Synthetic studies on the immunosuppressive agent FK-506: enantioselective synthesis of a C22-C34 fragment was written by Baker, Robert K.;Rupprecht, Kathleen M.;Armistead, David M.;Boger, Joshua;Frankshun, Robert A.;Hodges, Paul J.;Hoogsteen, Karst;Pisano, Judith M.;Witzel, Bruce E.. And the article was included in Tetrahedron Letters in 1998.Synthetic Route of C13H19NO3S This article mentions the following:
The C28-C32 cyclohexyl group of the natural product, FK-506 (I), was prepared enantioselectively from the iodolactone II by replacement of iodide with retention of configuration. The C27-C28 trisubstituted olefin was introduced stereoselectively via a classical aldol/elimination sequence employing titanium enolate methodol. Elaboration of this chem. has led to a synthesis of C22-C34 fragment III of the natural product. In the experiment, the researchers used many compounds, for example, 1-((3aR,6S,7aS)-8,8-Dimethyl-2,2-dioxidohexahydro-1H-3a,6-methanobenzo[c]isothiazol-1-yl)prop-2-en-1-one (cas: 119944-89-7Synthetic Route of C13H19NO3S).
1-((3aR,6S,7aS)-8,8-Dimethyl-2,2-dioxidohexahydro-1H-3a,6-methanobenzo[c]isothiazol-1-yl)prop-2-en-1-one (cas: 119944-89-7) belongs to isothiazole derivatives. Some representatives of isothiazoles have proven to be synergists of bioactive substances, which opens the way to lower the doses of drugs used and is especially important in cancer chemotherapy. Isothiazoles are readily prepared from isoxazoles. Thus, reductive ring opening of isoxazoles gives enaminones , which on treatment with phosphorus pentasulfide and chloranil give the corresponding isothiazoles.Synthetic Route of C13H19NO3S
Referemce:
Isothiazole – Wikipedia,
Isothiazole – ScienceDirect.com