tert-butyl pent-4-enoate synthesis
- Product Name:tert-butyl pent-4-enoate
- CAS Number:32400-25-2
- Molecular formula:C9H16O2
- Molecular Weight:156.22
Yield:32400-25-2 50%
Reaction Conditions:
Stage #1: with sulfuric acid;magnesium sulfate in dichloromethane;
Stage #2: pent-4-enoic acid;tert-butyl alcohol in dichloromethane at 20; for 96 h;
Steps:
114.A
Concentrated H2SO4 (24.5 g, 0.250 mol) was added dropwise at a rapid rate to a suspension of MgS04 (120 g, 1.00 mol) in DCM (11). The mixture was stirred magnetically overnight, however the next morning it was evident that solids prevented adequate stirring so a mechanical overhead stirring system was installed. 4-penteneoic acid (25 g, 0.25 mol) was added, followed by t-butanol (92.5 g, 1.25 mol). The mixture was stirred at rt for 4 days, upon which time TLC indicated that some starting material remained. None-the-less the reaction mixture was filtered through celite and washed with saturated NAHC03 solution (gas evolution). The aqueous layer was back extracted with DCM and the combined organic layers were then washed with saturated NAHC03 solution, twice with water, and with brine. The organic layer was dried over anhydrous MGS04, filtered, and concentrated. Flash chromatography (silica, 15% ether/pentane) afforded 19.6 g of pure ester (50% yield). H NMR (CDC13, 500 MHz) : 6 5.82 (m, 1H), 4.98-5. 07 (m, 2H), 2.32 (m, 4H), 1.44 (s, 9H).
References:
WO2004/41279,2004,A1 Location in patent:Page/Page column 195-196
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