Ethyl propionylacetate synthesis
- Product Name:Ethyl propionylacetate
- CAS Number:4949-44-4
- Molecular formula:C7H12O3
- Molecular Weight:144.17
Yield:-
Reaction Conditions:
Stage #1:cycl-isopropylidene malonate;propionyl chloride with pyridine in dichloromethane at 0 - 20; for 3 h;Inert atmosphere;
Stage #2: in ethanolReflux;
Steps:
3.1 Synthesis of 3-oxovalerate ethyl ester
On ice, 3.9 g of Meldrum’s acid was dissolved in 18 ml of dehydrated dichloromethane in a dry flask and stirredand a solution of 4.3 g of pyridine and 2.5 g of propionyl chloride dissolved in 18 ml of dehydrated dichloromethane wasslowly added thereto under a nitrogen stream. The mixture was stirred at 0°C for one hour and then at room temperaturefor two hours. The mixed solution was transferred to a separating funnel, washed with 3% hydrochloric acid solution fortwo times and with saturated saline for two times, dried over magnesium sulfate and evaporated in vacuo to give 3.4 gof crude oily acylated Meldrum’s acid in dark orange color which solidified slowly. The crude acyl Meldrum’s acid wasrefluxed in 80 ml of dehydrated ethanol. At that time, generation of carbon dioxide was observed. The solvent wasremoved by evaporation to give 1.7 g of crude 3-oxovalarate ethyl ester in red oil. This was purified by a columnchromatography (20 cm 3 1 cm diameter; eluent was hexane:ethyl acetate = 2:1) using silica gel 60 to give 0.50 g ofpure 3-oxovalerate ethyl ester as a slightly yellow oil. The yield to the unpurified substance was 29%. Result of NMRanalysis of this compound is as follows.1H NMR (in CDCl3) δ 4.19 (q, J = 7.1Hz, 2H), 3.40 (s, 2H), 2. 58 (q, J=7.2Hz, 2H), 1.28 (t, J = 7.2Hz, 3H), 1.08(t, J=7.2Hz3H);13C NMR (in CDCl3) δ203.48, 180.07, 61.33, 49.03, 36.32, 14.13, 7.56
References:
Showa Denko K.K.;KAMACHI, Motoaki, Showa Denko K.K.;KAMACHI, Harumi, Showa Denko K.K.;AOKI, Hirobumi, Showa Denko K.K.;ERATA, Tomoki;TAJIMA, Kenji EP1591531, 2016, B1 Location in patent:Paragraph 0095
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