- Remarkable switch in the regiochemistry of the iodination of anilines by N-iodosuccinimide: Synthesis of 1,2-dichloro-3,4-diiodobenzene
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Direct iodination of anilines by NIS in polar solvents (such as DMSO) affords p-iodinated products with up to >99% regioselectivity. Switching to less polar solvents (such as benzene) in the presence of AcOH inverts this outcome toward dramatically increased or preferential generation of the o-isomers, also with up to >99% regioselectivity. This finding was exploited in the synthesis of 1,2-dichloro-3,4-diiodobenzene. Georg Thieme Verlag Stuttgart - New York.
- Shen, Hao,Vollhardt, K. Peter C.
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supporting information; experimental part
p. 208 - 214
(2012/03/11)
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- Total synthesis of argyrins A and e
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The total synthesis of argyrins A and E were accomplished using a convergent strategy by condensation of one tripeptide and two dipeptide fragments. The synthesis strategy, which was developed for the protection of peptide fragments and identification of the optimum macrocylization site, can be applied to further synthetic studies involving other members of the argyrin family.
- Wu, Wenbin,Li, Zheng,Zhou, Guangbiao,Jiang, Sheng
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p. 2488 - 2491
(2011/05/09)
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- Solvent-free Heck-Jeffery reactions under ball-milling conditions applied to the synthesis of unnatural amino acids precursors and indoles
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The syntheses of various amino- and hydroxy-substituted dehydrophenylalanine derivatives using the Heck-Jeffery protocol under non-solvent conditions in a ball mill are presented. The influences of electron-withdrawing groups and of the location of the heteroatom substituent relative to the halide are discussed. Suitably substituted ortho-amino dehydrophenylalanine derivatives undergo a cyclization-elimination reaction to the corresponding 2-substituted indoles. Georg Thieme Verlag Stuttgart.
- Tullberg, Erik,Schacher, Felix,Peters, Dan,Frejd, Torbjoern
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p. 1183 - 1189
(2007/10/03)
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- Synthesis of ring-A-substituted tryptophan by a palladium-catalyzed heteroannulation reaction
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Coupling of substituted o-iodoanilines with methyl (S)-2-N,N-di-tert- butoxycarbonyl-5-oxo-pentanoate, derived from glutamic acid, in DMF in the presence of palladium acetate and DABCO provides substituted tryptophans in good to excellent yields. Georg Thieme Verlag Stuttgart.
- Jia, Yanxing,Zhu, Jieping
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p. 2469 - 2472
(2007/10/03)
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- The Synthesis and Ionization of Some Derivatives of 1-Biphenylenol
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2,7-Dimethyl-1,8-biphenylenediol has been synthesized from 2-methyl-5-nitrophenol in nine steps. 1,5-Biphenylenediol has been prepared by dimerization of 3-methoxybenzyne, separation of isomers, and demethylation. 8-Methoxy-1-biphenylenol has been made by the partial demethylation of 1,8-dimethoxybiphenylene.Ionization constants (pK1 8.04, pK2 11.47, pK1 8.35, pK2 9.97, and pK 9.15, respectively) have been determined for these compounds and for 1,8-biphenylenediol (pK1 8.01, pK2 11.00) and 1- biphenylenol (pK 8.64) by ultraviolet spectrophotomeric measurements in aqueous solution.
- Hine, Jack,Hahn, Soonkap,Miles, David E.,Ahn, Kyunghye
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p. 5092 - 5096
(2007/10/02)
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