- Iodine-Catalyzed Synthesis of Chiral 4-Imidazolidinones Using α-Amino Acid Derivatives via Dehydrogenative N-H/C(sp3)-H Coupling
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An efficient method for the asymmetric synthesis of 4-imidazolidinones via an iodine-catalyzed intramolecular N-H/C(sp3)-H activation of readily available and abundant feedstocks, amino acids, and amines is described. The reaction proceeded under visible light irradiation to afford a variety of 4-imidazolidinone derivatives under mild conditions in moderate to excellent yields. Secondary and tertiary C(sp3)-H bonds were aminated, and various functional groups were tolerated.
- Kanyiva, Kyalo Stephen,Tane, Marina,Shibata, Takanori
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p. 12773 - 12783
(2019/09/09)
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- Metal-Free N–H/C–H Coupling for Efficient Asymmetric Synthesis of Chiral Dihydroquinoxalinones from Readily Available α-Amino Acids
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We have developed a method for the synthesis of dihydroquinoxalinones via intramolecular N–H/C–H coupling using hypervalent iodine. The starting materials were prepared from inexpensive and readily available aniline and amino acid derivatives. Various functional groups were tolerated to give multisubstituted dihydroquinoxalinones in moderate to excellent yields. The chirality of the amino acid was transferred to the desired target compound without a loss of enantiomeric excess. Preliminary mechanistic studies indicated that the reaction proceeds via an ionic mechanism.
- Kanyiva, Kyalo Stephen,Horiuchi, Masashi,Shibata, Takanori
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p. 1067 - 1070
(2018/03/06)
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- Palladium-Catalyzed Modular Synthesis of Substituted Piperazines and Related Nitrogen Heterocycles
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We report here a novel method for the modular synthesis of highly substituted piperazines and related bis-nitrogen heterocycles via a palladium-catalyzed cyclization reaction. The process couples two of the carbons of a propargyl unit with various diamine components to provide nitrogen heterocycles in generally good to excellent yields and high regio- and stereochemical control. (Chemical Equation Presented).
- Montgomery, Thomas D.,Rawal, Viresh H.
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p. 740 - 743
(2016/03/01)
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- Synthetically amenable amide derivatives of tosylated-amino acids as organocatalysts for enantioselective allylation of aldehydes: Computational rationale for enantioselectivity
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A phenylalanine derived chiral amide is developed that serves as an effective organocatalyst for the reaction of allyltrichlorosilane with aryl, hetero-aryl and α,β-unsaturated aldehydes to afford the desired homoallylic alcohols in good yield (up to 90%)
- Ghosh, Debashis,Sahu, Debashis,Saravanan,Abdi, Sayed H. R.,Ganguly, Bishwajit,Khan, Noor-Ul H.,Kureshy, Rukhsana I.,Bajaj, Hari C.
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p. 3451 - 3460
(2013/06/05)
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- 1,5-rhodium shift in rearrangement of N -arenesulfonylazetidin-3-ols into benzosultams
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Benzosultams are synthesized in an enantiopure form starting from α-amino acids through a rhodium-catalyzed rearrangement reaction of N-arenesulfonylazetidin-3-ols. Mechanistically, this reaction involves C-C bond cleavage by β-carbon elimination and C-H bond cleavage by a 1,5-rhodium shift.
- Ishida, Naoki,Shimamoto, Yasuhiro,Yano, Takaaki,Murakami, Masahiro
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p. 19103 - 19106
(2014/01/17)
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- C2-symmetric recyclable organocatalyst for enantioselective Strecker reaction for the synthesis of α-amino acid and chiral diamine-an intermediate for APN inhibitor
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Recyclable chiral amide-based organocatalyst 5 efficiently catalyzed asymmetric Strecker reaction of various aromatic and aliphatic N-benzhydrylimines with ethyl cyanoformate as cyanide source at -10 °C to give a high yield (95%) of α-aminonitriles with excellent chiral induction (ee, up to 99%) with the added advantage of recyclability. Based on experimental observations a probable mechanism was proposed for this reaction. This protocol with catalyst 5 was extended for the synthesis of (R)-phenylalanine and pharmaceutically important drug intermediate (R)-3-phenylpropane-1,2-diamine in high yield with high enantioselectivity.
