Reporter genes are widely applied in biotechnology and biomedical research owning to their easy observation and lack of toxicity. Taking advantage of the reporter genes in conjunction with imaging technologies, a large number of reporter mouse models have been generated. Reporter mouse models provide systems that enable the studies of live cell imaging, cell lineage tracing, immunological research and cancers etc. in vivo. In this review, we describe the types of different reporter genes and reporter mouse models including, random reporter strains, Cre reporter strains and
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reporter strains. Collectively, these reporter mouse models have broadened scientific inquires and provided potential strategies for generation of novel reporter animal models with enhanced capabilities.
The first Pd/Cu catalyzed selective
C2-alkenylation of pyridines
with internal alkynes has been developed via the pyridinium salt activation
strategy. Importantly, the configuration of the product alkenylpyridines
could be tuned by the choice of the proper N-alkyl
group of the pyridinium salts, thus allowing for both the Z- and E-alkenylpyridines synthesized with
good regio- and stereoselectivity. A plausible mechanism was proposed
based on the Hammett study and KIE experiment.
An efficient Pd-catalyzed arylation of alkylpyridine
based on the
pyridinium activation strategy has been developed for synthesis of
mixed aryl alkylpyridines. It was found that (1) the N-methyl group in the pyridinium salts acted as a transient activator
and could be automatically departed after the reaction, (2) CuBr was
an indispensable additive for achieving the C6-selective
arylation, (3) the α-branched alkyl chain on the alkylpyridine
greatly increased the yield of the product. Deuterium labelling experiment
revealed that in the case of the α-branched alkylpyridine, the
presence of CuBr completely inhibited the H/D exchange at the benzylic
position and thus enabled the selective arylation at the C6 position. This protocol demonstrates a broad substrate scope, and
with respect to both the aryl iodides and the α-branched alkylpyridine,
the desired mixed aryl alkylpyridines were obtained in generally good
to excellent yields.
Herein, a Pd/Cu bimetallic-catalyzed direct C−H heteroarylation of pyridines via the traceless protecting group strategy is described. A series of N-methyl-activated pyridines and 1-methylindoles are coupled with high regioselectivity to produce the corresponding 3-(pyridin-2-yl)indoles in moderate to good yields, wherein related electron-rich heterocycles (e.g., indole, 1methylpyrrole, benzofuran, benzo[b]thiophene) are also applicable. Streamlined operation, good functional group tolerance, and late-stage modifications make this twofold C−H activation protocol an attractive route for the synthesis of 3-(pyridin-2-yl)indole derivatives.
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