| 摘要 |
<p>Prepn. of chrom-4-one-2-carboxylic acids. of formula (I) comprises reacting the corresp. o- hydroxybenzaldehyde with an acetylene dicarboxylic acid dialkyl ester in the presence of an oxidising agent and in an aprotic solvent under basic anhydrous conditions, and then hydrolysing and partially decarboxylating the resulting 2,3-dicarbalkoxychrom-4-one by refluxing with strong mineral acid. In the formula R is H, opt. protected OH, 3-halo-2-hydroxyprop-1-oxy, 2,3-epoxyprop-1-oxy or a 2'-carboxychrom-4'-one- 1-oxy-2-hydroxyprop-3-oxy gp in which the 2-OH gp. is opt. protected. (I) are intermediates in prepn. of 2-hydroxy-1,3-bis-(2',3'-dicarbalkoxychrom-4'-onyloxy)propane, which can be used against asthma and to inhibit allergic reactions.</p> |
