Deok Chan Ha

A facile synthesis of 2,3-disubstituted pyrrolo[2,3-b]pyridines via palladium-catalyzed heteroannulation with internal alkynes

2,3-Disubstituted pyrrolo[2,3-b]pyridines were synthesized by palladium-catalyzed heteroannulation of 2-amino-3-iodopyridine derivatives and internal alkynes with Pd(OAc)2, LiCl, and KOAc in DMF. The 2-trimethylsilyl-3-methylpyrrolo[2,3-b]pyridine was transformed to 2-substituted-3-methylpyrrolo[2,3-b]pyridines.

Reductive cyclization of N-iodoalkyl cyclic imides to nitrogen-fused polycyclic amides induced by samarium diiodide

SmI2-promoted cyclizations of cyclic imides having 3-iodopropyl or 4-iodobutyl groups on the imide nitrogen have been studied for construction of nitrogen-fused polycyclic amides.

Synthesis and structure–activity relationships of quaternary ammonium cephalosporins with 3-pyrazolylpyridinium derivatives

Cephalosporins with 3-pyazolylpyridinium at C-3 position, which is supposed to exhibit synergic activity of ceftazidime and cefoselis, were synthesized and their antibacterial activity against gram-positive and gram-negative was inspected.

Synthesis and biological evaluation of cyclic sulfamide derivatives as 11β-hydroxysteroid dehydrogenase 1 inhibitors.

A new series of cyclic sulfamide derivatives were synthesized and evaluated for their ability to inhibit 11β-HSD1. Among this series, 18e showed good in vitro activity toward human 11β-HSD1, selectivity against 11β-HSD2, microsomal stability, and pharmacokinetic and safety profiles (hERG, CYP, and acute toxicity). Additionally, 18e exhibited good in vivo efficacy in rat and monkey models.

Solid-phase synthesis of 1,3-oxazolidine derivatives

Abstract 1,3-Oxazolidines 9 were synthesized by using a solid support. Regioselective ring opening of resin-bound epoxy ether 3 with ammonium chloride followed by nucleophilic substitution with sodium azide gave azido alcohol 7. Reduction of 7 provided 1-amino-2-alkanol 6, which was treated with various aldehydes and acyl chlorides or isocyanates to afford the corresponding 1,3-oxazolidines immobilized on Wang resin. Oxidative cleavage with DDQ from the solid support yielded 1,3-oxazolidines as a mixture of 10 (cis) and 11 (trans).

Stereospecific ring expansion of β-lactams to γ-lactams with trimethylsilyldiazomethane

Abstract Ring opening of N -carboxylated β-lactams with trimethylsilyldiazomethane anion followed by photolytic Wolff rearrangement provided γ-lactams in a stereospecific manner.

Studies on the diastereoselective alkylation of enolate dianion of (S)-4-carboethoxymethyl-2-oxazolidinone

Abstract Diastereoselective alkylation of enolate dianion of ( S )-4-carboethoxymethyl-2-oxazolidinone has been studied. The increased anti -selectivity in the presence of HMPA was explained by stereoelectronic effect of the electron-rich nitrogen atom of the oxazolidinone amidate.

Stereoselectivity in the condensation reactions between malate enolate and imines to 2-pyrrolidinone derivatives

Abstract Enolate dianion of diethyl ( S )-malate was stereoselectively condensed with nonenoiizable N -arylimines to give 2-pyrrolidinone derivatives. The presence of HMPA changes the diastereoselectivity of this cyclization reaction.