- Stereospecific Synthesis of 3,4-Dihydro-2 H-naphtho-1,4-oxazin-2-ones by Unification of Benzoxepine-4-carboxylates with Chiral Amino Acid Ethyl Esters
-
A novel and efficient stereocontrolled method has been developed for the preparation of chiral 3,4-dihydro-2H-naphtho[1,2-b][1,4]oxazin-2-ones by the reaction of benzoxepine-4-carboxylates with chiral amino acid ethyl esters for the first time. The chiral 3,4-dihydro-2H-naphtho-1,4-oxazinones have been achieved in one step by the formation of C-N, C-C, and C-O bonds.
- Bhimapaka, China Raju,Kasagani, Veera Prasad,Kurma, Siva Hariprasad
-
supporting information
p. 2976 - 2983
(2020/03/23)
-
- Scope and limitations of reductive amination catalyzed by half-sandwich iridium complexes under mild reaction conditions
-
The conversion of aldehydes and ketones to 1° amines could be promoted by half-sandwich iridium complexes using ammonium formate as both the nitrogen and hydride source. To optimize this method for green chemical synthesis, we tested various carbonyl substrates in common polar solvents at physiological temperature (37 °C) and ambient pressure. We found that in methanol, excellent selectivity for the amine over alcohol/amide products could be achieved for a broad assortment of carbonyl-containing compounds. In aqueous media, selective reduction of carbonyls to 1° amines was achieved in the absence of acids. Unfortunately, at Ir catalyst concentrations of 1 mM in water, reductive amination efficiency dropped significantly, which suggest that this catalytic methodology might be not suitable for aqueous applications where very low catalyst concentration is required (e.g., inside living cells).
- Nguyen, Dat P.,Sladek, Rudolph N.,Do, Loi H.
-
supporting information
(2020/07/15)
-
- Boron-Catalyzed Azide Insertion of α-Aryl α-Diazoesters
-
A challenging metal-free azide insertion of α-aryl α-diazoesters in the presence of B(C6F5)3 (5 mol %) was developed for the first time. The reaction features an easy operation, wide substrate scope, and mild conditions an
- San, Htet Htet,Wang, Chun-Ying,Zeng, Hai-Peng,Fu, Shi-Tao,Tang, Xiang-Ying,Jiang, Min
-
p. 4478 - 4485
(2019/05/01)
-
- Palladium-Catalyzed Allylic Alkylation of Aldimine Esters with Vinyl-Cyclopropanes to Yield α,α-Disubstituted α-Amino Acid Derivatives
-
A synthetically useful approach for the synthesis of functionalized α, α-disubstituted α-amino acid derivatives via palladium-catalyzed 1,7 addition of readily available aldimine esters to vinylcyclopropanes is reported. This methodology was operated under mild conditions, affording α-allylic α-amino esters in good to excellent yields and excellent regio- and stereoselectivity. This transformation displays broad functional-group tolerance and enantioselective allylic alkylation has also been realized using a chiral phosphine ligand to provide the desired product. (Figure presented.).
- Wang, Jiahua,Dai, Zonghao,Xiong, Cheng,Zhu, Jin,Lu, Jinrong,Zhou, Qingfa
-
supporting information
p. 5105 - 5111
(2019/11/11)
-
- Site-Selective γ-C(sp3)?H and γ-C(sp2)?H Arylation of Free Amino Esters Promoted by a Catalytic Transient Directing Group
-
The first selective PdII-catalysed γ-C(sp3)?H and γ-C(sp2)?H arylation of free amino esters using a commercially available catalytic transient directing group. A variety of free amino esters, including α-amino esters and β-amino esters, amino monoesters and amino bis-esters, are shown to react with a diverse range of simple aryl and heteroaryl iodide reagents.
- Lin, Hua,Wang, Chao,Bannister, Thomas D.,Kamenecka, Theodore M.
-
supporting information
p. 9535 - 9541
(2018/07/14)
-
- MOF-derived cobalt nanoparticles catalyze a general synthesis of amines
-
The development of base metal catalysts for the synthesis of pharmaceutically relevant compounds remains an important goal of chemical research. Here, we report that cobalt nanoparticles encapsulated by a graphitic shell are broadly effective reductive amination catalysts. Their convenient and practical preparation entailed template assembly of cobaltdiamine- dicarboxylic acid metal organic frameworks on carbon and subsequent pyrolysis under inert atmosphere.The resulting stable and reusable catalysts were active for synthesis of primary, secondary, tertiary, and N-methylamines (more than 140 examples).The reaction couples easily accessible carbonyl compounds (aldehydes and ketones) with ammonia, amines, or nitro compounds, and molecular hydrogen under industrially viable and scalable conditions, offering cost-effective access to numerous amines, amino acid derivatives, and more complex drug targets.
