* All experimental methods are cited from the reference, please refer to the original source for details. We do not guarantee the accuracy of the content in the reference.
Reference：
[1] Journal of the American Chemical Society, 1949, vol. 71, p. 1885
2
[ 5409-39-2 ]
[ 75-65-0 ]
[ 40851-95-4 ]
Reference：
[1] Patent: US5624935, 1997, A,
3
[ 5409-39-2 ]
[ 78607-32-6 ]
Reference：
[1] Journal of the Chemical Society, 1952, p. 2042,2044
4
[ 5409-39-2 ]
[ 408314-14-7 ]
Reference：
[1] Journal of the American Chemical Society, 1949, vol. 71, p. 1885
5
[ 5409-39-2 ]
[ 97941-89-4 ]
Yield
Reaction Conditions
Operation in experiment
49%
With hydrogenchloride; tin(ll) chloride In water at 80 - 100℃; for 0.5 h;
5-Chloro-3-nitropyridin-2-amine (2000.0 mg, 11.52 mmol) and SnCl2 (8740.0 mg, 46.09 mmol) were added in conc. HCl (20.0 mL) and then stirred at 80-100° C. for 0.5 hour. The reaction mixture was neutralized with saturated 1N NaOH aqueous solution (pH=7), and it was then extracted with EtOAc (200.0 mL). The organic layer was washed with brine, dried over anhydrous Na2SO4, filtered and then distilled under reduced pressure. The residue was purified by column chromatography (n-Hex:EtOAc=90:10) on silica. The fractions containing the product were collected and evaporated to obtain ivory solid compound of 5,6-dichloropyridin-2,3-diamine (1000.0 mg, 49percent). [0523] 1H-NMR (300 MHz, DMSO-d6); δ: 6.80 (s, 1H), 6.04 (s, 2H), 5.11 (s, 2H)
Reference：
[1] Patent: US2014/315888, 2014, A1, . Location in patent: Paragraph 0522-0523
[2] Journal of Organic Chemistry, 1959, vol. 24, p. 1455,1459
6
[ 5409-39-2 ]
[ 21427-62-3 ]
Yield
Reaction Conditions
Operation in experiment
60%
Stage #1: With hydrogenchloride In water at -10℃; Stage #2: With sodium nitrite In water at 0℃; for 2 h; Stage #3: With sodium hydroxide In water at -10 - 0℃;
5-Chloro-3-nitro-2-pyridinamine (5.0 g, 28.8 mmol) was dissolved in cone. HCI (50 mL) and cooled to -10 0C in an ice-salt bath. Sodium nitrite (4.97 g, 72 mmol) in water (10 mL) was added dropwise to the cooled solution over 1 h and stirred at 0 °C for 1 h longer. The reaction mixture was cooled to -10 0C in an ice-salt bath and neutralized with 2N sodium hydroxide to pH 9.0 keeping the temperature below 0 0C. EtOAc (150 mL) was added and the mixture was filtered. The organic layer was separated, dried over sodium sulfate and concentrated in vacuo to afford the title compound as 3.36 g (60percent yield) of a light brown solid; 1H NMR (cfe-DMSO) δ 8.62 (d, 1 H, 2.5 Hz), 8.26 (d, 1 H, 2.2 Hz).
58.5%
With hydrogenchloride; sodium nitrite In water at -10 - 0℃; for 1.5 h;
5-chloro-3-nitropyridine-2-amine 10.0g of (57.6 mmol) was dissolved in concentrated hydrochloric acid 100 mL, and stirred at -10 ° C.. Here, sodium nitrite 9.94g of (144 mmol) Yuki dropwise over 30 minutes a liquid obtained by dissolving water 20 mL, after the addition, the mixture was stirred 1 hour at 0 ° C.. By adding 1N aqueous sodium hydroxide solution to the reaction solution and pH 9, and extracted with ethyl acetate. Insolubles were removed by filtration, the organic layer was washed with saturated brine, and dried over anhydrous magnesium sulfate. Filtered and the filtrate was evaporated under reduced pressure to give the title compound 6.50g of (58.5percent yield) as a solid.
