
David Darwish
Keyword(s):  
Sodium Methoxide ◽  
Room Temperature ◽  
Exchange Resin ◽  
Shift Reagent ◽  
Asymmetric Induction ◽  
High Yield ◽  
Sulfonium Salts ◽  
Sodium Methoxide Solution ◽  
Derivatives Of ◽  
Sulfone Derivatives

The Sommelet rearrangement of (+)-ethylmethyl-p-nitrobenzylsulfonium perchlorate, (+)-1, and (+)-ethylmethyl-p-chlorobenzylsulfonium perchlorate, (+)-2, are described. Elution of (+)-1 through an hydroxide exchange resin generated ethylmethylsulfonium p-nitro-benzylide (+)-3 which decomposed in methanol at room temperature to ethyl 2-methyl-5-nitro-benzyl sulfide, 6, and (+)-methyl α-(2-methyl-5-nitrophenyl)ethyl sulfide, (+)-7, with 18 to 20.3% asymmetric induction. Decomposition of (+)-2 in sodium methoxide solution at 70 °C for 2 h produced ethyl 2-methyl-5-chlorobenzyl sulfide, 8, and (+)-methyl α-(2-methyl-5-nitro-phenyl)ethyl sulfide, (+)-9, with 21 to 25.5% asymmetric induction. The lower estimates of asymmetric induction for each sulfide were made by comparison with specific rotations of authentic samples obtained by synthesis and resolution. The higher estimates were obtained by the use of a chiral lanthanide shift reagent Eu(hfbc)3 with the sulfone derivatives of these chiral sulfides. The ylide (+)-3 reacted with aldehydes in high yield to produce oxiranes with no induction of asymmetry.

Synthetic use of the ribosyl derivatives of 2,4- and 2,5-thiazolidinediones

1979 ◽  
Vol 44 (5) ◽  
pp. 1475-1482 ◽  
Author(s):  
Hubert Hřebabecký ◽  
Zdeněk Točík ◽  
Jiří Beránek
Keyword(s):  
Hydrazine Hydrate ◽  
Hydrogen Chloride ◽  
Sodium Methoxide ◽  
Aqueous Ammonia ◽  
Hydroxylamine Hydrochloride ◽  
Acetyl Derivative ◽  
High Yield ◽  
Derivatives Of ◽  
Methanolic Ammonia

On ribosidation of 2,4-thiazolidinedione (2,5-thiazolidinedione, respectively), the 3-β-D-ribofuranosyl derivative is formed in high yield, either the benzoyl derivative Ia (IIa) or the acetyl derivative Ib (IIb). The unsubstituted ribosyl derivative Ic is formed from the acetyl derivative Ib by methanolic hydrogen chloride. The benzoylated ribosyl-2,4-thiazolidinedione Ia affords the benzoylated ribosylurea III on reaction with aqueous ammonia, the hydroxyethylurea derivative IVa with 2-aminoethanol, the semicarbazide derivative Va with hydrazine hydrate, the ribosylhydroxyurea derivative VIa on reaction with hydroxylamine hydrochloride and triethylamine, the benzoyl derivative of ribosylbiuret VII with O-methylisourea hydrochloride and triethylamine, and (analogously) ribosylisothiobiuret VIII with S-methylisothiourea. Methanolysis of the benzoyl derivative of hydroxyethylurea IVa with sodium methoxide affords the unprotected riboside IVb. Ribosylhydroxyurea VIb is formed on debenzoylation of compound VIa with methanolic ammonia. Acetylation of compound VIb furnishes the pentaacetyl derivative VIc.

Preparation of the 2,3-anhydro-4,6-O-benzylidene derivatives of methyl α- and β-D-talopyranoside and of methyl α-D-gulopyranoside

1980 ◽  
Vol 33 (5) ◽  
pp. 1021 ◽  
Author(s):  
JL Frahn
Keyword(s):  
Dimethyl Sulfoxide ◽  
Sodium Methoxide ◽  
Room Temperature ◽  
Derivatives Of

Instructions are given for preparing the title compounds in reproducibly good yields from the appropriate anomer of methyl 4,6-O-benzylidene-2,3-di-O-tosyl-D-galactopyranoside. The α-anomer is converted into a mixture of the anhydro-α-taloside and anhydro-α- guloside by reaction with sodium methoxide in dimethyl sulfoxide as solvent at room temperature. The β-anomer forms the anhydro-β-taloside under similar conditions but with dioxan as solvent for the reactants.