- Jagadeesh, Rajenahally V.,Murugesan, Kathiravan,Alshammari, Ahmad S.,Neumann, Helfried,Pohl, Marga-Martina,Radnik, J?rg,Beller, Matthias
-
p. 326 - 332
(2017/09/28)
-
- High-selectivity herbicide N-substitutive alkyl aryloxy phenoxyl propanamide compound and preparation and application thereof
-
The invention discloses novel N-substitutive alkyl aryloxy phenoxyl propanamide with herbicidal activity represented by the formula (I) and a preparation method thereof, a purpose of controlling vacious grassy weeds in a rice field and a proper weeding composition.The formula (I) is shown in the description.In the formula, R1 is selected from hydrogen or C1-C6 alkane, R3 is selected from hydrogen or C1-C6 alkyl groups or C1-C6 halogenated alkyl groups or C2-C6 alkenyl or C2-C6 alkine groups or C5-C12 aryl groups or heterocyclic aryl, Ar is selected from C6-C12 aryl and C5-C12 heterocyclic aryl, part or all of hydrogen atoms in aryl and heterocyclic aryl are replaced with identical or different substituent groups selected from halogen, cyanogroups, nitryl, C1-C6 alkyl groups, C1-C6 alkoxy, C1-C6 alkylthiol, C1-C6 alkyl amidogen, C1-C6 halogen alkyl and C1-C6 halogen alkoxy, x is selected from N and O, and chiral carbon atoms marked with * are of R or S configuration or are a mixture with R and S with different proportions.
- -
-
-
- Ethyl 2,2-bis(4-methylphenylsulfonamido)acetate to aromatic α-amino acids: Stable substrates for catalytic arylation reactions
-
This paper reports the development of a novel methodology for the catalytic synthesis of aromatic α-amino acids, which involves the addition of aryl-organoboron reagents to α,α-ditosylamino esters derived from ethyl glyoxylate, using transition metal catalysts, like Rh and Pd. A library of α-amino esters (12 with Pd and 8 with Rh), was synthesized with moderate to excellent yields. A highest enantioselectivity of 30% ee was obtained using Hayashi's ligand. This method was applied to the synthesis of phenylglycine.
- Marques, Carolina S.,Burke, Anthony J.
-
supporting information
p. 10091 - 10097
(2013/11/06)
-
- 2-Aryl-2-nitroacetates as central precursors to aryl nitromethanes, α-ketoesters, and α-amino acids
-
Nitroarylacetates are useful small molecular building blocks that act as precursors to α-ketoesters and aryl nitromethanes as well as α-amino acids. Methods were developed that produce each of these compound types in good yields. Two different conditions
- Metz, Alison E.,Kozlowski, Marisa C.
-
p. 717 - 722
(2013/02/25)
-
- Preparation of cross-linked enzyme aggregates of l-aminoacylase via co-aggregation with polyethyleneimine
-
l-Aminoacylase from Aspergillus melleus was co-aggregated with polyethyleneimine and subsequently cross-linked with glutaraldehyde to obtain aminoacylase-polyethyleneimine cross-linked enzyme aggregates (termed as AP-CLEA). Under the optimum conditions, AP-CLEA expressed 74.9% activity recovery and 81.2% aggregation yield. The said method of co-aggregation and cross-linking significantly improved the catalytic stability of l-aminoacylase with respect to temperature and storage. AP-CLEA were employed for enantioselective synthesis of three unnatural amino acids (namely: phenylglycine, homophenylalanine and 2-naphthylalanine) via chiral resolution of their ester-, amide- and N-acetyl derivatives. The enantioselectivity of AP-CLEA was the highest for hydrolysis of amino acid amides; was moderate for hydrolysis of N-acetyl amino acids and was the least for hydrolysis of amino acid esters. Furthermore, AP-CLEA were found to retain more than 92% of the initial activity after five consecutive batches of (RS)-homophenylalanine hydrolysis suggesting an adequate operational stability of the biocatalyst.
- Vaidya, Bhalchandra K.,Kuwar, Suyog S.,Golegaonkar, Sandeep B.,Nene, Sanjay N.
-
experimental part
p. 184 - 191
(2012/03/22)
-
- Resolution of N-protected amino acid esters using whole cells of Candida parapsilosis ATCC 7330
-
Whole cells of Candida parapsilosis ATCC 7330 were used for the resolution of N-acetyl amino acid esters. Excellent enantioselectivities (E = 40 to >500) were achieved for the resolution of N-protected protein and non-protein amino acid esters giving good yields (28-50%) and high enantiomeric excesses (up to >99%) for both enantiomers.
- Stella, Selvaraj,Chadha, Anju
-
experimental part
p. 457 - 460
(2010/06/21)
-
- A vaulted biaryl phosphoric acid-catalyzed reduction of α-imino esters: The highly enantioselective preparation of α-amino esters
-
A new method for the chiral phosphoric acid-catalyzed reduction of α-imino esters using Hantzsch ester is described. A series of 11 α-imino esters were evaluated, and it was shown that imino substrates derived from substituted aryl and alkyl keto esters could be reduced to the corresponding α-amino ester in excellent yield and in enantiomeric excesses from 94 to 99%. Catalyst loading was 5 mol % in each case, and the reactions were run with toluene as the solvent. Copyright
- Li, Guilong,Liang, Yuxue,Antilla, Jon C.
