Novel preparation method for bromhexine hydrochloride

The invention discloses a preparation method for bromhexine hydrochloride. The preparation method comprises the following steps of: reacting acetic anhydride with boric acid to generate triacetic acid boric acid ester; reacting 2-amino-3,5- dibromo benzylalcohol with triacetic acid boric acid ester to generate 2-amino-3,5-dibromo benzylalcohol boron chelate; reacting 2-amino-3,5-dibromo benzylalcohol boron chelate with N- methylcyclohexylamine to generate N-(2-amino-3,5-dibromobenzyl)-N-methylcyclohexylamine (bromhexine); and reacting bromhexine with hydrogen chloride to generate crude bromhexine hydrochloride, and refining to obtain refined bromhexine hydrochloride. The bromhexine hydrochloride is suitable for treating chronic bronchitis and other respiratory diseases with phlegm which is difficult to cough out.