scholarly journals Room Temperature N-Arylation of 1,2,4-Triazoles under Ligand-Free Condition

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Nikhil V. Suramwar ◽  
Sanjay R. Thakare ◽  
Niraj T. Khaty
Keyword(s):  
Room Temperature ◽  
Cuo Nanoparticles ◽  
High Yield ◽  
Wide Scope ◽  
Aryl Iodide ◽  
Free Condition ◽  
Short Period ◽  
Ligand Free ◽  
Nitrogen Nucleophiles ◽  
Derivatives Of

A simple and efficient method for N-arylation of 1,2,4-triazole at room temperature was described by the use of predominant (111) facet CuO nanoparticles as a catalyst in ligand-free condition. The catalyst was recyclable, and a variety of substrates give N-arylation product in high yield with short period of reaction time. The wide scope of this catalyst led us to investigate transformations involving less-reactive nitrogen nucleophiles, such as imidazole and pyrazoles. We were pleased to find that various derivatives of azoles were effectively coupled with aryl iodide to afford the desired N-arylated product in excellent yield.

scholarly journals An efficient green synthesis of polyfunctional pyrazole-triazole hybrids and bis-triazoles via chromium incorporated fluorapatite encapsulated iron oxide nanocatalyst

2021 ◽  
Vol 10 (4) ◽  
pp. 445-458 ◽  
Author(s):  
Iman Rezaei ◽  
Manouchehr Mamaghani
Keyword(s):  
Iron Oxide ◽  
Reaction Time ◽  
Green Synthesis ◽  
Room Temperature ◽  
Reaction Times ◽  
Catalytic Performance ◽  
High Yield ◽  
External Magnet ◽  
Ft Ir ◽  
Derivatives Of

In this report, novel chromium incorporated fluorapatite encapsulated iron oxide (γ-Fe2O3@FAp@Cr) nanocatalyst was synthesized and characterized by FT-IR, TEM, SEM, XRD and EDX techniques. The catalyst was used in the synthesis of various derivatives of pyrazole-triazole hybrids via the reaction of thiosemicarbazide or semicarbaside and pyrazolecarbaldehydes at room temperature with excellent yields and short reaction times. The protocol was also used in the synthesis of bis-triazoles in high yield and reasonable reaction time. The nanocatalyst was comfortably separated from the reaction mixture by an external magnet and was reused in six consecutive cycles without any remarkable changes in its catalytic performance.

Synthesis of 3-methyl-4H-benzo[b][1,4]thiazine-2-carboxylates using CAN as a catalyst and its conversion into guanidines.

2020 ◽  
Vol 07 ◽  
Author(s):  
Dhanaji V. Jawale ◽  
Devendra Wagare ◽  
Dinesh L. Lingampalle ◽  
Prashant D. Netankar
Keyword(s):  
Efficient Method ◽  
Sodium Methoxide ◽  
Room Temperature ◽  
Medicinal Chemistry ◽  
Guanidine Hydrochloride ◽  
Nucleophilic Attack ◽  
Efficient Catalyst ◽  
Enolic Form ◽  
Keto Esters ◽  
Derivatives Of

Background: 1,4-benzothiazine carboxylates show wide application in the field of medicinal chemistry. Therefore, we have designed convenient and efficient method for the synthesis of 1,4-benzothiazine carboxylates. Objective: Synthesis of 1,4-benzothiazine carboxylates and its guanidines by simple and facile method using efficient catalyst. Method: Derivatives of 1,4-benzothiazine carboxylates were synthesized by cyclocondensing β-keto esters with 2- aminobenzenethiols using CAN as a catalyst at room temperature. 1,4-benzothiazine caboxylate,condensed with guanidine hydrochloride in the presence of sodium methoxide in DMF to obtained new 3-substituted-l-4Hbenzo[b][1,4]thiazine-2-carboxyguanidines (88-91%). Results: All the products were obtained with good to excellent yields within 40 min. Here, CAN oxidizes aminothiophenol into disulfide and then nucleophilic attack of enolic form of β-ketoesters on the disulphide and 1, 4-benzothiazine acetates, were obtained with good yields. Conclusion: We have designed convenient and efficient method for the synthesis of 1,4-benzothiazine carboxylates. Most remarkable features of this cyclocondensation such as use of efficient catalyst and non-volatile solvent under mild reaction condition to obtained excellent yield.

