نتایج جستجو برای: nucleophilic opening
تعداد نتایج: 54008 فیلتر نتایج به سال:
BACKGROUND The carbonyl group at position 2 of N-acetylisatin behaves as an amide which is more susceptible to nucleophilic attack via ring-opening in the presence of nucleophiles. Because of this behavior, in the present work we describe the microwave synthesis of a series of α-ketoamide and bis-(α-ketoamide) derivatives via the facile ring-opening of N-acylisatin with different amines and dia...
Background: The carbonyl group at position 2 of N-acetylisatin behaves as an amide which is more susceptible to nucleophilic attack via ring-opening in the presence of nucleophiles. Because of this behavior, in the present work we describe the microwave synthesis of a series of α-ketoamide and bis-(α-ketoamide) derivatives via the facile ring-opening of N-acylisatin with different amines and di...
Reactions which assemble multiple stereocenters in a highly convergent manner provide new avenues for the synthesis of complex natural products. Oxabicyclic compounds have been shown to be useful precursors to highly functionalized cyclic and acyclic compounds following reaction with a variety of nucleophiles including carbon, silicon and hydride. The regio-, stereo-, and enantioselectivity of ...
Oxiranes are famous and very interesting compounds with a wide range application, they have found in the chemistry and industry. It is well known, that their ring opening is possible as in acidand in base reaction conditions, as well as by nucleophilic attack from the internal or external nucleophile molecule. The acid-catalyzed ring opening reaction has been described by T. Biela, P. Kubisa, R...
FosA is a manganese-dependent enzyme that utilizes a Mn(2+) ion to catalyze the inactivation of the fosfomycin antibiotic by glutathione (GSH) addition. We report a theoretical study on the catalytic mechanism and the factors governing the regioselectivity and chemoselectivity of FosA. Density functional theory (DFT) calculations on the uncatalyzed reaction give high barriers and almost no regi...
Complementary electrostatic interaction between the zwitterionic merocyanine and dipolar molecules has emerged as a common strategy for reversibly structural conversion of spiropyrans. Herein, we report a concept-new approach for thermal switching of a spiropyran that is based on simultaneous nucleophilic-substitution reaction and electrostatic interaction. The nucleophilic-substitution at spir...
Stereodivergent SN2@P reactions of borane oxazaphospholidines: experimental and theoretical studies.
The stereodivergent ring-opening of 2-phenyl oxazaphospholidines with alkyl lithium reagents is reported. N-H oxazaphospholidines derived from both (+)-cis-1-amino-2-indanol and (-)-norephedrine provide inversion products in a highly stereoselective process. In contrast, N-Me oxazaphospholidines yield ring-opening products with retention of configuration at the P center, as previously reported ...
Precise structure-property relation of a biodegradable polymer (e.g., aliphatic polyester) is anticipated only if monomer units and chiral centers are arranged in a defined primary sequence as a biomacromolecule. An emerging synthetic methodology, namely segmer assembly polymerization (SAP), is introduced in this paper to reveal the latest progress in polyester synthesis. Almost any periodic po...
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