crystalline organic compounds of the type
Lycines are internal salts of trialkylsubstituted amino acids. A molecule of a lycine contains a positively charged quaternary nitrogen atom and a negatively charged carboxylate group and is therefore a bipolar ion. Lycines are readily soluble in water. They form insoluble compounds (for example, gold, platinum, and lead hydrochloride salts) with a number of acids and with the chlorides of heavy metals. This reaction is used to extract them. The lycines are abundant in animals and plants. They are obtained by the action of the alkyl halides or alkyl sulfates on amino acids and by other means.
The most abundant lycine is glycocoll (glycine), (CH3)3NN+CH2CCOO-, which is usually called simply betaine. It is a colorless, crystalline substance with a melting point of 293° C; upon melting it isomerizes into a methyl ester of dimethyl aminoacetic acid. Betaine is obtained from molasses (the by-product of beet-sugar production) and also synthetically, from the reaction of trimethylamine with chloroacetic acid. The chloride of betaine (Acidol) is used in medicine as a substitute for hydrochloric acid.
The hydrochloride salt of betaine gives methyl chloride upon destructive distillation.