131472-74-7

Upstream product

• 1013-88-3 Benzophenone imine 
• 7524-50-7 methyl (2S)-2-amino-3-phenylpropanoate hydrochloride 
• 5619-07-8 methyl 2-amino-3-phenylpropanoate hydrochloride 
• 131472-74-7 methyl 2-((diphenylmethylene)amino)-3-phenylpropanoate 
• 81167-39-7 methyl N-(diphenylmethylene)glycinate 
• 100-39-0 benzyl bromide 
• 67-56-1 methanol 
• 119-61-9 benzophenone 
• 150-30-1 Phenylalanine 

Downstream Products

• 138892-11-2 isopropyl (S)-2-[(diphenylmethylidene)amino]-3-phenylpropanoate 
• 152170-20-2 (2S,3S)-2--1-phenylhex-5-yn-3-ol 
• 286019-77-0 (3S)-1-chloro-3-(diphenylmethylene)amino-4-phenyl-2-butanone 
• 78631-06-8 threo amino-2 diphenyl-1,3 propanol-1 
• 1245904-22-6 methyl (2S,3'S)-2-(3-fluoro-2,2-diphenylaziridin-1-yl)-3-phenylpropanoate 
• 1245904-20-4 methyl (2S,3'R)-2-(3-fluoro-2,2-diphenylaziridin-1-yl)-3-phenylpropanoate 
• 64665-60-7 DL-α-methylphenylalanine methyl ester hydrochloride 
• 195601-05-9 Methyl 2-(2,2-dichloro-3,3-diphenylaziridin-1-yl)-3-phenylpropanoate 
• 199184-30-0 N-[1-(methoxycarbonyl)-1-benzyl-2-phenylethyl]benzophenone imine 
• 496799-03-2 (R)-1-amino-2-benzyl-1,3-diphenyl-2-propanol 
• 853303-76-1 methyl-α-butyl-N-(diphenylmethylene)phenylalaninate 
• 137582-40-2 methyl (3-phenyl-2-amino-2-benzyl)propanoate 
• 1204523-15-8 methyl N-diphenylmethylene-L-phenylalaninate-N-oxide 
• 1738-78-9 L-phenylalanine benzyl ester p-toluene-sulfonic acid salt 

Relevant academic research and scientific papers

Catalytic Dehydrogenative β-Alkylation of Amino Acid Schiff Bases with Hydrocarbon

A synthetic method for the synthesis of a highly congested α,β-dehydroamino acid through the β-C–H bond activation of an amino acid Schiff base is described. Abundant hydrocarbon feedstock could be used as an alkylating reagent to afford an α,β-dehydroamino acid bearing a quaternary carbon at the γ-position with an exclusively (Z)-geometry. Notably, a tetrasubstituted olefin could be constructed from saturated starting materials. The transformation of the synthesized α,β-dehydroamino acid into unnatural α-amino acid derivatives was also demonstrated.

Counter-rotatable dual cinchona quinuclidinium salts and their phase transfer catalysis in enantioselective alkylation of glycine imines

Dual cinchona quinuclidinium salts with a diphenyl ether linker were synthesized and used as powerful asymmetric phase transfer catalysts in the α-alkylation of imines of glycine and alanine ester with 0.01-0.1 mol% loading (17 examples, 92-99% ee). Skewed conformers of dual quinuclidiniums at TS were proposed to rationalize their high efficiencyviaDFT calculations.

Amino Acid Schiff Base Bearing Benzophenone Imine As a Platform for Highly Congested Unnatural α-Amino Acid Synthesis

Unnatural α-amino acids are invaluable building blocks in synthetic organic chemistry and could upgrade the function of peptides. We developed a new mode for catalytic activation of amino acid Schiff bases, serving as a platform for highly congested unnatural α-amino acid synthesis. The redox active copper catalyst enabled efficient cross-coupling to construct contiguous tetrasubstituted carbon centers. The broad functional group compatibility highlights the mildness of the present catalysis. Notably, we achieved successive β-functionalization and oxidation of amino acid Schiff bases to afford dehydroalanine derivatives bearing tetrasubstituted carbon. A three-component cross-coupling reaction of an amino acid Schiff base, alkyl bromides, and styrene derivatives demonstrated the high utility of the present method. The diastereoselective reaction was also achieved using menthol derivatives as a chiral auxiliary, delivering enantiomerically enriched α-amino acid bearing α,β-continuous tetrasubstituted carbon. The synthesized highly congested unnatural α-amino acid could be derivatized and incorporated into peptide synthesis.

