Classifications

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  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D311/00—Heterocyclic compounds containing six-membered rings having one oxygen atom as the only hetero atom, condensed with other rings
  • C07D311/02—Heterocyclic compounds containing six-membered rings having one oxygen atom as the only hetero atom, condensed with other rings ortho- or peri-condensed with carbocyclic rings or ring systems
  • C07D311/78—Ring systems having three or more relevant rings
  • C07D311/80—Dibenzopyrans; Hydrogenated dibenzopyrans
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D311/00—Heterocyclic compounds containing six-membered rings having one oxygen atom as the only hetero atom, condensed with other rings
  • C07D311/02—Heterocyclic compounds containing six-membered rings having one oxygen atom as the only hetero atom, condensed with other rings ortho- or peri-condensed with carbocyclic rings or ring systems
  • C07D311/78—Ring systems having three or more relevant rings
  • C07D311/80—Dibenzopyrans; Hydrogenated dibenzopyrans
  • C07D311/82—Xanthenes
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K31/00—Medicinal preparations containing organic active ingredients
  • A61K31/33—Heterocyclic compounds
  • A61K31/335—Heterocyclic compounds having oxygen as the only ring hetero atom, e.g. fungichromin
  • A61K31/35—Heterocyclic compounds having oxygen as the only ring hetero atom, e.g. fungichromin having six-membered rings with one oxygen as the only ring hetero atom
  • A61K31/352—Heterocyclic compounds having oxygen as the only ring hetero atom, e.g. fungichromin having six-membered rings with one oxygen as the only ring hetero atom condensed with carbocyclic rings, e.g. methantheline 
• • A—HUMAN NECESSITIES
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  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
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  • A61P1/00—Drugs for disorders of the alimentary tract or the digestive system
  • A61P1/02—Stomatological preparations, e.g. drugs for caries, aphtae, periodontitis
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  • A61P13/00—Drugs for disorders of the urinary system
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  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P15/00—Drugs for genital or sexual disorders; Contraceptives
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  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P17/00—Drugs for dermatological disorders
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  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P31/00—Antiinfectives, i.e. antibiotics, antiseptics, chemotherapeutics
• • A—HUMAN NECESSITIES
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  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P31/00—Antiinfectives, i.e. antibiotics, antiseptics, chemotherapeutics
  • A61P31/04—Antibacterial agents
• • A—HUMAN NECESSITIES
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  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P31/00—Antiinfectives, i.e. antibiotics, antiseptics, chemotherapeutics
  • A61P31/10—Antimycotics
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P31/00—Antiinfectives, i.e. antibiotics, antiseptics, chemotherapeutics
  • A61P31/12—Antivirals
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P33/00—Antiparasitic agents
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P5/00—Drugs for disorders of the endocrine system
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P9/00—Drugs for disorders of the cardiovascular system
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D493/00—Heterocyclic compounds containing oxygen atoms as the only ring hetero atoms in the condensed system
  • C07D493/02—Heterocyclic compounds containing oxygen atoms as the only ring hetero atoms in the condensed system in which the condensed system contains two hetero rings
  • C07D493/10—Spiro-condensed systems

Definitions

• the present invention relates to methods of preparation or synthesis and isolation of highly purified Rose Bengal, Rose Bengal Lactone and related xanthenes, and also relates to highly purified Rose Bengal, Rose Bengal Lactone and related xanthenes.
• One aspect of the present invention relates to synthetic procedures to prepare iodinated fluorescein derivatives that contain at most 2% by weight, and preferably less than 0.15% by weight, of individual organic impurities. Controlling impurities to the 0.15% or 1500 ppm level or lower is relevant for pharmaceutical utility since this represents the qualification threshold for compliance with International Conference of Harmonisation (ICH) guidelines.
• ICH International Conference of Harmonisation
• another aspect of this invention relates to the pharmaceutical utility and identification of the novel compounds that are disclosed herein, for which the above synthesis was specifically engineered to control their formation.
• the compounds have been used as textile dyes, biological stains, building blocks for non-volatile memory devices, thermoimaging substrates and food and cosmetics coloring.
• erythrosine FD&C No.3
• partially iodinated erythrosine D&C Nos. 1 1 and 12
• a particular tetraiodo-xanthene, Rose Bengal has been used for visualization of ocular disease and, in radiolabeled form, as a medical diagnostic for liver function, appearing in the United States Pharmacopeia in 1965.
• the CFR also allows residual impurities originating in the cyclization step, such as partially iodinated phthalic acids and resorcinols (for example, see: Kamikura, Shokuhin Eiseigaku Zasshi 1985: 26, 243 and Wada et al., Food. Add. Contain. 2004: 21, 1137).
• the present invention identifies, characterizes and establishes methods to efficiently control the synthesis of these by-products to meet the standards required for utility in pharmaceutical applications.
• the process of the present invention avoids undesirable formation of these by-products, avoids the necessity of using multiple solvents and sets strict control of reagents, all of which improve handling, yield, purity and applicability of the process for pharmaceutical use.
• the present invention relates to materials and methods to control the impurity level in iodinated xanthenes of Formula 3 and Formula 4 manufactured for pharmaceutical use, processes for the manufacture of these iodinated xanthene compounds, and the disclosure of related but previously unanticipated transhalogenated impurities.
