Processes for the convergent synthesis of calicheamicin derivatives

A process to prepare antitumor antibiotics of Formula (I):

• wherein:
• Z is selected from the group consisting of
• Alk1 is a branched or unbranched alkylene chain of 2 to 6 carbon atoms;
• Sp1 is selected from —S—, —O—, —CONH—, —NHCO—, and —NR′—;
• Z1 is H, or alkyl of 1 to 5 carbon atoms;
• Ar is 1,2-, 1,3-, or 1,4-phenylene optionally substituted with one, two, or three groups independently selected from alkyl of 1 to 6 carbon atoms, alkoxy of 1 to 5 carbon atoms, thioalkoxy of 1 to 4 carbon atoms, halogen, nitro, —COOR′, —CONHR′, —O(CH2)nCOOR′, —S(CH2)nCOOR′, —O(CH2)nCONHR′, and —S(CH2)nCONHR′ or a 1,2-, 1,3-, 1,4-, 1,5-, 1,6-, 1,7-, 1,8-, 2,3-, 2,6-, or 2,7-naphthylidene optionally substituted with one, two, three, or four groups independently selected from alkyl of 1 to 6 carbon atoms, alkoxy of 1 to 5 carbon atoms, thioalkoxy of 1 to 4 carbon atoms, halogen, nitro, —COOR′, —CONHR′, —O(CH2)nCOOR′, —S(CH2)nCOOR′, —O(CH2)nCONHR′, and —S(CH2)nCONHR′;
• n is an integer from 0 to 5;
• R′ is a straight or branched alkyl of 1 to 5 carbon atoms optionally substituted by one or two groups of —OH, alkoxy of 1 to 4 carbon atoms, thioalkoxy of 1 to 4 carbon atoms;
• Sp is a straight or branched-chain divalent or trivalent alkyl radical of 1 to 18 carbon atoms, divalent or trivalent aryl or heteroaryl radical, divalent or trivalent cycloalkyl of 3 to 18 carbon atoms or heterocycloalkyl radical, divalent or trivalent aryl- or heteroaryl-alkyl (C1-C18) radical, divalent or trivalent cycloalkyl- or heterocyclo-alkyl-alkyl (C1-C18) radical or divalent or trivalent unsaturated alkyl radical of 2 to 18 carbon atoms, wherein heteroaryl is furyl, thienyl, N-methylpyrrolyl, pyridinyl, N-methylimidazolyl, oxazolyl, pyrimidinyl, quinolyl, isoquinolyl, N-methylcarbazoyl, aminocoumarinyl, or phenazinyl and wherein if Sp is a trivalent radical, it can be additionally substituted by dialkylamino of 1 to 5 carbon atoms, alkoxy of 1 to 5 carbon atoms, hydroxy, or alkylthio of 1 to 5 carbon atoms groups;
• W′ is
• R1 is
• or CH3;
• R2 is
• or H;
• R3 is
• or H;
• R4 is
• or H;
• R6 is H or
• R7 is H or
• R5 is —CH3, —C2H5, or —CH(CH3)2;
• X is an iodine or bromine atom;
• R5′ is a hydrogen or the group RCO, wherein R is hydrogen, branched or unbranched alkyl of 1 to 10 carbon atoms, alkylene of 2 to 10 carbon atoms, aryl of 6 to 11 carbon atoms, a (C6-C11) aryl-alkyl (C1-C5) group, or a heteroaryl or heteroaryl-alkyl (C1-C5) group wherein heteroaryl is defined as 2- or 3-furyl, 2- or 3-thienyl, 2- or 3-(N-methylpyrrolyl), 2-, 3-, or 4-pyridinyl, 2-, 4-, or 5-(N-methylimidazolyl), 2-, 4-, or 5-oxazolyl, 2-, 3-, 5-, or 6-pyrimidinyl, 2-, 3-, 4-, 5-, 6-, 7-, or 8-quinolyl, or 1-, 3-, 4-, 5-, 6-, 7-, or 8-isoquinolyl, all aryl and heteroaryl groups optionally substituted by one or more hydroxy, amino, carboxy, halo, nitro, (C1-C3) alkoxy of 1 to 3 carbon atoms, or thioalkoxy of 1 to 5 carbon atoms;
• and
• Q is selected from the group consisting of —NNHCO—, —NNHCS—, —NNHCONH—, —NNHCSNH—, and —NO—;
• comprising the steps of:
• a. reacting a carboxylic acid of the formula
• with a mercapto compound of the formula
• H2Q-Sp-SH
• in an alcohol solvent in the presence of an alkyl carboxylic acid, alk2CO2H where alk2 is 1 to 4 carbon atoms at about 20° to 70° C. for about 1 to 24 hours, wherein Alk1, Sp1, Ar, Z1, Q, and Sp are as defined above, to produce a bilinker-carboxylic acid of the formula, wherein the mercapto compound and carboxylic acid are present in a ratio of about 1.2:1
• b. isolating the bilinker-carboxylic acid of step (a);
• c. reacting the isolated bilinker-carboxylic acid of step (b) with a methyltrithio antitumor antibiotic CH3—S—S—S—W′ in the presence of a base or an organic base in an inert organic solvent;
• d. reacting the compound of step (c) with an at least a 3 fold molar excess of N-hydroxysuccinimide, 2,3,5,6-tetrafluorophenol, pentafluorophenol, 4-nitrophenol, 2,4-dinitrophenol, or N-hydroxysulfosuccinimide in the presence of 1,3-dicyclohexylcarbodiimide (DCC), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDCI), or N,N′-disuccinimdyl carbonate in an inert solvent containing 0-50% N,N-dimethylformamide (DMF) and purifying to yield antitumor antibiotics of Formula (I)

