Synthesis of a new photolabile protectinggroup, bis(4,5-dimethoxy-2-nitrophenyl)ethylene glycol (4) from 4,5-dimethoxy-2-nitrobenzyl alcohol in three steps in good yields is described. The acetals and ketals of 4 are stable against acidic and basic reaction conditions and are cleaved smoothly on irradiation at 350 and 400 nm with regeneration of carbonyl compounds in high yields and efficiency.
Reduction of Activated Carbonyl Groups Using Alkylphosphanes as Reducing Agents: A Mechanistic Study
作者:Yin Wei、Xu-Guang Liu、Min Shi
DOI:10.1002/ejoc.201200019
日期:2012.4
investigation on the reduction of activated carbonylgroupsusing alkylphosphanes as reducing agents has been conducted through a combination of experimental as well as computational studies. Both approaches show that this kind of reduction proceeds either through proton transfer from alkylphosphanes and cleavage by water during work-up or through another reaction pathway involving the participation of
The present invention provides methods, processes, and systems for the manufacture of three-dimensional articles (35) of polymer materials using 3D printing. A syringe or an inkjet print head (30, 31) prints a solution of prepolymer onto a build plate (37). The printed prepolymer is exposed to a stimulus whereby the prepolymer is converted to the polymer. After a predetermined time, sequential layers are printed to provide the three-dimensional article (35). The three-dimensional article (35) can be cured to produce the 3D article made from the final polymer.
The present invention provides methods, processes, and systems for the manufacture of three-dimensional articles of polymer materials using 3D printing. A syringe or an inkjet print head prints a solution of prepolymer onto a build plate. The printed prepolymer is exposed to a stimulus whereby the prepolymer is converted to the polymer. After a predetermined time, sequential layers are printed to provide the three-dimensional article. The three-dimensional article can be cured to produce the 3D article made from the final polymer.
The present invention provides methods, processes, and systems for the manufacture of three-dimensional articles of polymer materials using 3D printing. A syringe or an inkjet print head prints a solution of prepolymer onto a build plate. The printed prepolymer is exposed to a stimulus whereby the prepolymer is converted to the polymer. After a predetermined time, sequential layers are printed to provide the three-dimensional article. The three-dimensional article can be cured to produce the 3D article made from the final polymer.