نتایج جستجو برای: heterocycles
تعداد نتایج: 2986 فیلتر نتایج به سال:
One-pot synthesis of heterocycles having a nitromethyl group was achieved by sequential steps that involved chloronitration of alkenes using iron(III) nitrate nonahydrate followed by elimination and intramolecular Michael addition. This reaction provides an efficient method for the synthesis of heterocycles due to the simple experimental procedure and the use of inexpensive reagents of low toxi...
We report here a novel method for the modular synthesis of highly substituted piperazines and related bis-nitrogen heterocycles via a palladium-catalyzed cyclization reaction. The process couples two of the carbons of a propargyl unit with various diamine components to provide nitrogen heterocycles in generally good to excellent yields and high regio- and stereochemical control.
Pd(II)-catalysed ortho-arylation of benzylic heterocycles with arylboronic acid pinacol esters (Ar-BPin) via directed C-H bond activation to generate the desired biaryl products is reported. This methodology is efficient and applicable to a wide range of functionalised Ar-BPin and benzylic heterocycles, allowing the direct synthesis of important biaryl motifs in modest to good yield.
The iron-catalyzed arylation of aromatic heterocycles, such as pyridines, thiophenes, and furans, has been achieved. The use of an imine directing group allowed for the ortho functionalization of these heterocycles with complete conversion in 15 min at 0 °C. Yields up to 88% were observed in the synthesis of 15 heterocyclic biaryls.
The utility of wild-type and variant carboxymethylproline synthases for biocatalysis was demonstrated by preparing functionalised 5-, 6- and 7-membered N-heterocycles from amino acid aldehydes and (alkylated) malonyl-coenzyme A derivatives; the N-heterocycles produced were converted to the corresponding bicyclic beta-lactams by a carbapenem synthetase.
Intermolecular [3 + 2] annulation of cyclopropylanilines with alkynes is realized using visible light photoredox catalysis, yielding a variety of cyclic allylic amines in fair to good yields. This method exhibits significant group tolerance particularly with heterocycles. It can also be used to prepare complex heterocycles such as fused indolines.
A range of heterocycles, namely thiazoles, imidazoles, imidazopyridines, thiazolidines and dimethoxyindoles, have been synthesised directly from alkenes via a two-step ketoidoination/cyclisation protocol. The alkene starting materials are themselves readily accessible using many different and well-established approaches, and allow access to a variety of heterocycles with excellent yields and re...
A versatile nitro-Mannich/lactamisation cascade for the direct stereoselective synthesis of heavily decorated 5-nitropiperidin-2-ones and related heterocycles has been developed. A highly enantioenriched substituted 5-nitropiperidin-2-one was synthesised in a four component one-pot reaction combining an enantioselective organocatalytic Michael addition with the diastereoselective nitro-Mannich/...
The Co(II) atom in the title compound, [Co(C(12)H(8)N(5))(2)(H(2)O)(4)]·2H(2)O, lies on a center of inversion and is bonded to two N-heterocycles and to four water mol-ecules in a slightly distorted octahedral coordination. The coordinated and lattice water mol-ecules inter-act with the N-heterocycles through O-H⋯N hydrogen bonds, generating a three-dimensional supra-molecular architecture.
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