- Synthesis and Structural Elucidation of 1,2-Disubstituted 3-Fluoropiperidines
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The work described details the reaction between Selectfluor and a series of 1-carbonyloxy and 1-sulfonyl 2-piperidines in order to generate 3-fluoro-2-methoxypiperidines 3a–f. Their subsequent reaction with allyltrimethylsilane, in the presence of BF3 and TiCl4, is then reported. Studies involving a combination of single-crystal X-ray crystallography and NMR spectroscopy indicate that the allylation process is cis-selective for both carbamate and sulfonamide variants and that optimal levels of diastereoselectivity are obtained using the N-2-nitrobenzene sulfonyl (2-Ns) group. In this manner, the synthesis of a series of 2-allyl 3-fluoro-substituted piperidines (5a, c–f) was achieved. The conversion of both the cis and trans-N-tosyl adducts (5d) into 3-fluorinated analogues of the natural products pelletierine (10) and coniine (11) is subsequently detailed.
- Evans, Paul,Fischer, Pauline,Müller-Bunz, Helge,Morris, Morgan
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- Synthesis of bioisosteric 5-sulfa-rutaecarpine derivatives
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Rutaecarpine (Evodia rutaecarpa) derivatives were synthesized by bioisosteric replacements of the quinazolone moiety of the pentacyclic system with benzothiadiazine 1,1-dioxide. Syntheses were performed efficiently by formation of phenylhydrazones via active methylene group transformations of pyrrolo-and pyrido[1,2-b]1,2,4-benzothiadiazine 5,5-dioxides, and subsequent Fischer-indolization. Preliminary testing of compound 3 showed cytotoxic activity against HeLa cells and apoptosis inducing effect. ARKAT-USA, Inc.
- Bubenyak, Mate,Takacs, Maria,Blazics, Balazs,Racz, Akos,Noszal, Bela,Pueski, Laszlo,Koekoesi, Jozsef,Hermecz, Istvan
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scheme or table
p. 291 - 302
(2011/02/27)
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- Ring expansion of lactones and lactams via propiolate 1-carbon intercalation
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(Chemical Equation Presented) Readily available five- and six-membered lactones and N-sulfonyllactams undergo efficient addition of t-butyl propiolate, and the resulting adducts undergo cycloisomerization to six- and seven-membered cyclic ethers or amines in the presence of pyridinium acetate. The ring expansion process occurs in generally good yields and is proposed to involve a nucleophilic catalysis mechanism.
- Grant, Tina N.,Benson, Chantel L.,West
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supporting information; experimental part
p. 3985 - 3988
(2009/05/30)
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