A process to prepare antitumor antibiotics of Formula (I):

• wherein:
• Z is selected from the group consisting of
• Alk1 is a branched or unbranched alkylene chain of 2 to 6 carbon atoms;
• Sp1 is selected from —S—, —O—, —CONH—, —NHCO—, and —NR′—;
• Z1 is H, or alkyl of 1 to 5 carbon atoms;
• Ar is 1,2-, 1,3-, or 1,4-phenylene optionally substituted with one, two, or three groups independently selected from alkyl of 1 to 6 carbon atoms, alkoxy of 1 to 5 carbon atoms, thioalkoxy of 1 to 4 carbon atoms, halogen, nitro, —COOK′, —CONHR′, —O(CH2)nCOOR′, —S(CH2)nCOOR′, —O(CH2)nCONHR′, and —S(CH2)nCONHR′ or a 1,2-, 1,3-, 1,4-, 1,5-, 1,6-, 1,7-, 1,8-, 2,3-, 2,6-, or 2,7-naphthylidene optionally substituted with one, two, three, or four groups independently selected from alkyl of 1 to 6 carbon atoms, alkoxy of 1 to 5 carbon atoms, thioalkoxy of 1 to 4 carbon atoms, halogen, nitro, —COOR′, —CONHR′, —O(CH2)nCOOR′, —S(CH2)nCOOR′, —O(CH2)nCONHR′, and —S(CH2)nCONHR′;
• n is an integer from 0 to 5;
• R′ is a straight or branched alkyl of 1 to 5 carbon atoms optionally substituted by one or two groups of —OH, alkoxy of 1 to 4 carbon atoms, thioalkoxy of 1 to 4 carbon atoms;
• Sp is a straight or branched-chain divalent or trivalent alkyl radical of 1 to 18 carbon atoms, divalent or trivalent aryl or heteroaryl radical, divalent or trivalent cycloalkyl of 3 to 18 carbon atoms or heterocycloalkyl radical, divalent or trivalent aryl- or heteroaryl-alkyl (C1-C18) radical, divalent or trivalent cycloalkyl- or heterocyclo-alkyl-alkyl (C1-C18) radical or divalent or trivalent unsaturated alkyl radical of 2 to 18 carbon atoms, wherein heteroaryl is furyl, thienyl, N-methylpyrrolyl, pyridinyl, N-methylimidazolyl, oxazolyl, pyrimidinyl, quinolyl, isoquinolyl, N-methylcarbazoyl, aminocoumarinyl, or phenazinyl and wherein if Sp is a trivalent radical, it can be additionally substituted by dialkylamino of 1 to 5 carbon atoms, alkoxy of 1 to 5 carbon atoms, hydroxy, or alkylthio of 1 to 5 carbon atoms groups;
• W′ is
• R1 is
• or CH3;
• R2 is
• or H;
• R3 is
• or H;
• R4 is
• or H;
• R6 is H or
• R7 is H or
• R5 is —CH3, —C2H5, or —CH(CH3)2;
• X is an iodine or bromine atom;
• R5′ is a hydrogen or the group RCO, wherein R is hydrogen, branched or unbranched alkyl of 1 to 10 carbon atoms, alkylene of 2 to 10 carbon atoms, aryl of 6 to 11 carbon atoms, a (C6-C11) aryl-alkyl (C1-C8) group, or a heteroaryl or heteroaryl-alkyl (C1-C5) group wherein heteroaryl is defined as 2- or 3-furyl, 2- or 3-thienyl, 2- or 3-(N-methylpyrrolyl), 2-, 3-, or 4-pyridinyl, 2-, 4-, or 5-(N-methylimidazolyl), 2-, 4-, or 5-oxazolyl, 2-, 3-, 5-, or 6-pyrimidinyl, 2-, 3-, 4-, 5-, 6-, 7-, or 8-quinolyl, or 1-, 3-, 4-, 5-, 6-, 7-, or 8-isoquinolyl, all aryl and heteroaryl groups optionally substituted by one or more hydroxy, amino, carboxy, halo, nitro, (C1-C3) alkoxy of 1 to 3 carbon atoms, or thioalkoxy of 1 to 5 carbon atoms;
• and
• Q is selected from the group consisting of —NNHCO—, —NNHCS—, —NNHCONH—, —NNHCSNH—, and —NO—;
• comprising the steps of:
• a. reacting a carboxylic acid of the formula
• with a mercapto compound of the formula
• H2Q-Sp-SH
• in an alcohol solvent in the presence of an alkyl carboxylic acid, alk2CO2H where alk2 is 1 to 4 carbon atoms at about 20° to 70° C. for about 1 to 24 hours, wherein Alk1, Sp1, Ar, Z1, Q, and Sp are as defined above, to produce a bilinker-carboxylic acid of the formula,
• b. isolating the bilinker-carboxylic acid of step (a);
• c. reacting the isolated bilinker-carboxylic acid of step (b) with an at least of N-hydroxysuccinimide, 2,3,5,6-tetrafluorophenol, pentafluorophenol, 4-nitrophenol, 2,4-dinitrophenol, or N-hydroxysulfosuccinimide in the presence of 1,3-dicyclohexylcarbodiimide (DCC), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDCI), or N,N′-disuccinimdyl carbonate in an inert solvent containing 0-50% N,N-dimethylformamide (DMF) to generate a trilinker-activated ester of the formula
• where Z is hereinbefore defined;
• d. reacting the trilinker-activated ester in step c in the presence of a base or an organic base with a methyltrithio antitumor antibiotic CH3—S—S—S—W′ in an inert organic solvent to generate an activated ester of the formula
• e. isolating the activated ester of step (d) and purifying to yield antitumor antibiotics of Formula (I)