58.5%
Stage #1: With hydrogenchloride; sodium nitrite In water at -10℃; for 0.5 h; Stage #2: With sodium hydroxide In water at 0℃; for 1 h;
5-chloro-3-nitropyridine-2-amine 10.0g of (57.6 mmol) was dissolved in concentrated hydrochloric acid 100 mL, and stirred at -10 ° C.. Here, sodium nitrite 9.94g of (144 mmol) add dropwise over 30 minutes a liquid obtained by dissolving water 20 mL, after the addition, the mixture was stirred 1 hour at 0 ° C.. By adding 1N aqueous sodium hydroxide solution to the reaction solution and pH 9, and extracted with ethyl acetate. Insolubles were removed by filtration, the organic layer was washed with saturated brine, and dried over anhydrous magnesium sulfate. Filtered and the filtrate was evaporated under reduced pressure to give the title compound 6.50g of (58.5percent yield) as a solid.
58.5%
With hydrogenchloride; sodium nitrite In water at -10 - 0℃; for 1.5 h;
(Step 1) 2,5-Dichloro-3-nitropyridine 5-Chloro-3-nitropyridin-2-amine (10.0 g, 57.6 mmol) was dissolved in concentrated hydrochloric acid (100 mL), and the solution was stirred at -10°C. A solution of sodium nitrite (9.94 g, 144 mmol) dissolved in water (20 mL) was added dropwise thereto over 30 minutes. After the completion of the addition, the mixture was stirred at 0°C for 1 hour. The pH of the reaction solution was adjusted to 9 by the addition of a 1 N aqueous sodium hydroxide solution, followed by extraction with ethyl acetate. Insoluble matter was removed by filtration, and the organic layer was washed with saturated saline and then dried over anhydrous magnesium sulfate. After filtration, the solvent in the filtrate was distilled off under reduced pressure to obtain the title compound (6.50 g, yield: 58.5percent) as a solid. 1H-NMR (CDCl3) δ: 8.60 (1H, d, J = 2.9 Hz), 8.24 (1H, d, J = 2.6 Hz).
Reference：
[1] Patent: WO2007/67875, 2007, A2, . Location in patent: Page/Page column 15
[2] Patent: JP2016/56134, 2016, A, . Location in patent: Paragraph 0165; 0166; 0167
[3] Patent: JP2016/56133, 2016, A, . Location in patent: Paragraph 0158; 0159
[4] Patent: EP3109239, 2016, A1, . Location in patent: Paragraph 0189
[5] Journal of the Chemical Society, 1952, p. 2042,2044
[6] Bioorganic and Medicinal Chemistry, 2004, vol. 12, # 10, p. 2625 - 2637
[7] Patent: US2007/167435, 2007, A1, . Location in patent: Page/Page column 29
7
[ 5409-39-2 ]
[ 21427-61-2 ]
[ 21427-62-3 ]
Reference：
[1] Bioorganic and Medicinal Chemistry, 2004, vol. 12, # 10, p. 2625 - 2637
8
[ 5409-39-2 ]
[ 75806-86-9 ]
Yield
Reaction Conditions
Operation in experiment
73%
With hydrogen bromide; bromine; sodium nitrite In water at 0 - 20℃; for 1 h;
To a solution of intermediate 32a (10.0 g, 57.6 mmol) in HBr [(31 .0 mL (100percent), 286.4 mmol)] at 0 00 sodium nitrite (13.8 g, 199.9 mmol) was added drop wise. To the stirred solution Br2 (10.0 mL, 197.1 mmol) was added in water and stirred at room temperature for 1 h. The reaction mixture was basified with NaHCO3 solution (pH=7) and extracted with ethyl acetate, washed with water, and dried over anhydrousNa2SO4 The solvent was removed under vacuo to yield the title product (10.0 g,73.0percent) as a yellow solid.
73%
With hydrogen bromide; bromine; sodium nitrite In water at 0 - 20℃; for 1 h;
To a solution of intermediate 32a (10.0 g, 57.6 mmol) in HBr [(31.0 mL (100percent), 286.4 mmol)] at 0 00, sodium nitrite (13.8 g, 199.9 mmol) was added drop wise. To the stirred solution Br2 (10.0 mL, 197.1 mmol)in water was added and stirred at roomtemperature for 1 h. The reaction mixture was basified with NaHCO3 solution (PH=7) and extracted with ethyl acetate, washed with water, and dried over anhydrous Na2SO4 The solvent was removed under vacuo to yield the title product (10.0 g, 73.0percent) as a yellow solid.
