15 research outputs found
4,7-Dichloroquinoline
The two molecules in the asymmetric unit of the title compound, C9H5Cl2N, are both essentially planar (r.m.s. deviations for all non-H atoms = 0.014 and 0.026 Å). There are no close C—H⋯Cl contacts
Solution-phase preparation of a 560-compound library of individual pure mappicine analogues by fluorous mixture synthesis
Solution-phase mixture synthesis has efficiency advantages and favorable reaction kinetics. Applications of this technique, however, have been discouraged by the difficulty in obtaining individual, pure final products by using conventional separation and identification processes. Introduced here is a new strategy for mixture synthesis that addresses the separation and identification problems. Members of a series of organic substrates are paired with a series of fluorous tags of different chain lengths. The tagged starting materials are then mixed and taken through a multistep reaction process. Fluorous chromatography is used to demix the tagged product mixtures on the basis of the fluorine content of the tags to provide the individual pure components of the mixture, which are detagged to release the final products. The utility of fluorous mixture synthesis is demonstrated by the preparation of a 560-membered library of analogues of the natural product mappicine. A seven-component mixture is carried through a four-step mixture synthesis (two one-pot and two parallel steps) to incorporate two additional points of diversity onto the tetracyclic core. Methods for analysis and purification of the intermediates are established for the quality control of the mixture synthesis
Nickel-Catalyzed Suzuki–Miyaura Cross-Coupling in a Green Alcohol Solvent for an Undergraduate Organic Chemistry Laboratory
A modern undergraduate organic chemistry
laboratory experiment
involving the Suzuki–Miyaura coupling is reported. Although
Suzuki–Miyaura couplings typically employ palladium catalysts
in environmentally harmful solvents, this experiment features the
use of inexpensive nickel catalysis, in addition to a “green”
alcohol solvent. The experiment employs heterocyclic substrates, which
are important pharmaceutical building blocks. Thus, this laboratory
procedure exposes students to a variety of contemporary topics in
organic chemistry, including transition metal-catalyzed cross-couplings,
green chemistry, and the importance of heterocycles in drug discovery,
none of which are well represented in typical undergraduate organic
chemistry curricula. The experimental protocol uses commercially available
reagents and is useful in both organic and inorganic instructional
laboratories