Synthesis of (+)-1-phenylethanesulfonic acid

Starting with ethylbenzene,1-bromoethylbenzene was prepared through lighting bromination and then S-(1-phenylethyl)isothiourea hydrobromide was obtained by condensation with thiourea.After that,(±)-1-phenyl-ethanesulfonate sodium[(±)-1-PES-Na] was produced by basic hydrolysis,oxidation by hydrogen peroxide and salification.Finally(+)-1-phenyl-ethanesulfonate[(+)-1-PES],a resolving agent of amino acids,was synthesized by resolution with D-HPG.The overall yield of(+)-1-phenyl-ethanesulfonate sodium was 29.6%.The resolution yield was 69.6%[based on(+)-PES].The structure of the title compound was confirmed by IR and 1H NMR.