With the rapid development and complex challenges of chemical substances, new drug synthesis pathways are usually the most effective.652-39-1,4-Fluoroisobenzofuran-1,3-dione,as a common compound, the synthetic route is as follows.
652-39-1, 3-Fluorophthalic anhydride (377 mg, 2.27 mmol) was dissolved in MeOH (6 ml_) and heated to reflux for 15 h. The mixture was concentrated in vacuo and the two products (400 mg, 89percent), 2-fluoro-6-(methoxycarbonyl)benzoic acid and 3-fluoro-2- (methoxycarbonyl)benzoic acid, were taken on to the next step without purification.; Step B: (Z)-Methyl 2-((((1 -aminoethylidene)amino)oxy)carbonyl)-3- fluorobenzoate. To a heterogeneous mixture of the two acids from step A (400 mg, 2 mmol) at 0 ¡ãC in DCM (5 ml_) was added oxalyl chloride (0.244 ml_, 2.32 mmol) followed by DMF (0.05 ml_). Gas evolution commenced immediately and after 5 min the ice bath was removed. When gas evolution had ceased and the mixture was homogeneous an aliquot was removed and quenched with MeOH. Formation of the methyl ester was confirmed by HPLC and the mixture was concentrated in vacuo. The viscous liquid was dissolved in fresh DCM (5 ml_) and treated with solid N-hydroxyacetamidine (165 mg, 2.22 mmol) in several portions followed by TEA (0.351 ml_, 2.52 mmol). After stirring for 14 h at ambient temperature the mixture was concentrated in vacuo.Chromatography (Hex to 100percent EtOAc/Hex) afforded two products (477 mg, 94percent), (Z)-methyl 2-((((1 -aminoethylidene)amino)oxy)carbonyl)-3- fluorobenzoate and (Z)-methyl 2-((((1 -aminoethylidene)amino)oxy)carbonyl)-6- fluorobenzoate, which were taken on to the next step as a mixture. MS (ESI) mass calculated for Cn H FN2O4, 254.07; m/z found, 255.0.; Step C: 3-Fluoro-2-(3-methyl-1 ,2,4-oxadiazol-5-yl)benzoic acid. To the mixture of products from Step B (477 mg, 1 .88 mmol) in t-BuOH (9 ml_) was added NaOAc (156 mg, 1 .88 mmol). The mixture was heated at 90 ¡ãC for 50 h and then concentrated in vacuo. This resulted in four products. The residue was dissolved in 1 M aq. K2CO3 and extracted with DCM to isolate methyl 2- fluoro-6-(3-methyl-1 ,2,4-oxadiazol-5-yl)benzoate and methyl 3-fluoro-2-(3- methyl-1 ,2,4-oxadiazol-5-yl)benzoate along with unreacted (Z)-methyl 2-((((1 – aminoethylidene)amino)oxy)carbonyl)-3-fluorobenzoate. The aqueous layer was then acidified with concentrated HCI and extracted with DCM. The combined organic layers from this extraction were dried over Na2SO4, filtered and concentrated in vacuo. The acid isomers were purified on a Prep Agilent system with a XBridge Ci8 OBD 50×100 mm column eluting with 5 to 99percent 0.05percent NH4OH in H2O/ACN over 17 min to afford the desired product (63 mg, 15percent) as a white solid after acidification with 1 M aq. HCI in Et2O. MS (ESI) mass calculated for C10H7FN2O3, 222.04; m/z found, 223.0.; Intermediate 69: 2-Fluoro-6-(3-methyl-1 ,2,4-oxadiazol-5-yl)benzoic acid.The title compound was isolated from the synthesis of Intermediate 68, Method A. MS (ESI) mass calculated for Ci0H7FN2O3, 222.04; m/z found, 223.0. 1H NMR (500 MHz, CDCI3): 7.89 (d, J = 7.7, 1 H), 7.65 – 7.59 (m, 1 H), 7.44 – 7.38 (m, 1 H), 2.50 (s, 3H).
The synthetic route of 652-39-1 has been constantly updated, and we look forward to future research findings.
Reference£º
Patent; JANSSEN PHARMACEUTICA NV; BRANSTETTER, Bryan, James; LETAVIC, Michael, A.; LY, Kiev, S.; RUDOLPH, Dale, A.; SAVALL, Brad, M.; SHAH, Chandravadan, R.; SHIREMAN, Brock, T.; WO2011/50200; (2011); A1;,
Benzofuran – Wikipedia
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