• the present invention also relates to materials and methods for preparing the same, and in paiticular processes for preparing eiythrosine (FD&C 3), Rose Bengal, and other related iodinated xanthenes in purity suitable for pharmaceutical use. In one embodiment, this process employs only a single organic solvent, low temperature (less than 100°C) and requires use of veiy limited and select additives and modifiers to avoid formation of impurities.
• Avoiding formation of transhalogented impurities can, for example, be accomplished by limiting chloride ion to less than 1500 ppm in the reaction mixtures, and especially in the reaction mixtures during the iodination step. No extraction, chromatographic or solvent concentration steps are required, and the intermediate, as well as final compounds, can be isolated via filtration or similar means.
• the present invention is also directed to specific analogs and new compounds, particularly those that can be made or are avoided via the method disclosed above. These compounds have been isolated and identified, and are adapted for
• each position 3 ⁇ 4 is independently C1-C4 alkyl, halogen or H; and R 2 , R3, R4 and R 5 are independently I, F, CI, C1-C4 alkyl or H, where at least one of R2, R3, R4 or R 5 is I, and each position Rg is independently H or C C 4 alkyl; comprising reacting a compound of Formula 3 in which each position Rj is independently C1-C4 alkyl, halogen or H; R 2 , R3, R4 and R 5 are independently F, CI, Q-C4 alkyl or H and at least one of R2, R3, Rt or R 5 is H with iodine (1 ⁇ 4) in the presence of aqueous base to replace at least one of R2, R3, R4 or R 5 with I.
• Another embodiment is directed to a method of making a compound of Formula 3 in which each position Ri is independently C1-C4 alkyl, halogen or H; R 2 , R3, R4 and R 5 are independently halogen, C1-C4 alkyl or H; and each position Rs is independently H or C C 4 alkyl; comprising reacting a compound of Formula 1,
• each of position Ri is independently halogen, C1-C4 alkyl or H, with a compound of Formula 2
• a further embodiment is directed to a method of making derivatives of Formula 3 in which each position R] is independently halogen or H; R 2 , R3, R4 and R 5 are independently I, Br, CI, F or H, where at least one of R2, R3, R4 and R 5 is CI; and Re is H; comprising reacting the compound of Formula 3 with a chlorine radical, chloride ion or chloride ion generated in situ (i.e., such as a sodium hypochlorite solution, or hypochlorous acid) such that any Ri, R 2 , R3, Rf or R 5 that is I or Br can be
• Another embodiment relates to compounds of Formula 3 where at least one, but no more than two, positions selected from R 2 , R3, R4 or R 5 is CI and each position Ri is independently Br, F, CI or I; provided that any R 2 , R3, R4 or R 5 that isn't CI or H is I and each position Re is independently H or C r C 4 alkyl.
• the compounds of Formula 3 described herein have properties useful in the pharmaceutical, medicinal, cosmetic and colorant industries. Accordingly, the present invention also relates to the claimed compounds in medicaments for topical or intracorporeal application, including as an active substance in medicaments for chemotherapeutic or photodynamic treatment of human or animal disease.
• the compounds of Formula 3, methods for their production, medicaments and uses so defined herein shall include all forms of such compounds that have been saponified or otherwise reacted to convert such compounds from their lactone form (Formula 3) to their quinoid form, (Formula 4), where R n and Ri 2 are independently H or Na, K, Li or another counter-ion capable of forming a salt.
• the present invention relates to a method for the preparation of a compound of Formula 4 in which 3 ⁇ 4 is independently CI or Br, R 2 , R3, R4 and R 5 are I, and Re is H.
• a compound of Formula 3a in which Ri is independently CI or Br, and R 2 , R 3 , R4, R 5 and Re are H with iodide in a solution substantially free of chloride ions to form a compound of Formula 4 in which Rj is independently CI or Br, R 2 , R3, R4 and R 5 are I, and R 6 is H, affords substantive improvement over prior methods for prepai'ation of a compound of Formula 4, the improvement comprising a substantial nonexistence of transhalogenated derivatives of the compound of Formula 4 where Rj is independently CI or Br, at least one of R 2 , R3, R and R 5 is CI and any R 2 , R3, R4 and R 5 that is not CI is I, and where Re is H.
• the present invention relates to a method for the preparation of a compound of Formula 3,
• Step 1 combining a compound of Formula 1,
• Rj is independently CI or Br and R 2 , R3, R4, R5 and 5 are H;
• Step 2 combining said intermediate of Formula 3a with a chloride-ion-free aqueous solution; treating said solution of intermediate of Formula 3a with iodine (I 2 ), and mixing at temperatures ranging from 20°C to 100°C for a time such that conversion to Formula 3 is substantially complete, for example as determined by HPLC or similar means;
• I 2 iodine
• the acidic solution of Step 1 in which the compounds of Formula 1 and Formula 2 are combined is free or substantially free of chloride ions and free or substantially free of reagents which can produce chloride ions in the reaction mixture.
• the intermediate of Formula 3a in Step 2 is free or substantially free of chloride ions and free or substantially free of reagents or other impurities which can produce chloride ions in the reaction mixture.
• Step 1 of the method for the preparation of a compound of Formula 3 may comprise combining a compound of Formula 1 with less than two equivalents of a compound of Formula 2. This embodiment is less preferred since the yield of
• Formula 3 will be lower yield than that provided using the stoichiometry of preferred embodiment.
