General procedure for the synthesis of methyl sarcosinate hydrochloride from methyl 2-((tert-butoxycarbonyl)(methyl)amino)acetate: To a stirring solution of methyl 2-((tert-butoxycarbonyl)(methyl)amino)acetate (1 mmol) in dichloromethane (2 mL) was slowly added a solution of 3.3 M HCl in dioxane (5 mL) at 0 °C. The temperature of the reaction mixture was gradually increased to 20 °C and stirring was continued at this temperature for 1 hour. Upon completion of the reaction, the solvent was removed by distillation under reduced pressure. The resulting residue was placed in anhydrous ether and stirred to promote the formation of crystalline products. For less crystalline or hygroscopic products, the residue can be dissolved in dry chloroform, followed by evaporation of the solvent and drying of the product in a vacuum desiccator using P4O10 or KOH as the desiccant. A portion of the product may be purified by silica gel column chromatography using eluent mixture B or by gel filtration through biogel P2 or Fractogel TCK HW 40, followed by lyophilization to obtain a pure product.
