2-butan-2-yl-2-ethylpropanedioic acid

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To dry ethyl ether (55.0 ml) under nitrogen was added ethyl 2-(2-butyl)malonic acid (55.0 g, 0.29 mole). Thionyl chloride (32.0 ml, 52.5 g, 0.44 mole) was added dropwise with stirring. The solution was heated to 50° C. for 2 hours under nitrogen, at which time no further HCl was evolved.