Jaemoon Lee

Asymmetric synthesis of (2S,3S)-3-hydroxy-2-phenylpiperidine via ring expansion

Abstract A catalytic highly enantioselective (99% ee) preparation of N - tert -butyloxycarbonyl-(2 S ,3 S )-3-hydroxy-2-phenyl-piperidine and N - tert -butyloxycarbonyl-(2 S )-2-phenyl-piperidin-3-one was developed using an intramolecular epoxide opening followed by ring expansion. The cis -epoxide starting material was available in high ee via Jacobsen epoxidation.

Ni-catalyzed nucleophilic conjugate additions of Grignard and organozincate reagents to substituted 4-vinylpyridines. General synthesis of phosphodiesterase IV inhibitors

Abstract Alkyl, aryl, and vinyl Grignard reagents were added to olefin II under Ni(acac) 2 or Cl 2 Ni(PPh 3 ) 2 catalysis to give products with the general formula I in 74–95% yield. Organozincates gave similar results with Ni(acac) 2 as the catalyst.

A chemical synthesis of nicotinamide adenine dinucleotide (NAD

A practical synthesis of nicotinamide mononucleotide (β-NMN) and a high yield coupling with AMP-morpholidate that also provides NAD+ in an efficient manner are reported.

Rapid conversion of API hydrates to anhydrous forms in aqueous media

Three anhydrous polymorphs, a monohydrate and a dihydrate of an active pharmaceutical ingredient, N-{[(5S)-3-(4-{6-[(1R,5S)-6-cyano-3-oxabicyclo[3.1.0]hex-6-yl]pyridin-3-yl}phenyl)-2-oxo-1,3-oxazolidin-5-yl]methyl}acetamide (Compound 1), have been crystallized and characterized. Slurry experiments and thermal data have been used to determine their relative thermodynamic stability. The hydrates of Compound 1 were found to be less stable than the most stable anhydrous Form I and converted into Form I in water within 15 min. The rate of conversion in a dry state was found to depend on the relative humidity (RH) and was highest at the two RH extremes examined, 5% and 97.5% RH.

Practical synthesis of α-amino acids using cis-aminoindanol derived hippuric acid amide as a glycine enolate equivalent

Abstract The use of cis -aminoindanol as a chiral auxiliary for asymmetric synthesis of α-amino acids is described. Alkylation of the chirally modified glycine enolate 2 with a number of alkyl halides in the presence of lithium chloride gave the corresponding alkylated product in 90 ∼ 99% diastereoselectivity.