| abstract |
A compound represented by the following general formula (I) (I) is described in the formula, R 1 represents a hydrogen atom or the like; R2 and independently represents a hydrogen atom, an optionally oxidized C1-C6 alkyl group or an optionally or alternatively protected hydroxyl group R2 and R3 can be combined to form an optionally oxidized C2-C5 alkylene group; R4 represents an optionally oxidized C1-C6 alkyl group or the like; R5 represents an optionally similar oxidized C1-C6 alkyl group; m represents 0 of an integer of 1-3; n represents 0 or an integer from 1-4; and i represents 0 or an integer from 1-7. |