• the present invention relates to a method for the preparation of a compound of Formula 3,
• R] is independently I, Br, CI, F, C1-C4 alkyl or H
• R 2 , R 3 , R4 and R 5 are independently I, F, CI, Q-C4 alkyl or H, where at least any one but no more than three of R 2 , R 3 , R4 or R 5 is I , comprising:
• Step 1 combining a compound of Formula 1,
• Ri is independently I, Br, CI, F, C1-C4 alkyl or H with a compound of
• R 7 , Rg, and R 10 are independently F, CI, H, or C1-C4 alkyl and at least two of R 7 , R 8 or Rjo are H and R 9 is H;
• Step 2 combining said intermediate of Formula 3a which is free or substantially free of chloride ions and free or substantially free of impurities or impurities which can produce chloride ions with a chloride-ion-free or substantially chloride-ion-free aqueous solution;
• the aqueous solution of Step 2 in which the intermediate of Fonnula 3a and iodine are combined has a basic pH.
• Step 2 it is further preferred that the mixing of Step 2 be continued for sufficient time such that conversion to Formula 3 is at least 90%, and more preferably at least 95%, and most preferably at least 98% complete, such time generally being in the range of about 1 to 24 hours, and more preferably from about 2 to 18 hours.
• the present invention relates to a compound of Formula 4 in which 3 ⁇ 4 is independently F, CI, Br, I, H or C 1 -C4 alliyl; R 2 , R3, R4, and R 5 are independently CI, H or I with at least one substituent selected from R 2 , R 3 , R4, R 5 is I and at least one other substituent is CI or H; and Re is independently H or C 1 -C4 alkyl; and all (a) tautomeric forms, (b) atropisomers, (c) closed lactone forms as depicted in Formula 3, (d) enantiomers of the lactone forms depicted in Formula 3, and (e) pharmaceutically acceptable salts thereof.
• FIGURE la is an illustration of 4,5,6,7-tetrachloro-3 ',6'-dihydroxy- 2',4',5',7'-tetraiodo-3H-spiro[isobenzofuran-l,9'-xanthen]-3-one, also named 4,5,6,7- tetrachloi -2',4',5',7 , -tetraiodofluorescein or Rose Bengal Lactone;
• FIGURE lb is an illustration of 4,5,6,7-tetrabromo-3',6'-dihydroxy- 2',4',5',7'-teti-aiodo-3H-spii [isobenzofuran-l,9 , -xanthen]-3-one, also named 4,5,6,7- tetrabromo-2 ' ,4', 5 ', 7'-tetraiodofluorescein;
• FIGURE lc is an illustration of 2',4,5,6,7-pentachloi -3 ',6'-dihydroxy- 4',5',7'-ta-iiodo-3H-spiro[isobenzofuran-l,9'-xanthen]-3-one, also named 2',4,5,6,7- pentachloro-4', 5 ', 7'-triiodofluorescein;
• FIGURE Id is an illustration of 4,4',5,6,7-pentachloro-3 , ,6 , -dihydroxy- 2',5 ⁇ 7'- iiodo-3H-spiiO[isobenzofuran-l,9'-xanthen]-3-one, also named 4,4',5,6,7- pentachloro-2', 5 ', 7'-triiodofluorescein;
• FIGURE le is an illustration of 2 ⁇ 4,5,6,7,7 iexachloro-3 ⁇ 6'-dihydroxy- 4',5'-diiodo-3H-spiiO[isobenzofuran-l,9'-xanthen]-3-one, also named 2',4,5,6,7,7'- hexachloro-4 ' , 5 '-diiodofluorescein;
• FIGURE If is an illustration of 4,4 ⁇ 5,5 ⁇ 6,7-hexachloro-3%6'-dihydroxy- 2',7'-diiodo-3H-spiro[isobenzofuran-l,9'-xanthen]-3-one, also named 4,4',5,5',6,7- hexachloro-2 ' ,7 ' -diiodofluorescein;
• FIGURE lg is an illustration of 2',4,5 ) 5 , ,6,7-hexachloi -3',6 , -dihydroxy- 4',7'-diiodo-3H-spiro[isobenzofuran-l,9'-xanthen]-3-one, also named 2',4,5,5',6,7 - hexachloro-4' ,7 ' -diiodofluorescein;
• FIGURE lh is an illustration of 4,5,6,7-tetrachloi -3',6'-dihydiOxy-2',4',5'- triiodo-3H-spiro[isobenzofuran-l,9'-xanthen]-3-one, also named 4,5,6,7-tetrachloro- 2 ' ,4 ' ,5 ' -triiodofluorescein;
• FIGURE li is an illustration of 4,5,6,7-tetrachloi -3 , ,6'-dihydroxy-2 , ,4',7'- tiiiodo-3H-spiro[isobenzofuran-l,9'-xanthen]-3-one, also named 4,5,6,7-tetrachloro- 2 ' ,4 ' ,7 ' -triiodofluorescein;
• FIGURE lj is an illustration of 4,5,6,7-tetrabromo-2'-chloi -3',6'- dihydroxy-4 , ,5',7'-triiodo-3H-spiro[isobenzofuran-l,9'-xanthen]-3-one, also named 2'- chloi -4,5,6,7-teti-abiOmo-4',5',7'-triiodofluorescein;
