agirl
(Stranger) 03-05-01 09:42 No 176650 |
protecting an amine group | Bookmark | ||||||
My aim is to synthesis 2,5-dimethoxy-4-(2-fluoroethylthio)phene By the way, I am currently messing around a bit with different variations of the Urushibara nickel catalyst to reduce nitrostyrene. If anyone is interesting in the results I can let them know. |
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Osmium (Stonium's Main Man) 03-05-01 11:06 No 176659 |
Re: protecting an amine group | Bookmark | ||||||
Insert that fluoroethyl group before preparing the nitrostyrene. Thiophenols are prone to oxidation, protecting and deprotecting the amine are another two steps which you could avoid, and I haven't seen any examples of thiophenol-containing benzaldehydes being used in nitrostyrene preparations and reductions. I don't know if they would work or not, but avoid all those uncertainties and alkylate the thiophenol at the beginning of your synth. |
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moo (Stranger) 03-06-01 12:24 No 176901 |
Re: protecting an amine group | Bookmark | ||||||
Hasn't trifluoroacetic anhydride been used for that purpose? I think the thiophenol route would still be better. And please tell us more about your experiments, surely many people would appreciate more information on Urushibara hydrogenations... |
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smiley_boy (Hive Bee) 03-14-01 06:24 No 178365 |
Re: protecting an amine group | Bookmark | ||||||
agirl, I'd have to agree with Os on this. It just makes more sense to alkylate before rather than after. Still, if you're absolutely intent on doing the alkylation later, then I'd suggest reacting the amine with phthalic anhydride, then deprotecting it with hydrazine. So what is your synthetic route here then? It sounds like you have something particular in mind. Please, please, please tell me you're investigating a route using benzoquinone as the starting material - I always wondered why this procedure showed so much promise for 2C-T-1, but a modified version was never even looked at for higher analogs. It just seems like such a terrible oversight, especially since it looks like it could be a great improvent over other synthetic procedures. Otherwise, have you looked at those Czech procedures using benzyl cyanides during the early 1990's? I always thought that looked decent as well... If you need any more information, just ask... |
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yellium (Hive Bee) 03-14-01 14:25 No 178414 |
Re: protecting an amine group | Bookmark | ||||||
Benzoquinone only works in 2C-T-1 because there are methyl groups all over the molecule :-). If you're really desperate, you could try to exploit the differences in reactivity of the thiol group and the hydroxyl groups by first alkylating 2,5-dihydroxythiophenol with 1 equivalent of your alkyl iodide/bromide, then adding 2 equivalents of methyl iodide after an hour or so, and then reflux for a night. Workup as usual, and I would carefully distill the product obtained. (if you used EtI/EtBr, you would end up with tweetio-precursors of 2ct2; I would guess that propyl or isopropyl-tweetios are inactive. But YMMV.) |
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smiley_boy (Hive Bee) 03-16-01 07:36 No 178880 |
Re: protecting an amine group | Bookmark | ||||||
yellium,
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