……………… The dried crude product was dissolved in 200 μL of DMSO and purified by reverse-phase HPLC. The product was quantified spectrophotometrically, the identity was characterized using ESI+MS and UV–vis spectroscopy, and the purity was found to be >95% using HPLC–MS. This yielded 0.21 mg (250 nmol) of 1b(0.7% yield). ESI+MS: [M]+ = 840 m/z. UV–vis (MeOH, λmax): 748, 517, 385, 332 nm.
CHEMICAL EXAMPLES
Example 1. Palladium 31-oxo-15-methoxycarbonylmethyl-Rhodobacteriochlorin 131-(2-sulfoethyl)amide dipotassium salt ( Compound 4)
Nine hundred and thirty five (935) mg of Pd-Bpheid (3) were dissolved in a 1 L round bottom flask with 120 ml of DMSO while stirring under Argon (bubbled in the solution). Taurine (1288 mg) was dissolved in 40 ml of 1M K2HPO4 buffer, and the pH of the solution was adjusted to 8.2 (with HCl ). This aqueous solution was added into the DMSO solution while stirring, and the Argon was bubbled in the solution for another 20 minutes. Then the reaction mixture was evaporated at 30°C for 3.5 hours under ~2 mbar and then for another 2 hours at 37°C to a complete dryness. The dry solids were dissolved in 300 ml of MeOH and the colored solution was filtered through cotton wool to get rid of buffer salts and taurine excess.
The progress of the reaction was determined by TLC (Rf of unreacted Pd- Bpheid is 0.8-0.85 and of the reaction (aminolysis) product is 0.08-0.1) and by following the optical absorption spectrum of the reaction mixture after liophylization and resolubihzation in MeOH. The absorption spectrum was characterized by a Qytransition shift from 756 nm (for Pd-Bpheid) to 747 nm (for the product 4) and by Qx shift from 534 nm of Pd-Bpheid to 519 nm (of the product 4). The MeOH was evaporated and the product 4 was purified by HPLC with ODS-A 250X20 S10P μm column (YMC, Japan). Solvent A: 95% 0.005 M phosphate buffer, pH 8.0 and 5% MeOH. Solvent B: 100% MeOH. The dry solid was dissolved in 42 ml of distilled water and injected in portions of 1.5 ml each .
The elution profile is described in Table 1. The product 4_(Scheme 1, see below) was eluted and collected at ~ 9-11 minutes. The main impurities, collected after at 4-7 min (ca 5-10%), corresponded to byproduct(s) with the proposed structure 7. Peaks at 22-25 min (ca 2-5%) possibly corresponded to the iso-form of the main product 4 and untreated Pd-Bpheid residues.
The solvent (aqueous methanol) was evaporated under reduced pressure. Then, the purified product 4 ]was re-dissolved in ~150 ml MeOH and filtered through cotton wool. The solvent was evaporated again and the solid pigment 4 was stored under Ar in the dark at -20°C. The reaction yield: ~90% (by weight, relative to 3).
The structure of product 4 was confirmed by electrospray mass spectroscopy. (ESI-MS, negative mode, Fig.2), (peaks at 875 (M–K-H), 859 (M–2K-H+Na), 837 (M–2K), 805 (M2K-H-OMe), 719) and 1H-NMR spectrum (Fig. 4 in MeOH-d4). Table 4 provides the shifts (in ppm units) of the major NMR peaks.
Optical absorption (UN-VIS) spectrum (MeOH): λ, 747 (1.00), 516 (0.13), 384 (0.41), 330 (0.50); ε747 (MeOH) is 1.2 x 105 mol-1 cm _1.
ΝMR (MeOH-d4): 9.38 (5-H, s), 8.78 (10-H, s), 8.59 (20-H, s), 5.31 and 4.95 (151-CH2, dd), 4.2-4.4 (7,8,17,18-H, m), 3.88 (153-Me, s), 3.52 (21-Me, s), 3.19 (121 -Me, s), 3.09 (32-Me, s), 1.92-2.41, 1.60-1.75 (171, 172-CH2, m), 2.19 (81-CH2, m), 1.93 (71-Me, d), 1.61 (181-Me, d), 1.09 (82-Me, t), 3.62, 3.05 (CH2‘s of taurine).
Octanol/water partition ratio is 40:60.
