Biocontrolled formal inversion or retention of L -α-amino acids to enantiopure (R)- or (S)-hydroxyacids
Natural L-α-amino acids and L-norleucine were transformed to the corresponding α-hydroxy acids by formal biocatalytic inversion or retention of absolute configuration. The one-pot transformation was achieved by a concurrent oxidation reduction cascade in aqueous media. A representative panel of enantiopure (R)- and (S)-2-hydroxy acids possessing aliphatic, aromatic and heteroaromatic moieties were isolated in high yield (67-85 %) and enantiopure form (>99 % ee) without requiring chromatographic purification.
Synthesis and antimycobacterial activity of novel camphane-based agents
A series of six new amidoalcohols was designed and synthesized on the base of the camphor scaffold. Natural amino acids were transformed into their α-hydroxy analogues with retention of configuration, and attached to isobornylamine. The compounds were evaluated for their in vitro activity against Mycobacterium tuberculosis H37Rv. Some of the new compounds show 25 times higher activity than the classical anti-TB drug ethambutol. The activity shifts from micromolar to nanomolar inhibitory concentrations depending on the α-hydroxy acid moiety. Two of the most potent compounds exert low level of cytotoxic activity. These camphane-based amido-alcohols present promising potential lead compounds for further elaboration of antimycobacterial agents.
Stavrakov, Georgi,Philipova, Irena,Valcheva, Violeta,Momekov, Georgi
p. 165 - 167
(2014/01/17)
Facile synthesis of α-hydroxy carboxylic acids from the corresponding α-amino acids
An effective and improved procedure is developed for the synthesis of α-hydroxy carboxylic acids by treatment of the corresponding protonated α-amino acid with tert-butyl nitrite in 1,4-dioxane-water. The amino moiety must be protonated and located α to a carboxylic acid function in order to undergo initial diazotization and successive hydroxylation, since neither β-amino acids nor acid derivatives such as esters and amides undergo hydroxylations. The method is successfully applied for the synthesis of 18 proteinogenic amino acids.
Stuhr-Hansen, Nicolai,Padrah, Shahrokh,Str?mgaard, Kristian
supporting information
p. 4149 - 4151
(2015/02/02)
Facile synthesis of α-hydroxy carboxylic acids from the corresponding α-amino acids
An effective and improved procedure is developed for the synthesis of α-hydroxy carboxylic acids by treatment of the corresponding protonated α-amino acid with tert-butyl nitrite in 1,4-dioxane-water. The amino moiety must be protonated and located α to a carboxylic acid function in order to undergo initial diazotization and successive hydroxylation, since neither β-amino acids nor acid derivatives such as esters and amides undergo hydroxylations. The method is successfully applied for the synthesis of 18 proteinogenic amino acids.
Stuhr-Hansen, Nicolai,Padrah, Shahrokh,Str?mgaard, Kristian
supporting information
p. 4149 - 4151
(2014/07/22)
Novel camphane-based anti-tuberculosis agents with nanomolar activity
A series of new amidoalcohols and amidodiols were designed on the base of the camphor scaffold and evaluated for their in vitro activity against Mycobacterium tuberculosis H37Rv and MDR strain 43. Some of the new compounds show 25 times higher activity than the classical anti-TB drug ethambutol. Small structural changes in the side chain shift the activity from micromolar to nanomolar inhibitory concentrations. Quantitative structure-activity relationship (QSAR) model is derived to guide the further lead optimization. Two hydrogen bond donors and up to three rings in the molecules are optimal for nanomolar activity. The camphane-based amides present novel promising scaffolds for antimycobacterial agents.