CHLORIN E6 synthesis

Yield:19660-77-6 2.6 g

Reaction Conditions:

with potassium hydroxide in tetrahydrofuran at 40; for 0.5 h;Inert atmosphere;

Steps:

2.2. Chemistry

Chenghai Chlorin (CHC), with same chemical structure as chlorin e6(Ce6), was extracted from the spirulina powers derived from ChenghaiLake in Yunnan Province of China. Spirulina powders (980 g) were reflux extracted with acetone (1500 ml) for 5 times, and then theconcentrated extract was obtained by silica gel flash column chromatography(CH2Cl2/ AcOEt). Solution of Et2O/HCl was added to thecrude product, and 3.1 g deep green powders pyropheophorbide-a(CHP) were gained (3‰). CHP was dissolved in THF (20 ml), and 5%KOH was dropwise added under N2 at 40 °C for 30 min. The pH ofsolution was adjusted to 5-6 with 2 M HCl, and 2.6 g dark greenpowder CHC was obtained (98%). CHC (C34H36N4O6): 1H NMR(400 MHz, DMSO) δ 9.78 (1H, s), 9.71 (1H, s), 9.10 (1H, s), 8.31 (1H,dd, J = 17.8, 11.6 Hz), 6.46 (1H, d, J = 17.8 Hz), 6.18 (1H, d,J = 11.6 Hz,), 5.39 (1H, d, J = 19.0 Hz), 5.31 (1H, d, J = 19.5 Hz),4.61 (1H, q, J = 6.8 Hz), 4.43 (1H, d, J = 10.2 Hz), 3.81 (2H, q,J = 7.4 Hz), 3.58 (3H, s), 3.52 (3H, s), 3.30 (3H, s), 2.49 (2H, m), 2.25(2H, m), 1.69 (3H, m), 1.65 (3H, m), -1.65 (1H, s), -1.93 (1H, s). 13CNMR (100 MHz, DMSO) δ 175.6, 174.7, 174.1, 170.2, 168.6, 153.9,148.8, 145.0, 138.7, 136.6, 135.7, 135.2, 134.6, 134.3, 130.8, 129.7,129.4, 126.6, 122.5, 103.8, 101.7, 98.7, 94.6, 53.0, 48.6, 40.6, 27.3,23.4, 19.3, 18.2, 12.5, 12.4, 11.4, 9.5. HRMS (ESI) m/z: [M + H]+calcd 597.2713, found 597.2699.

References:

Cao, Lei;Dong, Yi;Li, Guangzhe;Li, Yueqing;Wang, Liu;Zhao, Weijie [Journal of Photochemistry and Photobiology B: Biology,2020,vol. 211,art. no. 112015]