51.5%
With sodium hydroxide; hydrogen bromide; bromine; sodium nitrite In ethanol; water
2-Bromo-5-chloro-3-nitropyridine (103) To a stirred, ice bath cooled solution of HBr (48percent, 214 mL, d=1.49, 1.89 mol) was added 2-amino-5-chloro-3-nitropyridine (2) (66.0 g, 376 mmol). The mixture was stirred until the internal temperature was less than 0° C., and then bromine (65 mL, d=3.102, 1.3 mol) was added dropwise. The resulting orange mixture was stirred at a temperature below 0° C. A solution of NaNO2 (91.3 g, 1.32 mol, used as received) in water (125 mL) was added slowly to the mixture so as to maintain the internal temperature below 0° C. The mixture was stirred for an additional 45 min at below 0° C., and then NaOH (139.3 g, 3.482 mol) in water (200 mL) was slowly added to the mixture to maintain the internal temperature below 20° C. The mixture was stirred at below 20° C. for an additional hour, and then gravity filtered. The recovered brown solid was dried at 25° C. under vacuum for 6 h. It was purified by recrystalization from 95percent ethanol to obtain 103 as a yellow solid (46.0 g, 51.5percent), mp 68°-73° C. (Lit., 75° C., Berrie et al., J. Chem. Soc. 2042 (1952)); 1 H NMR (CDCl3): δ8.15 (d, J=2.1 Hz, 1H), 8,57 (d, J=2.1 Hz, 1H).
Reference：
[1] Patent: WO2014/202580, 2014, A1, . Location in patent: Page/Page column 100
[2] Patent: WO2014/202528, 2014, A1, . Location in patent: Page/Page column 97
[3] Synthetic Communications, 2012, vol. 42, # 19, p. 2791 - 2796
[4] Bioorganic and Medicinal Chemistry, 2001, vol. 9, # 8, p. 2061 - 2071
[5] Patent: US5801183, 1998, A,
9
[ 5409-39-2 ]
[ 181123-11-5 ]
Reference：
[1] Bioorganic and Medicinal Chemistry, 2001, vol. 9, # 8, p. 2061 - 2071
10
[ 1072-98-6 ]
[ 5409-39-2 ]
Yield
Reaction Conditions
Operation in experiment
67%
Stage #1: at 55℃; for 1.25 h; Stage #2: With sodium hydroxide In water
To a mixture of 2-amino-5-chloropyridine (2.57 g, 20.0 mmol) and sulfuric acid (6.30 ml), huming HNO3 (0.860 ml, 21.1 mmol) was added dropwise over 15 minutes at 55 °C and stirred at 55 "C for 1 hour. After cooling, the reaction mixture was poured into ice-water (60 g) and neutralized with aqueous NaOH solution (pH = 11). The precipitated material was collected, washed with H2O and dried under reduced pressure at 50 0C to give 5-chloro-3-nitropyridin-2-amine (2.31 g, 67 percent, yellow solid).