A process to prepare trilinker-activated esters of the formula:

• wherein:
• Z is selected from the group consisting of
• Alk1 is a branched or unbranched alkylene chain of 2 to 6 carbon atoms;
• Sp1 is selected from —S—, —O—, —CONH—, —NHCO—, and —NR′—;
• Z1 is H, or alkyl of 1 to 5 carbon atoms;
• Ar is 1,2-, 1,3-, or 1,4-phenylene optionally substituted with one, two, or three groups independently selected from alkyl of 1 to 6 carbon atoms, alkoxy of 1 to 5 carbon atoms, thioalkoxy of 1 to 4 carbon atoms, halogen, nitro, —COOR′, —CONHR′, —O(CH2)nCOOR′, —S(CH2)nCOOR′, —O(CH2)nCONHR′, and —S(CH2)nCONHR′ or a 1,2-, 1,3-, 1,4-, 1,5-, 1,6-, 1,7-, 1,8-, 2,3-, 2,6-, or 2,7-naphthylidene optionally substituted with one, two, three, or four groups independently selected from alkyl of 1 to 6 carbon atoms, alkoxy of 1 to 5 carbon atoms, thioalkoxy of 1 to 4 carbon atoms, halogen, nitro, —COOR′, —CONHR′, —O(CH2)nCOOR′, —S(CH2)nCOOR′, —O(CH2)nCONHR′, and —S(CH2)nCONHR′;
• n is an integer from 0 to 5;
• R′ is a straight or branched alkyl of 1 to 5 carbon atoms optionally substituted by one or two groups of —OH, alkoxy of 1 to 4 carbon atoms, thioalkoxy of 1 to 4 carbon atoms;
• Sp is a straight or branched-chain divalent or trivalent alkyl radical of 1 to 18 carbon atoms, divalent or trivalent aryl or heteroaryl radical, divalent or trivalent cycloalkyl of 3 to 18 carbon atoms or heterocycloalkyl radical, divalent or trivalent aryl- or heteroaryl-alkyl (C1-C18) radical, divalent or trivalent cycloalkyl- or heterocyclo-alkyl-alkyl (C1-C18) radical or divalent or trivalent unsaturated alkyl radical of 2 to 18 carbon atoms, wherein heteroaryl is furyl, thienyl, N-methylpyrrolyl, pyridinyl, N-methylimidazolyl, oxazolyl, pyrimidinyl, quinolyl, isoquinolyl, N-methylcarbazoyl, aminocoumarinyl, or phenazinyl and wherein if Sp is a trivalent radical, it can be additionally substituted by dialkylamino of 1 to 5 carbon atoms, alkoxy of 1 to 5 carbon atoms, hydroxy, or alkylthio of 1 to 5 carbon atoms groups;
• W′ is
• R1 is
• or CH3;
• R2 is
• or H;
• R3 is
• or H;
• R4 is
• or H;
• R6 is H or
• R7 is H or
• R5 is —CH3, —C2H5, or —CH(CH3)2;
• X is an iodine or bromine atom;
• R5′ is a hydrogen or the group RCO, wherein R is hydrogen, branched or unbranched alkyl of 1 to 10 carbon atoms, alkylene of 2 to 10 carbon atoms, aryl of 6 to 11 carbon atoms, a (C6-C11) aryl-alkyl (C1-C5) group, or a heteroaryl or heteroaryl-alkyl (C1-C5) group wherein heteroaryl is defined as 2- or 3-furyl, 2- or 3-thienyl, 2- or 3-(N-methylpyrrolyl), 2-, 3-, or 4-pyridinyl, 2-, 4-, or 5-(N-methylimidazolyl), 2-, 4-, or 5-oxazolyl, 2-, 3-, 5-, or 6-pyrimidinyl, 2-, 3-, 4-, 5-, 6-, 7-, or 8-quinolyl, or 1-, 3-, 4-, 5-, 6-, 7-, or 8-isoquinolyl, all aryl and heteroaryl groups optionally substituted by one or more hydroxy, amino, carboxy, halo, nitro, (C1-C3) alkoxy of 1 to 3 carbon atoms, or thioalkoxy of 1 to 5 carbon atoms;
• and
• Q is selected from the group consisting of —NNHCO—, —NNHCS—, —NHNCONH—, —NNCSNH—, and —NO—;
• comprising the steps of:
• a. reacting a carboxylic acid of the formula
• with a mercapto compound of the formula
• H2Q-Sp-SH
• in an alcohol solvent in the presence of an alkyl carboxylic acid, alk2CO2H where alk2 is 1 to 4 carbon atoms at about 20° to 70° C. for about 1 to 24 hours, wherein Alk1, Sp1, Ar, Z1, Q, and Sp are as defined above, to produce a bilinker-carboxylic acid of the formula
• b. isolating the bilinker-carboxylic acid of step (a);
• c. reacting the bilinker-carboxylic acid from step (b) in the presence of a base or an organic base with a methyltrithio antitumor antibiotic CH3—S—S—S—W′ in an inert organic solvent to generate a bilinker-methyltrithio antitumor antibiotic of the formula
• d. reacting the isolated bilinker-methyltrithio antitumor antibiotic of step (c) with N-hydroxysuccinimide, 2,3,5,6-tetrafluorophenol, pentafluorophenol, 4-nitrophenol, 2,4-dinitrophenol, or N-hydroxysulfosuccinimide in the presence of 1,3-dicyclohexylcarbodiimide (DCC), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDCI), or N,N′-disuccinimdyl carbonate in an inert solvent containing 0-50% N,N-dimethylformamide (DMF) to generate a trilinker-activated ester of the formula

