| 摘要 |
<p>A group of novel compounds which can pass through the blood-brain barrier (BBB) with a drug carried thereon and reside in the brain to release the drug and a group of known compounds having the above characteristics. More specifically, a compound represented by general formula (Ia) and a salt thereof, wherein R1 represents hydroxy, carboxy, amino which may be substituted by C¿1?-C6 alkyl, or C1-C6 alkyl which may be substituted by a 5- to 7-membered saturated heterocyclic group, R?2¿ represents hydrogen or C¿1?-C6 alkyl, R?3¿ represents hydrogen or C¿1?-C6 alkyl which may be hydroxylated, R?4¿ represents hydrogen or C¿1?-C6 alkyl, R?5¿ represents amino acid residue, or -S-R6 or -CO-R6 (wherein R6 represents C¿1?-C14 alkyl which may be substituted by a 5- to 7-membered saturated heterocyclic group, C1-C14 alkyl, C2-C6 alkenyl, aryl or a 5- to 7-membered saturated ring group), or a group represented by general formula (IVa), wherein R?1, R2, R3 and R4¿ are each as defined above, and symbol .^_.^_.^_.^_.^_.^_.^_.^_.^_.^ represents either a single or a double bond, provided that at least one of R?1, R3 and R5¿ represents hydroxy, carboxy or amino.</p> |