• FIGURE lk is an illustration of 4,5,6,7-tetrabromo-4'-chloi -3',6'- dihydroxy-2',5',7'-triiodo-3H-spiiO[isobenzofuran-l,9'-xanthen]-3-one, also named 4'- chloro-4,5,6,7-tetrabromo-2',5',7'-triiodofluorescein;
• FIGURE 11 is an illustration of ⁇ S ⁇ -tetrabromo ⁇ 'J'-dichloro-S' ⁇ '- dihydroxy-4',5'-diiodo-3H-spiro[isobenzofuran-l,9'-xanthen]-3-one, also named 2',7'- dichloro-4,5 ,6,7-tetrabromo-4 ' , 5 ' -diiodofluorescein;
• FIGURE lm is an illustration of 4,5,6 J 7-tetrabromo-4',5 , -dichlol ⁇ -3 , ,6 , - dihydiOxy-2',7'-diiodo-3H-spiro[isobenzofuran-l,9'-xanthen]-3-one, also named 4'5'- dic loro-4, 5,6, 7-teti-abromo-2 ' , 7 ' -diiodofluorescein;
• FIGURE In is an illustration of 4,5,6,7-tetrabromo-2 , ,5'-dichloro-3',6*- dihydroxy-4',7 , -diiodo-3H-spiro[isobenzofuran-l,9'-xanthen]-3-one, also named 2',5'- dichloi -4,5,6,7-tetrabromo-4',7'-diiodofluorescein;
• FIGURE lo is an illustration of 4,5,6,7-tetrabromo-3 , ,6'-dih.ydroxy-2',4 , ,5 , - triiodo-3H-spiro[isobenzofuran-l,9'-xanthen]-3-oiie, also named 4,5,6,7-tetrabromo- 2 ' ,4 ' ,5 ' -triiodofluorescein;
• FIGURE lp is an illustration of 4,5,6,7-tetrabi mo-3',6 , -dihydroxy-2',4',7'- ti-iiodo-3H-spiro[isobenzofuran-l,9 l -xanthen]-3-one, also named 4,5,6,7-tetrabromo- 2 ' ,4 ' ,7 ' -triiodofluorescein;
• FIGURE lq is an illustration of an atropisomer (aR depiction) of an asymmetrically substituted xanthene
• FIGURE lr is an illustration of an atropisomer (aS depiction) of an asymmetrically substituted xanthene.
• FIGURE Is is an illustration of 4,5,6, 7-tetrachloi -3',6'-dihydroxy-2',4',5'- triiodo-7'-isopropyl-3H-spii [isobenzofuran-l,9'-xanthen]-3-one, also named 7'- isopropyl-4,5,6,7-tetrachloro-2',4',5'-triiodofluorescein.
• FIGURE It is an illustration of 2,3 ,4,5-tetrachloro-6-(6-hydroxy-2,4,5 ,7- tetraiodo-3-oxo-3H-xanthen-9-yl)benzoic acid disodium salt, also named 4,5,6,7- tetrachloro-2',4',5',7'-tetraiodofluorescein disodium or Rose Bengal.
• C1-C4 alley 1 refers to straight chain and branched saturated or unsaturated hydrocarbon groups, generally having a specified number of carbon atoms.
• Examples of C1-C4 alkyl groups include, without limitation, methyl, ethyl, n-propyl, i-propyl, n- butyl, s-butyl, i-butyl and t-butyl.
• Halo and halogen may be used interchangeably, and refer to fluoro, chloro, bromo, and iodo functionalities.
• substantially chloride free and similar language refers to reaction conditions, reagents or intermediates that are free of chloride ion, impurities containing chloride ion, or impurities which can produce chloride ion, to a level of purity sufficient to avoid undesirable fonnation of transhalogenated impurities of Formula 3, Formula 3a or Formula 4 at levels of 0.15% (e.g., 1500 ppm) or greater, or wherein such reaction conditions, reagents or intermediates contain chloride ion, impurities containing chloride ion, or impurities which can produce chloride ion at a level of 1500 ppm or lower.
• Substantially free of transhalogenated impurities refers to the presence of compounds of Formula 3, and Formula 4 wherein, 3 ⁇ 4 is independently CI or Br, at least one of R 2 , R3, R4 and R 5 is CI and the remainder are I, and 3 ⁇ 4 is H, at a level of 0.15% (e.g., 1500 ppm) or lower.
• Scheme I shows one embodiment of the present invention which involves a method of making iodinated xanthenes (such as, for example, Formula 3).
• This method includes reacting a phthalic anhydride (Formula 1) with an excess of a resorcinol (Formula 2) to give a compound of Formula 3a where R 2 , R 3 , R4, 5 and Re are not I and at least one of R2-R5 is H.
• This compound, following minimal isolation, is then subjected to iodination to give a compound of Formula 3 where at least one of R 2 , R3, R4 or R 5 is substituted with I.
• the cyclization reaction, Step 1 above, may be carried out, for example, using neat to 10% methanesulfonic acid (MSA) in water, at temperatures from 0°C to reflux.
• MSA methanesulfonic acid
• neat methanesulfonic acid is used at 85°C - 95°C, for 1-16 hours.
