As washed with ethyl acetate. The solvent was removed in vacuo to afford a white strong, which was recrystallized from ethyl acetate and hexane to obtain the pure hydrogenated tetra-ester 13. Yield: 498 mg (99 ); m.p.: 128?30 ; 1H NMR (CDCl3, 300 MHz): = 1.30 (6H, t, J = 7.2 Hz), 1.55 (6H, t, J = 7.two Hz), two.30 (6H, s), 2.50 (4H, t, J = 7.five Hz), 2.75 (4H, t, J = 7.two Hz), two.90 (4H, s), 4.1 (4H, q, J = 7.2 Hz), four.30 (4H, q, J = 7.2 Hz), 8.75 (2H, brs) ppm; 13C NMR (CDCl3, 75 MHz): = 10.3, 14.0, 14.4, 19.1, 26.2, 35.0, 59.four, 59.5, 60.2, 60.2, 117.8, 120.two, 126.six, 132.three, 161.two, 173.0 ppm. The hydrogenated tetra-ester dipyrrole (500 mg, 0.732 mmol) was dissolved in 20 cm3 ethanol and to it was added 25 cm3 of 1 M aq. NaOH. The reaction mixture was stirred andMonatsh Chem. Author manuscript; available in PMC 2015 June 01.NIH-PA Author Manuscript NIH-PA Author Manuscript NIH-PA Author ManuscriptPfeiffer et al.Pageheated at reflux for three h (reaction completion was confirmed by TLC on silica gel). The ethanol was removed in vacuo, and for the residue was added 10 cm3 water. Right after cooling in an ice-salt bath to 0 the resolution was acidified by adding 50 HNO3 dropwise until a white precipitate formed. Then 1 cm3 much more HNO3 was added, and also the mixture was stirred inside the cold for 30 min. The resulting brown strong tetra-acid 13 was collected by filtration. Yield: 382 mg (99 ); m.p.: 150?52 (dec); 1H NMR (CDCl3, 300 MHz): = 2.00 (3H, s), two.25 (2H, t, J = 7.five Hz), two.50 (2H, t, J = 7.5 Hz), 2.60 (2H, s), 10.9 (1H, s), 11.9 (1H brs) ppm; 13C NMR (CDCl3, 75 MHz): = 10.six, 19.4, 26.four, 35.6, 117.5, 119.7, 125.4, 133.eight, 162.7, 174.3 ppm. 2,two -(1,3-Ethanediyl)bis[5-(ethoxycarbonyl)-4-methyl-1H-pyrrole-3-butanoic acid] (14C22H32N2O8) Dipyrrylethene 12 (250 mg, 0.448 mmol) was converted into 14 following the procedure for the synthesis of 13. Dipyrrylethane tetra-ester: yield: 245 mg (99 ); m.p.: 103?04 ; 1H NMR (CDCl3, 300 MHz): = 1.32 (6H, t, J = 7.2 Hz), 1.42 (6H, t, J = 7.two Hz), 1.82 (4H, q, J = 7.2 Hz), 2.20 (6H, s), 2.32 (3H, t, J = 7.2 Hz), two.45 (4H, t, J = 7.two Hz), two.90 (4H, s), 4.25 (4H, q, J = 7.two Hz), four.28 (4H, q, J = 7.2 Hz), 9.15 (2H, brs) ppm; 13C NMR (CDCl3, 125 MHz): = 10.5, 14.2, 14.6, 23.three, 26.1, 26.7, 33.four, 59.5, 60.5, 117.six, 121.two, 126.eight, 133.two, 161.9, 173.9 ppm. Dipyrrylethane tetra-acid: yield: 192 mg (97 ); m.p.: 152 (dec); 1H NMR (CDCl3, 500 MHz): = 1.48 (4H, q, J = 7.0 Hz), 2.06 (6H, s), two.12 (4H, t, J = 7.0 Hz), two.27 (4H, t, J = 7.0 Hz), 2.54 (4H, s), ten.87 (2H, brs), 11.88 (4H, brs) ppm; 13C NMR (CDCl3, 125 MHz): = ten.8, 23.1, 26.5, 26.five, 33.7, 117.5, 120.six, 125.six, 133.eight, 162.eight, 174.eight ppm.NIH-PA Author Manuscript NIH-PA Author Manuscript NIH-PA Author ManuscriptAcknowledgmentsWe thank the late Prof.1429238-55-0 site A.958451-91-7 Price F.PMID:23329319 McDonagh (Univ. California San Francisco) for the metabolism studies and also the National Institutes of Wellness (R01 HD 17779) for partial support.
Triple-negative breast cancer (TNBC) constituting 10?0 in breast cancer is hugely metastasizing and recurrent with poorer prognoses [1?]. Despite the fact that TNBC is sensitive to chemotherapies, TNBC metastases often occur and shorten 5-year survival rates of individuals [1, 3]. Furthermore, target therapies for TNBC remain but to be clearly elucidated in clinical trials. Recent studies in cancer therapeutics revisit a standard herbal medicine, because herbal extracts or mixtures determined by the traditional medicines have shown anticancer effects with no or significantly less side effects when compared with other an.
