ABSTRACT
Copper-catalyzed asymmetric dearomative azidation of tryptamines using azidobenziodoxolone as an azidating reagent was developed, which affords a variety of 3a-azido-pyrroloindolines in good to high enantioselectivities under mild reaction conditions. The azides could be readily transformed into the corresponding 3a-amino-pyrroloindolines via reduction and 1,2,3-triazole derivatives via a click reaction.
ABSTRACT
An efficient rhodium-catalyzed redox-neutral annulations of N-phenoxyacetamides and ynones via successive double C-H bond activations has been developed. A series of novel and complex indenols bearing a benzofuran unit were generated with moderate to excellent regioselecetivities under mild conditions. Adding N-ethylcyclohexanamine (CyNHEt) could restrict the formation of the mono C-H bond activation byproduct, which is not the intermediate of the reaction demonstrated via the mechanistic investigations.
ABSTRACT
Microneedle is a painless and minimally invasive transdermal drug delivery. It can enhance the permeability of skin for macromolecular drugs by puncturing and creating a micron-level drug delivery channel in the skin. The biodegradable microneedles aim to solve the problem that nondegradable-material microneedles may break under skin and cause adverse reaction. This article pro?vides an overview of the characteristics of biodegradable microneedles,the biodegradable materials used,its recent research progress, the development status and the tendency.
