Synthesis of new heterocycles via ring transformation and 1,4-dipolar cycloaddition reactions of thiazolium-betaines = 티아졸륨-베타인의 고리변환과 1,4-쌍극성 고리화첨가반응을 통한 새로운 헤테로고리 화합물들의 합성

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Thiazolium-betaines, which are highly reactive organic compounds, can be used for the synthesis of the complicated hetero cyclic compounds via ring transformation and 1,4-dipolar cycloaddion reactions. On the reaction of 7-dithiocarboxy-3-phenyl-5,6-dihydroimidzo [2,1-b]thiazolium-betaine(10c) with para-substituted phenacyl bromides, in case that the substituent R was chloro, bromo, or nitro group, the ring transformation compound(19) was obtained. But when R was methoxy group, the quartemary ammonium salt(20) was formed. The reaction of 10c with unsubstituted phenacyl bromide(R=H) gave 19a and 20a to the similar ratio, respectively. When 10c was reacted with $\alpha$ -chloroacetone or ethyl 4-chloroacetoacetate, the new heterocycle(23) was obtained via ring transformation reaction. On the other hand, in case that 10c was reacted with methyl bromoacetate or ethyl bromoacetate, the quarternary ammonium salt(24) was formed. The reaction of 3-phenyl-9-[N-phenyl (thiocarbamoyl)]5,6,7,8-tetrahydrothiazolo [3,2-a][1,3] diazepinium-betaine(10f) with alkylating agents gave two major products via ring transformation reaction. These products (25a,25b) were considered as the structural isomers of syn-and anti. The 1,4-dipolar cycloaddition reaction of 3-phenyl-7-[N-phenyl-(carbamoyl)]-5,6-dihydroimidazo[2,1-b] thiazolium-betaine(10b) with phenacyl bromide provided the new diastereomeric heterocycles(37a,37b) via 1,4-dipolar cycloaddition in place of ring transformation reaction. Also the reaction mechanism and structure elucidation of cycloadducts(37a,37b) were described. Then, the thermal conversion between 1,4-dipolar cycloadducts, from a kinetically controlled product to a thermodynamically controlled product, was detected by1H nmr spectroscopic study according to temperature and time. And various 1,4-dipolar cycloadduct derivatives (41-46) were synthesized by the reaction of 10b with a series of para-substituted phenacyl bromides. In case that the substituent R was me...
Advisors
Park, Sang-WooKim, Yong-Hae박상우김용해
Description
한국과학기술원 : 화학과,
Publisher
한국과학기술원
Issue Date
1991
Identifier
61621/325007 / 000835575
Language
eng
Description

학위논문(박사) - 한국과학기술원 : 화학과, 1991.8, [ ix, 104 p. ]

URI
http://hdl.handle.net/10203/31358
Link
http://library.kaist.ac.kr/search/detail/view.do?bibCtrlNo=61621&flag=dissertation
Appears in Collection
CH-Theses_Ph.D.(박사논문)
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