Diethyl isopropylidenemalonate synthesis
- Product Name:Diethyl isopropylidenemalonate
- CAS Number:6802-75-1
- Molecular formula:C10H16O4
- Molecular Weight:200.23
Yield:6802-75-1 50%
Reaction Conditions:
with acetic anhydride;zinc(II) chloride for 24 h;Reflux;
Steps:
Diethyl 2-Propan-2-ylidenemalonate
According to a published procedure4 a mixture of diethyl malonate (350 g, 2.19 mol), acetone (191 g, 4.98 mol), Ac2O (289 g, 2.83 mol), and ZnCl2 (44.7 g, 329 mmol) in a 1 l round bottom flask was heated to reflux for 24 h, cooled, and toluene (200 mL) was added. The solution was extracted with H2O (3×350 mL) and the aqueous layers were washed with toluene (100 mL). The organic layers were combined, concentrated at reduced pressure and the residue was distilled (110 °C, 13 mbar) to yield diethyl 2-propan-2-ylidenemalonate (220 g, 1.10 mol, 50%) as a yellowish oil. 1H NMR (300 MHz, CDCl3) δ 1.27 (t, 6 H, 3J = 7.1 Hz, CH2CH3), 2.05 [s, 6 H, C(CH3)2], 4.22 (q, 4 H, 3J = 7.1 Hz, CH2) ppm.
References:
Weingand, Daniel;Podlech, Joachim [Tetrahedron Letters,2016,vol. 57,# 50,p. 5608 - 5610] Location in patent:supporting information
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