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Fast and convenient synthesis of Fenclofenac using Ullmann ether coupling and the Willgerodt-Kindler reaction under microwave conditions
Fenclofenac is a non-steroidal anti-inflammatory drug with analgesic and anti-inflammatory activity. This short report describes the efficient synthesis of Fenclofenac using SmithSynthesizer (a single-mode automated microwave instrument). |
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A new approach to the synthesis of Atenolol
A powerpoint presentation "Integrating Microwave Synthesis and Flash Purification as Enabling Tools in Drug Discovery". |
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Efficient and versatile Microwave-Assisted Synthesis of Bezafibrate employing
Bezafibrate is a well-known lipid- and cholesterol-lowering drug. Development of bezafibrate synthesis under microwave conditions would allow fast preparation of analog libraries by combining combinatorial approaches into this developed protocol. |
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Regioselective and Rapid - Heck arylations using Microwave Synthesis
Heck reactions utilizing a therostable catalyst in combination with microwave irradiation have been performed. A substantial enhancement of reaction rates as well as excellent regiocontrol could be obtained under microwave conditions without using inert gas. |
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Suzuki Coupling on Solid-Phase using Microwave Synthesis
Solid-Phase Suzuki couplings using microwave irradiation have been performed. The reaction times were considerably shorter than those using conventional heating conditions. |
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One pot Synthesis of Acyclovir using Microwave Synthesis
A one-pot process for the preparation of Acyclovir from guanine is described. The key step involves a trimethylsilyl triflate (TfOTMS)-catalysed reaction of silylated guanine with 1,3-dioxalane under microwave irradiation. With this method, the yield is in the same range as with conventional heating, but the speed of the reaction is increased by a factor of 85. |
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Gel Phase 13C NMR Spectra Using ArgoGel Resin
Gel phase C NMR represent a powerful means of characterizing synthetic transformation on ArgoGel resin. The poloxyethylene (POE) chain and molecules bound to them are more mobile than the polystyrene back bone units and consequently give relatively sharp NMR lines. Signals from polystyrene backbone are largely absent due to anisotropic broadening.
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Expedient Deprotection of N-Alloc Groups Using PS-PPh3-Pd, a Polymer-Supported Palladium Catalyst in Conjunction with MP-Borohydride, a Polymer-Supported Borohydride
The selective protection and deprotection of functional groups is paramount in organic synthesis. Orthogonal protection and deprotection of primary and secondary amines is particularly important from the perspective of drug discovery, as amines and their derivaties are the most prevalent structural moieties found in the comprehensive medicinal chemistry database. |
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Microwave Assisted Copper-Free Sonogashira Coupling with a Polystyrene Bound Phosphine Ligand
Sonogashira coupling reactions of monosubstituted alkynes and aryl halides were performed with palladium acetate as catalyst and resin bound PS-Triphenylphosphine as ligand. No added copper salt was needed. Diethylamine or pyrrolidine was used as base and THF as solvent. The reactions were heated by microwaves to 130°C or 150°C for 15 minutes using Initiator™ Sixty. The observed conversions, measured by LC-MS, were typically 81-97 % for aryl bromides and aryl iodides and lower, 15-75 %, for aryl chlorides. Only traces of triphenylphosphine oxide could be detected after the reaction was completed. |
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Gould-Jacobs Quinoline-forming Reaction: A Comparision of Heating using Microwave Irradiation to 250oC and 300 oC
Quinolines are an important class of broad-spectrum antibiotics that were traditionally obtained by refluxing an aniline and diethyl ethoxymethylemalonate for several hours often in low yield. Heating the reaction mixture by microwaves to temperatures above the boiling points, with or without solvents, improves the yields and shortens the reaction time dramatically. |
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Diarylether-formation: A Comparison of Heating using Microwave Irradiation to
20 bar and 30 bar
The formation of diarylethers by reacting an arylhalide and phenol is usually a reaction demanding long reaction times, high temperatures and strong bases, in order to obtain acceptable yield. The substitution patent of the electrophile and the nucleophile affects the reaction times mostly. A sterically hindered electrophile and a strongly deactivated nucleophile as outlined, gives a very low yield (13 %) at conventional reflux for 2 weeks. Remainder was recovered starting material. We have previously reported the dramatically shortened reaction time to 1 hour along with improved yield running the reaction by heating by microwaves. |
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Nucleophilic Aromatic Substitution (SNAr)-Amination A Comparison of Heating using Microwave Irradiation to 250 oC and 300 oC
The formation of diarylamines by reacting anilines with aromatic electrophiles is, usually, a reaction demanding long reaction times, high temperatures and strong bases, in order to obtain acceptable yield, due to the low nucleophilicity of anilines. The Buchwald-Hartwig cross-coupling reaction is a very useable and elegant solution to this problem. Anticipating the classical metal-free SNAr-amination reaction, without using Pd-catalysts and strong bases, with only higher temperature and pressure as tool, gives no product at all at 180 ºC and very low conversion (9 %) at 220 ºC for 15 minutes when heating by microwaves. Remainder was unreacted starting material. |