5296-21-9Relevant academic research and scientific papers
Diastereoselective Desymmetrization of p-Quinamines through Regioselective Ring Opening of Epoxides and Aziridines
Jadhav, Sandip B.,Chegondi, Rambabu
supporting information, p. 10115 - 10119 (2019/12/24)
A highly diastereoselective desymmetrization of p-quinamines via regioselective ring opening of epoxides and aziridines under mild conditions has been developed. A chairlike six-membered transition state with minimized 1,3-diaxial interactions explains the relative stereoselectivity of the cyclization reaction. This transition-metal free [3 + 3] annulation reaction provides rapid access to fused bicyclic morpholines and piperazines with a tetrasubstituted carbon center in high yields. In addition, it also allows the synthesis of enantioenriched products by using easily accessible chiral nonracemic epoxides and aziridines.
α-Silyl Amides: Effective Bifunctional Lynchpins for Type i Anion Relay Chemistry
Montgomery, Thomas D.,Smith, Amos B.
supporting information, p. 6216 - 6219 (2017/11/24)
Lynchpins comprising α-silyl amides have been validated for type I anion relay chemistry (ARC) to permit ready access to γ-ketoamides. Importantly, the ARC protocol can be run at ambient temperature without the need of additional reagents to trigger the [
Silver nanoparticle-catalysed phenolysis of epoxides under neutral conditions: Scope and limitations of metal nanoparticles and applications towards drug synthesis
Seth, Kapileswar,Roy, Sudipta Raha,Kommi, Damodara N.,Pipaliya, Bhavin V.,Chakraborti, Asit K.
, p. 164 - 172 (2014/06/23)
Chemo- and regio-selective epoxide phenolysis is reported for the first time under neutral condition catalysed by silver nanoparticles. Other metal nanoparticles (e.g., Au, Pd, Cu, In, and Ru) are less effective. The choice of solvent is critical with 2-propanol being the best followed by DEF. Amongst various stabilisers used (surfactants, PEGs, tetra-alkylammonium halides) the tetra-alkylammonium halides are found to be the most effective (TBAF > TBAB > TBACl > TBAI). The role of the silver nanoparticles is envisaged as synchronous mode epoxide-phenol dual activation via a cooperative network of coordination, anion-π interaction, and hydrogen bond. The silver nanoparticles are recovered and reused for five consecutive times. The reaction has been used for the synthesis of propranolol and naftopidil as a few representative cardiovascular drugs.
Simple synthesis of β-acetoxy thiocyanates from oxiranes
Lukowska-Chojnacka, Edyta,Plenkiewicz, Jan
experimental part, p. 1999 - 2006 (2011/06/24)
A convenient and simple method for the preparation of previously unknown β-acetoxy thiocyanates by regioselective ring opening of the corresponding oxiranes with thiocyanate anion followed by acetylation is described. The shorter reaction times, better yields of the products, and easy workup are the advantages of this methodology.
Al(OTf)3-mediated epoxide ring-opening reactions: Toward piperazine-derived physiologically active products
Williams, D. Bradley G.,Cullen, Adam
supporting information; experimental part, p. 9509 - 9512 (2010/03/04)
(Chemical Equation Presented) Al(OTf)3 is a good catalyst for the ring opening of epoxides, forming β-amino alcohols bearing the piperazine motif. Two different strategies were examined, where the glycidyl ether resided on one-half of the molec
Substituent effects on the regiochemical and stereochemical course of the nussbaumer-frater variation of the prins cyclization
Bennett, Chad E.,Figueroa, Ruth,Hart, David J.,Yang, Dexi
, p. 119 - 128 (2007/10/03)
Eleven vinylogous carbonates were examined in the Nussbaumer-Frater variation of the Prins cyclization to provide 2,3,4,6-tetrasubstituted tetrahydropyrans. Results indicate that substrate olefin geometry is a more reliable control element than preset sub
Lipase-catalyzed separation of the enantiomers of 1-substituted-3-arylthio- 2-propanols
Wielechowska, Monika,Plenkiewicz, Jan
, p. 1199 - 1205 (2007/10/03)
Optically active (R)- and (S)-1-substituted-3-(arylthio)propan-2-ols have been prepared in the reaction of the appropriate 2-(arylthiomethyl)oxiranes with chloride and azide anions followed by a lipase-catalyzed transesterification. The effects of the enzyme preparation as well as of the reaction conditions have been compared in terms of the enantiomeric excess of the obtained acetate and unreacted alcohol.
Highly stereoselective cationic cyclization assisted by a sulfenyl group, scope, limitation, and mechanism
Liu, Changqing,Kudo, Kazuaki,Hashimoto, Yukihiko,Saigo, Kazuhiko
, p. 494 - 502 (2007/10/02)
When 8-acetoxy-2-naethyl-9-(phenylthio)-2-nonene (la) was treated with an acid, followed by a base, alkylative cyclization proceeded to give a mixture of 1,2-disubstituted cyclohexanes: 2a, 3a, and 4a. The stereochemistry of the reaction was only slightly affected by the leaving group and the reaction conditions, such as the temperature, solvent, and acid. However, the bulkiness of the sulfenyl group had a great effect on the stereochemical course of the reaction. High trans selectivity was attained when 1c (a derivative of 1a with a bulkier sulfenyl group) was used as a substrate. On the other hand, the length and rigidity of the carbon chain of the substrate also had a major effect on the stereochemistry of the reaction; a high cis selectivity was observed when 10a (a one-carbon-fewer analog of Ia) or 15a (a derivative with one more double bond in the carbon chain than in 1a) was used as the substrate. The reaction proceeded via a 6,5- or 5,5-fused-ring intermediate. The sulfenyl-group-assisted reaction could be a useful method for the stereoselective cyclization of acetates of α-sulfenylated secondary alcohols.
Thiazolidine and oxazolidine derivatives, their preparation and their medical use
-
, (2008/06/13)
Compounds of formula (I): STR1 and salts, esters and solyates thereof and pro-drugs therefor are useful for the treatment and/or prophylaxis of a variety of disorders, including one or more of: hyperlipemia, hyperglycemia, obesity, glucose tolerance insufficiency, insulin resistance and diabetic complications.
