43188-53-0

Upstream product

• 186581-53-3 diazomethane 
• 34235-88-6 (2S,3S)-3-hydroxy-2-(4-methylphenylsulfonamido)butanoic acid 
• 39994-75-7 L-threonine methyl ester hydrochloride 
• 98-59-9 p-toluenesulfonyl chloride 
• 3373-59-9 L-threonine methyl ester 
• 74-88-4 methyl iodide 
• 37460-24-5 N^α-Tosyl-L-threo-α,β-diaminobuttersaeure 
• 3373-59-9 Z-threonine methyl ester 
• 134019-97-9 N,O-Ditosyl-L-threonine methyl ester 

Downstream Products

• 141632-60-2 O-(3,4,6-tri-O-acetyl-2-deoxy-2-hydroxyimino-β-D-lyxo-hexopyranosyl)-N-tosyl-L-threonine methyl ester 
• 141632-60-2 O-(3,4,6-tri-O-acetyl-2-deoxy-2-hydroxyimino-α-D-lyxo-hexopyranosyl)-N-tosyl-L-threonine methyl ester 
• 43188-65-4 methyl (2S,3S)-3-methyl-1-[(4-methylphenyl)sulfonyl]aziridne-2-carboxylate 
• 128154-36-9 N-Tosyl-O-(2,3,4-tri-O-acetyl-β-D-arabinopyranosyl)-L-threonine methyl ester 
• 128154-36-9 N-Tosyl-O-(2,3,4-tri-O-acetyl-α-D-arabinopyranosyl)-L-threonine methyl ester 
• 128107-92-6 (1R,2S)-2-(4-tolylsulfamoyl)-2-(methoxycarbonyl)-1-methylethyl acetoacetate 
• 128154-30-3 O-(3,4-di-O-acetyl-2-deoxy-2-hydroxyimino-β-D-erythro-pentopyranosyl)-N-tosyl-L-threonine methylester 
• 128154-30-3 O-(3,4-di-O-acetyl-2-deoxy-2-hydroxyimino-α-D-erythro-pentopyranosyl)-N-tosyl-L-threonine methylester 
• 63658-16-2 (Z)-methyl 2-((tertbutoxycarbonyl)amino)but-2-enoate 
• 1421070-86-1 (2S,3R)-methyl 3-hydroxy-2-(4-methyl-N-(2-methylallyl)phenylsulfonamido)butanoate 
• 1421070-87-2 (2S,3R)-methyl 3-hydroxy-2-(4-methyl-N-(3-methylbut-2-en-1-yl)phenylsulfonamido)butanoate 
• 1421070-45-2 (2R,3S,6S)-methyl 6-bromo-2,7,7-trimethyl-4-tosyl-1,4-oxazepane-3-carboxylate 
• 1421070-42-9 (2R,3S,6R)-methyl 6-(bromomethyl)-2,6-dimethyl-4-tosylmorpholine-3-carboxylate 
• 219851-92-0 N-(4-toluenesulfonyl)-N-(tert-butoxycarbonyl)-2-dehydro-2-aminobutyric acid methyl ester 

Relevant academic research and scientific papers

Asymmetric Synthesis of β2-Aryl Amino Acids through Pd-Catalyzed Enantiospecific and Regioselective Ring-Opening Suzuki–Miyaura Arylation of Aziridine-2-carboxylates

A Pd-catalyzed enantiospecific and regioselective ring-opening Suzuki–Miyaura arylation of aziridine-2-carboxylates was developed. The cross-coupling allows for the asymmetric preparation of enantioenriched β2-aryl amino acids, starting from co

Regioselective O-sulfonylation of N,N-bis(2-hydroxyalkyl)tosylamides as a synthetic key step to enantiopure morpholines

The synthesis of enantiopure 2,6-disubstituted morpholines was realized through sequential ring opening of two different optically pure oxiranes by a tosylamide, under solid-liquid phase-transfer catalysis (SL-PTC) conditions, mono-O-sulfonylation of the

Stereoselective geminal difunctionalization of vinyl arenes mediated by the bromonium ion

An anti-Markovnikov geminal oxyamination of styrenyl alkenes in an intermolecular fashion using the umpolung strategy mediated by the bromonium ion is reported. Isotope labeling studies confirm the migration of the phenyl group in the semipinacol rearrang

Stereo- and regioselective synthesis of polysubstituted chiral 1,4-oxazepanes

The number of cyclic molecular scaffolds available to medicinal chemists remains limited, and simple structures such as oxazepanes are still made using multistep procedures, including a number of protection/deprotection steps and purifications. We report

Synthetic studies on polyoxypeptins: Stereoselective synthesis of (2S,3R)-3-hydroxy-3-methylproline using SmI2-mediated cyclization

Stereoselective synthesis of (2S,3R)-3-hydroxy-3-methylproline (3), a component of polyoxypeptins, has been achieved by use of SmI2-mediated diastereoselective cyclization reaction as a key step.

Enantioselective synthesis of optically active homoallylamines by nucleophilic addition of chirally modified allylboranes to N-silylimines

Enantioselectivity in the allylboration of W-silylimines with a variety of chirally modified allylboron reagents has been examined. Optically active N-sulfonylarhino alcohols (16,17 and 19) derived from D-camphor and norephedrine were found to be efficient chiral ligands for the allylboration reagent. These reagents smoothly reacted with Ar-silylimines to give the corresponding homoallylic amines in a high level of enantioselectivity up to 96% ee.

