| 摘要 |
<p>The invention provides a process for the preparation of a water-soluble salt of formula (I) <EMI ID=1.1 HE=42 WI=107 LX=583 LY=762 TI=CF> <PC>wherein: R<SB>1</SB> is hydroxy or C<SB>1</SB>-C<SB>4</SB> alkoxy, or R<SB>1</SB> and an adjacent R<SB>2</SB> together form a methylenedioxy ring; each R<SB>2</SB> is independently H, C<SB>1</SB>-C<SB>3</SB> alkyl, C<SB>1</SB>-C<SB>2</SB> alkoxy, OH or carboxymethoxy provided that at least two R<SB>2</SB> groups are H; R<SB>3</SB> is H or methyl; and X<SP>n+</SP> is a food-acceptable cation wherein n=1,2,3 or 4,, said process comprising the steps of:<BR> ```providing an alcoholic solution of a compound of formula (II) <EMI ID=1.2 HE=41 WI=94 LX=481 LY=1737 TI=CF> <PC>wherein R<SB>4</SB> is OH or a carboxylate protecting group and the solvent for said solution comprises one or more C<SB>1</SB> to C<SB>6</SB> alcohols; and<BR> ```treating said solution with an alkali salt of X<SP>n+</SP> in the presence of at least 0.5% w/v of water to precipitate said compound of formula (I) from said alcoholic solution. The presence of a small amount of water in the reaction mixture results in a more tractable product of higher yield and purity.</p> |
