Studies of arylthiazole oxamates in relation to oral antiallergic activity.

25 arylthiazole oxamate derivatives were synthesized and examined for antiallergic activity in the rat passive cutaneous anaphylaxis assay. These compounds were prepared by treatment of the appropriate bromoacetophenone with thioureas to give arylaminothiazoles. Further condensation with alkyloxalyl chloride gave the arylthiazolyl oxamates. Several derivatives showed a 70% inhibition at 5 mg/kg p.o. p-Alkoxy substitution on the phenyl ring resulted in enhanced activity while N-alkyl substitution on the nitrogen amide function inhibited the activity. Ethyl-N-(4-p-methoxyphenyl)-2-thiazolyl oxamate (tioxamast, F-1865) was selected for clinical studies.