نتایج جستجو برای: good yields
تعداد نتایج: 506625 فیلتر نتایج به سال:
a simple, mild and practical procedure has been developed for the synthesis of symmetrical and unsymmetrical ethers by using dmso, tbai in the presence of k2co3. we extended the utility of potassium carbonate as an efficient base for the preparation of ethers. a wide range of alkyl aryl and dialkyl ethers are synthesized from treatment of aliphatic alcohols and phenols with various alkyl halid...
silica sulfuric acid as an efficient and reusable heterogeneous catalyst has been used for the preparation of amidines 2 from formimidate 1 by reaction with aromatic amines at room temperature in good to excellent yields. imidate was prepared by treatment of equimolar quantities of triethyl orthoformate and diaminomaleonitrile in refluxing dioxane. all the compounds were characterized fully by ...
in the present of methylimidazolium hydrogen sulfate, the synthesis of arylidene heterobicyclic pyrimidinones is studied by condensation of aromatic aldehyde, cyclopentanone, and urea or thiourea. using solvent-free conditions, non-toxic and inexpensive materials, simple and clean work-up, short reaction times and good yields of the products are the advantages of this method.
poly(p-n-chlorostyrenesulphonamide) synthesized via direct chlorination of poly[(p-styrene) sulphonamide], can be used for selective chlorination of aromatic compounds. aromatic rings of the anisole, p-xylene, ethylbenzene and toluene are chlorinated with good yields. the polymer can be recovery, rechlorinated and reused several times.
some amide derivatives have been synthesized by the reaction of corresponding nitriles with potassium tert-butoxide as a nucleophilic oxygen source under ultrasonic irradiation. this new methodology provides good to excellent yields in short reaction times (15-90 min) at room temperature.
la(oac)3 has been used as an efficient catalytic system for the synthesis of quinoxalines. this method provides several advantages over methods that are currently employed such as a simple work-up, mild reaction conditions, good to excellent yields, and a process to recover and reuse the catalyst for five cycles with consistent activity.
a convenient synthesis of different types of polyfunctional dihydropyrrol-2-ones via one-pot four component reactions of formaldehyde, dialkyl acetylenedicarboxylates and amines, catalyzed by trichloroacetic acid (cl3cco2h) at room temperature has been investigated. the significant advantages of this synthetic method are mild reaction conditions, available and inexpensive material, short reacti...
vilsmeier-haack reaction of 2,3,3-trimethyl-3h-benzo[g]indole, then aqueous basic work-up, leads to benzo[g]indol-2-ylidene- malondialdehydes. these react with various arylhydrazines and quinolin-2-ylhydrazine to form 3,3-dimethyl-2-(1-aryl-1h-pyrazol-4-yl)- 3h-benzo[g]indoles in good yields.
a highly efficient and environmentally friendly synthesis of various 1,5-diaryl-3-(arylamino)-1h-pyrrol-2(5h)-ones catalyzed by 1-methylpiperidinium hydrogen sulfate via one-pot cyclo-condensation reaction ofaldehydes, amines and ethyl 2-oxopropanoate under ambient conditions has been explored. the presentmethodology offers several advantages such as good yields, simple procedure, shorter react...
cellulose was applied as a reusable and green catalyst for the facile four-component synthesis of 6-amino-4-aryl-3-methyl-1,4-dihydropyrano[2,3-c]pyrazole-5-carbonitrile derivatives using hydrazine monohydrate, ethyl acetoacetate, malononitrile and aryl aldehydes, under solvent-free and thermal conditions. the use of non-toxic and inexpensive catalyst, short reaction time, clean work-up and goo...
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