2-Quinolinecarboxaldehyde: an unusual partner in the Henry reaction and subsequent elimination

2-Quinolinecarboxaldehyde participates in a standard Henry reaction when combined with a nitroalkane and catalytic amounts of base. However, water is not readily eliminated from the resulting β-nitro alcohol intermediate to form the expected nitroalkene. Instead, the elimination of nitrous acid is observed furnishing an unexpected ketone product.