• between 2-6 volumes of MSA, more preferably between 4 and 5 volumes of MSA, and even more preferably approximately 4.8 volumes of MSA are used.
• p-toluenesulfonic acid benzenesulfonic acid, sulfuric acid or uifluoromethanesulfonic acid, ethanesulfonic acid, acetic acid, propionic acid, trifluoroacetic acid, camphorsulfonic acid, or an acidic solution comprised of one or more of an alkyl sulfonic acid or aiyl sulfonic acid with a melting point less than about 250°C, an alky carboxylic acid or aiyl carboxylic acid with a melting point less than about 250°C, a non-chloride Brcmsted acid, a non-chloride or chloride-immobilized Lewis Acid, or their respective polymer bound or salt preparations, or aqueous solutions thereof, alone or in combination with
• the cyclization to Formula 3a can be effected using substantially stoichiometric amounts of reactants (e.g., with a ratio of 2:1 resorcinols of Formula 1 to phthalic anhydrides of Formula 2).
• reactants e.g., with a ratio of 2:1 resorcinols of Formula 1 to phthalic anhydrides of Formula 2.
• the resultant solid can be re-suspended with or without agitation, preferably with heating to 50°C to 70°C, to improve purity, using water and a combination of acetone and water or DMF and water, and more preferably using acetone and water about 60 ° C. Isolation and re-suspension may be repeated until the material of Formula 3a is of a desired purity.
• the iodination reaction, Step 2 above, may be carried out using molar excess of iodine (I 2 ), preferably under basic conditions.
• the reaction may be carried out using 0.1-5 M sodium hydroxide, potassium hydroxide, sodium bicarbonate or potassium bicarbonate, at temperatures from 0°C to reflux.
• this reaction may be carried out using 0.4-1.0 M NaOH at 70°C- 95 °C.
• KI, Nal or a mixture of KI and Nal can be used to solubilize iodine in the reaction mixture, for example using Nal at 1-2.5 equivalents. Reaction times range from 1-24 h and are dependent on the number of iodine atoms added to the xanthene ring system.
• Iodine for this reaction may also be generated in situ using an oxidizing agent such as oxone or hydrogen peroxide and iodide salts selected from potassium iodide, lithium iodide, sodium iodide or some mixture thereof.
• an oxidizing agent such as oxone or hydrogen peroxide and iodide salts selected from potassium iodide, lithium iodide, sodium iodide or some mixture thereof.
• aqueous chloride, chlorine, HC1 or other components capable of producing halogen ions unless any oxidizing agent, including atmospheric oxygen and iodine, has been removed or quenched prior to addition of such components.
• sodium hypochlorite is a particularly undesireable component in this reaction mixture since it is a source of labile chloride ions and a potent oxidizer, also chloride ions, chloride radicals, other hypochlorite derivatives, hypochlorous acid and mixtures thereof can lead to the undesireable side reaction.
• the mixture can be cooled to approximately -20°C to 10°C, preferably below 10°C, and iodine can be quenched by addition of an iodine scavenger, such as sodium thiosulfate, potassium thiosulfate, ammonium thiosulfate, potassium sulfite, sodium sulfite or a mixture thereof.
• sodium sulfite is used to quench.
• Facile isolation of Formula 3 is possible if the pH of the reaction is then adjusted, preferably maintaining a temperature below 10 ° C and using neat aqueous sulfuric acid to 1% aqueous solution, preferably 5% sulfuric acid aqueous solution, until the pH is adjusted to between 1.5 and 5, causing Formula 3 to precipitate from solution.
• the pH is adjusted to between pH 1.5 and pH 3.
• the resultant solid can be re-suspended and further isolated at ambient temperature to remove impurities, for example using water and a combination of acetone and water or DMF and water, preferably acetone and water.
• pH may be adjusted to 5 or higher to solubilize Formula 3 as Formula 4 prior to conversion back to Formula 3 for isolation under acidic conditions.
• Scheme ⁇ shows another embodiment of the present invention, wherein compounds of Formula 3 may also exist in a quinoid form (Formula 4) at substantially neutral or at basic pH, and these quinoids may exist as salts where one or both hydroxyl groups are replaced with a basic counter-ion, R n and / or R 12 , including Na, K or Li ion.
• Scheme ⁇ shows a method of replacing I with CI to generate compounds of Formula 3b, where at least one position selected from R 2 ,R3, 4 and R 5 is CI, starting from compounds of Formula 3 where at least one position selected from R 2 ,R3,R4 and R 5 is I.
• Scheme IV shows another embodiment of the present invention, wherein compounds of Formula 4 may also be isolated as products of this process, and these quinoids may exist as salts where one or both hydroxyl groups at Rn and / or Ri 2 are replaced with a counter-ion capable of forming a pharmaceutically acceptable salt, including H, Na, K or Li ion.
• Preferred embodiments of the present invention relate to compounds of Formula 3 and Formula 4 where 3 ⁇ 4 is independently CI or Br, and R2-R5 are independently selected from CI, I or H where at least 3 hydrogen atom are present at R 2 -R 5 or at least one chlorine atom is present at R2-R5, and including ati pisomers when applicable.
