Permethylation of barbiturates: variation in product ratios with varying methylsulfinylmethide carbanion.

Permethylation of a barbiturate with the methylsulfinylmethide carbanion and methyl iodide gave three products clearly separable by GLC. Alteration of the reaction conditions by varying the barbiturate to carbanion ratio or the barbiturate to carbanion exposure time resulted in a single product for only one examined barbiturate, secobarbital. This derivatization technique is useful for the GLC analysis of polar barbiturate metabolites, such as glucuronides, in biological fluids but is of limited value for the analysis of the parent compounds.