Yoshinori Kato

Syntheses of isocarbacyclin by highly regioselective alkylation of allylic alcohols

Abstract Syntheses of isocarbacyclin (20) using highly regioselective alkylation of the new allylic alcohol intermediate 6 having an exocyclic double bond are described. The allylic alcohol 6 was prepared by (i) allylic rearrangement of the allylic alcohol 3 having an endocyclic double bond and (ii) reductive cyclization of γ-ethynyl aldehyde 11a which was synthesized from (R)-4-hydroxy-2- cyclopentenone derivative 1 in 5 steps. γ-Alkylation of the allylic alcohol 6 was achieved by the use of Murahashis method to result in the highly regioselective formation of isocarbacyclin (regioselectivity 99%). α-Alkylation of the allylic alcohol 3 was also achieved to construct isocarbacyclin.

Short synthesis of isocarbacyclin by regioselective SN2′ alkylation of bicyclic allylic esters with zinc-copper reagents☆

Abstract Isocarbacyclin [(+)-9(O)-methano-Δ6(9α)-prostaglandin I1] (2) was synthesized from bicyclic synthons such as 2-phosphorylated, 2-(thio)phosphorylated, 2-tosylated, 2-methoxycarbonylated, and 2-chloro-3-methylenebicyclo[3.3,0]octanes via highly regioselective SN2′ alkylation with zinc-copper reagents 9 in excellent yields.

Napthalene derivatives that selectively inhibit an antigen-specific IgE response in murine lymphocytes

When the spleen cells from BALB/c mice that had been immunized twice with TNP-KLH were cultured with the same antigen, the synthesis of anti-TNP IgE as well as anti-TNP IgG was induced. We found that the addition of a naphthalene derivative, (E)-N-(2-methoxy-carbonylphenyl)-8-(2-naphthyl)-5,6-trans-5,6-meth ano-7- octenamide (TEI-1338) or methyl-6,7-dihydroxy-2-naphthylthioacetate (TEI-3332) to this lymphocyte culture system resulted in a marked suppression of anti-TNP IgE response without affecting the corresponding IgG production. These compounds are expected to be a prototype for the drug that can be used for the treatment of IgE-mediated allergic diseases.