Tuesday, February 20, 2007

Crystalline Success

It looks like we have finally isolated one of the Ugi products we have been trying to make for a while. After analyzing the failed reactions and the kinetics of each step, we learned to stop using unstable aldehydes (like phenylacetaldehyde) and isonitriles (like 2-morpholinoethyl isonitrile).

It was then simply a question of mixing an amine (5-methylfurfurylamine) and aldehyde (piperonal) that we know cleanly form an imine in methanol then adding the carboxylic acid (boc-glycine) and isonitrile (t-butyl isonitrile) and waiting long enough to watch the crystals form.

Alicia was first (EXP052) to isolate and characterize her crystals by H NMR - see the assignment below. The tricky part was that one of the amide H's and the benzylic H were overlapping with the furan H's. Exchanging the amide H's with methanol-d4 made the assignment pretty clear.

Khalid is also getting crystals with another aldehyde and isonitrile and we should have an assignment for that Ugi product shortly as well. (EXP060)

On to boc deprotection and cyclization.....




Chemical Blogspace Tags

InChI=1/C6H9NO/c1-5-2-3-6(4-7)8-5/h2-3H,4,7H2,1H3
5-methylfurfurylamine

InChI=1/C7H13NO4/c1-7(2,3)12-6(11)8-4-5(9)10/h4H2,1-3H3,(H,8,11)(H,9,10)
boc-glycine

InChI=1/C8H6O3/c9-4-6-1-2-7-8(3-6)11-5-10-7/h1-4H,5H2
piperonal

InChI=1/C5H10N/c1-5(2,3)6-4/h4H,1-3H3
t-butyl isonitrile

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