68331-48-6

Upstream product

• 67-56-1 methanol 
• 28954-12-3 (2S,3S)-2-amino-3-hydroxybutanoic acid 
• 72-19-5 rac-allo-threonine 
• 72-19-5 DL-threonine 
• 87378-29-8 1-((S)-5-Isopropyl-3,6-dimethoxy-2,5-dihydro-pyrazin-2-yl)-ethanol 
• 72-19-5 L-threonine 
• 80-68-2 DL-threonine 

Downstream Products

• 108245-02-9 N-thiobenzoyl-allothreonine methyl ester 
• 83791-43-9 methyl 5-methyl-2-oxazolidinone-4-carboxylate 
• 78464-23-0 2-(2-Benzyloxycarbonylamino-acryloylamino)-3-hydroxy-butyric acid methyl ester 
• 78464-24-1 2-((E)-2-Benzyloxycarbonylamino-but-2-enoylamino)-3-hydroxy-butyric acid methyl ester 
• 78464-27-4 2-((E)-2-Benzyloxycarbonylamino-4-methyl-pent-2-enoylamino)-3-hydroxy-butyric acid methyl ester 
• 23010-55-1 (N^α-Boc-N^ε-Z-Lys)-Thr-OCH3 
• 78075-43-1 Z(OMe)-Ser-Thr-OMe 
• 80110-54-9 Boc-Tyr-Thr-OCH₃ 
• 142319-66-2 (S)-2-[(R)-2-((R)-2,2-Dimethyl-4-phenyl-oxazolidin-3-yl)-propionylamino]-3-hydroxy-butyric acid methyl ester 
• 142319-66-2 (S)-2-[(S)-2-((R)-2,2-Dimethyl-4-phenyl-oxazolidin-3-yl)-propionylamino]-3-hydroxy-butyric acid methyl ester 
• 43188-53-0 (2S,3R)-methyl-N-(4-methylphenylsulfonyl)-3-hydroxy-2-aminobutanoate 
• 2280-40-2 allothreonine amide 
• 515-93-5 (+/-)-erythro-2-amino-butanediol-(1.3) 
• 17791-90-1 3,6-Bis-(α-hydroxyethyl)-2,5-dioxopiperazin 

Relevant academic research and scientific papers

Biomimetic synthesis of esters of natural amino acids

A method for the synthesis of Gly, Ala, Phe, and Thr esters is proposed and considered as being a stage of possible biomimetic synthesis of peptides. The methyl esters of the said amino acids are obtained via intervention of 2-hydroxypropyl phosphonate. The resulting aminoacyl phosphonates reacts with methanol to produce the amino acid methyl esters, with the release of phosphoric acid. The reaction is carried out at room temperature in water.

Catalytic Mechanism Study on the 1,2- and 1,4-Transfer Hydrogenation of Ketimines and β-Enamino Esters Catalyzed by Axially Chiral Biscarboline-Based Alcohols

Axial N-O alcohols, which have two large carboline moieties connected to the axis were synthesized and used in catalytic enantioselective 1,2- and 1,4-transfer hydrogenations of total 26 ketimines and β-enamino esters. Excellent levels of enantioselectivity ranging from 91% to 99% were achieved by using catalyst (aS)-(S)-3,3′-bis((S)-2-(hydroxymethyl)pyrrolidine-1-carbonyl)-9,9′-dimethyl-9H,9′H-[1,1′-bipyrido[3,4-b]indole] 2-oxide. Interestingly, a mixture of (aS)-(S)-3,3′-bis((S)-2-(hydroxymethyl)pyrrolidine-1-carbonyl)-9,9′-dimethyl-9H,9′H-[1,1′-bipyrido[3,4-b]indole] 2-oxide and (aR)-(S)-3,3′-bis((S)-2-(hydroxymethyl)pyrrolidine-1-carbonyl)-9,9′-dimethyl-9H,9′H-[1,1′-bipyrido[3,4-b]indole] 2-oxide was also able to provide high enantioselectivities up to 95% that is the same as that using pure (aS)-(S)-3,3′-bis((S)-2-(hydroxymethyl)pyrrolidine-1-carbonyl)-9,9′-dimethyl-9H,9′H-[1,1′-bipyrido[3,4-b]indole] 2-oxide. A plausible catalytic mechanism was suggested and total four kinds of transition states (TS) including almost 60 TS structures were investigated using density functional theory (DFT) with different basis sets such as 6-311G(2d,p). The predicted activation energy data are consistent with the experimental results. (Figure presented.).