• One set of specific embodiments of the present invention include the following compounds and their pharmaceutically acceptable salts and are named as the lactone form (Formula 3) and the quinoid form (Formula 4), and are illustrated in Figure 1:
• Compounds of Formula 3 or Formula 4 of the present invention may contain chiral centers and therefore may exist in different enantiomeric and diastereomeric forms.
• the present invention relates to all optical isomers and all stereoisomers of compounds of Formula 3 or Formula 4, both as racemic mixtures and as individual enantiomers, and diasteroisomers of such compounds, and mixtures thereof, and to all pharmaceutical compositions and methods of treatment defined herein that contain or employ them, respectively.
• Individual isomers can be obtained by laiown methods, such as optical resolution, fractional crystallization, optically selective reaction conditions or chromatographic separation in the preparation of the final product or its intermediate.
• the process described herein encompasses both the minimization of the relative amount of racemic atropisomeric pairs when they may occur as reaction impurities as well as the preparation of these atropisomers as racemic mixtures.
• the compounds of Formula 3 are acidic compounds, they are capable of forming a wide variety of different salts with various inorganic and organic bases.
• the base addition salts of the acidic compounds of the present invention are readily prepared by treating the lactone of Formula 3 with at least one or two equivalents of the chosen mineral or organic base in an aqueous or suitable organic solvent, such as ethanol or methanol. Upon evaporation of the solvent, filtration or using directly an aqueous solution of the resulting salt, the desired salt is readily obtained in the quinoid form as described by Formula 4.
• compositions include, for example, those fonned with sodium, calcium, potassium, magnesium, meglumine, ammonium, aluminum, zinc, piperazine, tromethamin, lithium, choline, diethylamine, 4-phenylcyclohexylamine and benzathine.
• the present invention also includes isotopically labeled compounds, which are identical to those of Formula 3 and Formula 4, except that one or more atoms are replaced by an atom having an atomic mass or mass number different from the atomic mass or mass number usually found in nature.
• isotopes of hydrogen, carbon, oxygen, fluorine, chlorine and iodine such as 2 H, 3 H, 14 C, 13 C, 10 C, n C, 13 0, 14 0, ,5 0, 18 0, ,7 0, 17 F, 18 F, 32 C1, 33 C1, 34 C1, 36 C1, 74 Br, 75 Br, 76 Br, 77 Br, 1 ,7 I, , 18 I, ,
• Isotopically labeled compounds of the present invention are useful as diagnostic agents in drug/or substrate tissue distribution assays.
• Isotopically labeled compounds of Formula 3 and Formula 4 and prodrugs thereof can generally be prepared by canying out the procedures disclosed in the schemes and/or examples below, but substituting a readily available isotopically labeled reagent for a non-isotopically labeled reagent, i.e. 13I I for non-isotopically labeled iodine.
• One embodiment of the present invention is where the compound of Formula 4 comprises about 0.001% and less than about 20% by weight in a medicament.
• One embodiment of the present invention is directed to medicaments and certain medical uses of such medicaments, and methods for treatment using such medicaments, for treatment of disease of human or animal tissue, wherein a primary active component of such medicaments is a halogenated xanthene of Formula 3 or Formula 4.
• Such medicaments may function, for example, chemotherapeutically, as chemoablative agents, or as photodynamic agents, and are useful for the treatment of a variety of conditions affecting the skin and related organs, the mouth and digestive tract and related organs, the urinary and reproductive tracts and related organs, the respiratory tract and related organs, the circulatoiy system and related organs, the head and neck, the endocrine and lymphoreticular systems and related organs, various other tissues, such as connective tissues and various tissue surfaces exposed during surgery, as well as various tissues exhibiting microbial, viral, fungal or parasitic infection.
• These medicaments are available in various formulations that may include liquid, semisolid, solid or aerosol delivery vehicles, and are suitable for intracorporeal administration via various conventional modes and routes, including intravenous injection (i.v.), intraperitoneal injection (i.p.), intramuscular injection (i.m.), intracranial injection (i.e.), intratumoral injection (i.t.), intralesional injection (i.L), intraepithelial injection (i.e.), transcutaneous delivery (t.c), and per oesophageal (p.o.) administration. Additionally, such medicaments are suitable for topical administration via various conventional modes and routes, including topical application directly to or proximal to certain tissues.
• the active ingredients in such medicaments produce a desirable therapeutic response, such as destruction of microbial infection, reduction or elimination of tissue irritation or inflammation, reduction or elimination of
• hyperproliferative tissue reduction or elimmation of cancerous or precancerous tissue, reduction or elimination of surface or subsurface lipocytes or lipid deposits, and many other similar indications.
• such medicaments are produced in various formulations including liquid, semisolid, solid or aerosol delivery vehicles, as well as in tablet, capsule, suppository, and other similar forms.
• at least one targeting moiety is coupled to the halogenated xanthene, of Formula 3 or Formula 4, at any of positions 3 ⁇ 4 to 3 ⁇ 4 or via attachment at a hydroxyl or carbonyl group.
• targeting moieties may be selected from the group including but not limited to deoxyribonucleic acid (DNA), ribonucleic acid (KNA), amino acids, proteins, antibodies, ligands, haptens, carbohydrate receptors, carbohydrate complexing agents, lipid receptors, lipid complexing agents, protein receptors, protein complexing agents, chelators, encapsulating vehicles, short-chain aliphatic hydrocarbons, long-chain aliphatic hydrocarbons, aromatic hydrocarbons, aldehydes, ketones, alcohols, esters, amides, amines, nitriles, azides, hydrophilic moieties and hydrophobic moieties.
