The utilization of 2-(2-nitrophenyl)propyloxycarbonyl (NPPOC) as a photolabile primary amine cage enables the thiol-Michael 'click' reaction to be photo-triggered. The photolabile amine exhibits efficient catalytic activity upon UV irradiation and is shown to initiate the photopolymerization of tetrathiol and diacrylate comonomers via Michael addition.
SUMMARY: High molecular weight vinyl-type polynorbornene was obtained in high yields with a highly active nickel-based phosphoraneiminato complex in the presence of methylaluminoxane. This polynorbornene is soluble at room temperature in chlorobenzene and shows no indication of crystallinity in the solid state. Catalyst activity, polymer yield, and polymer molecular weight can be controlled over a wide range by variation of reaction parameters.
Artemisinin and its derivatives, such as artemether, are highly
sensitive compounds, which require careful optimized production processes for their manufacture. Due to robustness issues,
the manufacturing procedure of the reduction of artemisinin
with potassium borohydride to dihydroartemisinin was reinvestigated. The most important factor for obtaining optimal
yields is to ensure low levels of contamination of potassium
hydroxide in potassium borohydride. Application of a lower
reaction temperature, fast addition rate of potassium borohydride, and careful control of the pH during the quench with
acid are further important parameters in guaranteeing a robust
process. In the redesign of the conversion of dihydroartemisinin
to artemether, the yield was increased, and dichloromethane
was replaced by the ecologically friendlier methyl acetate. A
robust manufacturing process for artemether is now at hand,
allowing the production of this important medicine reliably and
in good quality and yield.
The organo-zinc heterocubanes [ZnR(NPMe3)I4 with R = CH, scopy, and by crystal-structure determinations. 1 and 2 possess (1) and n-C4Hg (2) were prepared by the reaction of heterocubane structures in which the zinc atoms are linked [ZnBr(NPMe,)
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