Synthesis of 3,4-Dihydropyrano[c]chromenes Using Carbon Microsphere Supported Copper Nanoparticles (Cu-NP/C) Prepared from Loaded Cation Exchange Resin as a Catalyst

2019 ◽  
Vol 16 (2) ◽  
pp. 288-293
Author(s):  
Yogesh W. More ◽  
Sunil U. Tekale ◽  
Nitishkumar S. Kaminwar ◽  
László Kótai ◽  
Tibor Pasinszki ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Cation Exchange ◽  
Copper Nanoparticles ◽  
Exchange Resin ◽  
Cation Exchange Resin ◽  
Environmentally Benign ◽  
High Yield ◽  
Carbon Microsphere ◽  
Catalytic Material ◽  
Operational Simplicity

Aim and Objective: The present study was performed with the aim to develop an efficient and environmentally benign protocol for the synthesis of biologically siginifcant 3, 4-dihydropyrano[c]chromenes using a new catalytic material. The protocol involves the use of a reusable, environment friendly materials and solvents with operational simplicity. Materials and Methods: Carbon microsphere supported copper nanoparticles (Cu-NP/C) prepared from loaded cation exchange resin were synthesized, characterized with well versed analytical techniques such as XRD, SEM and Raman spectroscopy and the synthesized material was used as a catalyst for the environmentally benign synthesis of 3,4-dihydropyrano[c]chromenes. Results: The formation of carbon microsphere supported copper nanoparticles (Cu-NP/C) prepared from loaded cation exchange resin was confirmed by XRD, SEM and Raman spectroscopy which was employed as a heterogeneous material for the synthesis of 3,4-dihydropyrano[c]chromenes. The products formed were characterized by the analysis of spectroscopic data - NMR, IR and mass. The safe catalytic system offers several advantages including operational simplicity, environmental friendliness, high yield, and reusability of catalyst and green chemical transformation. Conclusion: Herein we report an easy and efficient protocol for the one-pot synthesis of dihydropyrano[ c]chromenes using environmentally benign MCR approach in ethanol as the green solvent. The method developed herein constitutes a valuable addition to the existing methods for the synthesis of titled compounds.

Development of the room temperature protocol based on room temperature ionic liquids and surfactant ionic liquids for the synthesis of derivatives of 2-amino-thiazoles and thermo-physical analysis of the synthesized derivatives using TGA-DSC.

2020 ◽  
Vol 10 ◽  
Author(s):  
Chandrakant Sarode ◽  
Sachin Yeole ◽  
Ganesh Chaudhari ◽  
Govinda Waghulde ◽  
Gaurav Gupta
Keyword(s):  
Thermal Analysis ◽  
Heat Capacity ◽  
Ionic Liquids ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Room Temperature ◽  
Heat Capacity Data ◽  
General Strategy ◽  
Capacity Data ◽  
Derivatives Of

Aims: To develop an efficient protocol, which involves an elegant exploration of the catalytic potential of both the room temperature and surfactant ionic liquids towards the synthesis of biologically important derivatives of 2-aminothiazole. Objective: Specific heat capacity data as a function of temperature for the synthesized 2- aminothiazole derivatives has been advanced by exploring their thermal profiles. Method: The thermal gravimetry analysis and differential scanning calorimetry techniques are used systematically. Results: The present strategy could prove to be a useful general strategy for researchers working in the field of surfactants and surfactant based ionic liquids towards their exploration in organic synthesis. In addition to that, effect of electronic parameters on the melting temperature of the corresponding 2-aminothiazole has been demonstrated with the help of thermal analysis. Specific heat capacity data as a function of temperature for the synthesized 2-aminothiazole derivatives has also been reported. Conclusion: Melting behavior of the synthesized 2-aminothiazole derivatives is to be described on the basis of electronic effects with the help of thermal analysis. Additionally, the specific heat capacity data can be helpful to the chemists, those are engaged in chemical modelling as well as docking studies. Furthermore, the data also helps to determine valuable thermodynamic parameters such as entropy and enthalpy.

