potassium;methoxymethanedithioate

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: With the use of the apparatus described in Example 1, 143.6 g (1 mol) of 4-chloro-2-aminophenol and 181.3 g (1.02 mols) of potassium methyl xanthate (90%) in 500 ml of water were refluxed. The reaction was complete within 3 hours. The dark reaction solution was acidified with concentrated hydrochloric acid, the precipitate was suction-filtered and washed neutral with water. After drying in vacuo at 80° C., 179 g (96.7% of th.) of 5-chloro-2-mercaptobenzoxazole having a melting point of 269°-271° C. were obtained. were refluxed the precipitate was suction-filtered washed neutral with water After drying in vacuo at 80° C.

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 2-Methoxy-1,3,4-thiadiazol-5(4H)-one (7) was prepared from phosgene, potassium methyl xanthate, and hydrazine according to the method of K. Rufenacht, Helv. Chim. Acta, 51, 518 (1968). This was hydrolyzed to 1 by the following procedure. A mixture of 50 g of thiadiazole 7 in 300 ml of acetic acid was warmed to 80° to effect solution and then cooled to 70°, whereupon HBr gas was bubbled rapidly into the solution for 25 min. The HBr was shut off, the mixture was held at 70° for 35 min, and then it was cooled to 10°. Ether (200 ml) was added and the mixture was cooled back to 10°. The mixture was filtered through sintered glass and the filter cake was washed with ether, giving 37 g (75%) of 1,3,4-thiadiazoline-2,5-dione or 2-hydroxy-1,3,4-thiadiazol-5-(4H)-one (1). A thirty-gram sample was crystallized from 300 ml of ethanol, affording 18 g of pure 2, mp 175°-255°, infrared maxima (IR), νmax 1700 and 1680 cm-1, ultraviolet maxima (UV), λmax (EtOH) 235 nm (ε 3000) and λmax (EtOH+ NaOH), 258 nm (ε 2730), high resolution mass spectrum (HRMS), m/e calculated for C2H2N2O2S (M+): 117.9837; measured: 117.9825. was warmed to 80° was bubbled rapidly into the solution for 25 min it was cooled to 10° Ether (200 ml) was added the mixture was cooled back to 10° The mixture was filtered through sintered glass the filter cake was washed with ether

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: With the use of the apparatus described in Example 1, 143.6 g (1 mol) of 4-chloro-2-aminophenol and 181.3 g (1.02 mols) of potassium methyl xanthate (90%) in 500 ml of water were refluxed. The reaction was complete within 3 hours. The dark reaction solution was acidified with concentrated hydrochloric acid, the precipitate was suction-filtered and washed neutral with water. After drying in vacuo at 80° C., 179 g (96.7% of th.) of 5-chloro-2-mercaptobenzoxazole having a melting point of 269°-271° C. were obtained. were refluxed the precipitate was suction-filtered washed neutral with water After drying in vacuo at 80° C.

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: With the use of the apparatus described in Example 1, 143.6 g (1 mol) of 4-chloro-2-aminophenol and 181.3 g (1.02 mols) of potassium methyl xanthate (90%) in 500 ml of water were refluxed. The reaction was complete within 3 hours. The dark reaction solution was acidified with concentrated hydrochloric acid, the precipitate was suction-filtered and washed neutral with water. After drying in vacuo at 80° C., 179 g (96.7% of th.) of 5-chloro-2-mercaptobenzoxazole having a melting point of 269°-271° C. were obtained. were refluxed the precipitate was suction-filtered washed neutral with water After drying in vacuo at 80° C.

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 2-Methoxy-1,3,4-thiadiazol-5(4H)-one (7) was prepared from phosgene, potassium methyl xanthate, and hydrazine according to the method of K. Rufenacht, Helv. Chim. Acta, 51, 518 (1968). This was hydrolyzed to 1 by the following procedure. A mixture of 50 g of thiadiazole 7 in 300 ml of acetic acid was warmed to 80° to effect solution and then cooled to 70°, whereupon HBr gas was bubbled rapidly into the solution for 25 min. The HBr was shut off, the mixture was held at 70° for 35 min, and then it was cooled to 10°. Ether (200 ml) was added and the mixture was cooled back to 10°. The mixture was filtered through sintered glass and the filter cake was washed with ether, giving 37 g (75%) of 1,3,4-thiadiazoline-2,5-dione or 2-hydroxy-1,3,4-thiadiazol-5-(4H)-one (1). A thirty-gram sample was crystallized from 300 ml of ethanol, affording 18 g of pure 2, mp 175°-255°, infrared maxima (IR), νmax 1700 and 1680 cm-1, ultraviolet maxima (UV), λmax (EtOH) 235 nm (ε 3000) and λmax (EtOH+ NaOH), 258 nm (ε 2730), high resolution mass spectrum (HRMS), m/e calculated for C2H2N2O2S (M+): 117.9837; measured: 117.9825. was warmed to 80° was bubbled rapidly into the solution for 25 min it was cooled to 10° Ether (200 ml) was added the mixture was cooled back to 10° The mixture was filtered through sintered glass the filter cake was washed with ether

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: With the use of the apparatus described in Example 1, 143.6 g (1 mol) of 4-chloro-2-aminophenol and 181.3 g (1.02 mols) of potassium methyl xanthate (90%) in 500 ml of water were refluxed. The reaction was complete within 3 hours. The dark reaction solution was acidified with concentrated hydrochloric acid, the precipitate was suction-filtered and washed neutral with water. After drying in vacuo at 80° C., 179 g (96.7% of th.) of 5-chloro-2-mercaptobenzoxazole having a melting point of 269°-271° C. were obtained. were refluxed the precipitate was suction-filtered washed neutral with water After drying in vacuo at 80° C.