51%
Stage #1: at 0 - 50℃; for 1 h;
To a 250 mL 3 necked RK flask charged with conc.H2S04 (30 mL) at 0CC, 5 chloropyridin-2-amine (12.5 g) was added portion wise and allowed to stir for 1 h and heated at 50 00 to dissolve starting material completely. Then, conc. HNO3 (8 mL) was added drop wise through addition funnel. The reaction was monitored by every 10 minutes. After completion, 40percent sodium hydroxide solution (pH=6-7) was added,the product was extracted with ethyl acetate, washed with water, and dried over anhydrous Na2SO4. The solvent was removed under vacuo to yield the product (11 .0 g, 51.0percent) as a pale green solid. LCMS: (M-H) = 172.9
51%
Stage #1: at 0 - 50℃; for 1 h;
To a 250 mL 3 necked RK flask charged with conc.H2S04 (30 mL) at 000, 5 chloropyridin-2-amine (12.5 g) was added portion wise and solution was allowed to stir for 1 h and heated at 50 00 to dissolve starting material completely. Then, conc. HNO3 (8 mL) was added drop wise to the resulting solution through addition funnel. The reaction was monitored at every 10 minutes. After completion, 40percent sodiumhydroxide solution (PH=6-7) was added, the product was extracted with ethyl acetate, washed with water, and dried over anhydrous Na2SO4. The solvent was removed under vacuo to yield the product (11.0 g, 51.0percent) as a pale green solid. LOMS: (M-H) = 172.9
Reference：
[1] Synthetic Communications, 2012, vol. 42, # 19, p. 2791 - 2796
[2] Patent: WO2008/8398, 2008, A2, . Location in patent: Page/Page column 369
[3] Bioorganic and Medicinal Chemistry, 2001, vol. 9, # 8, p. 2061 - 2071
[4] New Journal of Chemistry, 2015, vol. 39, # 5, p. 3936 - 3947
[5] Bioorganic and Medicinal Chemistry Letters, 1997, vol. 7, # 6, p. 669 - 674
[6] Journal of Medicinal Chemistry, 1997, vol. 40, # 22, p. 3679 - 3686
[7] Patent: WO2014/202580, 2014, A1, . Location in patent: Page/Page column 100
[8] Patent: WO2014/202528, 2014, A1, . Location in patent: Page/Page column 96
11
[ 1072-98-6 ]
[ 5409-39-2 ]
Reference：
[1] Patent: US5801183, 1998, A,
12
[ 1072-98-6 ]
[ 5409-39-2 ]
Reference：
[1] Patent: US5620978, 1997, A,
13
[ 1072-98-6 ]
[ 5409-39-2 ]
[ 6945-68-2 ]
Reference：
[1] Patent: US5624935, 1997, A,
14
[ 71090-35-2 ]
[ 5409-39-2 ]
Reference：
[1] Bioorganic and Medicinal Chemistry, 2004, vol. 12, # 10, p. 2625 - 2637
Reference：
[1] Zhurnal Russkago Fiziko-Khimicheskago Obshchestva, 1928, vol. 60, p. 689[2] Chem. Zentralbl., 1928, vol. 99, # II, p. 1671
17
[ 1072-98-6 ]
[ 7664-93-9 ]
[ 7697-37-2 ]
[ 5409-39-2 ]
Reference：
[1] Yakugaku Zasshi, 1952, vol. 72, p. 431[2] Chem.Abstr., 1953, p. 6404
18
[ 1072-98-6 ]
[ 5409-39-2 ]
[ 6945-68-2 ]
Reference：
[1] Patent: US5624935, 1997, A,
19
[ 5409-39-2 ]
[ 21427-61-2 ]
Reference：
[1] Journal of the American Pharmaceutical Association (1912-1977), 1949, vol. 38, p. 70
[2] Journal of the Chemical Society, 1951, p. 2590,2593
20
[ 5409-39-2 ]
[ 27330-35-4 ]
Reference：
[1] Bioorganic and Medicinal Chemistry, 2001, vol. 9, # 8, p. 2061 - 2071
With hydrogen;2 % platinum on carbon; In methanol; at 25℃; for 2h;
The compound of formula BD was prepared as follows. A mixture of the compound of formula BC (<strong>[5409-39-2]5-chloro-3-nitropyridin-2-amine</strong>, 1736mg, lOmmol, Sigma- Aldrich) and 2% platinum on carbon (200mg, Sigma-Aldrich) in methanol (2OmL) was stirred under a hydrogen atmosphere at a temperature of about 250C for 2h. After filtering off the Pt/C and washing with EtOAc, the filtrate was concentrated under reduced pressure. The resulting solid was washed with 1 : 1 n-hexane: diethyl ether, filtered, washed with n-hexane, and dried under reduced pressure at a temperature of about 250C to provide the compound of formula BD as a pale brown solid (yield 88%). <n="189"/>The identity of the compound of formula BD was confirmed using 1H NMR.Compound BD: 1H NMR: δH (300 MHz, DMSO): 7.21 (IH, d, J=I.2Hz), 6.69 (IH, d, J= 1.2Hz), 5.57 (2H, m), 5.01 (2H, m).
