Built from chemistry morphemes:
乙 (yǐ, 'ethyl/2-carbon') +
酰 (xiān, 'acyl group, R-CO-') +
胆碱 (dǎnjiǎn, 'choline') — literally ethyl-acyl-choline, i.e. choline acetylated with an acetyl group. Match it character-for-component against the English: acet- + -yl + cholin-e.