نتایج جستجو برای: solvent free condition
تعداد نتایج: 857817 فیلتر نتایج به سال:
an efficient method for the friedel–crafts acylation of a wide range of aromatic compounds in good to excellent yields under solvent-free conditions, using iron zirconium phosphate (zpfe) was investigated. the catalyst is easy to prepare and shows interesting catalytic properties. the catalyst was characterized by some instrumental techniques such as xrd, icp-oes, sem and tem. a wide variety of...
p2o5-sio2 (30% w/w) was found to be a useful catalyst for the synthesis of various 2-substituted aryl benzimidazoles under solvent-less and in solvent conditions from o-phenylenediamine and aldehydes. the products were directly recrystallized from methanol.
a variety of alcohols readily add to 3,4-dihydro-2h-pyran under solvent free conditions in the presence of catalytic amount of acidic ionic liquid [et3n(ch2)4so3h][ots] to afford the corresponding tetrahydropyranyl ethers in good to excellent yields at room temperature. the use of this procedure allows easy separation of the desired products from ionic liquid and recycling the ionic liquid. som...
one of the most important goals in medicinal chemistry is the development of new techniques and new heterocyclic compounds with pharmaceutical activity. the present study aimed to use a method for the synthesis of some 1,2-dihydro-1-arylnaphtho [1,2-e] [1,3] oxazine-3-ones. the question this study tried to answer was this reaction can be performed in present of nano-fe2o3 as an acid catalyst an...
A simple, efficient, and cost-effective procedure for the N-tert-butoxycarbonylation and N-formylation of amines (primary, secondary) respectively, with di-tert-butyl dicarbonate and 85% aqueous formic acid under solvent-free condition using B(OSO3H)3/SiO2 (SBSA) as a heterogeneous and recyclable catalyst has been developed. We demonstrated that the resulting catalyst is applicable to various a...
dodecylbenzenesulfonic acid (dbsa) was used as an efficient, cheap and stable brønsted catalyst for acetylation of alcohols and phenols and formylation of alcohols under solvent-free conditions. various primary, secondary and tertiary alcohols were acetylated with acetic anhydride as an acetylating agent under solvent-free conditions in the presence of catalytic amount of dbsa at room temperatu...
an improved, simple, and facile synthesis of 3,4-dihydropyrimidin-2(1h)-ones by employing three-component, one-pot condensation reaction of β-keto ester, aromatic aldehydes, and urea or n-methylurea using lacl3/clch2cooh as an inexpensive and green chemistry catalyst system under solvent-free conditions described. compared with the classicalbiginelli reaction conditions, this method has the adv...
derivatives of thiazolidinone ring systems are known to act as anti-hiv infections , analgesic, anti-bacterial, anti-convulsant, anti parasitic, potential anti-inflammatory and herbicidal agents. due biological activities of thiazolidinones ring, several methods for their synthesis have been illustrated in literature. imidazolidine-2-thiones were synthesized by the oxidative cyclization of 1-be...
a series of tri- and tetra- substituted imidazoles were synthesized from benzyl, aldehyde and ammonium acetate in the presence of zeolite as an ecofriendly reusable catalyst under microwave irradiation in the absence of solvent. the yields are high to excellent and the use of microwave irradiation reduces reaction times to few minute.
cobalt hydrogensulfate is an efficient catalyst for the condensation of β-naphthol, aromatic aldehydes and 5,5-dimethyl-1,3-cyclohexanedione at 120 °c to afford 9,9-dimethyl-12-phenyl-8,10,11,12-tetrahydro-9-h-benzo[a]xanthen-11-one derivatives in high yields. also, polycondensation reactions of phenols with phthalic anhydride were carried out in the presence of cobalt hydrogensulphate under so...
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