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4th October 2016 @ 20:30

Starting material, MRLS 2-3 (0.14g, 0.921 mmol), was added to a round bottom flask, and NBS (0.145g, 0.81 mmol, 0.9 eq) was added along with 10 ml of chloroform. Brought to reflux for 48 hours, then allowed to cool overnight. 

Workup: reaction mixture diluted with 20 mL more chloroform, then washed with 10 mL potassium carbonate. Aqueous layer washed with 2x10 mL chloroform and combined with the other organic layers. Solvent removed under reduced pressure. 

 

Log

10-1, 8:45p 

Reaction started. Everything was very soluble in chloroform as expected. Turned a dark wine color once everything was dissolved. Brought to reflux over about 20 minutes.

10-2

Took TLC of the reaction mixture (60% EtOAc) which showed a good bit of starting material left, so another 0.5 eq NBS was added. I noticed that it seemed like there was less chloroform than we'd started with, so I greased the joints of the reflux condenser and added 4 more mL chloroform to be on the safe side.

10-3

All of the chloroform is gone! It's kind of a mystery, because the argon balloon is still full. very hard solid was left in the flask. More chloroform added in hopes of salvaging the reaction. Most of the solid was soluble in chloroform, but there was some stuck to the stir bar that was insoluble. I took it off of the heat and let it cool over night, still stirring. 

10-4

Workup done as described above. Nothing good resulted. The aqueous and organic layers were quite difficult to distinguish, and there was a gooey slab in the aqueous layer. Organic layers concentrated anyways, giving a thick black oil. NMR was done in DMSO, which looked nothing like expected. Product scrapped.

Attached Files
7-1faileddmso.pdf