Benzo-1,3-dioxole-5-acetic acid → 3-((Benzo[d][1,3]dioxol-5-yl)methyl)-6-(thiophen-2-yl)-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazole

Participants

Reaction Conditions

Reaction Steps

As shown in FIG. 2, 2-(benzo[d][1,3]dioxol-5-yl)acetic acid (1 mmol) and thiocarbonohydrazide (1.5 mmol) were heated at 170° C. for 15 min. The mixture was cooled and taken up in 5% MeOH/CH2Cl2 and saturated NaHCO3. The organics were washed with water, saturated NaCl, dried over Na2SO4, and concentrated in vacuo. The resulting 5-((benzo[d][1,3]dioxol-5-yl)methyl)-4H-4-amino-3-mercapto-1,2,4-triazole (compound 1001) was used as is in the next reaction. Accordingly, a mixture of compound 1001 and thiopene-2-carbonyl chloride (0.176 g, 1.2 mmol) suspended in excess phoshoryl chloride (˜10 mL) was refluxed 5 hours. The excess phoshoryl chloride was removed under reduced pressure and the subsequent residue was mixed with crushed ice. The solids were filtered, washed with water, and dried in vaciio. Purification by reversed-phase HPLC produced pure 3-((benzo[d][1,3]dioxol-5-yl)methyl)-6-(thiophen-2-yl)-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazole (compound 2).

Provenance & Evidence