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1.
J Org Chem ; 89(4): 2649-2655, 2024 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-38279928

RESUMO

A very short stereoselective synthesis of enantiomerically pure (3S, 4aS, 10aR)-quinagolide has been developed. The key steps involved are a copper-catalyzed regioselective arylation of (S)-epichlorohydrin with 1,6-dimethoxynaphthalene and a diastereoselective trans-reduction of a cyclic enamine intermediate. The possibility to use both enantiomers of epichlorohydrin and the diastereodivergency found in the reduction process paves the way for a general preparation also in the nonracemic form of chiral trans-fused 3-substituted octahydrobenzo[g]quinolines that are privileged structures in medicinal chemistry.

2.
Molecules ; 28(17)2023 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-37687015

RESUMO

1,2- and 1,4-dihydropyridines and N-substituted 2-pyridones are very important structural motifs due to their synthetic versatility and vast presence in a variety of alkaloids and bioactive molecules. In this article, we gather and summarize the catalytic and stereoselective synthesis of partially hydrogenated pyridines and pyridones via the dearomative reactions of pyridine derivatives up to mid-2023. The material is fundamentally organized according to the type of reactivity (electrophilic/nucleophilic) of the pyridine nucleus. The material is further sub-divided taking into account the nucleophilic species when dealing with electrophilic pyridines and considering the reactivity manifold of pyridine derivatives behaving as nucleophiles at the nitrogen site. The latter more recent approach allows for an unconventional entry to chiral N-substituted 2- and 4-pyridones in non-racemic form.

3.
Org Biomol Chem ; 21(31): 6389-6396, 2023 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-37492953

RESUMO

The stereoselective reduction of a diastereoisomeric mixture of benzo[g]octahydroquinolinium ion was examined in detail. A diastereoselective borohydride reduction in combination with an efficient deacylative enzymatic resolution of its ß-aminoester precursor are the key steps for a stereoselective installation of the three chiral centres present in the (3S,4aS,10aR)-eutomer of the medicinal drug quinagolide. The obtained data paves the way for an easy and practical attainment of chiral 3-substituted octahydrobenzo[g]quinolines that are privileged structures in medicinal chemistry.

4.
Molecules ; 26(23)2021 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-34885983

RESUMO

The possibility to form new C-B bonds with aziridines using diboron derivatives continues to be a particularly challenging field in view of the direct preparation of functionalized ß-aminoboronates, which are important compounds in drug discovery, being a bioisostere of ß-aminoacids. We now report experimental and computational data that allows the individuation of the structural requisites and of reaction conditions necessary to open alkyl aziridines using bis(pinacolate)diboron (B2pin2) in a regioselective nucleophilic addition reaction under copper catalysis.

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