A process for the preparation of trifunctional linker intermediates, of the formula

• wherein:
• Alk1 is a branched or unbranched alkylene chain of 2 to 6 carbon atoms;
• Sp1 is selected from —S—, —O—, —CONH—, —NHCO—, and —NR′—;
• Z1 is H, or alkyl of 1 to 5 carbon atoms;
• Ar is 1,2-, 1,3-, or 1,4-phenylene optionally substituted with one, two, or three groups independently selected from alkyl of 1 to 6 carbon atoms, alkoxy of 1 to 5 carbon atoms, thioalkoxy of 1 to 4 carbon atoms, halogen, nitro, —COOR′, —CONHR′, —O(CH2)nCOOR′, —S(CH2)nCOOR′, —O(CH2)nCONHR′, and —S(CH2)nCONHR′ or a 1,2-, 1,3-, 1,4-, 1,5-, 1,6-, 1,7-, 1,8-, 2,3-, 2,6-, or 2,7-naphthylidene optionally substituted with one, two, three, or four groups independently selected from alkyl of 1 to 6 carbon atoms, alkoxy of 1 to 5 carbon atoms, thioalkoxy of 1 to 4 carbon atoms, halogen, nitro, —COOR′, —CONHR′, —O(CH2)nCOOR′, —S(CH2)nCOOR′, —O(CH2)nCONHR′, and —S(CH2)nCONHR′;
• n is an integer from 0 to 5;
• R′ is a straight or branched alkyl of 1 to 5 carbon atoms optionally substituted by one or two groups of —OH, alkoxy of 1 to 4 carbon atoms, thioalkoxy of 1 to 4 carbon atoms;
• Sp is a straight or branched-chain divalent or trivalent alkyl radical of 1 to 18 carbon atoms, divalent or trivalent aryl or heteroaryl radical, divalent or trivalent cycloalkyl of 3 to 18 carbon atoms or heterocycloalkyl radical, divalent or trivalent aryl- or heteroaryl-alkyl (C1-C18) radical, divalent or trivalent cycloalkyl- or heterocyclo-alkyl-alkyl (C1-C18) radical or divalent or trivalent unsaturated alkyl radical of 2 to 18 carbon atoms, wherein heteroaryl is furyl, thienyl, N-methylpyrrolyl, pyridinyl, N-methylimidazolyl, oxazolyl, pyrimidinyl, quinolyl, isoquinolyl, N-methylcarbazoyl, aminocoumarinyl, or phenazinyl and wherein if Sp is a trivalent radical, it can be additionally substituted by dialkylamino of 1 to 5 carbon atoms, alkoxy of 1 to 5 carbon atoms, hydroxy, or alkylthio of 1 to 5 carbon atoms groups;
• Q is selected from the group consisting of —NNHCO—, —NNHCS—, and —NNHCONH—;
• Z is selected from the group consisting of
• comprising the steps of:
• a. reacting a carboxylic acid of the formula
• with a mercapto compound of the formula
• H2Q-Sp-SH
• in an alcohol solvent in the presence of an alkyl carboxylic acid, alk2CO2H, where alk2 is 1 to 4 carbon atoms at about 20° to 70° C. for about 1 to 24 hours, wherein Alk1, Sp1, Ar, Z1, Q, and Sp are as defined above, to produce a bilinker-carboxylic acid of the formula
• b. isolating the bilinker-carboxylic acid of step (a);
• c. reacting the isolated bilinker-carboxylic acid of step (b) with N-hydroxysuccinimide, 2,3,5,6-tetrafluorophenol, pentafluorophenol, 4-nitrophenol, 2,4-dinitrophenol, or N-hydroxysulfosuccinimide in the presence of 1,3-dicyclohexylcarbodiimide (DCC), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDCI), or N,N′-disuccinimdyl carbonate in an inert solvent containing 0-50% DMF to generate trifunctional linker intermediates, of the formula

A process to prepare compounds of Formula (I):

