To synthesize UC176C by a four component one pot Ugi reaction


To a one dram vial, charged with furfurylamine (1.0mmol, 97mg), phenanthrene-9-carboxaldehyde (1.0mmol, 206mg) and phenylacetic acid (1.0mmol, 136mg) added 1.5muL methanol. The solution was vortexed to dissolve the solid. Then n-butylisocyanide (1.0mmol, 104.5uL) was added to the reaction mixture and the solution was vortexed again. The next day, the precipitated product was wahsed with methanol (1mL x3) and dried under a high-vac desiccator to obtain 253-1B

253-1B (aka 176C): N-butyl-2-[2-furylmethyl-(2-phenylacetyl)amino]-2-(9-phenanthryl)‚Äčacetamide; C33H32N2O3; White solid; 1H NMR (external image delta.gif ppm, CDCl3) 0.89 (t, 3H, J=7.3Hz), 1.22-1.39 (m, 2H), 1.4-1.5 (m, 2H), 3.18-3.31 (m, 1H), 3.32-3.44 (m, 1H), 3.93-4.02 (m, 2H), 4.54 (d, 1H, J=17.5Hz), 4.67 (d, 1H, J=17.5Hz), 4.90 (d, 1H, J=2.9Hz), 5.58-5.68 (m, 1H), 5.95 (t, 1H, J= 5.8Hz),6.76-6.83 (m, 1H), 6.95 (s, 1H), 7.17-7.37 (m, 5H), 7.44-7.52 (m, 1H), 7.56-7.63 (m, 2H), 7.64-7.72 (m, 1H), 7.77-7.87 (m, 2H), 7.89 (s, 1H), 8.63 (d, 2H, J=8.3Hz); yield:42.6%.

Estimation of the final concentration per-component
Volume of fufurylamine (1.0mmol) = 0.08837mL
Volume of phenanthrene-9-aldehyde (1.0mmol) = 0.16946mL (density = 1.217g/mL)
Volume of phenylacetic acid (1.0mmol) = 0.11696mL (density = 1.164g/mL)
Total methanol added = 1.5mL
Total volume of the solution = 1.874mL
Concentration per component = 0.53M


Overlay of before and after D2O addition


When a Ugi reaction of phenanthrene-9-carboxaldehye, fufurylamine, phenylacetic acid and butylisocyanide is performed at 0.53M conc/component, precipitation of the product starts with in 5min upon sonication. HNMR of the isolated product indicates that clean of any impurities.
Labile proton exchange experiment with D2O, removed the amide hydrogen (5.9ppm), a residual water from D2O is observed after exchange at 4.8ppm, as expected.


A Ugi product was obtained in 42.6% yield


21:10 Weighed out fufurylamine (97mg) in a one dram vial
21:15 Weighed out phenanthrene-9-carboxaldehyde (206mg) and placed it in to the vial containing fufurylamine.
21:20 Weighed out phenylacetic acid (136mg) and added it to the amine/aldehyde mix in the one dram vial.
21:25 Pipetted out 1.5mL methanol in to the vial, then vortexed the reaction mixture for 30s..not all of the solid dissolved.
21:30 Pipetted out n-butylisocyanide (104.5uL) in to the reaction mixture, now most of the solid dissolved, however a few grains still remained at the bottom of the vial...vortexed the reaction mix for 30s...could still see some undissolved particles in the reaction mixture.
21:31 Placed the vial in to a sonicator water-bath. Started to sonicate the reaction mixture
21:36 The reaction mixture had completely solidified...from almost clear about 4min ago to a solid mass (UC253-1A)...this happened within 5min of sonication.
12:10 Pipetted out about 2mL methanol in to the solid mass developed in the reaction mixture, UC253-1A, vortexed it to break the solid mass. Now the solid seems well mixed with the solvent and looked like a paste (pale colored)
14:00 Poured out the paste in to a 100mL beaker and added 15mL methanol to it, then stirred the solution for ~30s.
14:10 Filtered off the residue by vacuum filtration. Washed the residue by pour a small amount of methanol over it.
14:15 Placed the obtained reside (still on the filter paper in the glass filter) in a desiccator connected to a high vac.The mother liquor was saved
18:10 Obtained an HNMR of UCExp253-1B in CDCl3.
18:20 Added about 700uL D2O in to the NMR tube containing UCExp252-1B in CDCl3 and set it to sonicate for 1h.
19:30 Removed the NMR tube from the sonicator obtained another HNMR, UC253-1B-Hxchange to see if the amide proton had been exchanged with deuterium from D2O.