1. Berkoz, B.; Cross, A. D.; Edwards, J. A.; Fried, J. H. German Patent DE 2021718; Chem. Abstr. 1971, 74, 142184q.
2. Marx, M.; Kertesz, D. J. European Patent EP 4765; Chem. Abstr. 1980, 92, 164174k.
3. Analytical HPLC conducted on 15 cm×0.46 cm Phenomenex Prodigy ODS-2 column, eluting with 0.05% aqueous TFA–MeCN using a gradient (15–95% MeCN) over 16 min, with a flow rate of 1.5 ml/min.
4. Mass spectrum: ES+ve m/z 395 (M+H)+ and 789 (2M+H)+. HRMS found: 395.1668 C21H25F2O5 requires 395.1670.
5. Data for 3: HPLC tR 7.02 min; IR (KBr) 3470, 1764, 1747, 1669, 1632 cm−1; NMR δ (250 MHz, DMSO-d6) 7.27 (1H, d, J 10 Hz), 6.29 (1H, d, J 10 Hz), 6.11 (1H, s), 5.72 and 5.56 (1H, 2m), 5.57 (1H, m), 5.22 (2H, m), 4.17 (1H, m), 2.67 (1H, t, J 7 Hz), 2.39 (2H, q, J 7 Hz), 1.49 (3H, s), 1.05 (6H, s and t, J 7 Hz); MS(ES+ve) m/z 451 (M+H)+, 901 (2M+H)+. Found: C, 63.61; H, 6.51 C24H28F2O6 requires C, 63.99; H, 6.27%.