• wherein:
• Z is selected from the group consisting of
• Alk1 is a branched or unbranched alkylene chain of 2 to 6 carbon atoms;
• Sp1 is selected from —S—, —O—, —CONH—, —NHCO—, and —NR′—;
• Z1 is H, or alkyl of 1 to 5 carbon atoms;
• Ar is 1,2-, 1,3-, or 1,4-phenylene optionally substituted with one, two, or three groups independently selected from alkyl of 1 to 6 carbon atoms, alkoxy of 1 to 5 carbon atoms, thioalkoxy of 1 to 4 carbon atoms, halogen, nitro, —COOR′, —CONHR′, —O(CH2)nCOOR′, —S(CH2)nCOOR′, —O(CH2)nCONHR′, and —S(CH2)nCONHR′ or a 1,2-, 1,3-, 1,4-, 1,5-, 1,6-, 1,7-, 1,8-, 2,3-, 2,6-, or 2,7-naphthylidene optionally substituted with one, two, three, or four groups independently selected from alkyl of 1 to 6 carbon atoms, alkoxy of 1 to 5 carbon atoms, thioalkoxy of 1 to 4 carbon atoms, halogen, nitro, —COOR′, —CONHR′, —O(CH2)nCOOR′, —S(CH2)nCOOR′, —O(CH2)nCONHR′, and —S(CH2)nCONHR′;
• n is an integer from 0 to 5;
• R′ is a straight or branched alkyl of 1 to 5 carbon atoms optionally substituted by one or two groups of —OH, alkoxy of 1 to 4 carbon atoms, thioalkoxy of 1 to 4 carbon atoms;
• Sp is a straight or branched-chain divalent or trivalent alkyl radical of 1 to 18 carbon atoms, divalent or trivalent aryl or heteroaryl radical, divalent or trivalent cycloalkyl of 3 to 18 carbon atoms or heterocycloalkyl radical, divalent or trivalent aryl- or heteroaryl-alkyl (C1-C18) radical, divalent or trivalent cycloalkyl- or heterocyclo-alkyl-alkyl (C1-C18) radical or divalent or trivalent unsaturated alkyl radical of 2 to 18 carbon atoms, wherein heteroaryl is furyl, thienyl, N-methylpyrrolyl, pyridinyl, N-methylimidazolyl, oxazolyl, pyrimidinyl, quinolyl, isoquinolyl, N-methylcarbazoyl, aminocoumarinyl, or phenazinyl and wherein if Sp is a trivalent radical, it can be additionally substituted by dialkylamino of 1 to 5 carbon atoms, alkoxy of 1 to 5 carbon atoms, hydroxy, or alkylthio of 1 to 5 carbon atoms groups;
• W′ is
• R1 is
• or CH3;
• R2 is
• or H;
• R3 is H;
• R4 is
• or H;
• R5 is —CH3, —C2H5, or —CH(CH3)2;
• X is an iodine or bromine atom;
• R5′ is a hydrogen or the group RCO, wherein R is hydrogen, branched or unbranched alkyl of 1 to 10 carbon atoms, alkylene of 2 to 10 carbon atoms, aryl of 6 to 11 carbon atoms, a (C6-C11) aryl-alkyl (C1-C5) group, or a heteroaryl or heteroaryl-alkyl (C1-C5) group wherein heteroaryl is defined as 2- or 3-furyl, 2- or 3-thienyl, 2- or 3-(N-methylpyrrolyl), 2-, 3-, or 4-pyridinyl, 2-, 4-, or 5-(N-methylimidazolyl), 2-, 4-, or 5-oxazolyl, 2-, 3-, 5-, or 6-pyrimidinyl, 2-, 3-, 4-, 5-, 6-, 7-, or 8-quinolyl, or 1-, 3-, 4-, 5-, 6-, 7-, or 8-isoquinolyl, all aryl and heteroaryl groups optionally substituted by one or more hydroxy, amino, carboxy, halo, nitro, (C1-C3) alkoxy of 1 to 3 carbon atoms, or thioalkoxy of 1 to 5 carbon atoms;
• and
• Q is selected from the group consisting of —NNHCO—, —NNHCS—, —NNHCONH—, —NNHCSNH—, and —NO—;
• comprising the steps of:
• a. reacting a carboxylic acid of the formula
• with a mercapto compound of the formula
• H2Q-Sp-SH
• in an alcohol solvent in the presence of an alkyl carboxylic acid, alk2CO2H where alk2 is 1 to 4 carbon atoms at about 20° to 70° C. for about 1 to 24 hours, wherein Alk1, Sp1, Ar, Z1, and Sp are as defined above, to produce a bilinker-carboxylic acid of the formula, wherein the mercapto compound and carboxylic acid are present in a ratio of about 1.2:1
• b. isolating the bilinker-carboxylic acid of step (a);
• c. reacting the isolated bilinker-carboxylic acid of step (b) with an at least a 3 fold molar excess of N-hydroxysuccinimide, 2,3,5,6-tetrafluorophenol, pentafluorophenol, 4-nitrophenol, 2,4-dinitrophenol, or N-hydroxysulfosuccinimide in the presence of 1,3-dicyclohexylcarbodiimide (DCC), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDCI), or N,N′-disuccinimdyl carbonate in an inert solvent containing 0-50% N,N-dimethylformamide (DMF) to generate a trilinker-activated ester of the formula
• where Z is hereinbefore defined;
• d. reacting the trilinker-activated ester formed in step c in the presence of a base or an organic base with a methyltrithio antitumor antibiotic CH3—S—S—S—W′ in an inert organic solvent to generate an activated ester of the formula below, wherein the trilinker-activated ester in step c and the CH3—S—S—S—W′ are in a ratio of 3.3:1 and the temperature of the reaction is ≦5° C.
• e. isolating the activated ester of step (d) and purifying to yield antitumor antibiotics of Formula (I)

A process to prepare antitumor antibiotics of Formula (I):

