The general procedure for the synthesis of compounds (CAS:1117842-29-1) and 4-chloro-2-methylbenzonitrile from 2-cyanofuran and compounds (CAS:25961-46-0) was as follows: crude oxathiazolone compound (2.0 g, 8.8 mmol) was mixed with 2-furanonitrile (16 g, 170 mmol) in a microwave reactor under 190°C for 20 min. This reaction was repeated for 10 batches, and the reaction solution was combined and subjected to Kugelrohr distillation at 100 °C, 30 mbar to recover excess 2-furanonitrile (for use in the next microwave reaction). Subsequently, the residue was further distilled at 150 °C, 20 mbar to remove the nitrile by-products. 5.5 g of the residue was combined with 4.5 g of the residue obtained from another 10 microwave reactions and purified by column chromatography. The 4.5 g of product obtained (HPLC purity 85%) was dissolved in methanol (50 mL) and recrystallized to give pure 3-(4-chloro-2-methylphenyl)-5-(furan-2-yl)-1,2,4-thiadiazole as a light brown solid in 3.6 g yield (7.5% yield). Chemical formula: C13H9ClN2OS; Molecular weight: 278.7; HPLC-ESMS: retention time tR = 6.36 min, m/z 277.0 (M + 1); HPLC purity: > 95% (220 nm), 95% (270 nm). 1H-NMR (300 MHz, CDCl3): δ 8.06 (dd, J = 7.8 Hz, 1H), 7.62-7.63 (m, 1H), 7.22-7.31 (m, 3H), 6.61-6.63 (m, 1H), 2.66 (s, 3H).