-
p. 5830 - 5831
(2008/02/10)
-
- Highly enantioselective synthesis of β-amino alcohols
-
N,N-Dialkyl-β-amino alcohols derived from α-amino acids can be rearranged enantiospecifically by using TFAA/Et3N/NaOH to give 1,2-amino alcohols with enantiomeric excess up to 99%.
- Metro, Thomas-Xavier,Appenzeller, Jerome,Pardo, Domingo Gomez,Cossy, Janine
-
p. 3509 - 3512
(2007/10/03)
-
- Improved Reagent for Electrophilic Amination of Stabilized Carbanions
-
(Equation presented) Enolate amination using O-di(p-methoxyphenyl) phosphinylhydroxylamine 2 is reported. Reagent 2 reacts efficiently with stabilized sodium or potassium enolates derived from malonates, phenylacetates, and phenylacetonitriles and is sufficiently soluble for use in solution at -78°C.
- Smulik, Jason A.,Vedejs, Edwin
-
p. 4187 - 4190
(2007/10/03)
-
- Chemo-Enzymic Synthesis of Optically Active α,α-Disubstituted α-Amino Acids
-
A series of α,α-disubstituted α-amino esters was chemically synthesized and then resolved through enantioselective hydrolysis catalysed by a new enzyme isolated from crude Humicola langinosa lipase.This enzyme only accepts free amino esters as substrates with neither lipase activity toward olive oil nor esterase activity toward o-nitrophenyl butyrate.It is unique in that it successfully catalyses the resolution of amino esters with two large α-alkyl groups including aliphatic, aromatic and cyclic amino esters.Examples of resolutions where the alkyl groups differ in size by as little as a single carbon atom have been demonstrated.For determination of absolute configuration, some of the optically active α,α-disubstituted amino acids were also prepared through Schoellkopf's asymmetric synthesis and the structures were verified by X-ray crystallography.A model depicting the substrate binding site of the enzyme is proposed.
- Liu, Weiguo,Ray, Paul,Benezra, Steven A.
-
p. 553 - 560
(2007/10/02)
-
- Diastereoselectivity of Organometallic Additions to Nitrones Bearing Sterogenic N-Substituents
-
The diastereoselectivity of organometallic additions to nitrones bearing stereogenic α-arylethyl, β-methoxyalkyl, and β-(silyloxy)alkyl substituents on nitrogen has been investigated.High and complementary diastereoselectivity (90-94percent) was observed in the additions of Grignard reagents to nitrones (e.g. 22 and 23) bearing the potentially chelating β-methoxyalkyl group.However, the opposite selectivity resulted from the reaction of methylmagnesium bromide with the corresponding silyl ether (27).The relative stereochemistry of selected hydroxylamine adducts wasestablished by reduction of their phosphate and carbonate derivatives to known amines (37a,b and 39), by periodate cleavage of a β-hydroxy hydroxylamine (41b), and by various correlations (Scheme II).The high facial diastereoselectivity observed with the N-(β-methoxyalkyl)nitrones is explained by a simple chelation model (Scheme III).
- Chang, Zen-Yu,Coates, Robert M.
-
p. 3464 - 3474
(2007/10/02)
-
- PRIMARY AMINES VIA ELECTROPHILIC AMINATION OF ORGANOMETALLIC COMPOUNDS WITH O-(DIPHENYLPHOSPHINYL)HIDROXYLAMINE
-
It is shown that O-(diphenylphosphinyl)hydroxylamine 4a transforms all kinds of "carbanions" into primary amines; best yields are received with "stabilized anions", e.g. of the benzylic type.
- Boche, Gernot,Bernheim, Michael,Schrott, Wolfgang
-
p. 5399 - 5402
(2007/10/02)
-
- Derivatives of pyrazole-5-acetic acid
-
Compounds having anti-inflammatory and antipyretic action have the general formula SPC1 In which each of R1 and R2 is a phenyl group which may be substituted by a halogen atom, an alkyl or alkoxy group having 1 to 4 carbon atoms or a trifluoromethyl group, R3 is a straight or branched chain saturated or unsaturated aliphatic hydrocarbon group or a cycloaliphatic hydrocarbon group having 3 to 7 carbon atoms, or a benzyl or phenyl group which benzyl or phenyl groups may be substituted in the benzene ring by a halogen atom, an alkyl or alkoxy group having 1 to 4 carbon atoms or a trifluoromethyl group or by any two of these substituents, R4 is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms and A is a group having one of the formulae --COOH, --COOR5 and --CONR6 R7 in which R5 is an alkyl group having 1 to 4 carbon atoms or a benzyl group and each of R6 and R7 is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms or R6 and R7 taken together with the nitrogen atom to which they are attached represents a pyrrolidino, a piperidino or a morpholino group.
- -
-
-