| abstract |
Tricyclic compounds of formula (I)n whereinn X' is a carboxyl or 5-tetrazolyl group X 2 is carbonyl or methylene X 3 is hydroxyl or a group -X 4 (C n H 2n )X 5 nwheren X 4 is oxygen or sulphur X 6 is hydrogen or a group -OX 6 nwheren X 6 is hydrogen, alkanoyl of 1 to 4 carbon atoms or a group -(C m H 2m )X 7 wheren X 7 is hydrogen or a group -OX 8 nwheren X 8 is hydrogen or alkanoyl of 1 to 4 carbon atoms and m and n are each, independently, an integer from 1 to 4, together with salts thereof, provided that when X 5 is a group -OX 6 then n is always greater than 1 and X 4 and X 5 are attached to different carbon atoms and that when X 7 is a group -OX 8 then m is always greater than 1 and no single carbon atom in the radical -(C m H 2m )-is attached to two oxygen atoms. n These compounds are of value in medicine in circumstances where it is desirable to provide a more effective delivery of oxygen to the tissues; in vivo applications include the relief or amelioration of tissue hypoxia as in, for example, cardiac or cerebral ischaemia while in vitro they maintain the oxygen-delivery capacity of stored red blood cells and prolong the cells' useful storage life. n The invention is also directed to methods for the preparation of the compounds, to pharmaceutical formulations and other presentation forms containing them and the preparation thereof, to the use of the compounds in medicine, and to novel intermediates for the said compounds and the preparation thereof. |