The direct cyanomethylation of indoles at the 2- or 3-position was achieved via photoredox catalysis. The versatile nitrile synthon is introduced as a radical generated from bromoacetonitrile, a photocatalyst, and blue LED as a light source. The mechanism of the reaction is explored by determination of the Stern-Volmer quenching constants. By combining photophysical data and mass spectrometry to follow the catalyst decomposition, the catalyst ligands were tuned to enable synthetically useful yields of radical coupling products. A range of indole substrates with alkyl, aryl, halogen, ester, and ether functional groups participate in the reaction, affording products in 16-90% yields. The reaction allows the rapid construction of synthetically useful cyanomethylindoles, products that otherwise require several synthetic steps.
We describe herein a small-molecule platform that exhibits key properties needed by an antidote for CO poisoning. The design features an iron-porphyrin complex with bulky substituents above and below the...
Tau prions feature in the brains of patients suffering from Alzheimer's disease and other tauopathies. For the development of therapeutics that target the replication of tau prions, a high-content, fluorescence-based cell assay was developed. Using this high-content phenotypic screen for nascent tau prion formation, a 4-piperazine isoquinoline compound (1) was identified as a hit with an EC 50 value of 390 nM and 0.04 K p,uu . Analogs were synthesized using a hypothesis-based approach to improve potency and in vivo brain penetration resulting in compound 25 (EC 50 = 15 nM; K p,uu = 0.63). We investigated the mechanism of action of this series and found that a small set of active compounds were also CDK8 inhibitors.
Cruz, instructors adapted to the necessity of remote laboratory instruction by creating choose-your-own-adventure-style video-based online experiments introduced to thousands of students across 11 different courses. These experiments are designed to provide students with the opportunity to make and receive feedback on experimental decisions and learn from common mistakes that they may have encountered in hands-on laboratory instruction. Students' and instructors' impressions of the online experiments and student learning outcomes in both online and traditional laboratory courses were assessed using surveys, focus groups, and interviews via a mixed-methods approach. Though most respondents (79%) did not agree that online laboratory instruction was as effective as in-person instruction, the majority agreed that the online experiments were clear and easy to follow (75%), interesting and engaging (52%), and helpful for learning about lab techniques (70%) and the concepts underlying these techniques (77%). Many also mentioned benefits of online laboratory instruction, including flexibility in scheduling and an increased focus on conceptual learning. Assessments of student learning also suggested that students who took the course online learned as much conceptually as students who had previously completed the course in-person. The results of this study highlight the positive and negative aspects of this type of interactive online laboratory instruction, which could help inform the design of future lab experiences whether they take place in an online, hybrid, or in-person environment.
Herein we report an investigation into the synthesis,
metalation,
and functionalization of bis-pocket porphyrins using the Suzuki–Miyaura
cross-coupling reaction. Steric limitations to accessing bis-pocket
porphyrins were overcome by using this Pd-catalyzed C–C-bond-forming
strategy to introduce steric bulk
after
macrocyclization:
2,6-dibromo-4-trimethylsilybenzaldehyde was condensed with pyrrole,
and a variety of boronic acids were coupled to the resulting porphyrin
in up to 95% yield. Furthermore, we show that these porphyrins can
be metalated with a variety of metals and sulfonated to create water-soluble
bis-pocket porphyrins.
We report the high-capacity and selective uptake of Cr(VI) from water using the coordination polymer silver bipyridine acetate (SBA, [Ag(4,4′-bipy)][CH 3 CO 2 ]•3H 2 O). Cr capture involves the release of acetate, and we have structurally characterized two of the product phases that form: silver bipyridine chromate (SBC, [Ag(4,. SBA maintains a high Cr uptake capacity over a wide range of pH values (2−10), reaching a maximum of 143 mg Cr/g at pH 4. This Cr uptake capacity is one of the highest among coordination polymers. SBA offers the additional benefits of a onestep, room temperature, aqueous synthesis and its release of a nontoxic anion following Cr(VI) capture, acetate. Furthermore, SBA capture of Cr(VI) remains >97% in the presence of a 50-fold molar excess of sulfate, nitrate, or carbonate. We also investigated the Cr(VI) sequestration abilities of silver 1,2-bis(4-pyridyl)ethane nitrate (SEN, [Ag(4,][NO 3 ]) and structurally characterized the silver 1,2-bis(4-pyridyl)ethane chromate (SEC, SLUG-58, [Ag(4,4′-bpe)][CrO 4 ] 0.5 ) product. SEN was, however, a less effective Cr(VI) sequestering material than SBA.
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