Enantioselective synthesis of α,β-substituted β-amino acids

Agami, Claude; Cheramy, Sandrine; Dechoux, Luc; Melaïmi, Mohand

doi:10.1016/s0040-4020(00)00997-2

Cited by 22 publications

(8 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Optically active (−)‐ 16 c may be converted into its parent amino acid, β 2 ‐alanine 19 , by oxidative cleavage of the PMP group with ceric ammonium nitrate, followed by hydrolysis of the N ‐imide group (Scheme ). The resultant amino acid was found to have the ( S )‐(+)‐configuration, by comparison of its optical rotation with the reported value 13. Hence, the use of ( R )‐ 1 leads to the formation of optically enriched products with the ( S )‐configuration.…”

Section: Resultsmentioning

confidence: 78%

“…Finally, the combined organic layers were washed with brine, dried (MgSO 4 ) and evaporated to afford ( S )‐(+)‐ 19 (35 mg, 100 %). [ α ]${{{23\hfill \atop {\rm D}\hfill}}}$ =+4.9° ( c =0.3 in 1 n HCl, 45 % ee ), (lit 13. +11.0°, c =0.3 in 1 n HCl, ( S )‐enantiomer); 1 H NMR (400 MHz, CDCl 3 ): δ =6.50 (br s, 1 H; OH), 3.08 (dd, 3 J (H,H)=8.4, 2 J (H,H)=12.8 Hz, 1 H; CH 2 ), 2.98 (dd, 3 J (H,H)=5.3, 2 J (H,H)=12.8 Hz, 1 H; CH 2 ), 2.58 (m, 1 H; CH), 2.00 (br s, 2 H; NH 2 ), 1.13 ppm (d, 3 J (H,H)=6.4 Hz, 3 H; CH 3 ); 13 C NMR (100.6 MHz, CDCl 3 ): δ =177.6 (s), 41.5 (s), 37.6 (s), 14.1 ppm (s).…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Synthesis of 5‐Aminotetrazole‐1 N‐oxide and Its Azo Derivative: A Key Step in the Development of New Energetic Materials

Fischer

Klapötke

Piercey

et al. 2013

Chemistry A European J

178

138

View full text Add to dashboard Cite

1-Hydroxy-5-aminotetrazole (1), which is a long-desired starting material for the synthesis of hundreds of new energetic materials, was synthesized for the first time by the reaction of aqueous hydroxylamine with cyanogen azide. The use of this unique precursor was demonstrated by the preparation of several energetic compounds with equal or higher performance than that of commonly used explosives, such as hexogen (RDX). The prepared compounds, including energetic salts of 1-hydroxy-5-aminotetrazole (hydroxylammonium (2, two polymorphs) and ammonium (3)), azo-coupled derivatives (potassium (5), hydroxylammonium (6), ammonium (7), and hydrazinium 5,5'-azo-bis(1-N-oxidotetrazolate (8, two polymorphs)), as well as neutral compounds 5,5'-azo-bis(1-oxidotetrazole) (4) and 5,5'-bis(1-oxidotetrazole)hydrazine (9), were intensively characterized by low-temperature X-ray diffraction, IR, Raman, and multinuclear NMR spectroscopy, elemental analysis, and DSC. The calculated energetic performance, by using the EXPLO5 code, based on the calculated (CBS-4M) heats of formation and X-ray densities confirm the high energetic performance of tetrazole-N-oxides as energetic materials. Last but not least, their sensitivity towards impact, friction, and electrostatic discharge were explored. 5,5'-Azo-bis(1-N-oxidotetrazole) deflagrates close to the DDT (deflagration-to-detonation transition) faster than all compounds that have been investigated in our research group to date.

show abstract

Section: Resultsmentioning

confidence: 78%

Section: Methodsmentioning

confidence: 99%

Synthesis of 5‐Aminotetrazole‐1 N‐oxide and Its Azo Derivative: A Key Step in the Development of New Energetic Materials

