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EXAMPLE 7 diethyl mesoxalate 258 g of diethyl methylenemalonate, prepared by a Knoevenagel condensation of malonic ester and formaldehyde, are dissolved in 1 liter of methanol and reacted with ozone, and subsequently hydrogenated, analogously to the procedure indicated in Example 5. 5 g of 10percent Pd-on-C in 200 ml of methanol are initially taken as the hydrogenation catalyst. The consumption of hydrogen is 28.9 standard liters (86percent of theory). Working up as in Example 5 and rectification in vacuo gives 214 g of diethyl mesoxalate boiling at 110°-112° C./20, corresponding to a yield of 82percent of theory.
Reference：
[1] Patent: US4769464, 1988, A,
[2] Tetrahedron Letters, 1981, vol. 22, # 46, p. 4607 - 4610
3
[ 3377-20-6 ]
[ 70775-39-2 ]
[ 1559-02-0 ]
Reference：
[1] Asian Journal of Chemistry, 2011, vol. 23, # 4, p. 1479 - 1487
EXAMPLE 7 diethyl mesoxalate 258 g of diethyl methylenemalonate, prepared by a Knoevenagel condensation of malonic ester and formaldehyde, are dissolved in 1 liter of methanol and reacted with ozone, and subsequently hydrogenated, analogously to the procedure indicated in Example 5. 5 g of 10% Pd-on-C in 200 ml of methanol are initially taken as the hydrogenation catalyst. The consumption of hydrogen is 28.9 standard liters (86% of theory). Working up as in Example 5 and rectification in vacuo gives 214 g of diethyl mesoxalate boiling at 110-112 C./20, corresponding to a yield of 82% of theory.
Assemble a short path distillation apparatus equipped with 250 mL round bottom flask, addition funnel, mechanical stirrer, condenser, receiving flask and vacuum. Charge 250 mL round bottom flask with copper zeolite (2g). Heat contents to 200 C with oil bath. Apply vacuum (100 mm Hg). Slowly add intermediary diethyl bis(hydroxymethyl) malonate (30g., 0.136 mol) drop-wise onto the copper zeolite. After completion of this addition, cool apparatusto 25 C and back fill apparatus with N2. Dry distillate over anhydrous Na2504 (ig). The desired reaction product is diethyl methylene malonate (DEMM). In an exemplary embodiment, the yield is 20.5 g (88%). See FIG. 2.
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