17186-53-7Relevant articles and documents
Access to Spirocyclic Benzothiophenones with Multiple Stereocenters via an Organocatalytic Cascade Reaction
Formánek, Bed?ich,Tauchman, Ji?í,Císa?ová, Ivana,Vesely, Jan
, p. 8510 - 8521 (2020/07/16)
The present report describes an organocatalytic cascade reaction between 2-alkylidene benzo[b]thiophenone derivatives and enones in the presence of the Cinchona alkaloid amine. Spirobenzothiophenonic cyclohexane derivatives containing three stereocenters were prepared via one-step synthesis in yields ranging from 88 to 96% and in enantioselectivities (enantiomeric excess (ee)) ranging from 85 to 97%, with diastereoselectivities of approximately 14/2/1. Therefore, this method provides an efficient route for the synthesis of a new class of optically active 2-spirobenzothiophenones.
Protecting-Group-Free Amidation of Amino Acids using Lewis Acid Catalysts
Sabatini, Marco T.,Karaluka, Valerija,Lanigan, Rachel M.,Boulton, Lee T.,Badland, Matthew,Sheppard, Tom D.
supporting information, p. 7033 - 7043 (2018/05/04)
Amidation of unprotected amino acids has been investigated using a variety of ‘classical“ coupling reagents, stoichiometric or catalytic group(IV) metal salts, and boron Lewis acids. The scope of the reaction was explored through the attempted synthesis of amides derived from twenty natural, and several unnatural, amino acids, as well as a wide selection of primary and secondary amines. The study also examines the synthesis of medicinally relevant compounds, and the scalability of this direct amidation approach. Finally, we provide insight into the chemoselectivity observed in these reactions.
Highly enantioselective epoxidation of α,β-unsaturated ketones catalyzed by primary-secondary diamines
Lu, Yingpeng,Zheng, Changwu,Yang, Yingquan,Zhao, Gang,Zou, Gang
, p. 3129 - 3133 (2012/01/03)
The asymmetric epoxidation of α,β-unsaturated ketones has been achieved by using functional and readily accessible primary-secondary diamines as the catalysts, giving the useful alkyl epoxy products with good yields and high enantioselectivities (up to 99% ee). Copyright
Development of potent bifunctional endomorphin-2 analogues with mixed μ-/δ-opioid agonist and δ-opioid antagonist properties
Fujita, Yoshio,Tsuda, Yuko,Li, Tingyou,Motoyama, Takashi,Takahashi, Motohiro,Shimizu, Yoshiro,Yokoi, Toshio,Sasaki, Yusuke,Ambo, Akihiro,Kita, Atsuko,Jinsmaa, Yunden,Bryant, Sharon D.,Lazarus, Lawrence H.,Okada, Yoshio
, p. 3591 - 3599 (2007/10/03)
The C terminus of endomorphin-2 (EM-2) analogues (Tyr-Pro-Phe-NH-X) was modified with aromatic, heteroaromatic, or aliphatic groups (X = phenethyl,benzyl, phenyl, naphthyl, pyridyl, quinolyl, isoquinolyl, tert-butyl, cyclohexyl, or adamantyl; 3-18) to study their effect on opioid activity. Only 9 (1-naphthyl), 11 (5-quinolyl), 16 (cyclohexyl), and 18 (2-adamantyl) exhibited μ-opioid receptor affinity in the nanomolar range (Ki = 2.41-6.59 nM), which, however, was 3-to 10-fold less than the parent peptide. Replacement of Tyr1 by Dmt (2′,6′-dimethyl-L-tyrosine) (19-32) exerted profound effects: (i) acquisition of high μ-opioid receptor affinity (Ki = 0.11-0.52 nM) except 23 (Ph); (ii) presence of potent functional μ-opioid receptor agonism (IC50 1]EM-2), 27 (1-naphthyl), 29 (5-quinolyl), and 32 (5-isolquinolyl); (iii) association of weak δ-opioid antagonist activity (pA2 = 5.41-7.18) except 19 ([Dmt1]EM-2), 20 (H), 27 (1-naphthyl), and in particular 29 (5-quinolyl) with its potent δ-agonism (IC50 = 0.62 nM, pA2 = 5.88); (iv) production of antinociception after ic administration of 32 (5-isoquinolyl) in mice, a bioactivity absent in the corresponding Tyr1 analogue (14); and (v) preferential cis orientation (cis/trans = 3:2 to 7:3) at the Dmt-Pro amide bond, in contrast to the Tyr-Pro amide trans orientation (cis/trans = 1:2 to 1:3). Thus, [Dmt1]EM-2 analogues with hydrophobic C-terminal extensions provide model compounds with potent μ-opioid receptor bioactivity and dual functional agonism.
