2-Aminothiazole → HCID 11046433, compound

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Reaction Steps

To 3.0 g (11.33 mmol) of 2,3,4,5-tetrafluoro-β-oxo-benzeneproprionic acid, ethyl ester was added 2.49 g of triethylorthoformate and 2.76 g of acetic anhydride. The mixture was refluxed for two hours and concentrated to dryness under high vacuum at 80° C. The residual oil was treated with 1.32 g (1.2 equivalents) of 2-aminothiazole suspended in 70 ml of isopropanol. At 70° C., 1.6 g (1.0 equivalent) of 1,8-diazobicyclo[5.4.0]undec-7-ene was added. After 18 hours, the mixture was cooled and filtered to give 2.73 g of the 6,8,7-trifluoro-1,4-dihydro-4-oxo-1-(2-thiazolyl)-3-quinolinecarboxylic acid, ethyl ester, mp 172°-174° C. This material was dissolved in 100 ml of hot acetic acid and 50 ml of 2N hydrochloric acid and was heated at 100° C. for 2.5 hours. The mixture was cooled, partially concentrated, and filtered to give 1.81 g of 6,7,8-trifluoro-1,4-dihydro-4-oxo-1-(2-thiazolyl)-3-quinolinecarboxylic acid, mp 198.5°-200° C.

Provenance & Evidence