The reaction of 2,3,6,2',3',4',6'-hepta-O-acetyl-β-lactosyl isothiocyanate (1) with 2-amino-4/6- substituted benzothiazoles 2a～2e gave lactosylthioureas 3a～3e, which were treated with amines in the presence of HgCl₂ to afford a series of novel N-alkyl/aryl-N'-(4/6-substituted benzothiazol-2-yl)-N''-perace- tylated lactosylguanidines 4～6. Compounds 4～6 then reacted with the solution of CH₃ONa/CH₃OH, resulting in the formation of the deacetylated lactosylguanidines 7～9. The structures of the new compounds were established on the basis of IR, ¹H NMR, mass spectral data and elemental analyses and all compounds were found to take the β-configuration. Bioassay indicates that these lactosylguanidines show little anti-HIV-1 PR activity and little anti-angiotensin converting enzyme activity.

Key words: benzothiazole, lactosylthiourea, lactosylguanidine, lactosyl isothiocyanate