Novel redox carriers for brain-specific drug delivery

Claim 1

A compound having the structural formula ##STR1231## or a nontoxic pharmaceutically acceptable salt thereof, wherein: each R a is independently hydrogen or a hydroxyl protective group selected from the group consisting of alkanoyl having 2 to 8 carbon atoms, ##STR1232## wherein the cycloalkyl portion contains 3 to 7 ring atoms and r is zero, one, two or three, phenoxyacetyl, and ##STR1233## wherein r is zero, one, two or three and phenyl is unsubstituted or is substituted by 1 to 3 alkyl each having 1 to 4 carbon atoms, alkoxy having 1 to 4 carbon atoms, halo, trifluoromethyl, dialkylamino having 2 to 8 carbon atoms, or alkanoylamino having 2 to 6 carbon atoms; R b is hydrogen or --COOR c wherein R c is hydrogen or a carboxyl protective group selected from the group consisting of alkyl having 1 to 7 carbon atoms, alkenyl having one or two double bonds and 2 to 7 carbon atoms, cycloalkyl --C r H 2r -- wherein the cycloalkyl portion contains 3 to 7 ring atoms and r is zero, one, two or three, phenoxy, and phenyl --C r H 2r -- wherein r is zero, one, two or three and phenyl is unsubstituted or is substituted by 1 to 3 alkyl each having 1 to 4 carbon atoms, alkoxy having 1 to 4 carbon atoms, halo, trifluoromethyl, dialkylamino having 2 to 8 carbon atoms, or alkanoylamino having 2 to 6 carbon atoms; and [DHC] is ##STR1234## wherein: the alkylene group can be straight or branched and can contain 1 to 3 carbon atoms; R o is hydrogen, methyl, --CH(CH 3 ) 2 , --CH 2 --CH(CH 3 ) 2 , ##STR1235## --CH 2 OH, --CH(OH)--CH 3 , --(CH 2 ) 2 --SCH 3 , --CH 2 --CONH 2 , --CH 2 CH 2 --CONH 2 , ##STR1236## --CH 2 SH, --CH 2 COOH or --CH 2 CH 2 COOH; p is 1 or 2, provided that, when p is 2, then the alkylene groups can be the same or different and the R o radicals can be the same or different; the dotted line in formula (a') indicates the presence of a double bond in either the 4 or 5 position of the dihydropyridine ring; the dotted line in formula (d') indicates a double bond in either the 2 or 3 position of the dihydroquinoline ring; R 1 is C 1 -C 7 alkyl, C 1 -C 7 haloalkyl or C 7 -C 10 aralkyl; the carbonyl-containing grouping in formula (a') can be attached at the 2, 3 or 4 position of the dihydropyridine ring; the carbonyl-containing grouping in formula (d') can be attached at the 2, 3 or 4 position of the dihydroquinoline ring; and the carbonyl-containing grouping in formula (g') can be attached at the 1, 3 or 4 position of the dihydroisoquinoline ring.