High yielding synthesis of dehydroamino acid and dehydropeptide derivatives

By using a 4-dimethylaminopyridine (DMAP) catalysed reaction of β-hydroxyamino acid derivatives with tert-butyl pyrocarbonate [(Boc)2O], dehydroamino acid derivatives are obtained in high yields. The same methodology applied to dipeptides with

Syntheses, calcium channel agonist-antagonist modulation activities, and voltage-clamp studies of isopropyl 1,4-dihydro-2,6-dimethyl-3-nitro-4- pyridinylpyridine-5-carboxylate racemates and enantiomers

A novel group of racemic isopropyl 1,4-dihydro-2,6-dimethyl-3-nitro-4- pyridinylpyridine-5-carboxylate isomers [(±)-12-14] were prepared using a modified Hantzsch reaction that involved the condensation of nitroacetone with isopropyl 3-aminocrotonate and 2-, 3-, or 4-pyridinecarboxaldehyde. Determination of their in vitro calcium channel-modulating activities using guinea pig ileum longitudinal smooth muscle (GPILSM) and guinea pig left atrium (GPLA) assays showed that the 2-pyridinyl isomer (±)-12 acted as a dual cardioselective calcium channel agonist (GPLA)/smooth muscle selective calcium channel antagonist (GPILSM). In contrast, the 3-pyridinyl [(±)-13] and 4-pyridinyl [(±)-14] isomers acted as calcium channel agonists on both GPLA and GPILSM. The agonist effect exhibited by (±)-12 on GPLA was inhibited by nifedipine and partially reversed by addition of extracellular Ca2+. In anesthetized rabbits, the 4-pyridinyl isomer (±)-14 exhibited a hypertensive effect that was qualitatively similar to that exhibited by the nonselective agonist Bay K 8644 and the 3-pyridinyl isomer (±)-13, whereas the 2-pyridinyl isomer (±)-12 induced a hypotensive effect similar to that of the calcium channel antagonist nifedipine. Similar results were obtained in a spontaneously hypertensive rat model. In vitro studies showed that the (+)-2-pyridinyl enantiomer (+)-12A exhibited agonist activity on both GPILSM and GPLA, but that the (-)-2-pyridinyl enantiomer (-)-12B exhibited agonist activity on GPLA and antagonist activity on GPILSM. Whole-cell voltage-clamp studies using isolated guinea pig ventricular myocytes indicated that (-)- 12B inhibited the calcium current (I(Ca)), that (+)-12A increased slightly I(Ca), and that (±)-12 inhibited I(Ca) but the latter inhibition was less than that for (-)-12B. (-)-12B effectively inhibited I(Ca) at all membrane potentials examined (-40-50 mV), whereas (+)-12A exhibited a weak agonist effect near the peak of the I-V curve. The 2-pyridinyl isomers (enantiomers) 12 represent a novel type of 1,4-dihydropyridine calcium channel modulator that could provide a potentially new approach to drug discovery targeted toward the treatment of congestive heart failure and probes to study the structure-function relationships of calcium channels.

Synthesis of the four stereoisomeric forms of α,β diaminobutyric acid and some derivatives suitable for peptide synthesis

A synthetic route to the four stereo isomers of α,β diaminobutyric acid (α,β-A2bu) has been developed. The L threo, D threo, L erythro and D erythro isomers were prepared from the corresponding threonine and allo threonine isomers. N tosylation under Schotten Baumann conditions was followed by esterification with diazomethane and O tosylation in pyridine to give N,O ditosyl threonine methyl ester (IV). Successive treatments with ammonia saturated methanol and 6N HCl afforded, after several recrystallizations from water, N(α) tosyl α,β diaminobutyric acid (V) of the same configuration as the starting threonine along with racemic mixtures. Presumably, the sulfonamide moiety influenced the steric course of the reaction, causing a double inversion of the C(β) asymmetry center via intermediate aziridine formation. Simultaneous α,β elimination produced the accompanying racemic mixtures via 1 tosylaminocrotonic acid methyl ester. Removal of the tosyl group by the action of sodium in liquid ammonia gave α,β diaminobutyric acid (VI). The configurations of the four isomers were established by NMR and ORD spectra and by conversion of N(α) tosyl L threo α,β diaminobutyric acid (L threo V) to N tosyl L threonine (L threo II) through treatment with nitrous acid. The threo and erythro isomers of α,β A2bu (VI) and N(α) tosyl α,β A2bu (V) were further characterized by their elution behavior on ion exchange colum chromatography (amino acid analyzer) and by their ninhydrin color constants (C(HW)). The erythro isomers of α,β A2bu gave higher color constants (20.6) than the threo isomers (5.6 to 5.8). In the case of N(α) tosyl α,β A2bu, however, the threo isomers produced higher ninhydrin color values (11.3-11.4) than the erythro isomers (1.7 to 1.8). The NMR spectra (in DCl) of N(α) tosyl L threo α,β A2bu (L threo V) exhibited an H(α)-H(β) coupling constant (6.6 Hz) which is identical with that of the erythro isomers of the free amino acid (α,β A2bu). Several derivatives of L threo α,β diaminobutyric acid (L threo VI) suitable for use in peptide synthesis were prepared, including N(α) Tos N(β) Boc α,β A2bu, N(β) Boc α,β A2bu, N(α) Z N(β) Boc α,β A2bu, N(α) Z N(β) Boc α,β A2bu OMe, and N(α) Z α,β A2bu Ome x HCl.