Reference of 1462-12-0, These common heterocyclic compound, 1462-12-0, name is Diethyl 2-ethylidenemalonate, its traditional synthetic route has been very mature, but the traditional synthetic route has various shortcomings, such as complicated route, low yield, poor purity, etc, below Introduce a new synthetic route.
EXAMPLE 8 3,6-Dimethyl-5-oxoheptanoic acid 8-A. (1,4-Dimethyl-3-oxopentyl)propanedioic acid, diethyl ester A cold (0 C.) solution of 2,2,6,6-tetramethylpiperdine (10.241 gm, 72.5 mmol) in tetrahydrofuran (120 mL) was treated with n-butyl lithium (2.5 M in hexane, 29.0 mL, 72.5 mmol). The light yellow solution was stirred at 0 C. for 30. minutes, then cooled to -78 C. and treated with neat methyl isopropyl ketone (7.70 mL, 6.20 gm, 72 mmol) over a five-minute period. After 50 minutes, a solution of diethyl ethylidenemalonate (10.000 gm, 53.7 mmol) in tetrahydrofuran (7 mL) was added to the above mixture over a 10-minute period. After 50 minutes, the mixture was quenched with glacial acetic acid (5.0 ml) and warmed to room temperature. The mixture was poured into 50% saturated ammonium chloride and extracted with ethyl ether. The ethyl ether extract was washed with 1 N hydrochloric acid, water, and brine, then dried (magnesium sulfate), filtered and stripped to give a pale yellow oil. Distillation of the oil (P=0.15-0.2 mm Hg) afforded compound 8-A (10.883 gm, 74%) as a colorless liquid which boiled at 110-114 C. Thin layer chromatography: Rf =0.25 (20% ethyl acetate in hexane).
The synthetic route of 1462-12-0 has been constantly updated, and we look forward to future research findings.
Reference:
Patent; E. R. Squibb & Sons, Inc.; US5072023; (1991); A;,
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