10.1021/np200411p.s001 George R. Pettit George R. Pettit Ricardo F. Mendonça Ricardo F. Mendonça John C. Knight John C. Knight Robin K. Pettit Robin K. Pettit The Cephalostatins. 21. Synthesis of Bis-steroidal Pyrazine Rhamnosides American Chemical Society 2011 21 c nosocomial pathogen Enterococcus faecalis steroidal pyrazine 10 rhamnosides 17 b Pyrazine 9 cancer cell growth 21. Synthesis iodide cancer cell line panel boron triflouride etherate orthoester pyrazine 10 2011-09-23 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/The_Cephalostatins_21_Synthesis_of_Bis_steroidal_Pyrazine_Rhamnosides/2611681 The synthesis of bis-steroidal pyrazines derived from 3-oxo-11,21-dihydroxypregna-4,17(20)-diene (<b>4</b>) and glycosylation of a D-ring side chain with α-l-rhamnose have been summarized. Rearrangement of steroidal pyrazine <b>10</b> to <b>14</b> was found to occur with boron triflouride etherate. Glycosylation of pyrazine <b>10</b> using 2,3,4-tri-<i>O</i>-acetyl-α-l-rhamnose iodide led to 1,2-orthoester-α-l-rhamnose pyrazine <b>17b</b>. By use of a persilylated α-l-rhamnose iodide as donor, formation of the orthoester was avoided. Bis-steroidal pyrazine <b>10</b> and rhamnosides <b>17b</b> and <b>21c</b> were found to significantly inhibit cancer cell growth in a murine and human cancer cell line panel. Pyrazine <b>9</b> inhibited growth of the nosocomial pathogen <i>Enterococcus faecalis</i>.