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.

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 Simple and Efficient Method for the Synthesis of Galactofuranosides

KIMIKA ◽  
2017 ◽  
Vol 27 (2) ◽  
pp. 38-49
Author(s):  
Gladys C. Completo ◽  
Reymart V. Sangalang ◽  
Beatrice M. I. Pique ◽  
Ruel C. Nacario
Keyword(s):  
Efficient Method ◽  
Room Temperature ◽  
One Pot ◽  
Tert Butanol ◽  
Derivatives Of ◽  
Selective Formation

An efficient and improved one-pot method for the synthesis of galactofuranosides via iodine-promoted cyclization of galactose diethyl dithioacetal in the presence of alcohol, acting both as solvent and nucleophile, is described. The reaction is carried out at room temperature. Alcohols, such as methanol, cyclohexanol and tert-butanol, were used as nucleophiles for the reaction using 2%, 3% and 5% iodine promoter, respectively. A key finding in this study was that the iodine-promoted cyclization of galactose diethyl dithioacetal with alcohol led to selective formation of β-galactofuranoside allowing the efficient preparation of derivatives of this monosaccharide.

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.

scholarly journals Semi-Industrial Fluorination of β-Keto Esters with SF4: Safety vs Efficacy

Synlett ◽  
2020 ◽  
Vol 31 (06) ◽  
pp. 565-574 ◽  
Author(s):  
Serhii A. Trofymchuk ◽  
Denys V. Kliukovskyi ◽  
Sergey V. Semenov ◽  
Andrii R. Khairulin ◽  
Valerii O. Shevchenko ◽  
...  
Keyword(s):  
Efficient Method ◽  
Medicinal Chemistry ◽  
Building Blocks ◽  
Keto Esters ◽  
Practical Recommendations

The possibility of deoxofluorination of β-keto esters using SF4 was investigated. The scope and limitation of the reaction were determined. The efficient method for the synthesis of β,β-difluorocarboxylic acids was elaborated based on the reaction. The set of mentioned acids, being the perspective building blocks for medicinal chemistry, were synthesized on multigram scale. The safety of SF4 use was discussed. The described method does not improve upon the safety of using SF4, but practical recommendations for working with the reagent are proposed. Despite the hazards of using toxic SF4, a significant increase of efficacy in the synthesis of medicinal-chemistry-relevant building blocks, based on the reaction, in comparison with earlier described approaches is shown.

Derivatives of cis-NPCl2(NSOCl)2 and (NPCl2)2NSOCl, Part X [1] Aminolysis of cis-NPCl2(NSOF)2 and (NPCl2)2NSOF

1978 ◽  
Vol 33 (9) ◽  
pp. 964-967 ◽  
Author(s):  
H. H. Baalmann ◽  
J. C. van de Grampel
Keyword(s):  
Data Structure ◽  
Nmr Spectroscopy ◽  
Spectral Data ◽  
Room Temperature ◽  
Nucleophilic Attack ◽  
Ring Systems ◽  
Cyclic Amines ◽  
Amino Derivatives ◽  
Derivatives Of

The aminolysis of the ring systems cis-NPCl2(NSOF)2 and (NPCl2) 2NSOF by cyclic amines in acetonitrile at room temperature shows the S-F bond to be stable towards a nucleophilic attack. The amino derivatives are characterized by their spectral data. Structure assignments are based on 31P NMR spectroscopy.

SuFEx Activation with Ca(NTf2)2: A Unified Strategy to Access Sulfamides, Sulfamates and Sulfonamides from S(VI) Fluorides

2020 ◽  
Author(s):  
Subham Mahapatra ◽  
Cristian P. Woroch ◽  
Todd W. Butler ◽  
Sabrina N. Carneiro ◽  
Sabrina C. Kwan ◽  
...  
Keyword(s):  
Room Temperature ◽  
Medicinal Chemistry ◽  
Mild Conditions ◽  
Broad Array

<p><br></p> <p>A method to activate sulfamoyl fluorides, fluorosulfates, and sulfonyl fluorides with calcium triflimide, and DABCO for SuFEx with amines is described. The reaction was applied to a diverse set of sulfamides, sulfamates, and sulfonamides at room temperature under mild conditions. Additionally, we highlight the application of this transformation to parallel medicinal chemistry to generate a broad array of nitrogen-based S(VI) compounds. </p>

SuFEx Activation with Ca(NTf2)2: A Unified Strategy to Access Sulfamides, Sulfamates and Sulfonamides from S(VI) Fluorides

2020 ◽  
Author(s):  
Subham Mahapatra ◽  
Cristian P. Woroch ◽  
Todd W. Butler ◽  
Sabrina N. Carneiro ◽  
Sabrina C. Kwan ◽  
...  
Keyword(s):  
Room Temperature ◽  
Medicinal Chemistry ◽  
Mild Conditions ◽  
Broad Array

