tag:blogger.com,1999:blog-51846086760422068.post2724066182861487441..comments2024-03-28T08:37:08.964-07:00Comments on Open Flask: Academia–industry collaboration in the route optimization of taxadienoneBaranLabhttp://www.blogger.com/profile/01806245988209508968noreply@blogger.comBlogger8125tag:blogger.com,1999:blog-51846086760422068.post-55831838263066176032015-03-03T02:09:09.419-08:002015-03-03T02:09:09.419-08:00nice ,i found it a very interesting blog . hay, i...nice ,i found it a very interesting blog . hay, i m dealing for <a href="http://www.descoinstruments.com" rel="nofollow">surgical instruments </a>Anonymoushttps://www.blogger.com/profile/06004286174699428351noreply@blogger.comtag:blogger.com,1999:blog-51846086760422068.post-59420478538070522782015-01-21T06:05:01.561-08:002015-01-21T06:05:01.561-08:00industry —> academia outsourcing, you sir are r...industry —> academia outsourcing, you sir are right !JustAnotherGuyhttps://www.blogger.com/profile/01784710988800928669noreply@blogger.comtag:blogger.com,1999:blog-51846086760422068.post-8338293779354838972015-01-17T17:21:33.157-08:002015-01-17T17:21:33.157-08:00It's always preferable to close two rings at o...It's always preferable to close two rings at once as compared to sequential and linear...as long as the yields are acceptable :)BHHhttps://www.blogger.com/profile/17674787259534472941noreply@blogger.comtag:blogger.com,1999:blog-51846086760422068.post-14358072300855432672015-01-17T13:40:17.363-08:002015-01-17T13:40:17.363-08:00Yes I know all about the B-ring of taxol. The enti...Yes I know all about the B-ring of taxol. The entirety of my nearly 4 years as a grad student has basically been focused on the formation and functionalization of that eight-membered ring. And yes I did see Nakada's synthesis. It is very nice, and focusing on the B-ring problem really highlights the strengths of that synthesis. If you're interested in the different ways to make the B-ring, you might be interested to know that we are not the only, or even the first, to use the Diels-Alder strategy. Williams made taxadiene (JOC 1995, 60, 7215) with pretty much the same conditions but with a slightly different substrate, and they report 31% yield.Anonymoushttps://www.blogger.com/profile/02901492454061651958noreply@blogger.comtag:blogger.com,1999:blog-51846086760422068.post-41515097883485037432015-01-16T18:02:44.276-08:002015-01-16T18:02:44.276-08:00Thanks, Nathan. It's really great work, noneth...Thanks, Nathan. It's really great work, nonetheless. As I'm sure you're aware, the strained 8-membered B-ring of taxol has been a problem for chemists for the last 25 years…not easy stuff. Masahisa Nakada's group recently reported a palladium-catalyzed process to close the B-ring in 97% yield, the most efficient to date…probably not conducted on gram-scale though. Reproducibility on scale is really important for a process to be considered viable in an industrial/manufacturing context. I'm sure that you guys will get there. Good luck!BHHhttps://www.blogger.com/profile/17674787259534472941noreply@blogger.comtag:blogger.com,1999:blog-51846086760422068.post-40585056264871128022015-01-16T12:36:23.080-08:002015-01-16T12:36:23.080-08:00They don’t mention the dr for the aldol/oxidation ...They don’t mention the dr for the aldol/oxidation sequence, and their aldol looks quite different from ours (no excess EtOH or water, run for 5 days when ours is 24 hours). I would guess the main issue they had was a decrease in diastereoselectivity. I have personally seen the dr waver a bit. Poorer dr gives a poorer yield for the Diels–Alder because we take both diastereomers on. I would guess loss in recrystallization could be a second problem. These reactions are also run at quite a bit larger scale than we reported, so differences in scale might be a third reason for the discrepancy.<br /><br />But to answer your question, we haven’t discussed this disparity with AMRI. They were very independent with their findings and with publishing this paper, which I think validates the route.Anonymoushttps://www.blogger.com/profile/02901492454061651958noreply@blogger.comtag:blogger.com,1999:blog-51846086760422068.post-13925351166371173892015-01-13T16:28:30.169-08:002015-01-13T16:28:30.169-08:00The DA reaction mix is quite rich: lots of isomer ...The DA reaction mix is quite rich: lots of isomer + unreacted start material. Seems kind of hard to separate, without running a column, in a good yield. milkshakehttps://www.blogger.com/profile/08188961610554710616noreply@blogger.comtag:blogger.com,1999:blog-51846086760422068.post-29605277161370842442015-01-13T14:28:27.047-08:002015-01-13T14:28:27.047-08:00AMRI seems to be indicating that the critical Diel...AMRI seems to be indicating that the critical Diels-Alder step doesn't scale very well under the current reaction conditions. They report a much lower isolated yield and, unfortunately, do not comment on the diastereoselectivity that was observed in their hands. Have your groups discussed this discrepancy? Are their recoveries low due to mother liquor loss or are they observing differences with regard to conversion or by-products? BHHhttps://www.blogger.com/profile/17674787259534472941noreply@blogger.com