Synthesis, Cytotoxic and Contraceptive Activity of 6,8,9-Trihydroxy-2-methyl-2H-naphtho[2,3-b]pyran-5,10-dione, a Pigment of Echinothrix diadema, and its Analogs

Abstract

6,8,9-Trihydroxy-2-methyl-2H-naphtho[2,3-b]pyran-5,10-dion, a pigment of the sea urchin Echinothrix diadema, and six analogs were synthesized. The cytotoxic activity and contraceptive properties of the synthesized pyranonaphthazarins have been investigated using the sperm and eggs of the sea urchin Strongylocentrotus intermedius.

Synthesis of Polyhydroxylated Aminonaphthazarins Related to Natural Pigments

“…UV spectra were obtained on a spectrophotometer UV-160 1PC. 1 H and 13 C NMR spectra were recorded on Bruker Avance 300, Bruker Avance-III 500 HD and Bruker Avance-III 700 spectrometers at 300 and 75 MHz, at 500 and 125 MHz, and 700 and 176 MHz, respectively. The chemical shifts (δ) are in parts per million (ppm) relative to TMS (δ=0.0 ppm).…”

“…Yields were not optimized. The compounds 4d,b were prepared according to previously described procedures [13,14].…”

“…1 H NMR (700 MHz, CDCl 3 ): 1.20 (3H, t, J = 7.5 Hz, CH 3 ), 2.98 (2H, q, J = 7.5 Hz, CH 2 -CH 3 ), 3.95 (3H, s, OCH 3 ), 6.24 (1H, s, H), 13.05 (1H, s, C-5-ОН), 13.24 (1H, s, C-8-ОН). 13 In accordance with the general procedure 1, the compound 4a gave 5a (22%), 6a (30%) and 7a (22%); 4c gave 5a (12%), 6a (37%) and 7a (9%); compound 4d gave 5b (9%), 6b (30%) and 7b (5%). HBr/HOAc, 1:1 (20 mL) was refluxed and reaction was monitored by TLC.…”

“…3 ): 2117, 1604, 1570, 1475, 1295 cm -1 .1 H NMR (700 MHz, CDCl 3 ): 1.13 (3H, t, J = 7.6 Hz, CH 3 ), 2.67 (2H, q, J = 7.6 Hz, CH 2 -CH 3 ), 3.96 (3H, s, С-2-OCH 3 ),6.41 (1H, s, С-3-H),12.72 (1H, s, C-5-ОН),13.29 (1H, s, C-8-ОН) 13. C NMR (176 MHz, CDCl 3 ): 12.8 (CH 3 ), 19.0 (СH 2 ), 56.1 (C-2-OCH 3 ), 105.5 (С-4a), 108.8 (С-3), 110.4 (С-8a), 137.7 (С-6), 138.28 (С-7), 158.5 (С-2), 165.4 (С-8), 170.0 (С-1), 171.6 (С-5), 172.7 (С-4).…”

Naphthoquinones of the spinochrome class: occurrence, isolation, biosynthesis and biomedical applications

“…As starting compounds, commercially available 5,8-dihydroxy-1,4-naphthoquinone (naphthazarin) or 2,3-dichloronaphthazarin are usually used. Thus, echinochrome A, 91 spinochrome C, 92,93 spinochrome D, 92 spinochrome E, 94 echinamines A and B, 95 spinamine E, 96 and a pigment of Echinothrix diadema containing a pyran unit, 2-hydroxy-2′-methyl-2′ H -pyrano[3,2- b ]-naphthazarin (18) 97 have been synthesized.…”