abstract |
There is provided a compound of the formulaÄIÜ: <CHEM> wherein R represents a hydrogen atom or a protective group for a hydroxyl group; and A represents a hydrogen atom, a halogen atom or a group of the formula A1: <CHEM> Q represents Q1, Q2 or Q3: <CHEM> or Q4: <CHEM> wherein R2 represents a hydrogen atom or a protective group for a hydroxyl group. |