Varacin is a bicyclic organosulfur compound originally found in marine Ascidiacea from the Polycitorgenus.[1] It contains an unusual pentathiepin ring which reacts with DNA, and varacin and synthetic analogues have been investigated for their antimicrobial and antitumour properties.[2][3] Because of its potent biological activity and unusual and challenging ring system, it has been a popular target of efforts toward its total synthesis.[4][5][6]
^Makarieva TN, Stonik VA, Dmitrenok AS, Grebnev BB, Isakov VV, Rebachyk NM, Rashkes YW (February 1995). "Varacin and three new marine antimicrobial polysulfides from the far-eastern ascidian Polycitor sp". Journal of Natural Products. 58 (2): 254–8. doi:10.1021/np50116a015. PMID7769392.
^Greer A (October 2001). "On the origin of cytotoxicity of the natural product varacin. A novel example of a pentathiepin reaction that provides evidence for a triatomic sulfur intermediate". Journal of the American Chemical Society. 123 (42): 10379–86. doi:10.1021/ja016495p. PMID11603989.
^Brzostowska EM, Greer A (January 2003). "The role of amine in the mechanism of pentathiepin (polysulfur) antitumor agents". Journal of the American Chemical Society. 125 (2): 396–404. doi:10.1021/ja027416s. PMID12517151.
^Behar V, Danishefsky SJ (1993-07-01). "Total synthesis of the novel benzopentathiepin varacinium trifluoroacetate: the viability of "varacin-free base"". Journal of the American Chemical Society. 115 (15): 7017–7018. doi:10.1021/ja00068a087. ISSN0002-7863.
^Ford PW, Narbut MR, Belli J, Davidson BS (1994-10-01). "Synthesis and Structural Properties of the Benzopentathiepins Varacin and Isolissoclinotoxin A". The Journal of Organic Chemistry. 59 (20): 5955–5960. doi:10.1021/jo00099a026. ISSN0022-3263.
^Toste FD, Still IW (1995-07-01). "A New Route to the Synthesis of the Naturally Occurring Benzopentathiepin Varacin". Journal of the American Chemical Society. 117 (27): 7261–7262. doi:10.1021/ja00132a033.