• wherein:
• Z is selected from the group consisting of divalent or trivalent cycloalkyl- or heterocyclo-alkyl-alkyl (C1-C18) radical or divalent or trivalent unsaturated alkyl radical of 2 to 18 carbon atoms, wherein heteroaryl is furyl, thienyl, N-methylpyrrolyl, pyridinyl, N-methylimidazolyl, oxazolyl, pyrimidinyl, quinolyl, isoquinolyl, N-methylcarbazoyl, aminocoumarinyl, or phenazinyl and wherein if Sp is a trivalent radical, it can be additionally substituted by dialkylamino of 1 to 5 carbon atoms, alkoxy of 1 to 5 carbon atoms, hydroxy, or alkylthio of 1 to 5 carbon atoms groups;
• W′ is
• or CH3;
• R2 is
• or H;
• R3 is H;
• R4 is
• or H;
• R5 is —CH3, —C2H5, or —CH(CH3)2;
• X is an iodine or bromine atom;
• Alk1 is a branched or unbranched alkylene chain of 2 to 6 carbon atoms;
• Sp1 is selected from —S—, —O—, —CONH—, —NHCO—, and —NR′—;
• Z1 is H, or alkyl of 1 to 5 carbon atoms;
• Ar is 1,2-, 1,3-, or 1,4-phenylene optionally substituted with one, two, or three groups independently selected from alkyl of 1 to 6 carbon atoms, alkoxy of 1 to 5 carbon atoms, thioalkoxy of 1 to 4 carbon atoms, halogen, nitro, —COOR′, —CONHR′, —O(CH2)nCOOR′, —S(CH2)nCOOR′, —O(CH2)nCONHR′, and —S(CH2)nCONHR′ or a 1,2-, 1,3-, 1,4-, 1,5-, 1,6-, 1,7-, 1,8-, 2,3-, 2,6-, or 2,7-naphthylidene optionally substituted with one, two, three, or four groups independently selected from alkyl of 1 to 6 carbon atoms, alkoxy of 1 to 5 carbon atoms, thioalkoxy of 1 to 4 carbon atoms, halogen, nitro, —COOR′, —CONHR′, —O(CH2)nCOOR′, —S(CH2)nCOOR′, —O(CH2)nCONHR′, and —S(CH2)nCONHR™;
• n is an integer from 0 to 5;
• R′ is a straight or branched alkyl of 1 to 5 carbon atoms optionally substituted by one or two groups of —OH, alkoxy of 1 to 4 carbon atoms, thioalkoxy of 1 to 4 carbon atoms;
• Sp is a straight or branched-chain divalent or trivalent alkyl radical of 1 to 18 carbon atoms, divalent or trivalent aryl or heteroaryl radical, divalent or trivalent cycloalkyl of 3 to 18 carbon atoms or heterocycloalkyl radical, divalent or trivalent aryl- or heteroaryl-alkyl (C1-C18) radical, R5′ is a hydrogen or the group RCO, wherein R is hydrogen, branched or unbranched alkyl of 1 to 10 carbon atoms, alkylene of 2 to 10 carbon atoms, aryl of 6 to 11 carbon atoms, a (C6-C11) aryl-alkyl (C1-C5) group, or a heteroaryl or heteroaryl-alkyl (C1-C5) group wherein heteroaryl is defined as 2- or 3-furyl, 2- or 3-thienyl, 2- or 3-(N-methylpyrrolyl), 2-, 3-, or 4-pyridinyl, 2-, 4-, or 5-(N-methylimidazolyl), 2-, 4-, or 5-oxazolyl, 2-, 3-, 5-, or 6-pyrimidinyl, 2-, 3-, 4-, 5-, 6-, 7-, or 8-quinolyl, or 1-, 3-, 4-, 5-, 6-, 7-, or 8-isoquinolyl, all aryl and heteroaryl groups optionally substituted by one or more hydroxy, amino, carboxy, halo, nitro, (C1-C3) alkoxy of 1 to 3 carbon atoms, or thioalkoxy of 1 to 5 carbon atoms;
• and
• Q is selected from the group consisting of —NNHCO—, —NNHCS—, —NNHCONH—, —NNHCSNH—, and —NO—;
• comprising the steps of:
• a. reacting a carboxylic acid of the formula
• with a mercapto compound of the formula
• H2Q-Sp-SH
• in an alcohol solvent in the presence of an alkyl carboxylic acid, alk2CO2H where alk2 is 1 to 4 carbon atoms at about 20° to 70° C. for about 1 to 24 hours, wherein Alk1, Sp1, Ar, Z1, Q, and Sp are as defined above, to produce a bilinker-carboxylic acid of the formula, wherein the mercapto compound and carboxylic acid are present in a ratio of about 1.2:1
• b. isolating the bilinker-carboxylic acid of step (a);
• c. reacting the isolated bilinker-carboxylic acid of step (b) with a methyltrithio antitumor antibiotic CH3—S—S—S—W′ in the presence of a base or an organic base in an inert organic solvent;
• d. reacting the compound of step (c) with an at least a 3 fold molar excess of N-hydroxysuccinimide, 2,3,5,6-tetrafluorophenol, pentafluorophenol, 4-nitrophenol, 2,4-dinitrophenol, or N-hydroxysulfosuccinimide in the presence of 1,3-dicyclohexylcarbodiimide (DCC), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDCI), or N,N′-disuccinimdyl carbonate in an inert solvent containing 0-50% N,N-dimethylformamide (DMF) and purifying to yield antitumor antibiotics of Formula (I)

A process to prepare antitumor antibiotics of Formula (I):