Preparation method of O-methyl-threonine/tyrosine

The invention relates to a preparation method of O-methyl-threonine/tyrosine. The preparation method mainly overcomes the disadvantages of the existing method that a toxic reagent is volatile, the reagent is dangerous, the steps are long, the yield is low, and the like. The preparation method of the O-methyl-threonine/tyrosine comprises the following steps: N-t-butyloxycarboryl-threonine/tyrosineis catalyzed by sodium hydroxide and reacts with dimethyl sulfate to generate N-t-butyloxycarboryl-O-methyl-threonine/tyrosine, and then t-butyloxycarboryl is removed from the N-t-butyloxycarboryl-O-methyl-threonine/tyrosine through acid substances to obtain the product O-methyl-threonine/tyrosine. The product has important application in the fields of antibiotics and polypeptide drugs.

HR-MALDI-MS imaging assisted screening of β-Carboline alkaloids discovered from mycena metata

Fruiting bodies of Mycena metata were screened for the presence of new secondary metabolites by means of HPLC-UV, LC-HR-ESIMS, and high-resolution matrix-assisted laser desorption/ionization mass spectrometry imaging (HRMALDI- MS imaging). Thus, a new β-carboline alkaloid, 6-hydroxymetatacarboline D (1d), was isolated from fruiting bodies of M. metata. 6-Hydroxymetatacarboline D consists of a highly substituted β-carboline skeleton, which is likely to be derived biosynthetically from L-tryptophan, 2-oxoglutaric acid, L-threonine, and L-proline. The structure of the alkaloid was established by 2D NMR spectroscopic methods and HR-ESIMS. Moreover, by extensive application of LC-HR-ESIMS, LC-HR-ESIMS/MS, and LC-HR-ESIMS3 techniques we were able to elucidate the structures of a number of accompanying β-carboline alkaloids, 1a- 1c, 1e-1i, and 2a-2g, structurally closely related to 6-hydroxymetatacarboline D, which are present in M. metata in minor amounts. The absolute configuration of the stereogenic centers of the β-carboline alkaloids was determined by GC-MS comparison with authentic synthetic samples after hydrolytic cleavage and derivatization of the resulting amino acids.

Comparison of liquid chromatography-isotope ratio mass spectrometry (LC/IRMS) and gas chromatography-combustion-isotope ratio mass spectrometry (GC/C/IRMS) for the determination of collagen amino acid δ13C values for palaeodietary and palaeoecological reconstruction

Results are presented of a comparison of the amino acid (AA) δ13C values obtained by gas chromatography-combustion-isotope ratio mass spectrometry (GC/C/IRMS) and liquid chromatography-isotope ratio mass spectrometry (LC/IRMS). Although the primary focus was the compound-specific stable carbon isotope analysis of bone collagen AAs, because of its growing application for palaeodietary and palaeoecological reconstruction, the results are relevant to any field where AA δ13C values are required. We compare LC/IRMS with the most up-to-date GC/C/IRMS method using N-acetyl methyl ester (NACME) AA derivatives. This comparison involves the analysis of standard AAs and hydrolysates of archaeological human bone collagen, which have been previously investigated as N-trifluoroacetyl isopropyl esters (TFA/IP). It was observed that, although GC/C/IRMS analyses required less sample, LC/IRMS permitted the analysis of a wider range of AAs, particularly those not amenable to GC analysis (e.g. arginine). Accordingly, reconstructed bulk δ13C values based on LC/IRMS-derived δ13C values were closer to the EA/IRMS-derived δ13C values than those based on GC/C/IRMS values. The analytical errors for LC/IRMS AA δ13C values were lower than GC/C/IRMS determinations. Inconsistencies in the δ13C values of the TFA/IP derivatives compared with the NACME- and LC/IRMS-derived δ13C values suggest inherent problems with the use of TFA/IP derivatives, resulting from: (i) inefficient sample combustion, and/or (ii) differences in the intra-molecular distribution of δ13C values between AAs, which are manifested by incomplete combustion. Close similarities between the NACME AA δ13C values and the LC/IRMS-derived δ13C values suggest that the TFA/IP derivatives should be abandoned for the natural abundance determinations of AA δ13C values.

