Patent ID: 6043241
Filing Date: 2000-03-28
Classification: C07C,C07D

Abstract:
A process for the preparation of trans keto acids of Formula I ##STR20## or a pharmaceutically acceptable salt thereof wherein: R.sub.1 is hydrogen,alkyl,alkoxy,O-allyl, orO-alkyl,R.sub.2 is hydrogen oralkoxy;R.sub.3 is hydrogen,alkyl, oralkoxy, orR.sub.2 and R.sub.3 together form--O--CH.sub.2 --O-- or--O--CH.sub.2 --CH.sub.2 --O--;R.sub.4 is hydrogen oralkoxy;R.sub.5 is hydrogen,alkoxy, orO-allyl;R.sub.6 is hydrogen,alkoxy, orO-allyl;R.sub.7 is hydrogen,alkoxy,O-allyl,--NH.sub.2,--NHMe,--NHEt,--N(Me).sub.2,--N(Et).sub.2, ##STR21## wherein n is an integer of from 4 to 5, --O(CH.sub.2).sub.m COOH, ##STR22## wherein m is an integer of from 2 to 5; R.sub.5 and R.sub.6 together can form --O--CH.sub.2 --O--;R.sub.6 and R.sub.7 together can form --O--CH.sub.2 --O--;R.sub.8 is hydrogen, oralkoxy;R.sub.9 is hydrogen,alkyl, oralkoxy;R.sub.10 is alkoxy oramino;R.sub.10 and R.sub.9 together can form --O--CH.sub.2 --O--;R.sub.11 is hydrogen,alkyl, oralkoxy; andR.sub.12 is hydrogen oralkoxywhich are useful in treating conditions caused by elevated levels of endothelin which comprises1) dissolving a .alpha.-hydroxy butenolide of Formula II ##STR23## in a solvent; 2) reacting it with one or more equivalents of a suitable base;3) exposing the solution from Step 2) above to an ultraviolet light source for a sufficient time, acidifying it, and isolating a compound of Formula I above from the solution.