• DNA deoxyribonucleic acid
• KNA ribonucleic acid
• amino acids proteins
• proteins antibodies
• ligands haptens
• carbohydrate receptors carbohydrate complexing agents
• lipid receptors lipid complexing agents
• protein receptors protein receptors
• protein complexing agents protein complexing agents
• the compounds of Formula 4 can be used in the manufacture of a medicament.
• UV-VIS spectroscopic data were obtained on a Hitachi U-2810 Double Beam Spectrophotometer or on a Spectronic Genesys 2 Spectrophotometer scanning from 200-600 nm, slit width 1.5 mn, path length 10.0 mm.
• Step 1 Cyclization.
• a 500 n L round bottom flask was equipped with a heating mantle, J-Kem thermocouple, large magnetic stir bar, nitrogen inlet line, and a magnetic stir plate.
• This apparatus was charged with tetrachlorophthalic anhydride (1.00 eq, 50.00 g, 174.9 mmol), resorcinol (2.10 eq, 40.44 g, 367.3 mmol), and neat methanesulfonic acid (250 mL).
• the resulting reaction mixture was a suspension at room temperature.
• the reaction mixture was purged with nitrogen and heated to 90°C to give a dark red-orange solution.
• reaction was held at 90°C for 5 hours, and then an additional 5.78 g of resorcinol (0.3 eq, 52.47 mmol) was added. The reaction continued to stir at 90°C for 2.5 hours. The reaction is deemed to be complete when the amount of residual tetrachlorophthalic anhydride is ⁇ 1.0% by HPLC.
• a I L round- bottomed flask (3 neck) equipped with a mechanical stirrer, ice bath and J-Kem thermocouple was charged with ambient USP water (500 mL). The 90°C reaction mixture was added slowly via transfer line to the USP water at ⁇ 10°C using a positive pressure of nitrogen.
• the transfer rate was controlled such that the temperature of the water quench mixture did not exceed 60°C.
• An additional 100 mL of USP water was used to rinse the reactor then transferred to the reactor containing the water.
• the resultant green-brown suspension was allowed to gradually cool to room temperature (RT) and stirred at RT for an additional 30 min.
• the solids were isolated via vacuum filtration.
• the reactor was rinsed with USP water (2 x 250 mL aliquots) and these rinses were used to rinse the wetcake. The wetcake was pulled dry for 60 min, and then dried in vacuo at 70°C overnight to give 88.60 g of greenish-brown solids.
• the mixture was stirred at room temperature for an additional 30 min, and then the yellowish-brown suspension was collected via vacuum filtration.
• the reactor was rinsed with 50% aqueous acetone (v/v, 4 x 100 mL), and these rinses were used to rinse the wetcake.
• the wetcake was allowed to pull diy over 48 h and then further dried in vacuo at 70°C overnight to give 74.43 g (90.5 % yield at 96.8% AUC purity) of tetrachlorofluorescein as a yellow brown solid.
• Step 2 Iodination.
• a 500 mL round bottom flask (3-neck) was equipped with a reflux condenser, Y-adapter, J-Kem thermocouple, mechanical stirrer, heating mantle, and a nitrogen inlet line.
• the reactor was purged with nitrogen and covered with aluminum foil. This was charged with 10.00 grams of tetrachlorofluorescein (21.3 mmol), 30 mL of 5 M NaOH solution and 300 mL of USP water to give a dark red solution. Then, 7.03 grams of sodium iodide (46.9 mmol) and 32.4 g of iodine (127.7 mmol) were charged to the reactor.
• the reaction mixture was allowed to stir at ambient temperature for 30 min, then it was heated to 90°C. HPLC analysis of an aliquot of the reaction mixture indicated complete consumption of starting material, no partially iodinated intermediates, and complete conversion to the desired product. After the reaction had been heated at 90°C for 1.5 hours, the heat was turned off, and the reaction mixture was allowed to gradually cool to room temperature over 1.5 hours. The dark purplish-pink reaction mixture was cooled to ⁇ 10°C with an ice bath. The pH of the reaction mixture was 7.13. Sodium sulfite (6.70 g) was added to the reaction mixture in small portions. 75 mL of acetone was charged to the reactor at ⁇ 10°C, and the mixture was allowed to stir for 10 min at ⁇ 10°C.
• Step 1 Treatment of tetrabromophthalic anhydride (28.63g, 61.74 mmol) and resorcinol (17 g, 154.4 mmol) in 143 mL methanesulfonic acid according to the procedure described in Example 1 Step 1 provided 33.64 g of tetrabromofluorescein was isolated as a light beige solid (84.1% yield, AUC purity of 97.4%).
• Step 2 Treatment of tetrabromofluorescein (22 g, 33.96 mmol), iodine (51.71 g, 203.7 mmol) and sodium iodide (11.22 g, 74.85 mmol) according to the procedure described in Example 1 Step 2 provided 36.02 g (31.2 mmol, 92.1 % yield, AUC purity of 96.3%) of 4,5,6,7-tetrabromo-3',6'-dihydroxy-2',4',5',7'-tetraiodo-3H- spii [isobenzofuran-l,9'-xanthen]-3-one that was isolated as a light pink solid.
