| 摘要 |
A compound of the formula: <CHEM> wherein R<1> and R<2> are the same or different and independently represent tert-alkyl or phenyl; R<3> represents hydrogen or alkyl; X represents -(CH2)w-B-(CH2)y- wherein B represents O, S, or CH2 and w and y can each independently be an integer from 0 to 3 with the proviso that the sum of w+y is equal to or less than 3; A represents O or S(O)n wherein n is 0, 1, or 2; p is an integer from 0 to 4; and R represents: (a) alkyl; (b) OH; (c) OR<4> wherein R<4> is alkyl of about 1 to about 4 carbon atoms; (d) NR<5>R<6> wherein R<5> is hydrogen or alkyl, and R<6> is hydrogen, alkyl, heterocyclealkyl, substituted heterocyclealkyl, cycloalkyl, substituted cycloalkyl, phenyl, substituted phenyl, phenylalkyl, or substituted phenylalkyl, or NR<5>R<6> together form a heterocyclic ring which may optionally be substituted; or (e) (CH2)tCOOR<7> wherein t is an integer from 1 to 4 and R<7> is hydrogen or alkyl of 1 to 4 carbon atoms; or a pharmaceutically acceptable salt thereof. |
