Chiral recognition of amino-acid esters by a glucose-derived macrocyclic receptor

We report a glucose-based crown ether capable of chiral recognition of a wide range of amino-acid methyl esters in aqueous environment. The enantioselectivities towards amino-acids with extended hydrophobic side chains...

Ribose conversion with amino acids into pyrraline platform chemicals – expeditious synthesis of diverse pyrrole-fused alkaloid compounds

One-pot conversion of sustainable d-ribose with l-amino acid, methyl esters produced pyrrole-2-carbaldehydes 5 in reasonable yields (32–63%) under pressurized conditions of 2.5 atm at 80 °C.

Protected Amino Acids as a Nonbonding Source of Chirality in Induction of Single-Handed Screw-Sense to Helical Macromolecular Catalysts

Chiral nonbonding interaction with N-protected amino acid methyl esters used as chiral additives in achiral solvents allows dynamic induction of single-handed helical conformation in poly(quinoxaline-2,3-diyl)s (PQX) bearing only achiral substituents....

Amino acid sulfonamides based on 4-(1-oxo-1H-isochromen-3-yl)benzenesulfonyl chloride

The creation of new amino acid derivatives of 4-(1-oxo-1H-isochromen-3-yl)benzenesulfonyl chloride 1 was investigated. The interaction of the sulfonyl chloride 1 with amino acid methyl esters (hydrochlorides) in 1,4-dioxane in the presence of triethylamine led to the corresponding amino acid sulfonamide derivatives of isocoumarin. The reaction of the sulfonyl chloride 1 with phenylalanine in the basic aqueous solution was complicated by the lactone system disclosure and led to 2'-carboxydeoxybenzoin ultimately (namely, 2-(2-(4-(N-(1-carboxy-2-phenylethyl)sulfamoyl)phenyl)-2-oxoethyl)benzoic acid). Similar product was obtained by the alkali hydrolysis of methyl ((4-(1-oxo-1H-isochromen-3-yl)phenyl)sulfonyl)leucinate.

Synthesis and antimalarial activity of (S)-methyl-(7-chloroquinolin-4-ylthio)acetamidoalquilate derivatives

The synthesis of five new ( S)-methyl-(7-chloroquinolin-4-ylthio)acetamidoalquilate derivatives is carried out under a modified version of the Steglich esterification reaction between different l-amino acid methyl esters and 2-(7-chloroquinolin-4-ylthio)acetic acid. Two of the compounds showed significant inhibition (>50%) of β-hematin formation. The two active structures were tested in vivo as potential antimalarials in mice infected with Plasmodium berghei ANKA, a chloroquine susceptible strain. Compounds 6b and 6e exhibited antimalarial activity comparable to that of chloroquine.

One-pot synthesis of 4-arylidene imidazolin-5-ones by reaction of amino acid esters with isocyanates and α-bromoketones

A one-pot multicomponent reaction for assembling substituted 4-arylidene imidazolin-5-ones from l-amino acid methyl esters, iso-, isothio- or isoselenocyanates, and α-bromoketones has been discovered.

N-Acylated amino acid methyl esters from marine Roseobacter group bacteria

Bacteria of the Roseobacter group (Rhodobacteraceae) are important members of many marine ecosystems. Similar to other Gram-negative bacteria many roseobacters produce N-acylhomoserine lactones (AHLs) for communication by quorum sensing systems. AHLs regulate different traits like cell differentiation or antibiotic production. Related N-acylalanine methyl esters (NAMEs) have been reported as well, but so far only from Roseovarius tolerans EL-164. While screening various roseobacters isolated from macroalgae we encountered four strains, Roseovarius sp. D12_1.68, Loktanella sp. F13, F14 and D3 that produced new derivatives and analogs of NAMEs, namely N-acyl-2-aminobutyric acid methyl esters (NABME), N-acylglycine methyl esters (NAGME), N-acylvaline methyl esters (NAVME), as well as for the first time a methyl-branched NAME, N-(13-methyltetradecanoyl)alanine methyl ester. These compounds were detected by GC–MS analysis, and structural proposals were derived from the mass spectra and by derivatization. Verification of compound structures was performed by synthesis. NABMEs, NAVMEs and NAGMEs are produced in low amounts only, making mass spectrometry the method of choice for their detection. The analysis of both EI and ESI mass spectra revealed fragmentation patterns helpful for the detection of similar compounds derived from other amino acids. Some of these compounds showed antimicrobial activity. The structural similarity of N-acylated amino acid methyl esters and similar lipophilicity to AHLs might indicate a yet unknown function as signalling compounds in the ecology of these bacteria, although their singular occurrence is in strong contrast to the common occurrence of AHLs. Obviously the structural motif is not restricted to Roseovarius spp. and occurs also in other genera.