I reported earlier that our attempts to run the thiamine catalyzed 4-methoxybenzaldehyde (anisaldehyde) coupling to 4,4’-dimethoxybenzoin (anisoin) did not appear to generate any products. I ended up pouring all the student prepared reaction mixtures into a 1 L Erlenmeyer flask and let it sit in my research lab. One day towards the end of August I noticed that a drop of fine yellow crystals had formed in the flask. I recovered the crystals and put the filtrate into the refrigerator. Analysis of the crystals showed that they represented a single compound by GC-FID. MP 123 – 125 oC. UV λmax at 305 nm in dichloromethane. The IR showed a very weak C-H stretch absorptions and strong absorptions at 1655, 1597, and 1572. Proton NMR (400 MHz in CHCl3) shows 3 signals: 3.900 (singlet 6H), 6.974 & 6.996 (doublet 4H), 7.953 & 7.975 (doublet 4H). 13C NMR: 55.627 (CH3), 114.289 (CH), 126.408 (C), 132.363 (CH) , 164.972 (C), 193.481 (C).
