3-(4-chlorophenyl)-2-sulfanylidene-1,3-thiazolidin-4-one

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

Procedure: As described in Example 1, triethylorthophenylacetate is reacted with 3-(4'-chlorophenyl)-rhodanine in acetic anhydride for 12 hours to yield 3-(4'-chlorophenyl)-5-(1'-ethoxy-2'-phenylethylidene)-rhodanine. To a suspension of the latter (15 g., 0.0385 m.) in 100 ml. of dioxane and 100 ml. of water is added 22 ml. of 10% sodium hydroxide solution. The mixture is stirred at room temperature for 3 hours, concentrated in vacuo at 40°-40°C. and the remaining solution is washed with ether, then decolorized. The aqueous layer is acidified with dilute hydrochloric acid and the precipitate is taken up in methylene chloride. The latter solution (after being washed with water and dried) is evaporated in vacuo. The residue is dissolved in 10% sodium hydroxide and water, washed with ether and acidified with dilute hydrochloric acid to give 3-(4'-chlorophenyl)-5-(1'-hydroxy-2'-phenylethylidene)-rhodanine, m.p. 134°-137°C.

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

Procedure: Following the procedures of Example 1, triethylorthopropionate is reacted with 3-(4'-chlorophenyl)-rhodanine in acetic anhydride for 51/2 hours to give 3-(4'-chlorophenyl)-5-(1'-ethoxypropylidene)-rhodanine. To a suspension of the latter (25 g., 0.0765 m.) in 200 ml. of dioxane and 200 ml. of water is added 50 ml. of 10% sodium hydroxide solution. The mixture is stirred at room temperature for 4 hours and then concentrated in vacuo at 40°-45°C. The residual solution is washed with ether, decolorized and acidified with dilute hydrochloric acid to yield 3-(4'-chlorophenyl)-5-(1'-hydroxypropylidene)-rhodanine, m.p. 145°-149°C.

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

Procedure: A mixture of 50 g. (0.2 m.) of the above-prepared rhodanine and 140 g. (0.86 m.) of triethylorthoacetate in 350 ml. of acetic anhydride is refluxed for four hours. The cooled reaction solution is filtered and the product is washed with 100 ml. of 70% aqueous acetic acid to yield 3-(4'-chlorophenyl)-5-(1'-ethoxyethylidene)-rhodanine, m.p. 168°-171°C. A mixture of 50 g The cooled reaction solution is filtered the product is washed with 100 ml

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

Procedure: A mixture of 27 g. (0.16 m.) of p-chlorophenyl isothiocyanate, 33 ml. (42.5 g., 0.475 m.) of mercaptoacetic acid and 5 drops of triethylamine is heated in a pressure bottle at 120°-130°C. for 21/2 hours. The reaction mixture is allowed to stand at room temperature overnight and filtered. The crude product is recrystallized from ethanol to give 3-(4'-chlorophenyl)-rhodanine, m.p. 124.5°-126°C. A mixture of 27 g filtered The crude product is recrystallized from ethanol