- Saravanan,Sadhukhan, Arghya,Khan, Noor-Ul H.,Kureshy, Rukhsana I.,Abdi, Sayed H. R.,Bajaj, Hari C.
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experimental part
p. 4375 - 4384
(2012/06/30)
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- Reductive aldol and mannich-type reactions of azetidin-3-ones promoted by titanium tetraiodide
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A convenient method is described for the generation and reaction of the enolates of aminoacetone equivalents, which uses the reduction of azetidin-3-one with titanium tetraiodide and subsequent reactions with electrophiles. This methodology provides a str
- Hata, Shingo,Fukuda, Daisuke,Hachiya, Iwao,Shimizu, Makoto
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supporting information; experimental part
p. 473 - 477
(2010/08/23)
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- Synthesis of some sulphonamide insect juvenile hormone - Part I
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Regular use of classical insecticides has drastically effected the environment and warm blooded animals. Therefore, there is an urgent need to look for a kind of chemicals which are very specific, targeted in their action and environment friendly. Since l
- Awasthi, Pamita,Mahajan
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p. 1291 - 1297
(2008/12/23)
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- Synthesis and structure of lower rim C-linked N-tosyl peptidocalix[4]arenes
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Chiral p-tert-butylcalix[4]arenes functionalized at the lower rim with amino acid residues have been prepared. The 1H and 13C NMR spectra indicate that the macrocycles preferably adopt a cone conformation. Calix[4]arenes bearing amin
- Sdira, Sofiane Ben,Felix, Caroline P.,Giudicelli, Marie-Beatrice A.,Seigle-Ferrand, Pascal F.,Perrin, Monique,Lamartine, Roger J.
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p. 6632 - 6638
(2007/10/03)
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- Synthesis and structural studies of new N-(p-toluenesulfonyl)amino acid o-phenolamides
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The synthesis and structural studies of N-(p-Toluenesulfonyl)amino acid o-phenolamides was discussed. The structure and conformation of these amides were established by NMR spectroscopy and x-ray crystallography. Variable temperature experiments showed th
- Aguilar-Castro, Liliana,Tlahuextl, Margarita,Tapia-Benavides, Antonio R.,Tlahuext, Hugo
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p. 247 - 253
(2007/10/03)
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- Composition and device for detecting leukocytes in urine
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Thiazole esters are suitable for detecting the presence of leukocytes in urine. Such thiazole esters are suitable for use in compositions, diagnostic devices, and methods for detecting the presence of leukocytes. In one embodiment, a thiazole ester is of
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- 6-Acylamino-2-[(alkylsulfonyl)oxy]-1H-isoindole-1,3-dione mechanism- based inhibitors of human leukocyte elastase
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A study of various 2-[(alkylsulfonyl)oxy]-6-substituted-1H-isoindole- 1,3-diones' inhibition of chymotrypsin compared to inhibition of HLE reveals that acylamino substitution in the 6-position increases selectivity and potency of these inhibitors for HLE.
- Kerrigan, John E.,Walters, Matthew C.,Forrester, Kerri J.,Crowder, Jason B.,Christopher, Lisa J.
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- Wolff rearrangement of diazo ketones derived from N-p-tolylsulfonyl-protected α- and β-amino acids
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Diazo ketones derived from N-p-tolylsulfonyl (tosyl)-protected α- and β-amino acids have been synthesized and their diazo decomposition under standard Wolff rearrangement conditions, PhCO2Ag-Et3N-MeOH, has been investigated. It is observed that, under these conditions, several different reaction pathways, including direct carbene N-H insertion, are possible. The reaction is markedly affected by the N-protecting group, the substrate structure and solvent. For those diazo ketones derived from N-tosyl-protected β-amino acids, the diazo decomposition with anhydrous THF as solvent and PhCO2Ag dissolved in Et3N as catalyst gives the corresponding 5-substituted pyrrolidinones in excellent yields.
