The SNAr reaction of 2,4-dichloropyrimidines, further substituted with an electron-withdrawing substituent at C-5, has selectivity for substitution at C-4. Here we report that tertiary amine nucleophiles show excellent C-2 selectivity. In situ N-dealkylation of an intermediate gives the product that formally corresponds to the reaction of a secondary amine nucleophile at C-2. This reaction is practical (fast under simple reaction conditions, with good generality for tertiary amine structure and moderate to excellent yields) and significantly expands access to pyrimidine structures.
Dinosylated α-d-glucopyranoside was directly transformed into α-d-altropyranosides via in situ formed N-4-nosyl Hough-Richardson aziridine with nitrogen nucleophiles under mild conditions in fair to excellent yields. The scope of the aziridine ring-opening reaction was substantially broadened contrary to the conventional methods introducing solely the azide anion at high temperatures. If necessary, the N-4-nosyl Hough-Richardson aziridine can be isolated by filtration in a very good yield and high purity.
Regioselective Control of the S NAr Amination of 5-Substituted-2,4-dichloropyrimidines Using Tertiary Amine Nucleophiles. -The regioselective reaction of 2,4-dichloro-5-nitropyrimidine (I) with tertiary amines (II) and (VI) leads to pyrimidin-2-amines (III) and (VII), resp., whilst the reaction with N-methylpyrrolidine gives rise to unexpected chloride (V). -(LEE, M.; RUCIL, T.; HESEK, D.; OLIVER, A. G.; FISHER, J. F.; MOBASHERY*, S.; J. Org. Chem. 80 (2015) 15, 7757-7763, http://dx.doi.org/10.
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