Coibamide A, a potent antiproliferative cyclic depsipeptide from the panamanian marine cyanobacterium Leptolyngbya sp.

Coibamide A (1) is a new, potent antiproliferative depsipeptide which was isolated from a marine Leptolyngbya cyanobacterium collected from the Coiba National Park, Panama. The planar structure of 1 was elucidated by a combination of NMR spectroscopy and mass spectrometry. Exhaustive 1D and 2D NMR spectroscopy included natural abundance 15N and variable temperature experiments; mass spectrometry included TOF-ESI-MSn and FT-MSn experiments. Chemical degradation followed by chiral HPLC- and GC-MS analyses was used to assign the absolute configuration of 1. This highly methylated cyclized depsipeptide exhibited an unprecedented selectivity profile in the NCI 60 cancer cell line panel and appears to act via a novel mechanism. Copyright

Design, synthesis, and bioactivity of novel inhibitors of E. coli aspartate transcarbamoylase

A series of inhibitors of the aspartate transcarbamoylase, an enzyme involved in pyrimidine nucleotide biosynthesis, has been synthesized. These inhibitors are analogues of a highly potent inhibitor of this enzyme, N-phosphonacetyl-l-aspartate (PALA). Analogues have been synthesized with modifications at the α- and β-carboxylates as well as at the aspartate moiety. The ability of these compounds to inhibit the enzyme was evaluated. These studies, with functional group modified PALA derivatives, showed that amide groups can be a useful substitute of the carboxylate in order to reduce the charge on the molecule, and indicate that the relative position of the functional group in the β-position is more critical than the nature of the functional group. Some of the molecules synthesized here are potent inhibitors of the enzyme.

Synthesis of bisaminoacylated pdCpAs and tandemly activated transfer RNAs

Described herein is the preparation of new bisacylated tRNAs and their participation in protein synthesis. It has been reported that Thermus thermophilus phenylalanyl-tRNA synthetase can introduce two phenylalanine moieties onto the 3′-terminal adenosine of its cognate tRNA. It is also possible to prepare bisactivated tRNAs in vitro; these participate in protein synthesis [Wang, B.; Zhou, J.; Lodder, M.; Anderson, R. D.; Hecht, S. M. J. Biol. Chem. 2006, 281, 13865]. Presently, the chemical strategy used for the synthesis of the key intermediate bisacylated pdCpAs is described. Bis-S-alanyl- and bis-S-methionyl-pdCpAs were prepared initially. Further, S-threonine, S-allo-threonine, S-homoserine, and (S)-(+)-2-amino-3-hydroxy-3-methylbutyric acid were coupled with the dinucleotide to define preparative methods applicable to more complex amino acids bearing additional functionality in the form of an OH group.

A new stereoselective approach to β-hydroxy-α-aminoacids and dipeptides

The chiral synthons 1, 2 and 1' were submitted to aldol condensation to achieve both β-hydroxy-α-aminoacids and dipeptides. The configuration of the new stereogenic centers was assigned on the basis of 1H NMR spectroscopic data.

Papuamides A-D, HIV-inhibitory and cytotoxic depsipeptides from the sponges Theonella mirabilis and Theonella swinhoei collected in Papua New Guinea

The novel cyclic depsipeptides papuamides A (1), B (2), C (3), and D (4) have been isolated from Papua New Guinea collections of the sponges Theonella mirabilis and Theonella swinhoei. Their structures were determined by a combination of spectroscopic analysis and chemical degradation and derivatization studies. In addition to glycine, alanine, and threonine, these peptides contain a number of unusual amino acids including 3,4- dimethylglutamine, β-methoxytyrosine, 3-methoxyalanine, and 2,3- diaminobutanoic acid or 2-amino-2-butenoic acid residues. Papuamides A-D (1- 4) are also the first marine-derived peptides reported to contain 3- hydroxyleucine and homoproline residues. These peptides also contain a previously undescribed 2,3-dihydroxy-2,6,8-trimethyldeca-(4Z,6E)-dienoic acid moiety N-linked to a terminal glycine residue. Papuamides A (1) and B (2) inhibited the infection of human T-lymphoblastoid cells by HIV-1(RF) in vitro with an EC50 of approximately 4 ng/mL. Compound 1 was also cytotoxic against a panel of human cancer cell lines with a mean IC50 of 75 ng/mL.