<p><br></p> <p>A method to activate sulfamoyl fluorides, fluorosulfates, and sulfonyl fluorides with calcium triflimide, and DABCO for SuFEx with amines is described. The reaction was applied to a diverse set of sulfamides, sulfamates, and sulfonamides at room temperature under mild conditions. Additionally, we highlight the application of this transformation to parallel medicinal chemistry to generate a broad array of nitrogen-based S(VI) compounds. </p>

A Comprehensive Review on the Therapeutic Versatility of Imidazo [2,1-b]thiazoles

2020 ◽  
Vol 27 (40) ◽  
pp. 6864-6887 ◽  
Author(s):  
Mohd Adil Shareef ◽  
Irfan Khan ◽  
Bathini Nagendra Babu ◽  
Ahmed Kamal
Keyword(s):  
Literature Review ◽  
Medicinal Chemistry ◽  
Therapeutic Agents ◽  
Present Review ◽  
Thiazole Derivatives ◽  
Pharmacological Activities ◽  
Comprehensive Review ◽  
Derivatives Of

Background:: Imidazo[2,1-b]thiazole, a well-known fused five-membered hetrocycle is one of the most promising and versatile moieties in the area of medicinal chemistry. Derivatives of imidazo[2,1-b]thiazole have been investigated for the development of new derivatives that exhibit diverse pharmacological activities. This fused heterocycle is also a part of a number of therapeutic agents. Objective:: To review the extensive pharmacological activities of imidazo[2,1-b]thiazole derivatives and the new molecules developed between 2000-2018 and their usefulness. Method:: Thorough literature review of all relevant papers and patents was conducted. Conclusion:: The present review, covering a number of aspects, is expected to provide useful insights in the design of imidazo[2,1-b]thiazole-based compounds and would inspire the medicinal chemists for a comprehensive and target-oriented information to achieve a major breakthrough in the development of clinically viable candidates.

Preparation and Characterization of a Novel Room Temperature Dicationic Ionic Liquid and its Application in the Synthesis of Xanthenediones Under Solvent-Free Conditions

2018 ◽  
Vol 21 (8) ◽  
pp. 602-608 ◽  
Author(s):  
Zainab Ehsani-Nasab ◽  
Ali Ezabadi
Keyword(s):  
Ionic Liquid ◽  
Room Temperature ◽  
Reaction Times ◽  
Significant Loss ◽  
Solvent Free ◽  
Acidity Function ◽  
Efficient Catalyst ◽  
Solvent Free Conditions ◽  
Hammett Acidity Function ◽  
Dicationic Ionic Liquid

Aim and Objective: In the present work, 1, 1’-sulfinyldiethylammonium bis (hydrogen sulfate) as a novel room temperature dicationic ionic liquid was synthesized and used as a catalyst for xanthenediones synthesis. Material and Method: The dicationic ionic liquid has been synthesized using ethylamine and thionyl chloride as precursors. Then, by the reaction of [(EtNH2)2SO]Cl2 with H2SO4, [(EtNH2)2SO][HSO4]2 was prepared and after that, it was characterized by FT-IR, 1H NMR, 13C NMR as well as Hammett acidity function. This dicationic ionic liquid was used as a catalyst for the synthesis of xanthenediones via condensation of structurally diverse aldehydes and dimedone under solvent-free conditions. The progress of the reaction was monitored by thin layer chromatography (ethyl acetate/n-hexane = 3/7). Results: An efficient solvent-free method for the synthesis of xanthenediones has been developed in the presence of [(EtNH2)2SO][HSO4]2 as a powerful catalyst with high to excellent yields, and short reaction times. Additionally, recycling studies have demonstrated that the dicationic ionic liquid can be readily recovered and reused at least four times without significant loss of its catalytic activity. Conclusion: This new dicationic ionic liquid can act as a highly efficient catalyst for xanthenediones synthesis under solvent-free conditions.

Therapeutic Journey of 5-Pyrazolones as a Versatile Scaffold: A Review

2021 ◽  
Vol 21 ◽  
Author(s):  
Ravinder Sharma ◽  
Pooja A. Chawla ◽  
Viney Chawla ◽  
Rajeev Verma ◽  
Nandita Nawal ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Protease Inhibitor ◽  
Medicinal Chemistry ◽  
Membered Ring ◽  
Present Review ◽  
Biological Profile ◽  
3C Protease ◽  
Structure Activity ◽  
Derivatives Of ◽  
Heterocyclic Moiety

Abstract: A sizeable proportion of currently marketed drugs come from heterocycles. The heterocyclic moiety 5-pyrazolone is well known five membered ring containing nitrogen. Derivatives of this wonder nucleus have exhibited activities as diverse as antimicrobial, anti-inflammatory, analgesic, antidepressant, anticonvulsant, antidiabetic, antihyperlipidemic, antiviral, antitubercular, antioxidant, anticancer and antiviral including action against severe acute respiratory syndrome (SARS) or 3C protease inhibitor. A number of drugs based on this motif have already made it to the market. Standard texts and literature on medicinal chemistry cite different approaches for the synthesis of 5-pyrazolones. The present review provides an insight view to 5-pyrazolone synthesis, their biological profile and structure activity relationship studies.

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