Microbial transformation method for the preparation of an epothilone

A method of altering the oxidation state of at least one epothilone compound of the formula,

• where:
• Q is selected from the group consisting of
• G1 is the following formula (VI)
• CH3-(A1)n-(Qa)m-(A2)o- (VI)
• A1 and A2 are independently selected from the group of optionally-substituted (C1-C3)alkylene and (C2-C3)alkenylene;
• Qa is an optionally-substituted ring system containing one to three rings and at least one carbon to carbon double bond in at least one ring;
• n, m, and o are integers independently selected from the group consisting of zero and 1, where at least one of m or n or o is 1;
• W is O or NF6;
• X is selected from the group consisting of O, and H, OR7;
• M is O, S, NR8, or CR9R10;
• B1 and B2 are selected from the group consisting of —OR11 and —OC(═O)R12;
• R1-R4 and R12-R17 are selected from the group consisting of H, alkyl, substituted alkyl, aryl, and heterocyclo, except R15 is not hydrogen, and when R1 and R2 are alkyl, they can be joined to form a cycloalkyl;
• R5 is hydrogen or methyl;
• R6 is selected from the group consisting of H, alkyl, and substituted alkyl;
• R7 and R11 are selected from the group consisting of H, alkyl, substituted alkyl, trialkylsilyl, alkyldiarylsilyl, and dialkylarylsilyl;
• R8 is selected from the group consisting of H, alkyl, substituted alkyl, R13C(═O)—, R14OC(═O)—, and R15S(O)2—;
• and
• R9 and R10 are selected from the group consisting of H, halogen, alkyl, substituted alkyl, aryl, heterocyclo, hydroxy, R16C(═O)—, and R17OC(═O)—;
• the pharmaceutically-acceptable salts thereof and any hydrates, solvates, or geometric, optical and stereoisomers thereof;
• comprising contacting said epothilone compound with a microorganism or enzyme derived therefrom capable of selectively catalyzing a terminal carbon atom to a hydroxy group, provided that when the epothilone compound is epothilone B, the addition of a hydroxy group to C-21 to yield epothilone F is excluded.