Fischer

Klapötke

Piercey

et al. 2013

Chemistry A European J

178

138

View full text Add to dashboard Cite

show abstract

“…Michael addition of iV-benzyl-a-methylbenzylamine to trans-3 afforded 4 after purification. 6 Subsequent methylation produced a mixture of diastereomers 7 that were separated after deprotection (5) as their l-fluoro-2,4-dinitrophenyl-leucinamide derivatives (FDLA). Comparison with the derivatized hydrogenated hydrolysate established the absolute configuration of the 3-amino-2-methyloct-7-ynoic acid as 2S, 3S using standard Marfey's conditions.…”

mentioning

confidence: 99%

Ulongapeptin, a Cytotoxic Cyclic Depsipeptide from a Palauan Marine Cyanobacterium Lyngbya sp.

et al. 2003

View full text Add to dashboard Cite

Ulongapeptin (1), a cyclic depsipeptide, was isolated from a Palauan marine cyanobacterium Lyngbya sp. The gross structure was elucidated through one-dimensional TOCSY experiments and other spectroscopic techniques. The absolute and relative stereochemistry of the /?-amino acid, 3-amino-2-methyl-7-octynoic acid (AMO), in 1 was determined by synthesis of the saturated a-alkyl-/3-amino acid and Marfey's analysis of the acid hydrolysate of tetrahydro-1. Ulongapeptin (1) was cytotoxic against KB cells at an IC 50 value of 0.63 fM..Cyanobacteria are photosynthetic microorganisms that inhabit diverse habitats ranging from marine to terrestrial. These ancient prokaryotes are believed to have played a key role in the evolution of the modern ecosystem since they were presumably the first organisms to produce molecular oxygen. 1 Filamentous cyanobacteria of the genus Lyngbya are the most frequently encountered cyanobacteria in tropical areas and have the ability to fix nitrogen through heterocysts. With few exceptions most secondary metabolites from Lyngbya arise by the incorporation of nitrogen into a combination of polyketide and peptide biosynthetic pathways. 2 Here we describe the isolation of a new nitrogen-containing compound, ulongapeptin (1), from a Palauan collection of Lyngbya sp.Results and Discussion.Lyophilized VP755 was extracted with 1:1 methanol/ ethyl acetate and the concentrated extract fractionated by normal and reversed-phase chromatography. After repeated RP-HPLC 1.1 mg of ulongapeptin (1), which had an IC50 of 0.63 ftM against KB cells, 3 was isolated in a yield of 0.10%.Ulongapeptin (1) was found to have a molecular weight of 808 Da based on FABMS pseudo-molecular ion peaks

show abstract

“…The product 3b was obtained in 92% yield. Other products 3a , 3c , and 3d were also prepared from the corresponding chiral amino alcohols in the similar procedure in good yields up to 95% 14 , 45 − 55 ( Figures S9–S16 ).…”

Section: Methodsmentioning

confidence: 99%

Synthesis of Chiral Allylic Esters by Using the New Recyclable Chiral Heterogeneous Oxazoline-Based Catalysts

2020

View full text Add to dashboard Cite

A new class of recyclable supported chiral heterogeneous ligands has been synthesized by the reaction of functionalized mesoporous SBA-15 with aliphatic- and aromatic-substituted chiral amino oxazoline ligands. The obtained chiral heterogeneous ligands were characterized by several techniques such as Fourier transform infrared, X-ray diffraction, thermogravimetric analysis, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and BET–BJH. The application of these new heterogeneous ligands in copper-catalyzed asymmetric allylic oxidation of olefins by using perester showed better yields up to 95% and better enantioselectivities up to 96% compared to the corresponding homogeneous catalysts. These findings can be considered as an important step in the advancement of green chemistry. Investigation of the recyclability of the catalysts confirmed that they were easily recovered and reused eight times without significant losses in reactivity, yield, and enantioselectivity.

show abstract

Enantioselective synthesis of α,β-substituted β-amino acids

Cited by 22 publications

References 17 publications

Synthesis of 5‐Aminotetrazole‐1 N‐oxide and Its Azo Derivative: A Key Step in the Development of New Energetic Materials

Synthesis of 5‐Aminotetrazole‐1 N‐oxide and Its Azo Derivative: A Key Step in the Development of New Energetic Materials

Ulongapeptin, a Cytotoxic Cyclic Depsipeptide from a Palauan Marine Cyanobacterium Lyngbya sp.

Synthesis of Chiral Allylic Esters by Using the New Recyclable Chiral Heterogeneous Oxazoline-Based Catalysts

Contact Info

Product

Resources

About