#formyl

[labphoto]

Reaction on molar scale. 

It was originally a Reimer–Tiemann formylation and the image what shot during the workup. That black gunk at the top of the flask is the raw product (surprisingly 90 pure) and under that white stuff is a highly over saturated sodium chloride/sulfate solution. It will look much better after a separation and a vacuum distillation.... 

[labphoto]

Formylation (aldehyde group insertion to the molecule) with the Vilsmeier–Haack reagent. 

This pretty useful reaction is named after Anton Vilsmeier and Albrecht Haack who discovered, that if phosphorous-oxychloride is added to a substituted amide (they used originally N-Methylformanilide, but N,N-dimethylformamide works also great) a chloroiminium ion will form. If an activated aromatic compound is present, an electrophilic aromatic substitution produces an iminium ion intermediate, which can be hydrolyzed to give an aryl aldehyde. This happens: 

-image from wikipedia.

The reaction depending on the temperature control and a few other things, could also produce a few side products. The "gunk", what is produced from the side reactions could easily result an intense, adorable colored reaction mixture, just as seen on my favorite picture: http://labphoto.tumblr.com/post/85408986808/the-blood-red-reaction-product-is-poured-on