2.2.2. 2-(3,4-Dibutoxybenzylidene)-1*H*-Cyclopenta[*b*]Naphthalene-1,3(2*H*)-Dione **PP2**

3,4-Dibutoxybenzaldehyde (0.64 g, 2.55 mmol), mexp = 0.92 g, 2.15 mmol, 84% yield. 1H nmR (CDCl3) δ: 1.01 (t, 3*H*, J = 7.6 Hz), 1.04 (t, 3*H*, J = 7.5 Hz), 1.50–1.64 (m, 4*H*), 1.82–1.94 (m, 4*H*), 4.14 (t, 2*H*, J = 6.5 Hz), 4.26 (t, 2*H*, J = 6.4 Hz), 6.97 (d, 1*H*, J = 8.4 Hz), 7.66–7.69 (m, 2*H*), 7.85 (d, 1*H*, J = 7.1 Hz), 7.92 (s, 1*H*), 8.07–8.10 (m, 2*H*), 8.49 (s, 2*H*), 8.83 (s, 1*H*); 13C nmR (CDCl3) δ: 13.8, 13.9, 19.2, 19.3, 31.0, 31.2, 68.8, 68.9, 112.1, 117.8, 123.8, 123.9, 126.9, 128.0, 129.0, 129.1, 130.4, 130.5, 131.7, 135.6, 136.3, 136.5, 137.6, 148.7, 148.8, 154.7, 189.5, and 190.7; HRMS (ESI MS) m/z: theor: 428.1988 found: 428.1987 ([M]+. detected).
