نتایج جستجو برای: green protocol
تعداد نتایج: 387391 فیلتر نتایج به سال:
The awarding of this year's Nobel Prize in Chemistry to Osamu Shimomura, Martin Chalfie, and Roger Tsien for their discovery and development of green fluorescent protein earns this humble jellyfish protein a place of honor in the biology research hall of fame.
A simple and green chemical procedure was reported for the synthesis of dihydropyrimidinones from various aldehydes, ethyl acetoacetate and urea or thiourea using holmium chloride as catalyst. The reactions were performed under solvent free conditions with ultrasound irradiation as the energy source. The advantages of this protocol include the excellent yield, operational simplicity, short tim...
A highly efficient, simple and green solvent-free protocol for the preparation of poly-substituted quinolines via Friedländer hetero-annulation reaction between 2-aminoaryl ketones and carbonyl compounds in the presence of silica-supported P2O5 (P2O5 / SiO2) is described. In this method, the title compounds are obtained in high to exc...
A very efficient one-pot three-component synthesis of pyran derivatives has been improved by condensation of aldehydes and malononitrile with dimedone under 80 °C using sucrose as natural and biodegradable catalyst in water. This method offers some advantages including inexpensive, high to quantitative yields, short reaction time, and easy work-up. Therefore, this methodology is entirely g...
A green and highly effective solvent-free protocol has been reported for the synthesis of N,N′-alkylidene bisamides via the reaction of arylaldehydes (1 eq.) with primary amides (2 eq.) in the presence of saccharin-N-sulfonic acid (SaSA) as a solid-acid catalyst. The mentioned compounds have been obtained in high yields and short reaction times.
A novel, organocatalytic and environmentally friendly protocol for the synthesis of polysubstituted tetrahydrofurans from trivial starting materials has been described. By employing 2,2,2-trifluoroacetophenone-mediated oxidation, which utilizes H2O2 as a green oxidant, we introduce a sustainable procedure that embraces the principles of green chemistry for the production of substituted tetrahyd...
In this protocol, 3-(2-carboxybenzoyl)-1-methyl-1H-imidazol-3-ium chloride [Cbmim]Cl and sulfonic acid functionalized pyridinium chloride [pyridine-SO3H]Cl as a new, reusable, and green Brønsted acidic ionic liquid (BAIL) catalyst were synthesized and successfully used for the one-pot ring opening of epoxide with sodium azide (NaN3) in water at room temperature. Epoxides under ring-opening easi...
background: recently different studies suggested that discontinuation of gonadotrophin releasing hormone analogue (gnrha) at beginning of ovarian stimulation (improvement of ovarian response to gonadotrophins) may have some benefit to poor responder patients in invitro fertilization (ivf) cycles. objective:the efficacy of gnrha stop protocol in poor responder patients in ivf cycles was assessed...
objective: this study was conducted to compare the results of fixed versus flexible gnrh antagonist protocols in controlled ovarian stimulation for intra cytoplasmic sperm injection (icsi) in patients with pcos. materials and methods: a randomized clinical trial was performed on 100 pcos women, who were admitted to a tertiary infertility clinic and were candidate for ivf/icsi. they were divided...
Na2SO4 as an inexpensive and effective catalyst has provided a green protocol for the synthesis of tetrahydrobenzo[b]pyran, pyrano[2,3-d]pyrimidinone and dihydropyrano[3,2c]chromene derivatives from the three-component domino reaction of aromatic aldehydes and malononitrile with 4-hydroxycoumarin/ dimedone/ barbituric acid in ethanol/water as a mixture of solvent that, this mixture entirely is ...
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