New Thyroxine Analogs. Halogen Derivatives of 3-Carbethoxy-5-hydroxy-2-methylbenzofuran

Synthesis of espicufolin based on 6-endo ring closure of o-alkynoylnaphthols †

“…Reaction of 5 with I 2 and N-methylmorpholine (NMM) gave mainly dimeric compounds such as 12 in 66% yield in addition to 2-iodonaphthol 11 (31%). 16 No formation of a 4-iodo derivative was observed. One of the dimers was isolated in 36% yield by recrystallization and the structure was determined as the 2,2Јdimer 12 by 1 H NMR analysis.…”

Highly efficient benzodifuran based ruthenium sensitizers for thin-film dye-sensitized solar cells

“…Lit [27]. 143.5e144 C. 1 To a dispersion of ethyl 5-hydroxy-2-methylbenzofuran-3-carboxylate (29.54 g, 134 mmol) in 1-octanol (300 mL), concentrated sulfuric acid (1 mL) was added and the mixture was heated to 150 C in opened flask and stirred at this temperature for 18 h. It was poured into concentrated solution of sodium bicarbonate (200 mL) and brine (100 mL), stirred for several minutes and extracted with ethyl acetate (3 Â 100 mL).…”

“…Precipitate was filtered off, washed with cold methanol of (À25 C, 3 Â 60 mL), and dried to obtain 46.91 g of beige solid. It was extracted with diethyl ether (450 mL) using a Soxhlet extractor for 48 h. The crude product was finally crystallized from methanol to obtain 13.97 g (34%) of pure white solid, mp ¼ 196e197 C. Lit [27]. 194e194.5 C. 1 …”

“…Acid catalyzed transesterification with 1-octanol led to octyl 5-hydroxy-2-methylbenzofuran-3-carboxylate (2) in 80% yield. Both 1 and 2 were iodinated by modified Giza and Hinman [27] protocol to give the desired products 3 and 4 in 34% and 52% yield respectively.…”

The Synthesis of 5-Hydroxybenzofurans via Tandem In Situ Oxidative Coupling and Cyclization

“…Gratifyingly, the yield of 3a was 61% when the oxidant selected was phenyliodine (III) diacetate (PIDA). We then screened catalysts for promoting the coupling-cyclization step and the results showed ZnI2 as Lewis acid catalyst led to best yields (Table 1, entries 1-7,- [14][15][16][17][18][19][20][21][22][23][24]. The effect of solvent on reaction was further examined, where reaction in chlorobenzene and toluene showed good yields (Table 1, entries 14,15,[21][22][23][24].…”