摘要 |
<p>There is provided a process for the preparation of a compound of formula (7): formula (7) wherein R<Sup>1</Sup> represents an alkyl group, R<Sup>2</Sup> represents an aryl group, R<Sup>3</Sup> represents hydrogen, a protecting group or an alkyl group; and R<Sup>4</Sup> represents hydrogen, a protecting group or a SO<Sub>2</Sub>R<Sup>5</Sup> group where R<Sup>6</Sup> is an alkyl group, which comprises
a) hydroxylating a compound of formula (1): formula (1) wherein Y represents a halo group, P<Sup>1</Sup> represents hydrogen or a protecting group, and W represents =O or -OP<Sup>2</Sup>, in which P<Sup>2</Sup> represents hydrogen or a protecting group, to give a compound of formula (2): formula (2) b) oxidising the compound of formula (2) to give a compound of formula (3): formula (3) c) coupling the compound of formula (3) with a compound of formula (4): formula (4) wherein R<Sup>3</Sup> represents a protecting group or an alkyl group, R<Sup>4</Sup> represents a protecting group or a SO<Sub>2</Sub>R<Sup>5</Sup> group where R<Sup>5</Sup> is an alkyl group; and R<Sup>6</Sup> represents (PR<Sup>7</Sup>R<Sup>8</Sup>)+X<Sup>-</Sup> or P (=O)R<Sup>7</Sup>R<Sup>8</Sup> in which X is an anion and R<Sup>7</Sup> and R<Sup>8</Sup> each independently is an alkyl, aryl, alkoxy or aryloxy group, to give a compound of formula (5): formula (5) wherein R<Sup>3</Sup> represents a protecting group or an alkyl group; and R4 represents a protecting group or a SO<Sub>2</Sub>R<Sup>5</Sup> group where R<Sup>5</Sup> is an alkyl group, d) when W represents -OP<Sup>2</Sup>, removing any P<Sup>2</Sup> protecting group and oxidising the compound of formula (5) to give a compound of formula (6): formula (6) and e) subjecting the compound of formula (5) when W represents =O, or compound of formula (6) to ring-opening, removal of any P<Sup>1</Sup> protecting groups, and optionally removing any additional protecting groups to give a compound of formula (7).</p> |