Furo[2,3-d]pyrimidine derivatives (I), their salts, solvates and solvated salts are new. Furo[2,3-d]pyrimidine derivatives of formula (I), their salts, solvates and solvated salts are new. A : O, S or NR 5>;; R 5>; : H, 1-6C alkyl, 3-7C cycloalkyl or 4-7C cycloalkenyl; L : 1-7C alkandiyl or 2-7C alkendiyl, optionally substituted by 1 or 2 F, or is -*L 1>;-Q-L 2>;, with * indicating attachment to CHR 3>;; L 1>; : 1-5C alkandiyl; L 2>; : bond or 1-3C alkandiyl, optionally substituted by 1 or 2 F; Q : O or NR 6>;; R 6>; : H, 1-6C alkyl or 3-7C cycloalkyl; Z : -COOR 7>;, -CO-COOR 7>;, 1H-tetrazol-5-yl, or 2-oxo-1,3,4-oxadiazol-5-yl; R 7>; : H or 1-4C alkyl; R 1>; and R 2>; each : halo, cyano, nitro, 1-6C alkyl, 2-6C alkenyl, 2-4C alkynyl, 3-7C cycloalkyl, 4-7C cycloalkenyl, 1-6C alkoxy, CF 3, CF 3O, 1-6C alkylthio, 1-6C acyl, amino, (di)1-6C alkylamino or 1-6C acylamino, where 1-6C alkyl or alkoxy may themselves be substituted by hydroxy, 1-4C alkoxy, amino, mono- or di-(1-6C)alkyl amino; or two R 1>; and/or R 2>; on adjacent positions may complete OCH 2O, OCHFO, OCF 2O, OCH 2CH 2O or OCF 2CF 2O; n and o : 0-3; R 3>; : H or 1-4C alkyl, optionally substituted by hydroxy or amino; R 4>; : H, 1-4C alkyl or cyclopropyl. An independent claim is included for several methods for preparing (I). [Image] ACTIVITY : Cardiant; Antianginal; Hypotensive; Cerebroprotective; Vasotropic; Antiarteriosclerotic; Hepatotropic; Antiinflammatory; Antiasthma; Antiarthritic; Osteopathic; Cytostatic. MECHANISM OF ACTION : (I) are metabolically stable, non-prostanoid activators of the IP (prostacyclin) receptor, so mimic the biological activity of prostacyclin (prostaglandin I 2). 6-{[5-(4-methoxyphenyl)-6-phenylfuro[2,3-d]pyrimidin-4-yl]amino}hexanoic acid had IC50 at this receptor of 206 nM.