79271-27-5Relevant academic research and scientific papers
Inhibition of Pseudomonas aeruginosa Alginate Synthesis by Ebselen Oxide and Its Analogues
Kim, Soo-Kyoung,Ngo, Huy X.,Dennis, Emily K.,Thamban Chandrika, Nishad,Deshong, Philip,Garneau-Tsodikova, Sylvie,Lee, Vincent T.
, p. 1713 - 1726 (2021/05/10)
Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen that is frequently found in the airways of cystic fibrosis (CF) patients due to the dehydrated mucus that collapses the underlying cilia and prevents mucociliary clearance. During this life-long chronic infection, P. aeruginosa cell accumulates mutations that lead to inactivation of the mucA gene that results in the constitutive expression of algD-algA operon and the production of alginate exopolysaccharide. The viscous alginate polysaccharide further occludes the airways of CF patients and serves as a protective matrix to shield P. aeruginosa from host immune cells and antibiotic therapy. Development of inhibitors of alginate production by P. aeruginosa would reduce the negative impact from this viscous polysaccharide. In addition to transcriptional regulation, alginate biosynthesis requires allosteric activation by bis (3′-5′)-cyclic dimeric guanosine monophosphate (c-di-GMP) binding to an Alg44 protein. Previously, we found that ebselen (Eb) and ebselen oxide (EbO) inhibited diguanylate cyclase from synthesizing c-di-GMP. In this study, we show that EbO, Eb, ebsulfur (EbS), and their analogues inhibit alginate production. Eb and EbS can covalently modify the cysteine 98 (C98) residue of Alg44 and prevent its ability to bind c-di-GMP. However, P. aeruginosa with Alg44 C98 substituted with alanine or serine was still inhibited for alginate production by Eb and EbS. Our results indicate that EbO, Eb, and EbS are lead compounds for reducing alginate production by P. aeruginosa. Future development of these inhibitors could provide a potential treatment for CF patients infected with mucoid P. aeruginosa.
Diprotonative stabilization of ring-opened carbocationic intermediates: conversion of tetrahydroisoquinoline to triarylmethanes
Kurouchi, Hiroaki
, p. 8313 - 8316 (2020/08/17)
Superacid-promoted conversion of tetrahydroisoquinolines to triarylmethanes via tandem reactions of C-N bond scission, Friedel-Crafts alkylation, C-O bond scission, and electrophilic aromatic amidation was developed. Dication formation was important for stabilizing the ring-opened carbocationic intermediate, which is a new role for diprotonation in reaction mechanisms. This journal is
Substituent effects on axial chirality in 1-aryl-3,4-dihydroisoquinolines: controlling the rate of bond rotation
Roselló, Josep Mas,Staniland, Samantha,Turner, Nicholas J.,Clayden, Jonathan
, p. 5172 - 5177 (2016/08/02)
A series of 1-aryl-3,4-dihydroisoquinolines (DHIQs) were synthesized and their barriers to bond rotation were determined by means of VT-NMR, dynamic HPLC or racemization studies. Although they all presented lower rotational stability than the related 1-ar
Enantioselective Synthesis of 1-Aryl-Substituted Tetrahydroisoquinolines Through Ru-Catalyzed Asymmetric Transfer Hydrogenation
Perez, Marc,Wu, Zi,Scalone, Michelangelo,Ayad, Tahar,Ratovelomanana-Vidal, Virginie
, p. 6503 - 6514 (2015/10/19)
A convenient and general asymmetric transfer hydrogenation of a wide array of 1-aryl-3,4-dihydroisoquinoline derivatives using a [RuIICl(η6-benzene)TsDPEN] complex in combination with a 5:2 HCOOH-Et3N azeotropic mixture as a hydrogen source was developed. Under mild reaction conditions, the described catalytic transformation secured a practical synthetic access to the corresponding valuable chiral 1-aryltetrahydroisoquinoline units with high atom economy, a broad substrate scope, high isolated yields (up to 97%) and good to excellent enantioselectivities (up to 99% ee). It was found that the stereochemical outcome of the reaction was strongly influenced by both the structure of the catalyst and the substituents present on the substrate. The synthetic utility of the present protocol has been demonstrated through the asymmetric synthesis of several biologically important alkaloids including the antiepileptic drug agent 1c, as well as (-)-nor-cryptostyline alkaloids I and II.
Amidation of aldehydes and alcohols through α-iminonitriles and a sequential oxidative three-component strecker reaction/thio-michael addition/alumina-promoted hydrolysis process to access β-mercaptoamides from aldehydes, amines, and thiols
Gualtierotti, Jean-Baptiste,Schumacher, Xavier,Fontaine, Patrice,Masson, Géraldine,Wang, Qian,Zhu, Jieping
supporting information, p. 14812 - 14819 (2013/01/15)
Mild and general alumina-promoted hydrolysis conditions for converting α-iminonitriles into carboxamides have been developed. In combination with the oxidative three-component Strecker reaction, the one-pot direct amidation of aldehydes and alcohols is reported. Subsequently, an Yb(OTf) 3-catalyzed Michael addition of thiols to α,β-unsaturated α-iminonitriles is reported for the synthesis of β-mercapto-α- iminonitriles. The successful integration of an oxidative Strecker reaction, thio-Michael addition, and neutral-alumina-promoted hydrolysis of β-mercapto-α-iminonitriles into a three-component one-pot process allowed us to develop the direct conversion of amines, aldehydes, and thiols into β-mercaptoamides. All of these procedures were applicable to aromatic and aliphatic amines and aldehydes. First direct: The direct amidation reactions of aldehydes and alcohols were performed in combination with the oxidative three-component synthesis of α-iminonitriles. In addition, β-mercaptoamides were readily accessed from α,β-unsaturated aldehydes, amines, and thiols by a sequential process that involved a three-component Strecker reaction, Yb(OTf)3-catalyzed thio-Michael addition, and hydrolysis of the resulting β-mercapto-α-iminonitriles (see scheme). Copyright
Silver- and gold-mediated intramolecular cyclization to substituted tetracyclic isoquinolizinium hexafluorostilbates
Liu, Fang,Ding, Xiao,Zhang, Lei,Zhou, Yu,Zhao, Linxiang,Jiang, Hualiang,Liu, Hong
experimental part, p. 5810 - 5820 (2010/10/18)
A convenient route for the synthesis of various charged tetracyclic isoquinolizinium hexafluorostilbates was developed using AgSbF 6/AuCl(PPh3) for the intramolecular addition of amine to alkyne. The described process is tolerant of a variety of functional groups and broadens the diversity of substrates with the use of 8-substituted tetracyclic isoquinolizinium salts.
Amides useful as brain imaging agents
-
, (2008/06/13)
Certain radioiodine containing amides useful as brain imaging agents are disclosed. The compounds of the subject invention are represented by the formula STR1 wherein I is a radioisotope of iodine with I-123 being preferred, R1 and R2 are the same or different and are selected from the grooup consisting of hydrogen, hydroxy, alkyl, aryl, substituted aryl, aralkyl, anilino and carbamoylmethyl or R1 and R2 taken together with the nitrogen to which they are attached form a 5- or 6-membered ring.