Stereoselectivity and regioselectivity in nucleophilic ring opening in derivatives of 3-phenylisoxazolo[2,3-a]pyrimidine. Unpredicted dimerization and ring transformation. Syntheses of derivatives of pyrimidinylmethylamine, pyrimidinylmethylamino acid ami
Zvilichovsky, Gury,Gbara-Haj-Yahia, Isra
, p. 4966 - 4973 (2007/10/03)
The nucleophilic ring opening of the isoxazolone ring in 2-oxo-3-phenylisoxazolo[2,3-a]pyrimidine derivatives by optically active amino acid amides and ephedrine led to pyrimidinylmethylamino acid amides. Using amides of different L-amino acids and (-)-ep
Novel syntheses of enantiopure hexahydroimidazo[1,5-b]isoquinolines and tetrahydroimidazo[1,5-b]isoquinolin-1(5H)-ones via iminium cation cyclizations
Katritzky, Alan R.,Suzuki, Kazuyuki,He, Hai-Ying
, p. 8224 - 8229 (2007/10/03)
Condensations of chiral diamines 11a-c with benzotriazole and formaldehyde gave benzotriazolyl intermediates 12a-c; similar condensations of α-amino-amides 10a-c with benzotriazole and paraformaldehyde gave 14a-c. Subsequent treatment of 12a-c and 14a-c with AlCl3 led to enantiopure tricyclic 1,2,3,5,10,10a-hexahydroimidazo[1,5-b]isoquinolines 1a-c and 2,3,10,10a-tetrahydroimidazo[1,5-b]isoquinolin-1(5H)-ones 15a-c, respectively, via Lewis acid promoted iminium cation cyclizations.
Practical resolution of an atropoisomeric α,α-disubstituted glycine with L-phenylalanine cyclohexylamide as chiral auxiliary
Mazaleyrat, Jean-Paul,Boutboul, Aurelia,Lebars, Yann,Gaucher, Anne,Wakselman, Michel
, p. 2701 - 2713 (2007/10/03)
L-Phenylalanine cyclohexylamide has been used as a chiral auxiliary for the medium-scale resolution of 2', 1 ':1,2;1,2' :3,4-dinaphthcyclohepta- 1,3-diene-6-amino-6-carboxylic acid (Bin), an α,α-disubstituted glycine with only axial dissymmetry
A Novel Synthesis of (R)- and (S)-α-Alkylated Aspartic and Glutamic Acids: α-Alkylated Aspartic Succinimides as New Type of β-Turn Type II and II' Mimetics
Obrecht, Daniel,Bohdal, Udo,Daly, John,Lehmann, Christian,Schoenholzer, Peter,Mueller, Klaus
, p. 10883 - 10900 (2007/10/02)
A novel and efficient synthesis of optically pure (R)- and (S)-α-methyl glutamic acid (1), (R)-and (S)-α-methyl aspartic acid (2a) and (R)- and (S)-α-isobutyl aspartic acid (2b) using L-phenylalanine cyclohexylamide 4 as chiral auxiliary is described.Crystal structures show that the (R)- and (S)-α-methyl glutamic acid derivatives (S,S)-5 and (R,S)-6 adopt β-turn type I geometries, whereas the corresponding aspartimide derivatives (R,S)-12a,b form a β-turn type II and (S,S)-11a a β-turn type II'.These findings suggest, that the succinimide derivatives of (R)- and (S)-α-alkyl aspartic acids can serve as building blocks to stabilise β-turns of type II (or II') in peptides depending on their absolute configuration.
L-phenylalanine cyclohexylamide: A simple and convenient auxiliary for the synthesis of optically pure α,α-disubstituted (R)- and (S)-amino acids
Obrecht,Bohdal,Broger,Bur,Lehmann,Ruffieux,Schonholzer,Spiegler,Muller
, p. 563 - 580 (2007/10/02)
This work describes L-phenylalanine cyclohexylamide (5c) as a simple, cheap, and powerful chiral auxiliary for the synthesis of a series of optically pure α,α-disubstituted (R)- and (S)-amino acids of type 1, such as (R)- and (S)-2-methyl-phenylalanine (1a), (R)- and (S)-2-methyl-2-phenylglycine (1b), and (R)- and (S)-2-methylvaline (1c). These amino acids were efficiently transformed into the suitably protected and activated amino-acid building blocks (R)- and (S)-12b and (R)- and (S)-12c which are ready for incorporation into peptides by solution or solid-phase techniques. Based on the crystal structures of 6b, 6c, and 7a belonging to the diastereoisomeric peptides series 6 and 7, the absolute configurations of each member of the series were determined. β-Turn geometries of type II' and I were observed for 6b and 7a, respectively, whereas 6c crystallized in an extended conformation. The impacts of side-chain variation on conformation and crystal packing of these triamides are discussed.
