The present invention relates to a compound of the general formula (I), and (II)wherein one of R11 and R12 is hydrogen and the other is -CH2-R70, and one of R13 and R14 is hydrogen and the other is -CH2-R71, or wherein one of R11 and R12 is hydrogen and the other is -CH2-R70, and both of R13 and R14 are hydrogen, and wherein two of R21, R22 and R23 is hydrogen and the other is -CH2-R70, and one of R24 and R25 is hydrogen and the other is -CH2-R71, wherein R31, R32 and R33 are hydrogen and R34 is -CH2-R71, and R70 and R71 are independently form each other and are selected from the group consisting of a linear or branched C5 to C20 alkyl, a (C2 to C10)-alkyloxy-(C2 to C10)-alkyl, a C5 to C10 cycloalkyl and C6 to C12 aryl.