3-(7-amino-3-oxo-1H-isoindol-2-yl)piperidine-2,6-dione

Conditions: temp:30.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Into a 5.0 L 4 necked RB flask, charged 100.0 g of 3-(4-nitro-1-oxo-1,3 dihydro-isoindol-2-yl)-piperidine-2,6-dione, 10.0 g of 10% Pd/C and 3200 ml of DMF under nitrogen atmosphere. Stirred the mass and raise the reaction mass temperature to 60 -65° C. Started the hydrogen gas bubbling into reaction mass at temperature 60-65° C. for 6 hours. The progress of the reaction is monitored by TLC. Cooled the mass to temperature 25to 30° C. Filtered the catalyst Pd/C under plant vacuum in the presence of nitrogen atmosphere and wash with dimethylformamide; wet Pd/C is transferred into a polythene bag for recovery. Distilled off the above organic layer solvent completely under vacuum below 60° C. Charged ethyl acetate 800 ml (lot-I) to the mass and stirred for 60 min. Filtered the solid and wash with 200 mL of ethyl acetate (Lot-II). Dried the above wet material in a oven at temperature 65-75° C. for 120-180 min. Dried Weight of the compound is 78.0 g. raise the reaction mass temperature to 60 -65° C bubbling into reaction mass at temperature 60-65° C. for 6 hours Filtered the catalyst Pd/C under plant vacuum in the presence of nitrogen atmosphere wash with dimethylformamide Distilled off the above organic layer solvent completely under vacuum below 60° C Charged ethyl acetate 800 ml (lot-I) to the mass and stirred for 60 min Filtered the solid wash with 200 mL of ethyl acetate (Lot-II) Dried the above wet material in a oven at temperature 65-75° C. for 120-180 min

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: By catalytic hydrogenation of 3-(4-nitro-1-oxo-1,3 dihydro-isoindol-2-yl)-piperidine-2,6-dione in solvents such as dimethylformamide, methanol, ethanol, isopropyl alcohol or mixture of these solvents at temperature 50-100.0° C. under pressure or bubbling of hydrogen gas at atmospheric pressure, then filteration of the catalyst followed by distillation under high vacuum Lenalidomide polymorphic form-I is obtained. The polymorphic form-I of Lenalidomide can also be obtained by transfer hydrogenation of 3-(4-nitro-1-oxo-1,3 dihydro-isoindol-2-yl)-piperidine-2,6-dione using solvents dimethylformamide, methanol, ethanol, isopropyl alcohol or mixture of these solvents at temperature 50-100.0° C. using ammonium formate or formic acid as source of hydrogen. The precious metal catalysts used in the hydrogenation are Raney Nickel, palladium etc., followed by filteration of catalyst and distillation of the solvent under high vacuum. bubbling of hydrogen gas at atmospheric pressure filteration of the catalyst followed by distillation under high vacuum Lenalidomide polymorphic form-I is obtained

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 3-(4-Amino-1-oxo-1,3-dihydro-isoindol-2-yl)-piperidine-2,6-dione (1.04 g, 4 mmol) was dissolved in acetic acid (7 ml) with heat. The mixture was cooled slightly and methylene chloride (50 ml) was added slowly followed by 3-chlorobenzaldehyde (0.91 ml, 8 mmol) and sodium triacetoxyborohydride. (2.54 g, 12 mmol). The reaction mixture was stirred at room temperature under a nitrogen atmosphere for 2 h, diluted with methylene chloride (100 ml), washed with water (2×100 ml), saturated aqueous sodium bicarbonate (2×100 ml), brine (100 ml), dried (magnesium sulfate), and filtered. The solvent was evaporated in vacuo to give a white solid. The solid was recrystallized from methylene chloride/methanol to give 0.48 g (31%) of product as a white solid: mp 253-255° C.; 1H NMR (DMSO-d6) δ 11.05 (s, 1H), 7.45 (s, 1H), 7.37-7.19 (m, 4H), 6.95 (d, J=7.4 Hz, 1H), 6.63 (d, J=8.0 Hz, 1H), 6.45 (t, J=5.9 Hz, 1H), 5.14 (dd, J=5.1 and 13.1 Hz, 1H), 4.41 (d, J=5.8 Hz, 2H), 4.34 (d, J=17.3 Hz, 1H), 4.20 (d, J=17.2 Hz, 1H) 3.01-2.87 (m, 1H), 2.66-2.60 (m, 1H), 2.42-2.25 (m, 1H), 2.08-2.04 (m, 1H); 13C NMR (DMSO-d6) δ 172.90, 171.24, 168.74, 143.03, 142.59, 133.08, 132.16, 130.19, 129.12, 126.80, 126.70, 125.73, 112.27, 110.55, 51.54, 45.73, 45.47, 31.25, 22.79; Anal. Calcd. For C20H18ClN3O3: C, 62.58, H, 4.73; N, 10.95. Found: C, 62.32; H, 4.61; N, 10.80. with heat The mixture was cooled slightly washed with water (2×100 ml), saturated aqueous sodium bicarbonate (2×100 ml), brine (100 ml) dried (magnesium sulfate) filtered The solvent was evaporated in vacuo to give a white solid The solid was recrystallized from methylene chloride/methanol

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a stirred solution of 3-(4-amino-1-oxoisoindolin-2-yl)piperidine-2,6-dione (0.52 g, 2.0 mmol) in DMF (10 ml) was added pentanal (0.26 g, 3.0 mmol), acetic acid (0.24 g, 4.0 mmol), and sodium triactoxyborohydride (0.85 g, 4.0 mmol). The reaction mixture was stirred at room temperature for 6 hours. The solvent was evaporated in vacuo and the residue was dissolved in ethyl acetate (100 ml), washed with H2O (3×100 ml), brine (1×100 ml), and dried over MgSO4. The solvent was evaporated and the residue was partially purified by chromatography (ethyl acetate/hexane, 75:25) to give an off-white solid which was slurried in ethyl acetate and filtered to give 0.14 g (21%) of product as a white solid: mp 244-246° C.; 1H NMR (DMSO-d6) δ 11.00 (s, 1H), 7.28 (t, J=7.7 Hz, 1H), 6.92 (d, J=7.3 Hz, 1H), 6.73 (d, J=8.0 Hz, 1H), 5.54 (t, J=5.3 Hz, 1H), 5.12 (dd, J=5.1 and 13.2 Hz, 1H), 4.24 (d, J=17.2 Hz, 1H), 4.13 (d, J=17.2 Hz, 1H) 3.15-3.07 (m, 2H), 3.00-2.86 (m, 1H), 2.65-2.59 (m, 1H), 2.39-2.23 (m, 1H), 2.08-1.99 (m, 1H), 1.61-1.57 (m, 2H), 1.41-1.32 (m, 4H), 0.89 (t, J=6.8 Hz, 3H); 13C NMR (DMSO-d6) δ 172.83, 171.19, 168.86, 143.74, 132.00, 129.15, 126.42, 111.66, 109.86, 51.46, 45.69, 42.68, 31.20, 28.80, 28.21, 22.79, 21.96, 13.89; Anal. Calcd. For C18H23N3O3: C, 65.63; H, 7.04; N, 12.76. Found: C, 65.69; H, 7.22; N, 12.55. The solvent was evaporated in vacuo the residue was dissolved in ethyl acetate (100 ml) washed with H2O (3×100 ml), brine (1×100 ml) dried over MgSO4 The solvent was evaporated the residue was partially purified by chromatography (ethyl acetate/hexane, 75:25) to give an off-white solid which filtered

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a stirred solution of 3-(4-amino-1-oxoisoindolin-2-yl)piperidine-2,6-dione (0.52 g, 2.0 mmol) in DMF (10 ml) was added pentanal (0.26 g, 3.0 mmol), acetic acid (0.24 g, 4.0 mmol), and sodium triactoxyborohydride (0.85 g, 4.0 mmol). The reaction mixture was stirred at room temperature for 6 hours. The solvent was evaporated in vacuo and the residue was dissolved in ethyl acetate (100 ml), washed with H2O (3×100 ml), brine (1×100 ml), and dried over MgSO4. The solvent was evaporated and the residue was partially purified by chromatography (ethyl acetate/hexane, 75:25) to give an off-white solid which was slurried in ethyl acetate and filtered to give 0.14 g (21%) of product as a white solid: mp 244-246° C.; 1H NMR (DMSO-d6) δ 11.00 (s, 1H), 7.28 (t, J=7.7 Hz, 1H), 6.92 (d, J=7.3 Hz, 1H), 6.73 (d, J=8.0 Hz, 1H), 5.54 (t, J=5.3 Hz, 1H), 5.12 (dd, J=5.1 and 13.2 Hz, 1H), 4.24 (d, J=17.2 Hz, 1H), 4.13 (d, J=17.2 Hz, 1H) 3.15-3.07 (m, 2H), 3.00-2.86 (m, 1H), 2.65-2.59 (m, 1H), 2.39-2.23 (m, 1H), 2.08-1.99 (m, 1H), 1.61-1.57 (m, 2H), 1.41-1.32 (m, 4H), 0.89 (t, J=6.8 Hz, 3H); 13C NMR (DMSO-d6) δ 172.83, 171.19, 168.86, 143.74, 132.00, 129.15, 126.42, 111.66, 109.86, 51.46, 45.69, 42.68, 31.20, 28.80, 28.21, 22.79, 21.96, 13.89; Anal. Calcd. For C18H23N3O3: C, 65.63; H, 7.04; N, 12.76. Found: C, 65.69; H, 7.22; N, 12.55. The solvent was evaporated in vacuo the residue was dissolved in ethyl acetate (100 ml) washed with H2O (3×100 ml), brine (1×100 ml) dried over MgSO4 The solvent was evaporated the residue was partially purified by chromatography (ethyl acetate/hexane, 75:25) to give an off-white solid which filtered

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a stirred suspension of 3-(4-amino-1-oxoisoindolin-2-yl)piperidine-2,6-dione (0.52 g, 2.0 mmol) in methanol (50 ml) was added furan-2-carbaldehyde (0.200 g, 2.05 mmol). The mixture was heated to reflux for 4 hours. The solvent was evaporated in vacuo and the residue was dissolved in acetic acid (20 ml). Sodium triacetoxyborohydride (0.450 g, 2.05 mmol) was added to the reaction mixture. The reaction mixture was stirred for 24 hours. The solvent was evaporated in vacuo and the residue was dissolved in ethyl acetate (100 ml), washed with H2O (3×100 ml), saturated aqueous NaHCO3 (2×100 ml), brine (1×100 ml), and dried over MgSO4. The solvent was evaporated in vacuo and the residue was partially purified by chromatography (100% ethyl acetate) to give an off-white solid which was recrystallized from ethanol to give 0.20 g of product as a white solid: mp 248-250° C.; 1H NMR (DMSO-d6) δ 11.02 (s, 1H), 7.57 (s, 1H), 7.27 (t, J=7.6 Hz, 1H), 6.96 (d, J=7.3 Hz, 1H), 6.85 (d, J=8.0 Hz, 1H), 6.36 (d, J=11.2 Hz, 2H), 6.22 (t, J=5.4 Hz, 1H), 5.12 (dd, J=4.9 and 13.1 Hz, 1H), 4.37 (d, J=5.5 Hz, 2H), 4.27 (d, J=17.2 Hz, 1H), 4.14 (d, J=17.2 Hz, 1H) 3.00-2.86 (m, 1H), 2.65-2.59 (m, 1H), 2.37-2.23 (m, 1H), 2.08-1.99 (m, 1H); 13C NMR (DMSO-d6) δ 172.83, 171.16, 168.70, 152.82, 143.06, 142.00, 132.09, 129.02, 126.76, 112.35, 110.63, 110.33, 107.08, 51.50, 45.73, 31.20, 22.75; Anal. Calcd. For C18H17N3O4: C, 63.71; H, 5.05; N, 12.38. Found: C, 63.41; H, 5.03; N, 11.98. The mixture was heated to reflux for 4 hours The solvent was evaporated in vacuo the residue was dissolved in acetic acid (20 ml) The solvent was evaporated in vacuo the residue was dissolved in ethyl acetate (100 ml) washed with H2O (3×100 ml), saturated aqueous NaHCO3 (2×100 ml), brine (1×100 ml) dried over MgSO4 The solvent was evaporated in vacuo the residue was partially purified by chromatography (100% ethyl acetate) to give an off-white solid which was recrystallized from ethanol

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a stirred suspension of 3-(4-amino-1-oxoisoindolin-2-yl)piperidine-2,6-dione (3.89 g, 15.0 mmol) in THF (50 ml) was added chloroacetyl chloride (1.86 g, 16.5 mmol). The mixture was heated to reflux for 45 minutes. To the reaction mixture was added additional chloroacetyl chloride (0.15 g, 0.13 mmol). The reaction mixture was heated at reflux for an additional 30 minutes. The solvent was evaporated in vacuo and the resulting solid was slurried in diethyl ether (20 ml) and filtered to give 4.64 g (92%) of product as an off-white solid: 1H NMR (DMSO-d6) δ 11.04 (s, 1H), 10.22 (s, 1H), 7.82 (dd, J=1.6 and 7.2 Hz, 1H), 7.59-7.50 (m, 2H), 5.16 (dd, J=5.1 and 13.2 Hz, 1H), 4.46-4.30 (m, 4H), 3.00-2.85 (m, 1H), 2.65-2.58 (m, 1H), 2.44-2.28 (m, 1H), 2.06-2.01 (m, 1H). The mixture was heated to reflux for 45 minutes The reaction mixture was heated at reflux for an additional 30 minutes The solvent was evaporated in vacuo filtered

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A stirred mixture of 3-(4-amino-1-oxoisoindolin-2-yl)piperidine-2,6-dione (518 mg, 2.0 mmol) and benzaldehyde (0.21 ml, 2.0 mmol) in methanol (20 ml) was heated to reflux for 5 h. The solvent was removed in vacuo to give a solid. The solid was re-dissolved in acetic acid (20 ml). The stirred solution was heated to reflux for 1 h, and was then allowed to cool to room temperature. To the stirred solution was added sodium borohydride (90 mg, 2.3 mmol) and stirring continued at room temperature for 18 h. The resulting suspension was filtered and washed with acetic acid (10 ml) and ether (20 ml) to give 3-{1-oxo-4-[benzylamino]isoindolin-2-yl}piperidine-2,6-dione as an off-white solid (420 mg, 60% yield): mp, 257-259° C.; 1H NMR (DMSO-d6) δ 2.01-2.07 (m, 1H, CHH), 2.23-2.30 (m, 1H, CHH), 2.49-2.65 (m, 1H, CHH), 2.85-3.00 (m, 1H, CHH), 4.19 (d, J=17 Hz, 1H, CHH), 4.31 (d, J=17 Hz, 1H, CHH), 4.39 (d, J=5.7 Hz, 2H, CH2), 5.12 (dd, J=5.1, 13 Hz, 1H, NCH), 6.37 (t, J=5.9 Hz, 1H, NH), 6.62 (d, J=8.0 Hz, 1H, Ar), 6.91 (d, J=7.3 Hz, 1H, Ar), 7.19-7.40 (m, 6H, Ar), 11.02 (s, 1H, NH); 13C NMR (DMSO-d6) δ 22.79, 31.25, 45.79, 46.09, 51.56, 110.32, 112.34, 126.72, 127.05, 128.32, 129.07, 132.08, 139.72, 143.33, 168.82, 171.22, 172.90; Anal Calcd for C20H19N3O3: C, 68.75; H, 5.48; N. 12.03. Found C, 68.73; H, 5.41; N, 12.04. was heated to reflux for 5 h The solvent was removed in vacuo to give a solid The stirred solution was heated to reflux for 1 h The resulting suspension was filtered washed with acetic acid (10 ml) and ether (20 ml)

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A solution of lenalidomide (0.020 g, 0.077 mmol) in pyridine (0.8 mL) was cooled to 0° C. (ice bath). Propionyl chloride (0.009 mL, 0.100 mmol) was added dropwise and the reaction was allowed to warm to room temperature over 16 h. Volatiles were removed in vacuo and the crude residue was purified by flash chromatography on silica gel (0→5% MeOH in DCM as eluant) to afford desired product 27 (0.012 g, 50%) as an off-white powder. 1H NMR (400 MHz, DMSO) δ 11.04 (s, 1H), 9.79 (s, 1H), 7.80 (dd, J=6.6, 2.3 Hz, 1H), 7.64-7.29 (m, 2H), 5.14 (dd, J=13.2, 4.9 Hz, 2H), 4.35 (q, J=7.5 Hz, 2H), 3.00-2.79 (m, 1H), 2.60 (m, 1H), 2.35 (m, 1H), 2.05-1.92 (m, 1H), 1.08 (t, J=7.5 Hz, 3H). MS (ESI) m/z calcd for C16H18N3O4 [M+H]+ 316.3, found: 316.8. Volatiles were removed in vacuo the crude residue was purified by flash chromatography on silica gel (0→5% MeOH in DCM as eluant)

Conditions: temp:2.51; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A 250 mL-3N-RBF was charged with 3-(4-amino-1-oxoisoindolin-2-yl)piperidine-2,6-dione and H2O (10 vol) and cooled to 0-5° C. NaNO2 (1.1 eq) and HCl (1.1 eq) were added, and the mixture was stirred for 30 minutes. The mixture was then heated to 75-80° C. for 2 hours. The mixture was cooled to room temperature, filtered and dried in vacuo (18 h, 35-40° C.). The crude product was purified by prep-HPLC (Conditions: C18 Symmetry Column, 90:10 H2O: MeCN isocratic, 60 mL/min flow rate, product retention time ˜30 min) to give an off-white solid (240 mg, 2.4%, 99.5 HPLC AP); mp 296.39° C.; HPLC: Hypersil DBS C8 5 m column, 250×4.6 mm, 35° C.; 99:1 to 85:15 Gradient CH3CN/10 mM aq. KH2PO4, 1.0 mL/min over 20 minutes; 7.60 min, 99.5% AP at 210/240 nm: 1H-NMR (DMSO-d6): 10.97 (1H, br s), 10.11 (1H, br s), 7.34 (1H, t), 7.17 (1H, d), 7.03 (1H, d), 5.09 (1H, dd), 4.25 (2H, dd), 2.97-2.85 (1H, m), 2.62-2.36 (2H, m), 2.03-1.96 (1H, m) ppm; 13C-NMR (DMSO-d6): 172.85, 171.04, 168.27, 152.55, 133.41, 129.44, 127.94, 117.97, 113.71, 51.59, 45.09, 31.22, 22.42 ppm; LC-MS ES+ (M+1) 261; CHN-Analysis, calcd for C13H12N2O4: C, 60.00%; H, 4.65%; N, 10.76%. Found: C, 59.54%; H, 4.88%; N, 10.48%. The mixture was then heated to 75-80° C. for 2 hours The mixture was cooled to room temperature filtered dried in vacuo (18 h, 35-40° C.) The crude product was purified by prep-HPLC (Conditions: C18 Symmetry Column, 90:10 H2O: MeCN isocratic, 60 mL/min flow rate, product retention time ˜30 min) to give an off-white solid (240 mg, 2.4%, 99.5 HPLC AP) 7.60 min, 99.5% AP

Conditions: temp:2.51; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A 250 mL-3N-RBF was charged with 3-(4-amino-1-oxoisoindolin-2-yl)piperidine-2,6-dione and H2O (10 vol) and cooled to 0-5° C. NaNO2 (1.1 eq) and HCl (1.1 eq) were added, and the mixture was stirred for 30 minutes. The mixture was then heated to 75-80° C. for 2 hours. The mixture was cooled to room temperature, filtered and dried in vacuo (18 h, 35-40° C.). The crude product was purified by prep-HPLC (Conditions: C18 Symmetry Column, 90:10 H2O: MeCN isocratic, 60 mL/min flow rate, product retention time ˜30 min) to give an off-white solid (240 mg, 2.4%, 99.5 HPLC AP); mp 296.39° C.; HPLC: Hypersil DBS C8 5 m column, 250×4.6 mm, 35° C.; 99:1 to 85:15 Gradient CH3CN/10 mM aq. KH2PO4, 1.0 mL/min over 20 minutes; 7.60 min, 99.5% AP at 210/240 nm: 1H-NMR (DMSO-d6): 10.97 (1H, br s), 10.11 (1H, br s), 7.34 (1H, t), 7.17 (1H, d), 7.03 (1H, d), 5.09 (1H, dd), 4.25 (2H, dd), 2.97-2.85 (1H, m), 2.62-2.36 (2H, m), 2.03-1.96 (1H, m) ppm; 13C-NMR (DMSO-d6): 172.85, 171.04, 168.27, 152.55, 133.41, 129.44, 127.94, 117.97, 113.71, 51.59, 45.09, 31.22, 22.42 ppm; LC-MS ES+ (M+1) 261; CHN-Analysis, calcd for C13H12N2O4: C, 60.00%; H, 4.65%; N, 10.76%. Found: C, 59.54%; H, 4.88%; N, 10.48%. The mixture was then heated to 75-80° C. for 2 hours The mixture was cooled to room temperature filtered dried in vacuo (18 h, 35-40° C.) The crude product was purified by prep-HPLC (Conditions: C18 Symmetry Column, 90:10 H2O: MeCN isocratic, 60 mL/min flow rate, product retention time ˜30 min) to give an off-white solid (240 mg, 2.4%, 99.5 HPLC AP) 7.60 min, 99.5% AP

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Lenalidomide (200 mg, 0.771 mmol) was taken up in 5 mL of CH3CN and 2 mL of DMF along with (4Z,7Z,10Z,13Z,16Z,19Z)-docosa-4,7,10,13,16,19-hexaenoic acid (DHA, 253 mg, 0.771 mmol), HATU (322 mg, 0.848 mmol) and DIEA (200 μL, 2.3 mmol). The resulting reaction mixture was stirred at room temperature for 3 h and diluted with EtOAc (20 mL). The organic layer was washed with water (3×5 mL), brine, dried (Na2SO4) and concentrated under reduced pressure. Purification by silica gel chromatography (95% CH2Cl2, 5% MeOH) afforded 280 mg of (4Z,7Z,10Z,13Z,16Z,19Z)-N-(2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-4-yl)docosa-4,7,10,13,16,19-hexaenamide (63%). MS (EI) calculated for C35H43N3O4: 569.33; found: [M+H]+ 570. The resulting reaction mixture The organic layer was washed with water (3×5 mL), brine dried (Na2SO4) concentrated under reduced pressure Purification by silica gel chromatography (95% CH2Cl2, 5% MeOH)