- Orthogonal synthesis of pyrroles and 1,2,3-triazoles from vinyl azides and 1,3-dicarbonyl compounds
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Tri- and tetrasubstituted N-H pyrroles were prepared by the simple treatment of vinyl azides with 1,3-dicarbonyl compounds in toluene at 100 °C via 2H-azirine intermediates generated in situ. When the reactions of vinyl azides and 1,3-dicarbonyl compounds were performed in DMF in the presence of a catalytic amount of K2CO3, 1-vinyl-1,2,3-triazoles were obtained via 1,3-dipolar cycloaddition. These methodologies exploited orthogonal modes of chemical reactivity of vinyl azides, which could be achieved by slight modification of the reaction conditions.
- Ng, Eileen Pei Jian,Wang, Yi-Feng,Hui, Benjamin Wei-Qiang,Lapointe, Guillaume,Chiba, Shunsuke
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experimental part
p. 7728 - 7737
(2011/10/13)
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- Novel and convenient routes to substituted pyrroles and imidazoles
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S-Methyl N-(benzotriazol-1-ylmethyl)thioimidate 6 is obtained by lithiation of the corresponding N-(benzotriazol-1-ylmethyl)thioamide 5 and subsequent reaction with methyl iodide. Derivative 6 undergoes [2+3] cycloaddition reactions with α,β-unsaturated -esters, -ketones and -nitriles, and vinylpyridines which are followed by elimination of benzotriazole and the thioalkoxy group, to give 2,3,4-trisubstituted pyrroles. Lithiation of 6 followed by reactions with imines gives cyclized 4,5-dihydroimidazoles 14 which upon further treatment with ZnBr2 or direct refluxing in toluene yield the 1,2,5-trisubstituted imidazoles 15 in good yields.
- Katritzky, Alan R.,Zhu, Lie,Lang, Hengyuan,Denisko, Olga,Wang, Zuoquan
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p. 13271 - 13276
(2007/10/02)
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- Substituted pyrroles as stabilisers for chlorinated polymers
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A composition comprising a) a chlorinated polymer, and b) at least one compound of formula I STR1 wherein X is a group STR2 R1 and R2 are each independently of the other C1 -C20 alkyl, hydroxy- and/or halogen-su
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- Base-Induced Cycloaddition of N-(Tosylmethyl)imino Compounds to Michael Acceptors. Synthesis of 2,3,4-Trisubstituted Pyrroles
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A series of N-(tosylmethyl)imino compounds has been prepared, and applied to a new, base induced, one operational synthesis of otherwise more difficulty accesible 2,3,4-trisubstituted pyrroles from electron deficient olefins.This regiospec
- Houwing, Hendrik A.,van Leusen, Albert M.
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p. 1127 - 1132
(2007/10/02)
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