نتایج جستجو برای: 4 dihydropyridines
تعداد نتایج: 1304881 فیلتر نتایج به سال:
Copper-catalyzed 6-endo cyclization of N-propargylic β-enaminocarbonyls was developed for the synthesis of oxidation-labile 1,6-dihydropyridines. This synthetic method allows flexible and regio-defined assembly of various substituents at the N1, C2, C3, C4, and C6 positions of 1,6-dihydropyridines under mild conditions.
The ethoxycarbonylmethyl esters of 1,4-dihydropyridines were directly converted into carbamoylmethyl esters in the presence of 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) in good to excellent yields under mild conditions. The use of TBD is crucial for the successful aminolysis of ethoxycarbonylmethyl ester of 1,4-dihydropyridines with secondary amines as without it the reaction does not proceed a...
Enantioselective N-heterocyclic carbene-catalyzed nucleophilic dearomatization of alkyl pyridiniums.
NHC-catalyzed nucleophilic dearomatization of alkyl pyridiniums has been achieved to generate 1,4-dihydropyridines with high enantioselectivity. This is a rare example of catalytic, asymmetric addition of a nucleophile to the activated pyridinium that prefers C-4 functionalization leading to the 1,4-dihydropyridine with high selectivity.
Pacemaking activity in adult substantia nigra (SN) dopamine neurons relies on L-type Ca2+ channels, but a surprising study in Nature by Chan et al. demonstrates that blockade of these channels by dihydropyridines re-establishes the pacemaking driven by sodium and HCN channels found in juvenile SN. This shift protects SN neurons in chemical models of Parkinson's disease (PD), suggesting that ele...
SYNTHESIS AND BIOLOGICAL ACTIVITY OF NITROOXYMETHYL- AND NITROOXYACYLOXY-PHENYL-l,4-DIHYDROPYRIDINES
the o-nitrophenyl group at position 4 of dihydropyridine of nifedipine analogues was replaced with 2-alkylthio-1-benzyl-5-imidazolyl substituent. starting from dihydroxyacetone 2-alkythio-1-benzyl- 5-formyl imidazole (3) was first synthesized which was subsequently used in synthesizing symmetrical (5a-f) and asymmetrical (6a,b) dihydropyridines. primarily pharmacological studies of the title co...
Organoammonium salts composed of a Brønsted acid and an anilinothiourea promoted the Michael addition of ß-keto esters and α,ß-unsaturated aldehydes in the presence of primary amines to give functionalized 1,4-dihydropyridines enantioselectively. With the use of the different Brønsted acids such as DFA and HBF(4) with the same bifunctional thiourea, both enantiomers of 4-substituted 1,4-dihydro...
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