| abstract |
1435721 Benzoxazoles LILLY INDUSTRIES Ltd 15 May 1973 [18 May 1972] 23409/72 Heading C2C [Also in Division A5] Novel benzoxazoles of the general formula wherein -CR<SP>1</SP>R<SP>2</SP>R<SP>3</SP> is in the 5- or 6-position of the benzoxazole nucleus, each of R<SP>1</SP> and R<SP>2</SP> is a hydrogen atom or C 1-6 alkyl group, R<SP>3</SP> is a nitrile group, a carboxy group or a salt, ester, amide or hydroxamic acid derivative thereof, or a hydroxymethyl group or an ester derivative thereof and R<SP>4</SP> is a cyclohexyl group or a heteroaryl or phenyl group optionally substituted by at least one radical selected from halogen atoms and C 1-6 alkylsulphonyl, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl, nitro, C 2-7 acyl, hydroxy, amino, C 1-6 alkylamino and C 2-7 acylamino groups or, in two adjacent positions, by a methylene- or ethylene-dioxy group, provided that R<SP>4</SP> is not a 3 - alkyl - 4 - hydroxyphenyl or 3,5 - dialkyl - 4- hydroxyphenyl group, are prepared by cyclizing a compound of the general formula wherein either X is a hydrogen atom or the group R<SP>4</SP>CO- and Y is H 2 N- or X is a hydrogen atom and Y is the group R<SP>4</SP>CONH- or R<SP>4</SP>CH=N-, the cyclization being carried out, in the case where X is a hydrogen atom and Y is H 2 N-, in the presence of a cyclizing agent capable of donating the required group R<SP>4</SP>. R<SP>1-3</SP> may subsequently be transformed in conventional manner within the above definitions. 2 - (3 - Benzamido - 4 - hydroxyphenyl)propionitrile is prepared by diazotizing 2-(4-aminophenyl)-propionitrile and treating the product with boiling sulphuric acid, nitrating the resulting 2 - (4 - hydroxyphenyl)propionitrile, reducing the resulting 2-(3-nitro-4-hydroxyphenyl)-propionitrile and treating the resulting 2-(3-amino-4- hydrozyphenyl)-propionitrile with benzoylchloride. 2 - (3 - Benzamido - 4 - hydroxyphenyl)propionic acid, 2 - (3 - o - chlorobenzamido - 4 - hydroxyphenyl)propionic acid and 2-(3-p-chlorobenzamido-4-hydroxyphenyl)-propionic acid are prepared by hydrolysing the corresponding nitrile with an acid. 6 - Bromomethyl - 2 - phenylbenzoxazole is prepared by reacting benzoyl chloride with 6- amino-3-cresol, treating the resulting 2<SP>1</SP>- hydroxy - 4<SP>1</SP>- methylbenzanilide and reacting the resulting 6 - methyl - 2 - phenylbenzoxazole with N-bromosuccinimide in the presence of benzoyl peroxide and U.V. light. Ethyl 2 - (3 - hydroxy - 4 - aminophenyl)- propionate is prepared by treating ethyl 2-(2- phenyl - 6 - benzoxazolyl)propionate in concentrated hydrochloric acid and reacting the resulting 2 - (3 - hydroxy - 4 - aminophenyl)- propionic acid hydrochloride with ethanol in the presence of hydrogen chloride. |