Process for the preparation of dialkali metal cromoglycates
AssigneeHoechst Celanese Corporation
InventorsApurba Bhattacharya, Boyd A. Keys
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Abstract
A process for preparing a dialkali metal cromoglycate which comprises (1) condensing a hydroxy substituted ketone with a condensing agent in the presence of a base material and an organic solvent; (2) subjecting the condensed material to ring-closure conditions, first in the presence of an alkali metal alkoxide and a suitable organic solvent, then followed by the addition of substantially dry mineral acid and a suitable organic solvent; and (3) hydrolyzing the ring-closed material in the presence of a base material and a suitable organic solvent to form said cromoglycate.
Claims7
A process for preparing an alkali metal cromoglycate which comprises the steps of:
- a. condensing 2,6-dihydroxyacetophenone with a condensing agent in the presence of a base material and an organic solvent under suitable condensation conditions to form 1,3-bis(2-acetyl-3-hydroxyphenoxy)-2-hydroxypropane;
- b. subjecting said hydroxypropane, formed in step (a), to suitable ring-closure conditions, first in the presence of a ring closing agent, an alkali metal alkoxide and a suitable organic solvent, then followed by the addition of substantially dry mineral acid and a suitable organic solvent to form 1,3-bis(2-carboalkoxychromon-5-yloxy)-2-hydroxypropane;
- and
- c. hydrolyzing said hydroxypropane, formed in step (b), for a sufficient period of time, temperature, and pressure, under suitable hydrolysis conditions, to form said alkali metal cromoglycate.
The process as set forth in claim 4 wherein in step (b), there is included a ring-closing agent is a diester of oxalic acid.
A process for preparing disodium cromoglycate which comprises the steps of:
- a. reacting 2,6-dihydroxyacetophenone with epichlorohydrin in the presence of potassium hydroxide and isopropanol to form 1,3-bis(2-acetyl-3-hydroxyphenoxy)-2-hydroxypropane;
- b. reacting said hydroxypropane with diethyl oxalate, first in the presence of sodium ethoxide and ethanol, then followed by the addition of dry hydrochloric acid and ethanol to form 1,3-bis(2-carboethoxychromon-5-yloxy)-2-hydroxypropane;
- and
- c. hydrolyzing said hydroxypropane, formed in step (b), for a sufficient period of time and temperature, and in the presence of sodium hydroxide and ethanol, to form said disodium cromoglycate.
Dependencies are inferred from the claim text.