Reactions of 3-cyano-1-methylquinolinium methyl sulphate with some C-acids and with p-nitroaniline

1981 ◽  
Vol 46 (2) ◽  
pp. 503-505 ◽  
Author(s):  
Oldřich Kocián ◽  
Miloslav Ferles
Keyword(s):  
Sodium Methoxide ◽  
Ethyl Cyanoacetate ◽  
Derivatives Of

The action of malononitrile, ethyl cyanoacetate, dibenzoylmethane and/or p-nitroaniline on compound I in the presence of sodium methoxide gives rise to derivatives of 3-cyano-1-methyl-1,4-dihydroquinoline, II and III

Preparation of Chloro and Sulfanyl Derivatives of 1-(2-Deoxy-4-C-hydroxymethyl-α-L-threo-Pentofuranosyl)uracil

1997 ◽  
Vol 62 (7) ◽  
pp. 1114-1127 ◽  
Author(s):  
Hubert Hřebabecký ◽  
Jan Balzarini ◽  
Antonín Holý
Keyword(s):  
Nucleophilic Substitution ◽  
Hydrogen Chloride ◽  
Thionyl Chloride ◽  
Sodium Methoxide ◽  
Thioacetic Acid ◽  
Uracil Derivatives ◽  
Derivatives Of ◽  
Hiv 1

3'-Chloro and 3'-acetylsulfanyl derivatives of 1-(2-deoxy-4-C-hydroxymethyl-α-L-threo-pentofuranosyl)uracil were prepared by reaction of 2,3'-anhydro-1-{5'-O-benzoyl-4'-C-[(benzoyloxy)methyl]-2'-deoxy-α-L-erythro-pentofuranosyl}uracil (3) with hydrogen chloride and thioacetic acid, respectively. The reaction with hydrogen chloride gave a mixture of N-1 and N-3 substituted uracil derivatives 12 and 14. Reaction of 1-{3-O-benzoyl-4-C-[(benzoyloxy)methyl]-2-deoxy-α-L-threo-pentofuranosyl}uracil (7) with thionyl chloride and subsequent debenzoylation afforded 1-(4-C-chloromethyl-2-deoxy-β-D-erythro-pentofuranosyl)uracil (19). Nucleophilic substitution with lithium thioacetate, followed by deacylation, converted 1-{3-O-benzoyl-4-C-[(benzoyloxy)methyl]-2-deoxy-5-O-p-toluenesulfonyl-α-L-threo-pentofuranosyl}uracil (9) into 1-(2-deoxy-4-C-sulfanylmethyl-β-D-erythro-pentofuranosyl)uracil (21). The obtained thiols were oxidized with iodine or air to give 1,1'-[disulfandiylbis(2,3-dideoxy-4-hydroxymethyl-α-L-threo-pentofuranose-3,1-diyl]di(pyrimidine-2,4-(1H,3H)-dione) (17) and 1,1'-[disulfandiylbis(2,5-dideoxy-4-hydroxymethyl-α-L-threo-pentofuranose-5,1-diyl]di(pyrimidine-2,4(1H,3H)-dione) (22). Reaction of 1-{3-acetylsulfanyl-5-O-methanesulfonyl-4-C-[(benzoyloxy)methyl]-2,3-dideoxy-α-L-threo-pentofuranosyl)}uracil (24) with methanolic sodium methoxide afforded 1-(3,5-anhydro-2,3-dideoxy-4-C-hydroxymethyl-3-sulfanyl-α-L-threo-pentofuranosyl)uracil (25). The same reagent was used in the preparation of 1-(3,5-anhydro-2-deoxy-4-C-hydroxymethyl-α-L-threo-pentofuranosyl)uracil (26) from 1-{4-C-[(benzoyloxy)methyl]-2-deoxy-5-O-p-toluenesulfonyl-α-L-threo-pentofuranosyl}uracil (8). From the series of 4'-substituted 2'-deoxyuridine derivatives, synthesized in this study, solely the 4'-chloromethyl derivative 19 and the oxetane derivative 26 exhibited an appreciable activity against HIV-1 and HIV-2.

4‐Aryl‐2‐Imino‐1,3‐Dithiolanes from the Room Temperature Coupling of Sodium Dithiocarbamates with Sulfonium Salts

2021 ◽  
Vol 2021 (10) ◽  
pp. 1615-1622
Author(s):  
Giulio Bresciani ◽  
Fabio Marchetti ◽  
Gianluca Ciancaleoni ◽  
Guido Pampaloni
Keyword(s):  
Room Temperature ◽  
Sulfonium Salts
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