149437-67-2Relevant articles and documents
Conversion of γ- and δ-Keto Esters into Optically Active Lactams. Transaminases in Cascade Processes
Mourelle-Insua, ángela,Zampieri, Luiz Arthur,Lavandera, Iván,Gotor-Fernández, Vicente
, p. 686 - 695 (2018/02/21)
A one-pot two-step enzymatic strategy has been designed for the production of optically active γ- and δ-lactams in aqueous medium under mild conditions. The approach is based on the biotransamination of ethyl or methyl keto esters bearing different alkyl or aryl substitution patterns at α-position to the ketone functionality. In this manner, the keto esters were transformed into the corresponding amino esters with excellent conversions, which underwent spontaneous cyclisation in the reaction medium without addition of external reagents. Depending on the transaminase selectivity, both lactam enantiomers can be obtained, so initial enzyme screenings were performed using commercially available and made in house enzymes. Reaction conditions were optimised focusing on the substrate concentration, temperature and ratio of amine donor vs acceptor. Thus, ten γ- and δ-lactams were obtained in good to high isolated yields (70–90%) and excellent selectivities (94–99%) after one or two days at 30 or 45 °C. (Figure presented.).
Asymmetric iodolactonization utilizing chiral squaramides
Tungen, Jorn E.,Nolsoe, Jens M. J.,Hansen, Trond V.
supporting information, p. 5884 - 5887 (2013/02/23)
Asymmetric iodolactonization of γ- and δ-unsaturated carboxylic acids has been explored in the presence of six different chiral organocatalysts 5-8. The catalyst 6b was found to facilitate the cyclization of 5-arylhex-5-enoic acids 1 to the corresponding
PROCESS FOR THE PREPARATION OF TRANS-ISOMERS OF DIPHENYLAZETIDINONE DERIVATIVES
-
Page 8, (2010/02/09)
The invention relates to processes for the preparation of trans-isomers of diphenylazetidinone derivatives, using a chiral delta-lactone. It also relates to processes for the preparation of the chiral delta-lactone. The invention also relates to pharmaceutical compositions that include the trans-isomers of diphenylazetidinone derivatives.
