triethylamine pyridine or an inorganic base such as sodium hydroxide or potassium hydroxide in a preferred embodiment the base used is sodium hydroxide or triethylamine the amino acid or ester or salt carbon disulfide and base can be combined in a 1 1 1 mole ratio in the presence of a solvent this 1 1 1 mole ratio is the stoichiometric ratio generally up to about a 1 10 mole ratio of amino acid to carbon disulfide can be used with up to about a 1 3 mole ratio being desirable and up to about a 1 1 5 mole ratio being most preferable mole ratios above 1 10 of amino acid to carbon disulfide are not usually economical for mole ratios of amino acid to base generally up to about 1 3 can be used with up to about 1 2 being most preferable the solvent can be for example water or ethanol or other organic solvents such as toluene or tetrahydrofuran the reaction will proceed at temperatures in the general range of from about 0 u00b0 c to about 60 u00b0 c with temperatures from about 10 u00b0 c to about 30 u00b0 c being desirable and a temperature of about 20 u00b0 c being preferable the dithiocarbamic acid salt is formed the dithiocarbamic acid salt is reacted with dihalomethane the dihalomethane can be either dichloro or dibromomethane the dithiocarbamic acid salt and the dihalomethane can be combined in a 1 0 5 mole ratio this 1 0 5 mole ratio is the stoichiometric ratio generally about a 0 5 10 mole ratio of the acid salt to the dihalomethane can be used with about a 0 5 2 mole ratio being.