• Knoevenagel condensation with aldehydes yields substituted acrylic (e.g. cinnamic) acids; review: Org. React., 15, 204 (1967). For an example of the Doebner modification, using pyridine as solvent/base, see: Org. Synth. Coll., 3, 425 (1955); a catalytic amount of piperidine often gives superior results; see, e.g.: Org. Synth. Coll., 4, 327 (1963).