Example 2. Preparation of 31-oxo-15-methoxycarbonylmethyl- Rhodobacteriochlorin 131-(2-sulfoethyl)amide dipotassium salt (Compound 5) One hundred and sixty (160) mg of taurine were dissolved in 5 ml of 1M
K2HPO4 buffer, and the pH of the solution was adjusted to 8.2. This solution was added to 120 mg of compound 2 dissolved in 15 ml of DMSO, and the reaction and following purification were analogous to those described in previous Example.
Absorption spectrum (MeOH): λ, 750 (1.00), 519 (0.30), 354 (1.18) nm.
ESI-MS (-): 734 (M–2K).
ΝMR (MeOH-d4): 9.31 (5-H, s), 8.88 (10-H, s), 8.69 (20-H, s), 5.45 and 5.25 (151-CH2, dd), 4.35 (7,18-H, m), 4.06 (8,17-H, m), 4.20 and 3.61 (2-CH2, m of taurine), 3.83 (153-Me, s), 3.63 (21-Me, s), 3.52 (3-CH2, m oftaurine), 3.33 (121-Me, s), 3.23 (32-Me, s), 2.47 and 2.16 (171-CH2, m), 2.32 and 2.16 (81-CH2, m), 2.12 and 1.65 (172-CH2, m), 1.91 (71-Me, d), 1.66 (181– Me, d), 1.07 (82-Me, t).
Octanol/water partition ratio is 60:40.
Example 3. Preparation of copper(II) 31-oxo-15-methoxycarbonylmethyl- Rhodobacteriochlorin 131-(2-sulfoethyl)amide dipotassium salt (Compound 10)
Fifty (50) mg of compound 5 of Example 2 and 35 mg of copper (II) acetate were dissolved in 40 ml of methanol, and argon was bubbled into solution for 10 minutes. Then 500 mg of palmitoyl ascorbate was added, and the solution was stirred for 30 min. The absorption spectrum was characterized by a Qy transition shift from 750 nm (for 5) to 768 nm (for the product 10) and by Qx shift from 519 nm of 5 to 537 nm (of the product 10). Then the reaction mixture was evaporated, re-dissolved in acetone and filtered through cotton wool to get rid of acetate salt excess. The acetone was evaporated and the product was additionally purified by HPLC at the conditions mentioned above with the elution profile, described in Table 2.
The solvent (aqueous methanol) was evaporated under reduced pressure. Then, the purified pigment 10 was re-dissolved in methanol and filtered through cotton wool. The solvent was evaporated again and the solid pigment 10 was stored under Ar in the dark at -20°C. Reaction yield: -90%.
Absorption spectrum (MeOH): λ, 768 (1.00), 537 (0.22), 387 (0.71) and 342 (0.79) nm.
ESI-MS (-): 795 (M–2K).
Octanol/water partition ratio is 40:60.
Example 4. Preparation of zinc 31-oxo-15-methoxycarbonylmethyl-Rhodobacteriochlorin 131-(2-sulfoethyl)amide dipotassium salt (Compound 11)
Zn insertion into compound 5 was carried out with Zn acetate in acetic acid as previously described (US Patent No. 5,726,169). Final purification was carried out by HPLC in the same conditions as for compound 5 in Example 2 above.
Absorption spectrum (MeOH): λ, 762 (1.00), 558 (0.26), 390 (0.62) and 355 (0.84) nm.
Octanol/water partition ratio is 50:50.
Example 5. Preparation of manganese(III) 31-oxo-15-methoxycarbonylmethyl-Rhodobacteriochlorin 131-(2-sulfoethyl)amide dipotassium salt (Compound 12)
Mn insertion into compound 5 was carried out with Zn acetate in acetic acid as previously described (WO 97/19081; US 6,333,319) with some modifications. Thus, fifty (50) mg of compound 5 in 10 ml of DMF were stirred with 220 mg of cadmium acetate and heated under argon atmosphere at 110°C about 15 min (Cd-complex formation is monitored by shifting Qx transition absorption band from 519 to 585 nm in acetone). Then the reaction mixture was cooled and evaporated. The dry residue was re-dissolved in 15 ml of acetone and stirred with manganese (II) chloride to form the Mn(III)-product 12. The product formation is monitored by shifting Qx transition band from 585 to 600 nm and Qy transition band from 768 to 828 nm in acetone. The acetone was evaporated and the product 12 was additionally purified by HPLC in the conditions mentioned in Example 2 above with the elution profile described in Table 3 below where the] solvent system consists of: A – 5% aqueous methanol, B -methanol.
The solvent (aqueous methanol) was evaporated under reduced pressure and the solid pigment 12 was stored under Ar in the dark at -20°C.
Absorption spectrum (MeOH): λ, 828 (1.00), 588 (0.32) and 372 (0.80) nm. Octanol/water partition ratio is 5:95.
Example 6. Preparation of palladium bacteriopheophorbide a 17 -(3-sulfo-1-oxy- succinimide)ester sodium salt (Compound 6)
Fifty (50) mg of Pd-Bpheid (compound 2), 80 mg of N-hydroxy- sulfosuccinimide (sulfoNHS) and 65 mg of 1-(3-dimethylaminopropyl)-3- ethylcarbodiimide (EDC) were mixed in 7 ml of dry DMSO for overnight at room temperature. Then the solvent was evacuated under reduced pressure. The dry residue was re-dissolved in chloroform (ca. 50 ml), filtered from insoluble material, and evaporated. The conversion was ab. 95%) (TLC). The product 6 was used later on without further chromatographic purification. ESI-MS (-): 890 (M–Na).
NMR (CDCl3): 9.19 (5-H, s), 8.49 (10-H, s), 8.46 (20-H, s), 5.82 (132-H, s), 4.04- 4.38 (7,8,17,18-H, m), 3.85 (134-Me, s), 3.47 (21-Me, s), 3.37 (^-Me, s), 3.09 (32– Me, s), 1.77 (71-Me, d), 1.70 (lδ’-Me, d), 1.10 (82-Me, t), 4.05 (CH2 of sNHS), 3.45 (CH ofs NHS).
Example 7. Preparation of palladium bacteriopheophorbide a 173-(3-sulfopropyl) amide potassium salt (Compound 7)
Ten (10) mg of compound 6 in 1 ml of DMSO was mixed with 20 mg of homotaurine (3-amino-1-propane-sulfonic acid) in 1 ml of 0.1 M K-phosphate buffer, pH 8.0 for overnight. Then the reaction mixture was partitioned in chloroform/water. The organic layer was dried over anhydrous sodium sulfate and evaporated. The dry residue was re-dissolved in chloroform-methanol (19:1) and applied to a chromatographic column with silica. The product 7 was obtained with chloroform-methanol (4:1) elution. The yield was about 80-90%.
ESI-MS (-): 834 (M-K) m/z.
NMR (MeOH-d4): 9.16 (5-H, s), 8.71 (10-H, s), 8.60 (20-H, s), 6.05 (132-H, s), 4.51, 4.39, 4.11, 3.98 (7,8,17,18-H, all m), 3.92 (134-Me, s), 3.48 (21-Me, s), 3.36 (121-Me, s), 3.09 (32-Me, s), 2.02-2.42 (171 arid 172-CH2, m), 2.15 ( 81-CH2, q), 1.81 (71-Me, d), 1.72 (181-Me, d), 1.05 (82-Me, t), 3.04, 2.68, and 2.32 (CH2‘s of homotaurine, m).
Example 8. Preparation of palladium 31-oxo-15-methoxycarbonylmethyl-Rhodo-bacteriochlorin 13 ,17 -di(3-sulfopropyl)amide dipotassium salt (Compound 8)
Ten (10) mg of compound 6 or 7 were dissolved in 3 ml of DMSO, mixed with 100 mg of homotaurine in 1 ml of 0.5 M K-phosphate buffer, pH 8.2, and incubated overnight at room temperature. The solvent was then evacuated under reduced pressure as described above, and the product 8 was purified on HPLC. Yield: 83%.
Absorption spectrum (MeOH): 747 (1.00), 516 (0.13), 384 (0.41), 330 (0.50), ε747 =1.3×105 modern-1.
ESI-MS(-):1011 (M–K), 994 (M–2K+Na),972 (M–2K), 775 (M–2K-CO2Me-homotaurineNHCH2CH2CH2SO3), 486 ([M-2K]/2)
NMR (MeOH-d4): 9.35 (5-H, s), 8.75 (10-H, s), 8.60 (20-H, s), 5.28 and 4.98 (15-1-CH2, dd), 4.38, 4.32, 4.22, 4.15 (7,8,17,18-H, all m), 3.85 (15~3-Me, s), 3.51 (21-Me, s), 3.18 (121-Me, s), 3.10 (32-Me, s 2.12-2.41 (171-CH2, m), 2.15-2.34 (81-CR2, m), 1.76-2.02 (172-CH2, m), 1.89 (71-Me, d), 1.61 (lδ^Me, d), 1.07 (82-Me, t). 3.82, 3.70,
3.20, 3.10, 2.78, 2.32, 1.90 (CH2‘s of homotaurine at C-131 and C-173)
Example 9. Palladium 31-(3-sulfopropylimino)-15-methoxycarbonylmethyl-Rhodo-bacteriochlorin 131,173-di(3-sulfopropyl)amide tripotassium salt (Compound 9)
Compound 9 was obtained from HPLC as a minor product during synthesis of 8.
Absorption spectrum (MeOH): 729 (1.00), 502 (0.10), 380 (0.69), 328 (0.57).
ESI-MS (30.4.2000): 1171 (M-K+H), 1153 (M–2K-H+Na), 1131 (M-2K), 566 ([M-K]/2), 364 ([M-3K]/3).
NMR (MeOH-d4): 8.71 (1H), 8.63 (1.5H), 8.23 (0.5H) (5-, 10- and 20-H, all-m), 5.30 and 4.88 (151-CH2, dd), 4.43 and 4.25 (7,8,17,18-H, m), 3.85 (15~3-Me, s), 3.31 (21-Me, s), 3.22 (121-Me, s), 3.17 (32-Me, m), 1.89-2.44 (171 and 172-CH2, m), 2.25 (81-CH2, m), 1.91 (71-Me, s), 1.64 (181– Me, s), 1.08 (82-Me, t), 4.12, 3.56, 3.22, 3.16, 2.80 and 2.68 (CH2‘s of homotaurine).
Example 10. Palladium 31-oxo-15-methoxycarbonylmethyl-Rhodobacteriochlorin 131-(2-sulfoethyl)amide, 173-(N-immunoglobulin G)amide potassium salt (Compound 13)
Ten (10) mg of compound 4 were reacted with 20 mg of sulfo-NHS and 15 mg of EDC in 1 ml of dry DMSO for 1 hour at room temperature, then rabbit IgG (0.6 mg) in PBS (2.5 ml) was added, and the mixture was further incubated overnight at room temperature. The mixture was evaporated to dryness, then re-dissolved in 1 ml of PBS and loaded on Sephadex G-25 column equilibrated with PBS. A colored band was eluted with 4-5 ml of PBS. The pigment/protein ratio in the obtained conjugate 13 was determined by optical density at 753 and 280 mn, respectively, and varied between 0.5/1 to 1/1 of pigment 13/protein.
Example 11. Preparation of palladium 31-oxo-15-methoxycarbonylmethyl-Rhodobacteriochlorin 131-(2-carboxyethyl)amide dipotassium salt (Compound
M)
The preparation and purification of the title compound 14 were carried out as described in Example 2, by reaction of compound 2 with 3-aminopropionic acid (β-alanine) (150 mg) instead of taurine. Yield: 85%.
Example 12. Preparation of palladium 31-oxo-15-methoxycarbonylmethyl-Rhodobacteriochlorin 131-(3-phosphopropyl)amide tripotassium salt (Compound
15)
The preparation and purification of the title compound 15 were carried out as described in Example 2, by reaction of compound 2 with 3 -amino- 1-propanephosphonic acid (180 mg) instead of taurine. Yield: 68%.
Example 13. Palladium 31-(3-sulfopropylamino)-15-methoxycarbonylmethyl-Rhodobacteriochlorin 131,173-di(3-sulfopropyl)amide tripotassium salt (Compound 16)
For reduction of the imine group in 31-(3-sulfopropylimino) to the correspondent 31-(3-sulfopropylamino) group, compound 9 (8 mg) was reacted by stirring with sodium cyanoborohydride (15 mg) in 5 ml of methanol overnight at room temperature. Then the reaction mixture was treated with 0.05 M HCl (5 ml), neutralized with 0.01 M KOH, and evaporated. The title product 16 was purified using HPLC conditions as described in Example 2. Yield: 80-90%).
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