• wherein:
• Z is selected from the group consisting of
• Alk1 is a branched or unbranched alkylene chain of 2 to 6 carbon atoms;
• Sp1 is selected from —S—, —O—, —CONH—, —NHCO—, and —NR′—;
• Z1 is H, or alkyl of 1 to 5 carbon atoms;
• Ar is 1,2-, 1,3-, or 1,4-phenylene optionally substituted with one, two, or three groups independently selected from alkyl of 1 to 6 carbon atoms, alkoxy of 1 to 5 carbon atoms, thioalkoxy of 1 to 4 carbon atoms, halogen, nitro, —COOR′, —CONHR′, —O(CH2)nCOOR′, —S(CH2)nCOOR′, —O(CH2)nCONHR′, and —S(CH2)nCONHR′ or a 1,2-, 1,3-, 1,4-, 1,5-, 1,6-, 1,7-, 1,8-, 2,3-, 2,6-, or 2,7-naphthylidene optionally substituted with one, two, three, or four groups independently selected from alkyl of 1 to 6 carbon atoms, alkoxy of 1 to 5 carbon atoms, thioalkoxy of 1 to 4 carbon atoms, halogen, nitro, —COOR′, —CONHR′, —O(CH2)nCOOR′, —S(CH2)nCOOR′, —O(CH2)nCONHR′, and —S(CH2)nCONHR′;
• n is an integer from 0 to 5;
• R′ is a straight or branched alkyl of 1 to 5 carbon atoms optionally substituted by one or two groups of —OH, alkoxy of 1 to 4 carbon atoms, thioalkoxy of 1 to 4 carbon atoms;
• Sp is a straight or branched-chain divalent or trivalent alkyl radical of 1 to 18 carbon atoms, divalent or trivalent aryl or heteroaryl radical, divalent or trivalent cycloalkyl of 3 to 18 carbon atoms or heterocycloalkyl radical, divalent or trivalent aryl- or heteroaryl-alkyl (C1-C18) radical, divalent or trivalent cycloalkyl- or heterocyclo-alkyl-alkyl (C1-C18) radical or divalent or trivalent unsaturated alkyl radical of 2 to 18 carbon atoms, wherein heteroaryl is furyl, thienyl, N-methylpyrrolyl, pyridinyl, N-methylimidazolyl, oxazolyl, pyrimidinyl, quinolyl, isoquinolyl, N-methylcarbazoyl, aminocoumarinyl, or phenazinyl and wherein if Sp is a trivalent radical, it can be additionally substituted by dialkylamino of 1 to 5 carbon atoms, alkoxy of 1 to 5 carbon atoms, hydroxy, or alkylthio of 1 to 5 carbon atoms groups;
• W′ is
• R1 is
• or CH3;
• R2 is
• or H;
• R3 is H;
• R4 is
• or H;
• R5 is —CH3, —C2H5, or —CH(CH3)2;
• X is an iodine or bromine atom;
• R5′ is a hydrogen or the group RCO, wherein R is hydrogen, branched or unbranched alkyl of 1 to 10 carbon atoms, alkylene of 2 to 10 carbon atoms, aryl of 6 to 11 carbon atoms, a (C6-C11) aryl-alkyl (C1-C5) group, or a heteroaryl or heteroaryl-alkyl (C1-C5) group wherein heteroaryl is defined as 2- or 3-furyl, 2- or 3-thienyl, 2- or 3-(N-methylpyrrolyl), 2-, 3-, or 4-pyridinyl, 2-, 4-, or 5-(N-methylimidazolyl), 2-, 4-, or 5-oxazolyl, 2-, 3-, 5-, or 6-pyrimidinyl, 2-, 3-, 4-, 5-, 6-, 7-, or 8-quinolyl, or 1-, 3-, 4-, 5-, 6-, 7-, or 8-isoquinolyl, all aryl and heteroaryl groups optionally substituted by one or more hydroxy, amino, carboxy, halo, nitro, (C1-C3) alkoxy of 1 to 3 carbon atoms, or thioalkoxy of 1 to 5 carbon atoms;
• and
• Q is selected from the group consisting of —NNHCO—, —NNHCS—, —NNHCONH—, —NNHCSNH—, and —NO—;
• comprising the steps of:
• a. reacting a carboxylic acid of the formula
• with a mercapto compound of the formula
• H2Q-Sp-SH
• in an alcohol solvent in the presence of an alkyl carboxylic acid, alk2CO2H where alk2 is 1 to 4 carbon atoms at about 20° to 70° C. for about 1 to 24 hours, wherein Alk1, Sp1, Ar, Z1, Q, and Sp are as defined above, to produce a bilinker-carboxylic acid of the formula,
• b. isolating the bilinker-carboxylic acid of step (a);
• c. reacting the isolated bilinker-carboxylic acid of step (b) with an at least of N-hydroxysuccinimide, 2,3,5,6-tetrafluorophenol, pentafluorophenol, 4-nitrophenol, 2,4-dinitrophenol, or N-hydroxysulfosuccinimide in the presence of 1,3-dicyclohexylcarbodiimide (DCC), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDCI), or N,N′-disuccinimdyl carbonate in an inert solvent containing 0-50% N,N-dimethylformamide (DMF) to generate a trilinker-activated ester of the formula
• where Z is hereinbefore defined;
• d. reacting the trilinker-activated ester in step c in the presence of a base or an organic base with a methyltrithio antitumor antibiotic CH3—S—S—S—W′ in an inert organic solvent to generate an activated ester of the formula
• e. isolating the activated ester of step (d) and purifying to yield antitumor antibiotics of Formula (I)

A process to prepare trilinker-activated esters of the formula:

• wherein:
• Z is selected from the group consisting of
• Alk1 is a branched or unbranched alkylene chain of 2 to 6 carbon atoms;
• Sp1 is selected from —S—, —O—, —CONH—, —NHCO—, and —NR′—;
• Z1 is H, or alkyl of 1 to 5 carbon atoms;
• Ar is 1,2-, 1,3-, or 1,4-phenylene optionally substituted with one, two, or three groups independently selected from alkyl of 1 to 6 carbon atoms, alkoxy of 1 to 5 carbon atoms, thioalkoxy of 1 to 4 carbon atoms, halogen, nitro, —COOR′, —CONHR′, —O(CH2)nCOOR′, —S(CH2)nCOOR′, —O(CH2)nCONHR′, and —S(CH2)nCONHR′ or a 1,2-, 1,3-, 1,4-, 1,5-, 1,6-, 1,7-, 1,8-, 2,3-, 2,6-, or 2,7-naphthylidene optionally substituted with one, two, three, or four groups independently selected from alkyl of 1 to 6 carbon atoms, alkoxy of 1 to 5 carbon atoms, thioalkoxy of 1 to 4 carbon atoms, halogen, nitro, —COOR′, —CONHR′, —O(CH2)nCOOR′, —S(CH2)nCOOR′, —O(CH2)nCONHR′, and —S(CH2)nCONHR′;
• n is an integer from 0 to 5;
• R′ is a straight or branched alkyl of 1 to 5 carbon atoms optionally substituted by one or two groups of —OH, alkoxy of 1 to 4 carbon atoms, thioalkoxy of 1 to 4 carbon atoms;
• Sp is a straight or branched-chain divalent or trivalent alkyl radical of 1 to 18 carbon atoms, divalent or trivalent aryl or heteroaryl radical, divalent or trivalent cycloalkyl of 3 to 18 carbon atoms or heterocycloalkyl radical, divalent or trivalent aryl- or heteroaryl-alkyl (C1-C18) radical, divalent or trivalent cycloalkyl- or heterocyclo-alkyl-alkyl (C1-C18) radical or divalent or trivalent unsaturated alkyl radical of 2 to 18 carbon atoms, wherein heteroaryl is furyl, thienyl, N-methylpyrrolyl, pyridinyl, N-methylimidazolyl, oxazolyl, pyrimidinyl, quinolyl, isoquinolyl, N-methylcarbazoyl, aminocoumarinyl, or phenazinyl and wherein if Sp is a trivalent radical, it can be additionally substituted by dialkylamino of 1 to 5 carbon atoms, alkoxy of 1 to 5 carbon atoms, hydroxy, or alkylthio of 1 to 5 carbon atoms groups;
• W′ is
• R1 is
• or CH3;
• R2 is
• or H;
• R3 is H;
• R4 is
• or H;
• R5 is —CH3, —C2H5, or —CH(CH3)2;
• X is an iodine or bromine atom;
• R5′ is a hydrogen or the group RCO, wherein R is hydrogen, branched or unbranched alkyl of 1 to 10 carbon atoms, alkylene of 2 to 10 carbon atoms, aryl of 6 to 11 carbon atoms, a (C6-C11) aryl-alkyl (C1-C5) group, or a heteroaryl or heteroaryl-alkyl (C1-C5) group wherein heteroaryl is defined as 2- or 3-furyl, 2- or 3-thienyl, 2- or 3-(N-methylpyrrolyl), 2-, 3-, or 4-pyridinyl, 2-, 4-, or 5-(N-methylimidazolyl), 2-, 4-, or 5-oxazolyl, 2-, 3-, 5-, or 6-pyrimidinyl, 2-, 3-, 4-, 5-, 6-, 7-, or 8-quinolyl, or 1-, 3-, 4-, 5-, 6-, 7-, or 8-isoquinolyl, all aryl and heteroaryl groups optionally substituted by one or more hydroxy, amino, carboxy, halo, nitro, (C1-C3) alkoxy of 1 to 3 carbon atoms, or thioalkoxy of 1 to 5 carbon atoms;
• and
• Q is selected from the group consisting of —NNHCO—, —NNHCS—, —NHNCONH—, —NNCSNH—, and —NO—;
• comprising the steps of:
• a. reacting a carboxylic acid of the formula
• with a mercapto compound of the formula
• H2Q-Sp-SH
• in an alcohol solvent in the presence of an alkyl carboxylic acid, alk2CO2H where alk2 is 1 to 4 carbon atoms at about 20° to 70° C. for about 1 to 24 hours, wherein Alk1, Sp1, Ar, Z1, Q, and Sp are as defined above, to produce a bilinker-carboxylic acid of the formula
• b. isolating the bilinker-carboxylic acid of step (a);
• c. reacting the bilinker-carboxylic acid from step (b) in the presence of a base or an organic base with a methyltrithio antitumor antibiotic CH3—S—S—S—W′ in an inert organic solvent to generate a bilinker-methyltrithio antitumor antibiotic of the formula
• d. reacting the isolated bilinker-methyltrithio antitumor antibiotic of step (c) with N-hydroxysuccinimide, 2,3,5,6-tetrafluorophenol, pentafluorophenol, 4-nitrophenol, 2,4-dinitrophenol, or N-hydroxysulfosuccinimide in the presence of 1,3-dicyclohexylcarbodiimide (DCC), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDCI), or N,N′-disuccinimdyl carbonate in an inert solvent containing 0-50% N,N-dimethylformamide (DMF) to generate a trilinker-activated ester of the formula