Preparation of chiral amino esters by asymmetric phase-transfer catalyzed alkylations of schiff bases in a ball mill

The asymmetric alkylation of Schiff bases under basic conditions in a ball mill was performed. The starting Schiff bases of glycine were prepared beforehand by milling protected glycine hydrochloride and benzophenone imine, in the absence of solvent. The Schiff base was then reacted with a halogenated derivative in a ball mill in the presence of KOH. By adding a chiral ammonium salt derived from cinchonidine, the reaction proceeded asymmetrically under phase-transfer catalysis conditions, giving excellent yields and enantiomeric excesses up to 75 %. Because an equimolar amount of starting material was used, purification was greatly simplified. Copyright

A convenient method for the enantiomeric separation of α-amino acid esters as benzophenone imine schiff base derivatives

A convenient liquid chromatographic method for the separation of α-amino acid esters as benzophenone Schiff base derivatives on coated chiral stationary phases (CSPs) (Chiralcel OD-H, Chiralcel OD, Chiralpak AD-H, Chiralpak AD, and Chiralpak AS) or covalently immobilized CSPs (Chiralpak IA, Chiralpak IB, and Chiralpak IC) derived from polysaccharide derivatives is described. Benzophenone imine derivatives of α-amino acid esters were readily prepared by stirring benzophenone imine and the hydrochloride salts of α-amino acid esters in 2-propanol. The chromatographic separations were conducted at a flow rate 1.0 mL/min and a detection wavelength of 254 nm; 0.5% 2-propanol/hexane (v/v) was used on CSPs. In general, the resolution of Chiralpak IC was superior to those of the other CSPs. In addition, the resolutions of other arylimine derivatives of α-amino acid esters and the effects of different mobile phases on the enantiomeric separation of α-amino acid esters as benzophenone imine derivatives on Chiralpak IC were investigated.

Investigations concerning the syntheses of TADDOL-derived secondary amines and their use to access novel chiral organocatalysts

A structurally carefully diversified library of novel TADDOL-derived chiral secondary amines was synthesized and investigated for their applicability to obtain new organocatalysts like chiral Lewis bases and chiral phase-transfer catalysts. The scope and limitations of the developed syntheses routes to access these catalysts as well their catalytic performance in different benchmark reactions were systematically investigated. The most powerful of the catalysts prepared was found to be highly useful for the phase-transfer catalyzed α-alkylation of glycine Schiff base (high yields and up to 93% ee). Georg Thieme Verlag KG Stuttgart · New York.

Monofluorinated aziridines in asymmetric synthesis of chiral fluorinated prop-2-yn-1-amines

Nonracemic C-fluoroaziridines were synthesized for the first time by reaction of fluorocarbene with N-diphenylmethylidene-substituted natural amino acid esters. The products were shown to be used in asymmetric synthesis of chiral fluorinated prop-2-yn-1-amines via one-pot process involving isomerization of 2-fluoroaziridines into α-fluoro imines and subsequent reaction with alkynyldifluoroborane generated in situ.

Process for producing alpha-aminoketones

An amino group of an α-amino acid ester is protected as an imine, and it is then reacted with a halomethyllithium to obtain an N-protected-α-aminohalomethylketone. Further, this N-protected-α-aminohalomethylketone is treated with an acid to obtain an α-aminohalomethylketone. This process is suited for industrial production, and can produce an α-aminohalomethylketone and its related compounds economically and efficiently.

Alkylation of N′-[(S)-1′-phenylethyl]-N-(diphenylmethylene)glycinamide using a phase transfer catalyst (PTC) for practical asymmetric syntheses of α-amino acid derivatives

The chiral auxiliary mediated stereoselective alkylation reaction of N′-[(S)-1′-phenylethyl]-N-(diphenylmethylene)glycinamide (1) using a phase transfer catalyst (PTC) is described. Alkylation of 1 using 18-crown-6 as a PTC for liquid-solid extraction of KOH in toluene gives best results. This methodology provides a practical protocol for the preparation of a variety of enantio-enriched unnatural α-amino acid derivatives up to 83:17 enantiomeric ratio.

Investigation into the enantioselective protonation of enolate Schiff bases with (R)-pantolactone

The effect of several factors on the enantioselective protonation of the enolates of α-amino acid derivatives with (R)-pantolactone were studied. The highest stereoselectivity (74-76% e.e.) was generally observed by associating lithium chloride with LHMDS