ABSTRACT
To address the growing demand for more elastic sutures free from unwanted knot loosening, we fabricated an absorbable monofilament suture from poly(3-hydroxybutyrate-co-4-hydroxybutyrate) and subjected it to physical property characterization and performance evaluation (in vitro and in vivo degradability tests and a porcine abdominal wall suture test). As this flexible, highly stretchable, and difficult-to-untie suture exhibited additional advantages of small knot size and medium to long-term bioabsorbability, it was concluded to be a safe alternative to existing monofilament sutures, with far-reaching potential applications.
Subject(s)
Suture Techniques , Sutures , Animals , Swine , Physical PhenomenaABSTRACT
The catalytic enantioselective desymmetrization of aziridines with malononitrile has been developed. Good yield and enantioselectivity were obtained by using cinchona alkaloid amide/Zn(ii) catalysts. The obtained product can be converted to ß-aminoester, ß-aminoamide and triamide compounds.
ABSTRACT
The enantioselective oxidative ring-opening reaction of aziridines with α-nitroacetates has been developed. Good yields and enantioselectivity were observed for the reaction of various aziridines using a novel cinchona alkaloid amide/NiBr2 catalyst. Both enantiomers of products could be obtained by using pseudoenantiomeric chiral catalysts. This process offers an efficient route for the synthesis of α-aminoketones.
ABSTRACT
The enantioselective direct Mannich-type reaction of ketimines with α-isocyanoacetates has been developed. Excellent yields and enantioselectivity were observed for the reaction of various ketimines and α-isocyanoacetates using cinchona alkaloid/Cu(OTf)2 and a base. Both enantiomers of the products could be obtained by using pseudoenantiomeric chiral catalysts. This process offers an efficient route for the synthesis of α,ß-diamino acids.
Subject(s)
Acetates/chemistry , Cinchona Alkaloids/chemistry , Imines/chemistry , Nitriles/chemistry , Catalysis , Molecular Structure , StereoisomerismABSTRACT
The first highly enantioselective desymmetrization of aziridines with phosphites has been developed. Excellent yields and enantioselectivities were observed for the reaction with various aziridines using a new class of readily accessible chiral catalysts derived from 9-amino-9-deoxy-epi-cinchona alkaloids. In studies probing the reaction mechanism, we observed some complexes for the cinchona alkaloid amide-Zn(II) by ESI-MS analysis.
