Synthesis and antihistamine evaluations of novel loratadine analogues

Wang, Yue; Wang, Juan; Yan, Lin; Si-Ma, Li-Feng; Wang, Donghua; Chen, Ligong; Liu, Dengke

doi:10.1016/j.bmcl.2011.06.012

Cited by 19 publications

(3 citation statements)

References 26 publications

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“… 380 It is also sold in combination with pseudoephedrine, a decongestant, known as loratadine/pseudoephedrine. 381 As a matter of fact, loratadine, cetirizine and astemizole are second-generation antihistamines that have substituted first-generation antihistamines for example diphenhydramine and ketotifen. 382–388 Loratadine 362 can be produced via various routes.…”

Section: Synthesis Of Nitrogen Prescribed Drugs Havingmentioning

confidence: 99%

Prescribed drugs containing nitrogen heterocycles: an overview

2020

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Section: Synthesis Of Nitrogen Prescribed Drugs Havingmentioning

confidence: 99%

Prescribed drugs containing nitrogen heterocycles: an overview

2020

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“…Clopidogrel, 13 a medication for heart disease and stroke known as Plavix, underwent the one-pot, Ir-catalyzed borylation and copper-catalyzed methylation with PO(OMe) 3 to install a methyl group selectively at the 2-position of the thiophene ring in high yield ( 5a, 79%). A similar one-pot process enabled the late-stage site-selective methylation of loratadine, sold as Claritin for the treatment of allergies, 14 in moderate yield ( 5b ). The benzothiazole-based heterocycle, PMX-610, 15 which has exhibited high antitumor activity in breast-cancer cell lines, was modified by a stepwise borylation and methylation in 54% overall yield ( 5c ).…”

Section: Resultsmentioning

confidence: 99%

Trimethylphosphate as a Methylating Agent for Cross Coupling: A Slow-Release Mechanism for the Methylation of Arylboronic Esters

Haydl

et al. 2018

J. Am. Chem. Soc.

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A methyl group on an arene, despite its small size, can have a profound influence on biologically active molecules. Typical methods to form a methylarene involve strong nucleophiles or strong and often toxic electrophiles. We report a strategy for a new, highly efficient, copper and iodide co-catalyzed methylation of aryl- and heteroarylboronic esters with the mild, nontoxic reagent trimethylphosphate, which has not been used previously in coupling reactions. We show that it reacts in all cases tested in yields that are higher than those of analogous copper-catalyzed reactions of MeOTs or MeI. The combination of C−H borylation and this methylation with trimethylphosphate provides a new approach to the functionalization of inert C−H bonds and is illustrated by late-stage methylation of four medicinally active compounds. In addition, reaction on a 200 mmol scale demonstrates reliability of this method. Mechanistic studies show that the reaction occurs by a slow release of methyl iodide by reaction of PO(OMe)3 with iodide catalyst, rather than the typical direct oxidative addition to a metal center. The low concentration of the reactive electrophile enables selective reaction with an arylcopper intermediate, rather than nucleophilic groups on the arylboronate, and binding of tert-butoxide to the boronate inhibits reaction of the electrophile with the tert-butoxide activator to form methyl ether.

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“…1 Examples of these compounds include loratadine ( 1 , H 1 histamine antagonist), 2 SCH 66336 ( 2 , anti-cancer agent), 3 and MK-2461 ( 3 , anti-cancer agent). 4 The cycloheptabenzopyridine ring system has been previously prepared by intramolecular cyclizations of carboxylic acids, 5 nitriles, 6 alcohols, 7 ketones, 8 and by other routes.…”

Section: Introductionmentioning

confidence: 99%

Cyclizations of phenylethyl-substituted pyridinecarboxaldehydes

Naredla

Klumpp

2013

Tetrahedron

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Several phenylethyl-substituted pyridinecarboxaldehydes were prepared from 2-bromo-3-pyridinecarboxaldehyde and these substances are found to undergo cyclization reactions in acidic media. In the absence of added nucleophile, acid promoted cyclization and oxidation (MnO2) provides an efficient route to 10,11-dihydro-5H-benzo[4,5]cyclohepta[1,2-b]pyridin-5-ones. Arene nucleophiles may also be added to the acidic mixture to provide good yields of triarylmethane products. Mechanisms are proposed involving dicationic superelectrophilic intermediates.

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Synthesis and antihistamine evaluations of novel loratadine analogues

Cited by 19 publications

References 26 publications

Prescribed drugs containing nitrogen heterocycles: an overview

Prescribed drugs containing nitrogen heterocycles: an overview

Trimethylphosphate as a Methylating Agent for Cross Coupling: A Slow-Release Mechanism for the Methylation of Arylboronic Esters

Cyclizations of phenylethyl-substituted pyridinecarboxaldehydes

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