GB1333586A - Oxazole derivatives and their use as optical brightening agents - Google Patents

Abstract

1333586 Oxazole derivatives KODAK Ltd 9 Sept 1971 [11 Sept 1970] 43500/70 Heading C2C [Also in Division G2] The invention comprises compounds of formula in which R<SP>1</SP> is a hydrogen atom or an optionally substituted alkyl group or aryl group, and R<SP>4</SP> and R<SP>5</SP> each represent one or more optional alkyl. or aryl substituents. Examples describe the preparation of (a) 4-methyl-2,5-di-(5,7-di-tpentylbenzoxazol - 2 - yl)oxazole by (i) chlorinating ethyl acetoacetate with sulphuryl chloride to give ethyl α-chloroacetoacetate which is reacted with a mixture of ammonium acetate and potassium carbonate in the presence of acetic anhydride to give 5-carboxy-2,4- dimethyl oxazole; (ii) treating the 5-carboxy compound with thionyl chloride to give 2,5- dichloro carbonyl-4-methyl oxazole, and (iii) treating the latter compound with 2-amino-4,6- di-t-pentylphenol to give the required compound; and (b) 2,5-di-(5,7-di-t-pentylbenzoxazol- 2 - yl) - 4 - phenyloxazole by (i) reacting ethyl-2- chlorobenzoyl acetate with a mixture of ammonium acetate and potassium carbonate in acetic acid in the presence of acetic anhydride to give 5-ethoxycarbonyl-2-methyl-4-phenyloxazole which is hydrolysed to give 5-carboxy-2- methyl-4-phenyloxazole; (ii) treating this latter compound with thionyl chloride to give 2,5 - dichlorocarbonyl - 4 - phenyloxazole; and (iii) treating this 2,5-dichloro compound with 2-amino-4,6-di-t-pentyl phenol to give the required compounds. Other compounds of the general formula given above may be prepared by analogous methods. The products may be used as optical brightening agents.