77%
With ethanol; tin(ll) chloride; for 4h;Reflux;
5-Chloro-3-nitropyridin-2-amine 40a (346 mg, 2 mmol) was dissolved in ethanol (20 ml), then stannous chloride (756 mg, 4 mmol) was added and heated and refluxed for 4 hr. After cooling to room temperature, quenched with water, then with 1N sodium hydroxide solution was adjusted to pH = 8-9 and extracted with ethyl acetate (30ml × 3). The organic phases were combined, dried over anhydrous sodium sulfate and filtered. The filtrate is then removed under reduced pressure to give the desired product 5-chloropyridine-2,3-diamine.40b (220 mg, brown solid), yield: 77%.This product was used directly in the next step without further purification.
70%
To a suspension of <strong>[5409-39-2]5-chloro-3-nitropyridin-2-amine</strong> (1.04 g, 6.00 mmol) in ethanol (6 ml), SnC-2-2H2θ (6.77 g, 30.0 mmol) was added portionwise at room temperature and stirred at 90 C for 1 hour. After cooling, the reaction mixture was basified with aqueous NaOH solution (pH = 14), extracted with ethyl acetate, dried (MgSO4) and evaporated under reduced pressure to give 5-chloropyridine-2,3-diamine (604 mg, 70 %, tan solid).
With hydrogenchloride; tin(ll) chloride; In water; at 80 - 100℃; for 0.5h;
5-Chloro-3-nitropyridin-2-amine (2000.0 mg, 11.52 mmol) and SnCl2 (8740.0 mg, 46.09 mmol) were added in conc. HCl (20.0 mL) and then stirred at 80-100 C. for 0.5 hour. The reaction mixture was neutralized with saturated 1N NaOH aqueous solution (pH=7), and it was then extracted with EtOAc (200.0 mL). The organic layer was washed with brine, dried over anhydrous Na2SO4, filtered and then distilled under reduced pressure. The residue was purified by column chromatography (n-Hex:EtOAc=90:10) on silica. The fractions containing the product were collected and evaporated to obtain ivory solid compound of 5,6-dichloropyridin-2,3-diamine (1000.0 mg, 49%). [0523] 1H-NMR (300 MHz, DMSO-d6); delta: 6.80 (s, 1H), 6.04 (s, 2H), 5.11 (s, 2H)
5-Chloro-3-nitro-2-pyridinamine (5.0 g, 28.8 mmol) was dissolved in cone. HCI (50 mL) and cooled to -10 0C in an ice-salt bath. Sodium nitrite (4.97 g, 72 mmol) in water (10 mL) was added dropwise to the cooled solution over 1 h and stirred at 0 C for 1 h longer. The reaction mixture was cooled to -10 0C in an ice-salt bath and neutralized with 2N sodium hydroxide to pH 9.0 keeping the temperature below 0 0C. EtOAc (150 mL) was added and the mixture was filtered. The organic layer was separated, dried over sodium sulfate and concentrated in vacuo to afford the title compound as 3.36 g (60% yield) of a light brown solid; 1H NMR (cfe-DMSO) delta 8.62 (d, 1 H, 2.5 Hz), 8.26 (d, 1 H, 2.2 Hz).
58.5%
With hydrogenchloride; sodium nitrite; In water; at -10 - 0℃; for 1.5h;
5-chloro-3-nitropyridine-2-amine 10.0g of (57.6 mmol) was dissolved in concentrated hydrochloric acid 100 mL, and stirred at -10 C.. Here, sodium nitrite 9.94g of (144 mmol) Yuki dropwise over 30 minutes a liquid obtained by dissolving water 20 mL, after the addition, the mixture was stirred 1 hour at 0 C.. By adding 1N aqueous sodium hydroxide solution to the reaction solution and pH 9, and extracted with ethyl acetate. Insolubles were removed by filtration, the organic layer was washed with saturated brine, and dried over anhydrous magnesium sulfate. Filtered and the filtrate was evaporated under reduced pressure to give the title compound 6.50g of (58.5% yield) as a solid.
58.5%
5-chloro-3-nitropyridine-2-amine 10.0g of (57.6 mmol) was dissolved in concentrated hydrochloric acid 100 mL, and stirred at -10 C.. Here, sodium nitrite 9.94g of (144 mmol) add dropwise over 30 minutes a liquid obtained by dissolving water 20 mL, after the addition, the mixture was stirred 1 hour at 0 C.. By adding 1N aqueous sodium hydroxide solution to the reaction solution and pH 9, and extracted with ethyl acetate. Insolubles were removed by filtration, the organic layer was washed with saturated brine, and dried over anhydrous magnesium sulfate. Filtered and the filtrate was evaporated under reduced pressure to give the title compound 6.50g of (58.5% yield) as a solid.