• Step 1 Treatment of tefrachlorophthalic anhydride (5 g, 17.48 mmol), 4- chlororesorcinol (2.78 g, 19.23 mmol) and resorcinol (2.12 g, 19.23 mmol) according to the procedure described in Example 1 Step 1 provided 7.24 g of 18.6% pure 2',4,5,6,7-pentachloro-3 , ,6 , -dihydi xy-3H-spiro[isobenzofuran-l,9'-xanthen]-3-one that was collected and taken to the next step as a mixture.
• Step 2 2 4,5,6,7-pentachloro-3 ⁇ 6'-dihydroxy-3H-spiro[isobenzofuran-l,9'- xanthen]-3-one (7.24 g, 15.4 mmol) was iodinated according to the procedure described in Example 1, Step 2.
• Step 1 Tetrachlorophthalic anhydride (2.5 g, 8.74 mmol), 2- chlororesorcinol (1.33 g, 9.18 mmol) and resorcinol (1.01 g, 9.18 mmol) were combined with 12.5 mL of neat methanesulfonic acid and heated to 90°C for 19 h then to 97°C for 10 h whereupon the hot mixture was carefully added to 25 mL of ice water. This suspension was extracted into ethyl acetate and washed with water and brine, then dried over sodium sulfate. The product was isolated via a silica gel plug using
• Step 2 4,4',5,6,7-pentachloro-3',6'-dihydi xy-3H-spiiO[isobenzofuran-l,9'- xanthen]-3-one (1.95 g, 4.15 mmol) was iodinated according to the procedure described in Example 1, Step 2. Crude yield, 2.70 g of a mixture.
• Step 1 Treatment of tetrachlorophthalic anhydride (5 g, 17.49 mmol) and 4-chlororesorcinol (6.32 g, 43.73 mmol), according to the procedure described in Example 1 Step 1, provided 10.3 lg of crude product. Suspension of a 9.25 g portion of this in DMF:water (1 :1) followed by filtration, provided 9.70 g (2:1 DMF complex 17.16 mmol, 92.3% yield) of 2',4,5,6,7,7'-hexachloro-3',6'-dihydroxy-3H- spiro[isobenzofuran-l,9'-xanthen]-3-one that was isolated as an orange solid. 3 ⁇ 4 NMR (300 MHz; DMSO d 6 ) ⁇ 11.13 (S, 2H), 7.31 (s, 2H), 6.89 (s, 2H).
• Step 2 Treatment of 2',4,5,6,7,7'-hexachloro-3',6'-dihydi xy-3H- spiro[isobenzofuran-l,9'-xanthen]-3-one (2 g, 3.71 mmol) according to the procedure described in Example 1, Step 2 provided 2.56 g (3.22 mmol, 87.3 % yield) of 2',4,5,6,7, 7'-hexachloi -3',6'-dihydroxy-4',5'-diiodo-3H-spiro[isobenzofuran-l,9'- xanthen]-3-one that was isolated as a pink-orange solid in 97.9% AUC HPLC purity.
• Step 2 Treatment of 4,4',5,5 , ,6,7-hexachloro-3',6 , -dihydroxy-3H- spiro[isobenzofuran-l,9'-xanthen]-3-one (2 g, 3.71 mmol) according to the procedure described in Example 1, Step 2 provided 2.20 g (2.78 mmol, 75.1% yield) of 4,4', 5, 5', 6, 7-hexachloro-3 ⁇ 6'-dihydroxy-2 ⁇ 7'-diiodo-3H-spiro[isobenzofuran-l,9'- xanthen]-3-one that was isolated as a pink-orange solid at 97.7% AUC HPLC purity.
• Step 1 Treatment of tetrachlorophthalic anhydride (5 g, 17.48 mmol), 4- chlororesorcinol (2.78 g, 19.23 mmol) and 2-chlororesorcinol (2.78 g, 19.23 mmol) according to the procedure described in Example 1, Step 1 provided 6.2 g of crude product (approximately 54% pure by HPLC 2',4,5,5',6,7-hexachloro-3 , ,6'-dihydroxy- 3H-spiro[isobenzofuran-l,9'-xanthen]-3-one) that was collected and taken to the next step as a mixture.
• Step 2 2',4,5,5',6,7-pentachloro-3',6'-dihydiOxy-3H-spiro[isobenzofuran- l,9'-xanthen]-3-one (6.2 g, 54.4% desired compound,6.25 mmol) was iodinated according to the procedure described in Example 1, Step 2, yielding 7.16 g (60.8% desired compound, 5.50 mmol, 88% yield).
• the column was eluted using the same solution and the fractions containing product were combined, concentrated under reduced pressure and axeotropically dried from heptane. This procedure was repeated a second time before the resultant isolated solids were dissolved in anhydrous THF and loaded onto a silica gel prep plate.
• the prep plate was eluted once using 66% toulene:14% dioxane: 18% heptane: 4% acetic acid.
• the upper band was scraped off the prep plate and digested with 10 mL of anhydrous THF, filtered and rinsed with 20 mL of THF. The filtrate was concentrated in vacuo to afford 59 mg of title compound as an orange red residue in 85% AUC HPLC purity.

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