Development of direct C-H amidation at the C-8 position of quinoline N-oxides = 탄소-수소 결합 활성화를 통한 퀴놀린엔옥사이드 8번 탄소 위치의 아미드 결합 형성 반응에 대한 연구

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8-Aminoquinoline is an important structural motif found in numerous natural and synthetic compounds with broad applications in medicinal and coordination chemistry. For efficient synthetic protocol, we have developed an iridium-catalyzed regioselective C-H amidation of quinoline N-oxides at the 8-position by using N-oxide as directing group and azides as amidation source. This high selectivity was found to be achieved through the smooth formation of an intermediate of N-oxide-chelated iridacycle. Mechanistic studies revealed a key role of acid additives. The amidation proceeded efficiently over a wide range of heterocyclic substrates under mild conditions with high functional group tolerance. Using our protocol, Zinquin ethyl ester (a fluorescent zinc indicator) was synthesized in a straightforward manner. A practical synthetic route to 8-aminoquinolines has been developed by using readily installable and easily deprotectable carbamate amidating reagents. This reaction was facile to afford directly 8-aminoquinoline N-oxides protected by practical protecting group such as Cbz, Boc and Fmoc, resulting in high synthetic efficiency. Two scalable procedures were optimized under the Rh(III)-catalyzed conditions using either pre-generated chlorocarbamates or carbamates in a two-step one-pot process. Both approaches are highly convenient to perform under mild conditions enabling scalable processes. Facile deprotection of the synthetically versatile amidating groups was achieved under mild Pd-catalyzed transfer hydrogenation conditions with the simultaneous deoxygenation of quinoline N-oxides in excellent overall efficiency.
Advisors
Chang, Sukbokresearcher장석복researcher
Description
한국과학기술원 :화학과,
Publisher
한국과학기술원
Issue Date
2016
Identifier
325007
Language
eng
Description

학위논문(박사) - 한국과학기술원 : 화학과, 2016.2 ,[ii, 78 p. :]

Keywords

Quinoline N-oxides; C-H activation; amidation; 8-aminoquinolines; carbamates; 퀴놀린엔옥사이드; 탄소-수소 결합 활성화; 아미드화반응; 8-아미노퀴놀린; 카바메이트

URI
http://hdl.handle.net/10203/222496
Link
http://library.kaist.ac.kr/search/detail/view.do?bibCtrlNo=648320&flag=dissertation
Appears in Collection
CH-Theses_Ph.D.(박사논문)
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