Mannich base N-oxide drugs

A compound having Formula IV:

• or a pharmaceutically acceptable salt thereof, wherein:
• each of R1-R4 is independently hydrogen, hydroxy;
• OC(═O)R11,OR12 or one of R1 and R2 and one of R3 and R4 together form a double bond or a —OC(═X3)O— group, wherein X3 is S or O;
• each of R5 and R6 is independently hydrogen, alkyl, CH2OR13 or C(═O)—CR′R″H;
• wherein R′ is alkyl, alkoxy, or trifluoroacetamido;
• R″ is phenyl or phenylmethyl;
• R7 is hydrogen, halo, alkyl, amine, alkylamine, dialkylamine, dialkylamine N-oxide, trifluoromethyl or trifluoromethyl amine;
• each of R8 and R9 is independently alkyl, aryl, aralkyl, alkoxyalkyl, hydroxyalkyl, or R8 and R9 together with the nitrogen to which they are attached form a heterocyclic ring comprising one, two or three heteroatoms selected from the group consisting of N, O, S, SO and SO2, said heterocycle having 1-4 substituents selected from the group consisting of hydroxy, alkoxy, halogen or hydroxyalkyl;
• R10 is O or is absent, provided that R10 is O when R7 is not dialkylamine N-oxide;
• R11 is hydrogen, acyl, alkylcarboxy, alkyl;
• R12 is hydrogen, acyl or a group of the formula:
• wherein X1 and X2 are independently O or S;
• R4 is optionally substituted phenyl, optionally substituted benzyl or optionally substituted naphthyl;
• R5 is alkyl or alkenyl;
• and
• R13 is hydrogen, acyl, alkylcarboxy, alkyl, aralkyl, a monosaccharide, or a group of the formula:
• wherein X1 and X2 are independently O or S;
• R6 is optionally substituted phenyl, optionally substituted benzyl or optionally substituted naphthyl;
• R7 is alkyl or alkenyl.