| 摘要 |
<p>1,237,877. Bis-chromone derivatives. FISONS PHARMACEUTICALS Ltd. 12 Nov., 1968 [22 Nov., 1967], No. 53076/67. Heading C2C. Compounds of the general formula where P, Q, P<SP>1</SP> and Q<SP>1</SP> are hydrogen, halogen, hydroxy, alkyl, alkoxy, substituted alkyl or alkoxy, and X is a saturated or unsaturated, substituted or unsubstituted, straight or branched hydrocarbon chain, any carbon of which may be replaced by one or more carbocyclic rings, oxygen atoms or carbonyl groups, are prepared by cleaving the coumarin rings in a compound of formula to yield a compound of formula where R 1 is H or acetyl, and R 2 and R 3 are alkyl or aryl, and converting the pairs of groups HO- and R 1 to the chains Several methods of ring cleavage are described, and the formation of the chromone ring system may be achieved by many specified routes. Reference has been directed by the Comptroller to Specification 1,144,905.</p> |
