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【结 构 式】 
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【分子编号】49670 【品名】(E)-3-methylene-5-(2,6,6-trimethyl-1-cyclohexen-1-yl)-4-pentenal 【CA登记号】 |
【 分 子 式 】C15H22O 【 分 子 量 】218.33908 【元素组成】C 82.52% H 10.16% O 7.33% |
合成路线1
该中间体在本合成路线中的序号：(VI)The formylation of the beta-ionone (I) with methyl formate and NaOMe gives the enol (II), which by reaction with methanol and H2SO4 yields the dimethylacetal (III). The reaction of (III) with methylenetriphenylphosphorane (IV) affords the methylene compound (V), which is treated with formic acid to provide the aldehyde (VI). The condensation of (VI) with isopropylidenemalonic acid dimethyl ester (VII) by means of NaOH gives the polyenic malonic acid (VIII) as a mixture of isomers that is separated by crystallization in ethyl ether to yield the desired all-trans-isomer (IX). Finally, this malonic acid is selectively monodecarboxylated by means of refluxing 2,6-dimethylpyridine to afford the target (E,E,E,Z)-isomer.
| 【1】 Valia, A.; et al.; Stereoselective synthesis of 13 E retinoic and 13 Z retinoic acids via a new intermediate compound, C-15 beta-methylenealdehyde. Tetrahedron 2000, 56, 37, 7211. |
| 中间体序号 | 中间体编号 | 品名 | CAS号 | 分子式 | 供应商 | 用于合成 |
|---|---|---|---|---|---|---|
| (VIIIa),(IX) | 49672 | 2-[(2E,4E,6E)-1,5-dimethyl-7-(2,6,6-trimethyl-1-cyclohexen-1-yl)-2,4,6-heptatrienylidene]malonic acid | C21H28O4 | 详情 | 详情 | |
| (VIIb) | 49673 | 2-[(2E,4Z,6E)-1,5-dimethyl-7-(2,6,6-trimethyl-1-cyclohexen-1-yl)-2,4,6-heptatrienylidene]malonic acid | C21H28O4 | 详情 | 详情 | |
| (I) | 39584 | (E)-4-(2,6,6-trimethyl-1-cyclohexen-1-yl)-3-buten-2-one | 14901-07-6 | C13H20O | 详情 | 详情 |
| (II) | 49667 | (1E,4E)-1-hydroxy-5-(2,6,6-trimethyl-1-cyclohexen-1-yl)-1,4-pentadien-3-one | C14H20O2 | 详情 | 详情 | |
| (III) | 49668 | (E)-5,5-dimethoxy-1-(2,6,6-trimethyl-1-cyclohexen-1-yl)-1-penten-3-one | C16H26O3 | 详情 | 详情 | |
| (IV) | 27301 | methylene(triphenyl)phosphorane | C19H17P | 详情 | 详情 | |
| (V) | 49669 | (E)-1-methoxy-3-methylene-5-(2,6,6-trimethyl-1-cyclohexen-1-yl)-4-pentenyl methyl ether; 2-[(1E)-3-(2,2-dimethoxyethyl)-1,3-butadienyl]-1,3,3-trimethyl-1-cyclohexene | C17H28O2 | 详情 | 详情 | |
| (VI) | 49670 | (E)-3-methylene-5-(2,6,6-trimethyl-1-cyclohexen-1-yl)-4-pentenal | C15H22O | 详情 | 详情 | |
| (VII) | 49671 | dimethyl 2-(1-methylethylidene)malonate | 22035-53-6 | C8H12O4 | 详情 | 详情 |