Patent ID: 8846752

Claim:
A compound of the following formula I or II R 1 represents: C 11 -C 30 fatty alkyl groups; R 2 represents H, OH, OR′, SR′, NHR′, N(CH 3 ) 2 , NO 2 , halogen, CF 3 or C(O)R′ respectively, R 3 represents H, OR′, SR′, NHR′, N(CH 3 ) 2 , NO 2 , halogen, CF 3 or C(O)R′ respectively and R 4 represents H, OR′, SR′, NHR′, N(CH 3 ) 2 , NO 2 , halogen, CF 3 or C(O)R′ respectively, in which R′ represents C 1 -C 4 alkyl group and when R 3 and R 4 represent H R 2 does not represent OH; R 5 represents H, OR′, SR′, NHR′, N(CH 3 ) 2 , NO 2 , halogen, CF 3 or C(O)R′, in which R′ represents C 1 -C 4 alkyl group; when R 4 represents H, R 2 and R 3 can form with their combined carbon atom.