Patent ID: 8263614

Claim:
A compound of formula (I): wherein: R 1 and R 2 represent, independently of one another: a hydrogen atom, or a C 1 -C 7 alkyl group optionally substituted by one or more alkoxy groups; R 3 represents a C 1 -C 7 alkyl group; R 4 represents a hydrogen atom or a C 1 -C 4 alkyl group; Y represents a C 1 -C 4 alkoxy group or an —NRR′ or —O(CH 2 ) n —C(O)—NRR′ group where R and R′ are as defined below and n is an integer equal to 1 or 2; R″ represents a C 1 -C a alkyl group; and R and R′ represent, independently of one another, a hydrogen atom, a —CO—(C 1 -C 4 alkyl) group or a —COOR″ group, where R″ is as defined above; or an acid addition salt thereof, or an enantiomer or diastereoisomer thereof, or a mixture thereof.