Abstract: Enantiomerically enriched disubstituted tetrahydrofurans, tetrahydrothiophenes, pyrrolidines and cyclopentanes are disclosed that reduce the chemotaxis and respiratory burst leading to the formation of damaging oxygen radicals of polymorphonuclear leukocytes during an inflammatory or immune response. The compounds exhibit this biological activity by acting as PAF receptor antagonists, by inhibiting the enzyme 5-lipoxygenase, or by exhibiting dual activity, i.e., by acting as both a PAF receptor antagonist and inhibitor of 5-lipoxygenase.It has been determined that 5-lipoxygenase activity, oral availability, and stability in vivo (for example, glucuronidation rate) can vary significantly among the optical isomers of the disclosed compounds.

Abstract: A method is provided for the synthesis of synthesis of acyclic purine nucleosides, particularly 9-(2-hydroxy-ethoxymethyl)-guanine (acyclovir) and 9-[(1,3-dihydroxy-2-propoxy)methyl]guanine ("DHPG") where the N.sup.2,N.sup.9 -diprotected guanine is reacted with CH.sub.3 C(O)OCH.sub.2 O(CH.sub.2).sub.2)OC(O)CH.sub.3 or 2-acetoxymethoxy-1,3-diacetoxypropane, respectively, in the presence of a mixture of an acid and acetic anhydride, or in the presence of an acid, where the acid can be phosphoric acid or polyphosphoric acid.