# Product of Diels-Alder reaction + Consecutive Reaction with base and heat

there is a problem regarding a Diels-Alder reaction that I do not understand (see image).

The Diels-Alder reaction of the diene and the dienophile should lead to the product A. I hope I did it correctly, because the molecular formular shall be C9H6O2N2.

Now, the base triethylamine is added and heat is applied. Because it is a very strong base I would deprotonate the proton next to the ester-group -COOR, since it has a -M effect. I think applying heat leads to decarboxylation (B = carbon dioxide). But I don't know what the product C looks like, since there is another reaction to product D.