Total synthesis of (±)-Anastatins A and B

Discovery of Novel Apigenin–Piperazine Hybrids as Potent and Selective Poly (ADP-Ribose) Polymerase-1 (PARP-1) Inhibitors for the Treatment of Cancer

“…All AMF derivatives were obtained by the de novo synthesis sequence with phloroglucinol ( 1 ) and 2 ′ ,4 ′ ,6 ′ -trihydroxyacetophenone monohydrate ( 5 ) as initial materials. − In this convergent total synthesis route, Friedel–Crafts acylation of 1 with chloroacetyl chloride in the presence of anhydrous aluminum chloride yielded intermediate chloroacetophenone 2 . The subsequent addition/cyclization reaction with aromatic aldehydes, followed by methylation (or isopropylation) of phenolic hydroxyl in the presence of 2-indopropane, successfully delivered B-ring divergent alkyl protected flavonoids ( 3a–h ) in high yields.…”

“…General Experimental Details. All chemical reagents were obtained from Sigma-Aldrich, TCI, or Energy and used without further purification; thin-layer chromatography (TLC) was carried out on a precoated GF254 plate (Qingdao Marine Chemical Co., Ltd., China) and visualized with UV light, stained with iodine (I 2 ) vapor or anisaldehyde in acidic ethanol; flash chromatography was performed on silica gel as the stationary phase (100−200 and 200−300 mesh, Qingdao Marine Chemical Co., Ltd., China); column chromatography was performed on silica gel (100−200 and 200−300 mesh, Qingdao Marine Chemical Co., Ltd., China); reactions were done under nitrogen; 1 H, 13 C NMR, and 19 F spectra were recorded at 298 K on Bruker AV-300, AV-400, or AV-500 spectrometers. The signals observed were described as follows: br s (broad singlet), s (singlet), d (doublet), t (triplet), q (quartet), and m (multiplets).…”

Total Synthesis of Boletopsin 11 Enabled by Directed ortho-C(sp2)–H Arylation

“…= 0.32. 1 H NMR (400 MHz, CDCl 3 ) δ 10.40 (s, 1H), 7.31 (s, 1H), 7.30 (s, 1H), 7.15 (s, 1H), 6.22 (s, 2H), 3.99, (s, 3H), 3.98 (s, 3H); 13 C NMR (100 MHz, CDCl 3 ) δ 186.1, 155.9, 151.8, 150.4, 146.7, 145.3, 143.8, 114.2, 111.7, 109.9, 103.4, 103.3, 102.9, 95.7, 56.6, 56.3 8,9-Dimethoxy-4-(4-methoxyphenyl)benzo [b][1,3]dioxolo[4,5-e]benzofuran-5-carbaldehyde (10). In a sealed tube, benzaldehyde 4 (137 mg, 0.457 mmol, 1.0 equiv), p-iodoanisole (214 mg, 0.914 mmol, 2.0 equiv), Pd(OAc) 2 (10.3 mg, 0.0457 mmol, 10 mol %), DG 9 (18.8 mg, 0.183 mmol, 40 mol %), AgTFA (202 mg, 0.914 mmol, 2.0 equiv), and ClCH 2 CO 2 H (432 mg, 4.57 mmol, 10 equiv) were suspended in 2.3 mL of HFIP, and the mixture was stirred for 10 min and then heated to 100 °C in an oil bath covered in aluminum foil to minimize exposure to light.…”

“…Based on related studies published from within our group, 9 we anticipated benzaldehyde 4 could be disconnected back to catechol 5 via an [O]-oxa-Michael transform. 10 We presumed catechol 5 would be easily accessible through Suzuki−Miyaura cross-coupling of known bromide 6 and commercially available 3,4-dimethoxyphenyl boronic acid followed by chemoselective demethylation.…”

Accessing Polyoxygenated Dibenzofurans via the Union of Phenols and o-Benzoquinones: Rapid Syntheses of Metabolites Isolated from Ribes takare

“…In the synthesis of vialinin B reported by Ye and co-workers, the dibenzofuran core of the natural product was accessed via copper­(I) mediated Ullmann coupling (Scheme , eq 2) . Pan and co-workers disclosed a silver­(I) oxidation followed by an intramolecular oxa-Michael addition of the hydroxyl moiety to the o -benzoquinone in their syntheses of anastatins A and B (Scheme , eq 3) …”