Acetic Acid → Ethyl 2-cyano-2-(1,4-dioxaspiro[4.5]decan-8-ylidene)acetate

Participants

Reaction Conditions

Reaction Steps

To a stirred solution of 1,4-dioxa-spiro[4.5]decan-8-one (261) (5.0 g, 32.01 mmol) and cyano-acetic acid ethyl ester (3.99 g, 35.31 mmol) in toluene (50 mL) were added acetic acid (0.3 mL, 5.09 mmol) and ammonium acetate (123 mg, 1.60 mmol). A Dean Stark trap and reflux condenser were attached to the reaction flask and the mixture was heated to reflux and stirred for 16 h. Thereafter, the reaction mixture was cooled to 0° C. and quenched with saturated aqueous NaHCO3 (100 ml). The aqueous layer was extracted with ethyl acetate (2×200 ml) and the combined organic layer was dried with sodium sulfate, filtered and concentrated under reduced pressure. The crude yellow oil was re-crystallized with 20% ethyl acetate in hexane to afford pure cyano-(1,4-dioxa-spiro[4.5]dec-8-ylidene)-acetic acid ethyl ester (262) (3.2 g, 39.78%) as a light yellow solid.

Provenance & Evidence