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Abstract
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The mild bromine-magnesium exchange reaction using i-PrMgBr in THF on the 2-bromomethyl-1,4-dihydropyridine
Hantzsch esters allowed the synthesis of highly functionalized magnesiated 1,4-dihydropyridines with ester
groups tolerance. Treatment of the resulting anionic intermediates with hard electrophile methyl iodide gave Nmethylated
product 6 and pyridine derivative 7 in 60 % and 10 % yields, respectively. In trapping the reaction
mixture of magnesiated 1,4-dihydropyridine with ethyl bromide, pyridine derivative 8, and dimer 9 were obtained.
Also, FeCl3-catalyzed cross-coupling reaction of allylMgBr, i-PrMgBr, and n-BuMgBr Grignard reagents
with 2-bromomethyl-1,4-dihydropyridine derivative 2 afforded unsymmetrical 1,4-dihydropyridine derivatives
10a-c in good yields.
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