How is Methyl N-methylglycinate hydrochloride (CAS: 13515-93-0) typically synthesized?

Methyl N-methylglycinate hydrochloride is typically synthesized by the reaction of glycine and methyl chloride in the presence of hydrochloric acid. The process involves the formation of methyl N-methylglycinate followed by its protonation to form the hydrochloride salt. The reaction is carried out under reflux conditions and is known to be selective and efficient, yielding up to 95% product purity.