Prodrugs of fulvestrant

A compound of formula IV:

• wherein R7 is
• wherein each R25 and R26 is selected independently from hydrogen, optionally substituted alkyl, aryl or heteroaryl;
• and
• R8 is selected independently from group comprising of:
• i)
• wherein R21 is selected from group comprising optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl;
• or —CR22R23;
• where R22 and R23 are taken together along with the carbon to which they are attached to form a three to seven membered saturated, partially unsaturated or unsaturated heterocyclic ring in which up to 4 carbon atoms are replaced by heteroatoms chosen from the group consisting of O, S or N and may optionally be substituted at a substitutable position with one or more R24 radicals, wherein one or more R24 radicals are independently selected at each occurrence from the group consisting of optionally substituted alkyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl, alkylcarbonyl, formyl, halo, alkylphosphate, phosphate, cyano, nitro, alkoxy, amino, alkoxycarbonyl, alkenyl, alkynyl, alkylthio and arylcarbonyl;
• ii)
• wherein R17 is selected from NH2, NHR18 or NR19R20;
• R18 is selected from group comprising optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, heterocycloalkyl, aryl, or heteroaryl;
• R19 and R20 are selected independently from group comprising optionally substituted alkyl, aryl, heteroaryl, heterocycloalkyl, cycloalkyl;
• or R19 and R20 are taken together along with the nitrogen to which they are attached to form a three to seven membered saturated, partially unsaturated or unsaturated heterocyclic ring and may optionally be substituted at a substitutable position with one or more R21 radicals, wherein the one or more R21 radicals are independently selected at each occurrence from the group consisting of optionally substituted alkyl, alkylcarbonyl, formyl, halo, haloalkyl, alkylphosphate, phosphate, oxo, cyano, nitro, amino, alkoxy, alkoxycarbonyl, —C(O)-aminoacid, carboxyl, carboxyalkyl, hydroxyalkyl, alkenyl, alkynyl, alkylthio, cycloalkyl, aryl, heteroaryl, aralkyl, heterocycloalkyl, alkylthioalkyl, arylcarbonyl, aralkylcarbonyl, alkoxyalkyl;
• iii)
• wherein R27 is selected from group comprising optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, heterocycloalkyl, aryl, or heteroaryl;
• iv)
• wherein R28 is selected from group comprising optionally substituted alkyl, alkenyl, alkynyl, alkoxy, cycloalkyl, heterocycloalkyl, aryl or heteroaryl;
• wherein one or more substitution is selected from formyl, halo, phosphate, cyano, nitro, or amino;
• v) amino acid, wherein the amino acid is linked via ester linkage at the point of attachment;
• enantiomers, diastereomers, racemates, pharmaceutically acceptable salts or solvates thereof.

A compound of formula VI:

• wherein, R10 is
• wherein R28 is selected from group comprising optionally substituted alkyl, alkenyl, alkynyl, alkoxy, cycloalkyl, heterocycloalkyl, aryl, or heteroaryl;
• wherein one or more substitution is selected from formyl, halo, phosphate, cyano, nitro, amino, hydroxy, heterocycloalkyl, or alkoxy;
• and
• R11 is hydrogen or
• where R21 is selected from group comprising optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl;
• or —CR22R23;
• where R22 and R23 are taken together along with the carbon to which they are attached to form a three to seven membered saturated, partially unsaturated or unsaturated heterocyclic ring in which up to 4 carbon atoms are replaced by heteroatoms chosen from the group consisting of O, S or N and may optionally be substituted at a substitutable position with one or more R24 radicals, wherein one or more R24 radicals are independently selected at each occurrence from the group consisting of optionally substituted alkyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl, alkylcarbonyl, formyl, halo, alkylphosphate, phosphate, cyano, nitro, alkoxy, amino, alkoxycarbonyl, alkenyl, alkynyl, alkylthio, arylcarbonyl;
• with the proviso that when R11 is hydrogen, R10 is not methyl or ethyl;
• enantiomers, diastereomers, racemates, pharmaceutically acceptable salts or solvates thereof.

A compound of formula VIII:

• wherein R13 are selected from group comprising H;
• optionally substituted alkyl, aryl, heteroaryl, heterocycloalkyl, cycloalkyl;
• and R14 are selected from group comprising optionally substituted alkyl, aryl, heteroaryl, heterocycloalkyl, cycloalkyl;
• or R13 and R14 are taken together along with the nitrogen to which they are attached to form a three to seven membered saturated, partially unsaturated or unsaturated heterocyclic ring and may optionally be substituted at a substitutable position with one or more R21 radicals, wherein the one or more R21 radicals are independently selected at each occurrence from the group consisting of optionally substituted alkyl, alkylcarbonyl, formyl, halo, haloalkyl, alkylphosphate, phosphate, phosphonyl, oxo, cyano, nitro, amino, alkoxy, alkoxycarbonyl, carboxyalkyl, hydroxyalkyl, alkenyl, alkynyl, alkylthio, cycloalkyl, aryl, heteroaryl, aralkyl, heterocycloalkyl, alkylthioalkyl, arylcarbonyl, aralkylcarbonyl, alkoxyalkyl;
• enantiomers, diastereomers, racemates, pharmaceutically acceptable salts or solvates thereof.

A compound of formula X:

• wherein, Q is selected from C or N;
• and
• when Q is C, P1 is selected independently from optionally substituted alkyl, optionally substituted
• wherein substitution on
• is alkyl;
• and P2 and P3 is selected independently from hydrogen or alkyl;
• and
• when Q is N, P2 is selected independently from optionally substituted alkyl, optionally substituted
• wherein substitution on
• is alkyl;
• P1 is hydrogen and P3 is optionally substituted alkyl;
• enantiomers, diastereomers, racemates, pharmaceutically acceptable salts or solvates thereof.

A compound of formula XI:

• wherein R15 and R16 together forms a cyclic structure;
• wherein the said cyclic structure is selected from optionally substituted cycloalkyl, or heterocycloalkyl;
• wherein one or more substitution is selected from alkyl, alkoxy, halo, amino, or hydroxy;
• m and n can be independently 1 to 3;
• enantiomers, diastereomers, racemates, pharmaceutically acceptable salts or solvates thereof.