- Wang, Jianbo,Hou, Yihua
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p. 1919 - 1923
(2007/10/03)
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- Effect of the 7-Amino Substituent on the Inhibitory Potency of Mechanism-Based Isocoumarin Inhibitors for Porcine Pancreatic and Human Neutrophil Elastases: A 1.85-Angstroem X-ray Structure of the Complex between Porcine Pancreatic Elastase and 7--4-chloro-...
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A series of new acyl, urea, and carbonate derivatives of 7-amino-4-chloro-3-methoxyisocoumarin were synthesized and evaluated as irreversible inhibitors of human neutrophil elastase (HNE) and porcine pancreatic elastase (PPE).Inhibition of HNE is directly related to the hydrophobicity of the substituent on the 7-amino group.The N-Tos-Phe derivative (19) is the best HNE inhibitor with a second-order rate constant kobs/ = 200 000 M-1s-1.The closest analogue in this series, the 3,3-diphenylpropionyl derivative 5, had kobs/ = 130 000 M-1s-1 with HNE.In contrast to the Tos-Phe derivative 19, phenylacetyl derivative 2 and carbonates 22 and 25 gave extremely stable enzyme-inhibitor complexes with deacylation half-lives longer than 48 h with both elastases.N-Phenylurea derivative 25 was the best inhibitor for PPE with a second-order rate constant kobs/ = 7300 M-1s-1.The crystal structure of a complex of PPE with N-tosyl-Phe derivative 19 was determined at 1.85 Angstroem resolution and refined to a final R factor of 16.9percent.The isocoumarin forms an acyl enzyme with Ser-195, while His-57 is near the inhibitor, but not covalently linked.The Tos-Phe makes a few hydrophobic contacts with the S' subsites of PPE, but appears to be interacting primarily with itself in the PPE structure.This region of HNE is more hydrophobic and modeling indicates that the inhibitor would probably make additional contacts with the enzyme.
- Hernandez, Maria A.,Powers, James C.,Glinski, Jan,Oleksyszyn, Jozef,Vijayalakshmi, J.,Meyer, Edgar F.
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p. 1121 - 1129
(2007/10/02)
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- SULFUR YLIDES. 3. SYNTHESIS OF KETO-GROUP STABILIZED AMINO-CONTAINING SULFUR YLIDES FROM AMINO ACIDS
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An effective path of synthesis was developed of new synthetic intermediates, the optically active, keto-group stabilized amino-substituted sulfur ylides.
- Tolstikov, G. A.,Galin, F. Z.,Lakeev, S. N.,Khalilov, L. M.,Sultanova, V. S.
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p. 535 - 541
(2007/10/02)
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- Chromogenic acridinone enzyme substrates
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Chromogenic acridinone enzyme substrate compounds comprising 7-hydroxy-9H-acridin-2-one chromogens derivatized at the 7-hydroxy-position with an enzymatically-cleavable group and disubstituted at the 9-position with alkyl or aryl groups, which can be the same or different, preferably lower alkyl or phenyl, respectively, or together form a cyclohexa-2,5-diene-4-one residue or a 4-hydroxycycloxhexyl residue, and 7-hydroxy-1,3-dihalo-9,9-dimethyl-acridin-2-one intermediates useful for the preparation of the novel chromogenic acridinone enzyme substrate compounds and methods therefor. The enzymatically-cleavable group is a radical of a compound Y-OH comprising an enzyme-specific moiety which is capable of being cleaved by a specific enzyme wherein a deprotonated form of the chromogen is liberated having an absorbance maximum in basic solution which is substantially greater than the absorbance maximum of the chromogenic acridinone enzyme substrate compound to provide a distinct change in absorbance which can be accurately measured and correlated to the amount of enzyme present in a liquid test sample.
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