The acyclic precursors, methyl 3-perfluoroalkyl-4-carbethoxy-5-methoxy-6-(triphenylphosphoranylidene)hexa- 2,4-dienoates (4) were obtained via the addition reaction of ethyl 3-methoxy-4-(triphenylphosphoranylidene)but...The acyclic precursors, methyl 3-perfluoroalkyl-4-carbethoxy-5-methoxy-6-(triphenylphosphoranylidene)hexa- 2,4-dienoates (4) were obtained via the addition reaction of ethyl 3-methoxy-4-(triphenylphosphoranylidene)but-2- enoate (2) with equally molar methyl 2-perfluoroalkynoates (3). Ethyl 2,4-dimethoxy-6-perfluoroalkylbenzoates (5) were synthesized in high yield via an intramolecular elimination of Ph3PO of 4 by heating in anhydrous benzene in a sealed tube. The structure of these compounds was confirmed by IR, 1H, 13C, 2D C-H cosy NMR and mass spectra and elemental analyses. The possible reaction mechanisms were also proposed.展开更多
The title compounds 5a-5c were prepared via the reaction of methyl 2-perfluoroalkynoates (4) with methyl 5-oxo-4-(triphenylphosphoranylidene)hex-2-enoate (3), which was obtained from the reaction of methyl propynate (...The title compounds 5a-5c were prepared via the reaction of methyl 2-perfluoroalkynoates (4) with methyl 5-oxo-4-(triphenylphosphoranylidene)hex-2-enoate (3), which was obtained from the reaction of methyl propynate (2) with acetylmethylenetriphenylphosphorane (1) at -5-0 degrees C. Intramolecular elimination of Ph(3)PO took place when compound 5 was heated in aqueous methanol at 115-120 degrees C in sealed tube, yielding dimethyl 2-trifluoromethyl-4-methylisophthalate (6a) from 5a and methyl 5-acetyl-4-hydroxy-2-heptafluoropropanylbenzoate (6b) from 5b, respectively. The structures of compounds 5, 6a and 6b were confirmed by IR, MS, H-1 NMR, F-19 NMR and C-13 NMR spectroscopy and elemental analyses. Rection mechanisms for the formation of compounds 5, 6a and 6b were proposed.展开更多
基金Project supported by the National Natural Science Foundation of China (No. 20172037).
文摘The acyclic precursors, methyl 3-perfluoroalkyl-4-carbethoxy-5-methoxy-6-(triphenylphosphoranylidene)hexa- 2,4-dienoates (4) were obtained via the addition reaction of ethyl 3-methoxy-4-(triphenylphosphoranylidene)but-2- enoate (2) with equally molar methyl 2-perfluoroalkynoates (3). Ethyl 2,4-dimethoxy-6-perfluoroalkylbenzoates (5) were synthesized in high yield via an intramolecular elimination of Ph3PO of 4 by heating in anhydrous benzene in a sealed tube. The structure of these compounds was confirmed by IR, 1H, 13C, 2D C-H cosy NMR and mass spectra and elemental analyses. The possible reaction mechanisms were also proposed.
基金Project supported by the National Natural Science Foundation of China.
文摘The title compounds 5a-5c were prepared via the reaction of methyl 2-perfluoroalkynoates (4) with methyl 5-oxo-4-(triphenylphosphoranylidene)hex-2-enoate (3), which was obtained from the reaction of methyl propynate (2) with acetylmethylenetriphenylphosphorane (1) at -5-0 degrees C. Intramolecular elimination of Ph(3)PO took place when compound 5 was heated in aqueous methanol at 115-120 degrees C in sealed tube, yielding dimethyl 2-trifluoromethyl-4-methylisophthalate (6a) from 5a and methyl 5-acetyl-4-hydroxy-2-heptafluoropropanylbenzoate (6b) from 5b, respectively. The structures of compounds 5, 6a and 6b were confirmed by IR, MS, H-1 NMR, F-19 NMR and C-13 NMR spectroscopy and elemental analyses. Rection mechanisms for the formation of compounds 5, 6a and 6b were proposed.
