نتایج جستجو برای: disubstituted urea
تعداد نتایج: 40692 فیلتر نتایج به سال:
Objective: The objective of the study is to synthesize some novel 1,5-benzodiazepine derivatives from chalcones. The structures of the newly synthesized compounds were characterized by elemental analysis, infrared, 1H nuclear magnetic resonance, and mass spectroscopic studies. All titled compounds were screened for their anti-inflammatory activity. Methods: In this study, a series of novel 2-(s...
BACKGROUND Prior work from these laboratories has centred on the development of enaminones as versatile intermediates for the synthesis of alkaloids and other nitrogen-containing heterocycles. In this paper we describe the enantioselective synthesis of indolizidine and quinolizidine analogues of bicyclic amphibian alkaloids via pyrrolidinylidene- and piperidinylidene-containing enaminones. RE...
Aminoglycoside 6'-acetyltransferase-Im (AAC(6')-Im) is the closest monofunctional homolog of the AAC(6')-Ie acetyltransferase of the bifunctional enzyme AAC(6')-Ie/APH(2")-Ia. The AAC(6')-Im acetyltransferase confers 4- to 64-fold higher MICs to 4,6-disubstituted aminoglycosides and the 4,5-disubstituted aminoglycoside neomycin than AAC(6')-Ie, yet unlike AAC(6')-Ie, the AAC(6')-Im enzyme does ...
Proline is unique among the natural amino acids in the similar propensity of its peptide bond to be in the cis or trans conformation.1 This attribute affects many processes, including the rate at which proteins fold,2 their structures,3 and their activities.4 Other aliphatic amino acids can serve as mimics for proline residues with transpeptide bonds. In contrast, chemical synthesis is needed t...
A diastereoselective access to β-lactam fused spirocyclic oxindoles and related compounds bearing all carbon spiro centers is described. This N-heterocyclic carbene-catalyzed process employed challenging β,β-disubstituted α,β-unsaturated imines to react with enals.
We have developed a highly effective copper-catalyzed decarboxylative coupling of alkynylcarboxylic acids with various aryl and alkyl halides at 2 mol% loading of copper. This method is simple, economical and practical for the synthesis of disubstituted alkyne compounds.
The nature of the 7-substituent has a remarkable effect on the diastereoselectivity of the oxidative rearrangement of indole-2-carboxamides derived from (S)-2-methoxymethylpyrrolidine into chiral 3,3-disubstituted oxindoles.
A silver-catalyzed tandem decarboxylative radical addition/cyclization of N-arylcinnamamides with aliphatic carboxylic acids is reported. This method affords a novel and straightforward route to various 3,4-disubstituted dihydroquinolin-2(1H)-ones in aqueous solution.
5-Substituted and 5,5-disubstituted hydantoins are synthesised from the corresponding aldehydes or ketones, using a one-pot, gallium(III) triflate-catalysed procedure that is compatible with a range of substrates and solvents.
A chemo-, regio-, and stereoselective iron-catalyzed 1,4-hydroboration of dienes that affords gamma-disubstituted allylboranes has been developed. 1,4-Hydroboration of 2-substituted dienes forms allylborane products with (E)-trisubstituted double bonds exclusively.
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