7-BROMO-2,3-DIHYDROTHIENO[3,4-B][1,4]DIOXINE-5-CARBOXALDEHYDE 97

powder

Compound 1 (4.04 g, 23.7 mmol) was suspended in dry acetonitrile (100 mL) and cooled to0 C. NBS (4.36 g, 26.0 mmol), 1.1 equiv, was added and the mixture was stirred for 60 h atroom temperature, shielded from light and under nitrogen. The color changed from yellow topurple. The mixture was transferred with 150 mL of ethyl acetate to a separation funnel, washed with 10% aqueous Na2CO3 (2×200 mL), saturated Na2S2O3 (2×200 mL) and water(2×200 mL), dried with MgSO4, and evaporated in vacuo. Recrystallization twice from ethanol (60 mL) yielded 5.35 g (91%) of the bromide as yellow needles. 1H NMR (300 MHz, CDCl3 delta ppm ): 9.83 (s, 1H), 4.36 (m, 4H); 13C NMR (75 MHz, CDCl3 delta ppm):179.0, 147.9, 140.4, 118.8, 102.0, 65.5, 65.1.S2: Take 0.6 g of 5-formyl-2-bromoethylenedioxythiophene, 0.023 g of tetratriphenylphosphine palladium and 0.142 g of potassium carbonate dissolved in a mixed solution of 6 mL of tetrahydrofuran and 2 ml of water, Then add the solution containing the boric acid ester compound represented by formula (IV) obtained in step S1, and react under reflux under a protective atmosphere of N2 for 12 hours;After the reaction was completed, 10 mL of water was added to the reaction solution for dilution, and extraction was performed three times (15 mL × 3) with dichloromethane. The organic layers were combined and washed with saturated brine, dried over anhydrous sodium sulfate, and the solvent was spin-dried.Then separated by column chromatography (eluent is a mixed solution of CH2Cl2 and PE with a volume ratio of 1: 4) to obtain a compound having the structure represented by formula (II-1) as a yellow solid 0.25 g (yield 43%), mp. 195-197 C50 mL Schlenk tube was charged with (5-formylfuran-2-yl)boronic acid (0.140 g, 1 mmol)and [Pd(PPh3)4] (0.113 g, 0.01 mmol). Dimethoxy ethane (8 mL) and 2m aqueous sodiumcarbonate (2 mL) were added, and the tube was purged with argon gas with fiveevacuate/refill cycles. Compound 5a (0.534 g, 1 mmol) was subsequently added as a neatliquid. The tube was sealed and heated at 908C for 18 h. Upon cooling to ambienttemperature, the organic compounds were extracted into dichloromethane (3× 30 mL) fromwater (30 mL). The combined organic layers were washed with water (1×30 mL) and brine(1×30 mL), dried over Na2SO4, filtered, and the solvent was removed under reduced pressure.The crude product was preadsorbed onto silica gel and purified by column chromatography(9:1 hexane/ethyl acetate) to give 6a (0.395 g, 74%).1HNMR (300 MHz, CDCl3, deltappm )10.11 (s, 1H), 7.86 (d, 1H), 6.51 9d, 1H) 4.32 (m, 4H), 3.92 (s, 3H), 3.84 (s, 6H).General procedure: 50 mL Schlenk tube was charged with (5-formylfuran-2-yl)boronic acid (0.140 g, 1 mmol)and [Pd(PPh3)4] (0.113 g, 0.01 mmol). Dimethoxy ethane (8 mL) and 2m aqueous sodiumcarbonate (2 mL) were added, and the tube was purged with argon gas with fiveevacuate/refill cycles. Compound 5a (0.534 g, 1 mmol) was subsequently added as a neatliquid. The tube was sealed and heated at 908C for 18 h. Upon cooling to ambienttemperature, the organic compounds were extracted into dichloromethane (3× 30 mL) fromwater (30 mL). The combined organic layers were washed with water (1×30 mL) and brine(1×30 mL), dried over Na2SO4, filtered, and the solvent was removed under reduced pressure.The crude product was preadsorbed onto silica gel and purified by column chromatography(9:1 hexane/ethyl acetate) to give 6a (0.395 g, 74%).General procedure: 50 mL Schlenk tube was charged with (5-formylfuran-2-yl)boronic acid (0.140 g, 1 mmol)and [Pd(PPh3)4] (0.113 g, 0.01 mmol). Dimethoxy ethane (8 mL) and 2m aqueous sodiumcarbonate (2 mL) were added, and the tube was purged with argon gas with fiveevacuate/refill cycles. Compound 5a (0.534 g, 1 mmol) was subsequently added as a neatliquid. The tube was sealed and heated at 908C for 18 h. Upon cooling to ambienttemperature, the organic compounds were extracted into dichloromethane (3× 30 mL) fromwater (30 mL). The combined organic layers were washed with water (1×30 mL) and brine(1×30 mL), dried over Na2SO4, filtered, and the solvent was removed under reduced pressure.The crude product was preadsorbed onto silica gel and purified by column chromatography(9:1 hexane/ethyl acetate) to give 6a (0.395 g, 74%).

Molecular Weight:249.08
XLogP3:2.1
Hydrogen Bond Acceptor Count:4
Rotatable Bond Count:1
Exact Mass:247.91428
Monoisotopic Mass:247.91428
Topological Polar Surface Area:63.8
Heavy Atom Count:12
Complexity:190
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes