Patent ID: 8664238

Claim:
A compound of formula 1 or the pharmaceutically acceptable salts thereof: Wherein R 1 and R 2 independently represent H, OH, C 1 -C 4 alkoxy or C 1 -C 6 alkoxycarbonyl; R 3 and R 4 independently represent —CO(CH 2 ) 2 CH 3 , —CO(CH 2 ) 3 CH 3 or C 1 -C 6 alkyl; or R 3 and R 4 , when combined with their adjacent nitrogen atom, represent piperidyl, 2-methylpiperidyl, homopiperidyl, morpholinyl, pyrrolidinyl, 3-methylpyrrolidinyl, 3,3-dimethylpyrrolidinyl, 3,4-dimethoxypyrrolidinyl, piperazinyl, N-methylpiperazinyl, N-ethylpiperazinyl, N-phenylpiperazinyl or N-benzylpiperazinyl; X represents O, S, NH, CH 2 or —CO—; m=0 or 1; and n=2 or 3.