- Preparation of N-alkyl 2-pyridones via a lithium iodide promoted oto N-alkyl migration: Scope and mechanism
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An efficient and inexpensive LiI-promoted O- to N-alkyl migration of 2-benzyloxy-, 2-allyloxy-, and 2-propargyloxypyridines and heterocycles is reported. The reaction produces the corresponding N-alkyl 2-pyridones and analogues under green, solvent-free conditions in good to excellent yields (30 examples, 20-97% yield). This method has been shown to be intermolecular and requires heat and lithium cation to occur.
- Tasker, Sarah Z.,Bosscher, Michael A.,Shandro, Christina A.,Ryu, Keun Ah,Snapper, Gregory S.,Utter, Jarrad M.,Anderson, Carolyn E.,Lanni, Erica L.,Ellsworth, Bruce A.
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p. 8220 - 8230,11
(2020/10/15)
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- New modular and efficient approach to 6-substituted pyridin-2-yl C-nucleosides
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A novel modular, efficient, and practical methodology of preparation of 6-substituted pyridin-2-yl C-nucleosides was developed. An addition of 2-lithio-6-bromopyridine 2b to TBDMS-protected 2-deoxyribonolactone 5 gave aduct 7 as an equilibrium mixture of anomeric hemiketals 1-(6-bromopyridin-2-yl)-1- hydroxynucleosides 7a,b and its open form 7c. Reduction of the adduct 7 with Et3SiH and BF3-Et2O afforded the desired 6-bromonucleoside 8a as pure β-anomer in a total yield of 32% over two steps from 5. Intermediate 8a was then subjected to a series of palladium catalyzed cross-coupling reactions and aminations to give a series of protected 1β-(6-alkyl-, 6-aryl-, and 6-aminopyridin-2-yl)-2-deoxyribonucleosides 9. Catalytic hydrogenation of 8a gave an unsubstituted pyridine C-nucleoside, and diazotative oxodeamination of 6-aminopyridine nucleoside 9f by isopentyl nitrite in acetic acid gave 6-oxopyridine nucleoside 10i. Deprotection of silylated nucleosides 9 by Et3N-SHF gave a series of free C-nucleosides 10.
- Urban, Milan,Pohl, Radek,Klepetarova, Blanka,Hocek, Michal
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p. 7322 - 7328
(2007/10/03)
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- A platform for designing HIV integrase inhibitors. Part 1: 2-Hydroxy-3-heteroaryl acrylic acid derivatives as novel HIV integrase inhibitor and modeling of hydrophilic and hydrophobic pharmacophores
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We present a novel series of HIV integrase inhibitors, showing IC50s ranging from 0.01 to over 370 μM in an enzymatic assay. Furthermore, pharmacophore modeling study for the inhibitors was carried out to elucidate the structure-activity relationships. Finally, we found a 3D-pharmacophore model, which is composed of a hydrophilic and a hydrophobic domain, providing valuable information for designing other novel types of integrase inhibitors.
- Kawasuji, Takashi,Yoshinaga, Tomokazu,Sato, Akihiko,Yodo, Mitsuaki,Fujiwara, Tamio,Kiyama, Ryuichi
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p. 8430 - 8445
(2008/02/05)
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