3433-80-5Relevant articles and documents
Preparation of 1,5-Dihydropyrazolo[3′,4′:5,6]pyrano[3,4- b]pyridines via a Microwave-Assisted, Palladium-Catalyzed Regioselective C-H Heteroarylation of Electron-Rich Pyrazoles
Garrison, Aaron T.,Childress, Elizabeth S.,Davis, Dexter C.,Lindsley, Craig W.
, p. 5855 - 5862 (2019)
Here we report the first synthesis of a family of novel heterocyclic compounds based on a 5-dihydropyrazolo[3′,4′:5,6]pyrano[3,4-b]pyridine core. In the course of our drug discovery programs, we had need to access the previously unknown 5-dihydropyrazolo[3′,4′:5,6]pyrano[3,4-b]pyridine core. Initial attempts required long reaction times, which led to degradation and side products. Reaction optimization identified a Pd-catalyzed, microwave-assisted C-H heteroarylation protocol for the rapid, general, and high yielding synthesis of this tricyclic core (as well as related analogs) suitable to drive optimization efforts.
tBuOK-Promoted Cyclization of Imines with Aryl Halides
Li, Ya-Wei,Zheng, Hong-Xing,Yang, Bo,Shan, Xiang-Huan,Qu, Jian-Ping,Kang, Yan-Biao
supporting information, p. 4553 - 4556 (2020/06/08)
A transition-metal-free indole synthesis using radical coupling of 2-halotoluenes and imines via the later-stage C-N bond construction was reported for the first time. It includes an aminyl radical generation by C-H cleaving addition of 2-halotoluenes to imines via the carbanion radical relay and an intramolecular coupling of aryl halides with aminyl radicals. One standard condition can be used for all halides including F, Cl, Br, and I. No extra oxidant or transition metal is required.
Halogenation through Deoxygenation of Alcohols and Aldehydes
Chen, Jia,Lin, Jin-Hong,Xiao, Ji-Chang
supporting information, p. 3061 - 3064 (2018/05/28)
An efficient reagent system, Ph3P/XCH2CH2X (X = Cl, Br, or I), was very effective for the deoxygenative halogenation (including fluorination) of alcohols (including tertiary alcohols) and aldehydes. The easily available 1,2-dihaloethanes were used as key reagents and halogen sources. The use of (EtO)3P instead of Ph3P could also realize deoxy-halogenation, allowing for a convenient purification process, as the byproduct (EtO)3Pa?O could be removed by aqueous washing. The mild reaction conditions, wide substrate scope, and wide availability of 1,2-dihaloethanes make this protocol attractive for the synthesis of halogenated compounds.