An asymmetric synthesis of chiral nifedipine analogues

Abstract

The addition of aryl-lithium reagents to chiral pyridyl-dihydro-oxazoles gave (S)-4-aryl-I ,4-dihydropyridines in 80-90% enantiomeric excess. H), 7.82 (br.s, 1 H), 7.35-7.15 (m, 5 H), 7.04 (m, 2 H), 6.79 (m, 2 H), 5.26 (d, J 6.3 Hz, 1 H), 5.00 (s, 1 H), 4.30-4.00 (m, 3 H), 3.95 (s, 3 H), 3.77 (s, 3 H), 3.70-3.40(AB m, 2H), 3.39(s, 3H),and 1.23 (t,3 HI-

Synthesis, Structure, and Pharmacological Evaluation of the Stereoisomers of Furnidipine

“…8-1.6 (m, 3H), 1.3-1.1 (m, 1H); MS (Cl) (rel intens) h i b i t e d .m/z 85 (44), 152 (52), 153 (41), 221 (53), 236 (46), 237 (61),238 (58), 253 (65), 270 (100), 398(13). Anal.…”

Highly Regioselective Addition of Organozinc Reagents to 2‐Oxo‐1,2‐dihydropyrimidine‐5‐carboxylates Activated by BF3·OEt2: Synthesis of 2‐Oxo‐1,2,3,4‐tetrahydropyrimidine‐5‐carboxylates

“…The formation of 16a – p by the addition of carbon nucleophiles represents a smooth formation of those DHPMs that are otherwise not easily accessible through traditional methods employing aliphatic aldehydes because of their non‐availability and operational difficulties. Furthermore, the addition of organolithium reagents to pyridines requires activation of the pyridine moiety as a 1‐alkoxycarbonyl derivative,25 and the regioselectivity of the reactions of 1‐acylpyridinium salts with Grignard reagents26 is additionally influenced by the structures of the Grignard reagent and the 1‐acyl group. In the reaction protocol described herein, the addition of alkyl‐ or arylzinc reagents to 15a – d (Table 1) proceeded regioselectively in a straight forward manner upon activation with the mild Lewis acid, BF 3 OEt 2 , in case of the former.…”

An Efficacious Protocol for 4‐Substituted 3,4‐Dihydropyrimidinones: Synthesis and Calcium Channel Binding Studies

“…Therefore the reactions in the present case represent addition of only carbon nucleophiles. Further, whereas the addition reactions of pyridines with aryl lithium [16] reagents required activation of pyridine as 1-alkoxycarbonyl derivative, the regioselectivity of the reactions of 1-acylpyridinium salts with Grignard reagents [17] , was additionally influenced by the structures of the Grignard reagent and the 1-acyl group. However, the addition reactions of pyrimidin-2(1 H )-ones 7 with carbon nucleophiles proceeded regioselectively without activation of the pyrimidinone substrates.…”