The cyclization reaction of N-(2-hydroxyethyl)-N'-phenylthioureas 2 containing ambident nucleophile was ex-amined in the combination of a variety of bases and p-toluenesulfonyl chloride (TsCl). N-(2-Hydroxyeth-yl)thioureas 2 were readily obtained in high yields from the reaction of the corresponding 1,2-aminoalcohols with phenyl isothiocyanate, avoiding the need for O-protection. The use of a one-pot reaction (NaOH/TsCl) was found to be most effective in producing the requisite 2-phenylaminothiazolines (S-cyclization) 3 in the case of thioureas 2a-2e derived from N-unsubstituted aminoalcohols, while in the thioureas 2f and 2g prepared from N-substituted aminoalcohols the combination of Et 3 N and TsCl led to the S-cyclization products.