58.5%
With hydrogenchloride; sodium nitrite; In water; at -10 - 0℃; for 1.5h;
(Step 1) 2,5-Dichloro-3-nitropyridine 5-Chloro-3-nitropyridin-2-amine (10.0 g, 57.6 mmol) was dissolved in concentrated hydrochloric acid (100 mL), and the solution was stirred at -10C. A solution of sodium nitrite (9.94 g, 144 mmol) dissolved in water (20 mL) was added dropwise thereto over 30 minutes. After the completion of the addition, the mixture was stirred at 0C for 1 hour. The pH of the reaction solution was adjusted to 9 by the addition of a 1 N aqueous sodium hydroxide solution, followed by extraction with ethyl acetate. Insoluble matter was removed by filtration, and the organic layer was washed with saturated saline and then dried over anhydrous magnesium sulfate. After filtration, the solvent in the filtrate was distilled off under reduced pressure to obtain the title compound (6.50 g, yield: 58.5%) as a solid. 1H-NMR (CDCl3) delta: 8.60 (1H, d, J = 2.9 Hz), 8.24 (1H, d, J = 2.6 Hz).
With tert.-butylnitrite; copper dichloride; In acetonitrile; at 70℃; for 17.5h;
Example 14; Preparation of Compound 14A ; To a stirred solution of tert-butyl nitrite (55.2 ml, 466 mmol) and anhydrous Cu(II)Cl2 (50.0 g, 372 mmol) in CH3CN (500 mL), maintained at 70 C., was added 2-amino-5-chloro-3-nitrobenzene 38 (53.6 g, 310 mmol) portionwise over 30 min. The mixture turned from greenish to brown, and gas evolution was observed. Stirring at 70 C. was continued for 16 h. The reaction mixture was cooled and partitioned between 20% aqueous HCl (400 mL) and diethyl ether (1 l). Layers were separated, and the aqueous phase was extracted with EtOAc (500 mL). Combined extracts were washed successively with 20% aqueous HCl (200 mL) and brine (300 mL), dried over anhydrous MgSO4, filtered and concentrated under vacuum. The residue was flash chromatographed on silica gel, eluting with EtOAc-hexanes (1:4), to provide 17.3 g of compound 39 as a yellow oil, which spontaneously crystallized upon standing at room temperature.
To a mixture of 2-amino-5-chloropyridine (2.57 g, 20.0 mmol) and sulfuric acid (6.30 ml), huming HNO3 (0.860 ml, 21.1 mmol) was added dropwise over 15 minutes at 55 C and stirred at 55 "C for 1 hour. After cooling, the reaction mixture was poured into ice-water (60 g) and neutralized with aqueous NaOH solution (pH = 11). The precipitated material was collected, washed with H2O and dried under reduced pressure at 50 0C to give 5-chloro-3-nitropyridin-2-amine (2.31 g, 67 %, yellow solid).
51.0%
To a 250 mL 3 necked RK flask charged with conc.H2S04 (30 mL) at 0CC, 5 chloropyridin-2-amine (12.5 g) was added portion wise and allowed to stir for 1 h and heated at 50 00 to dissolve starting material completely. Then, conc. HNO3 (8 mL) was added drop wise through addition funnel. The reaction was monitored by every 10 minutes. After completion, 40% sodium hydroxide solution (pH=6-7) was added,the product was extracted with ethyl acetate, washed with water, and dried over anhydrous Na2SO4. The solvent was removed under vacuo to yield the product (11 .0 g, 51.0%) as a pale green solid. LCMS: (M-H) = 172.9
51%
To a 250 mL 3 necked RK flask charged with conc.H2S04 (30 mL) at 000, 5 chloropyridin-2-amine (12.5 g) was added portion wise and solution was allowed to stir for 1 h and heated at 50 00 to dissolve starting material completely. Then, conc. HNO3 (8 mL) was added drop wise to the resulting solution through addition funnel. The reaction was monitored at every 10 minutes. After completion, 40% sodiumhydroxide solution (PH=6-7) was added, the product was extracted with ethyl acetate, washed with water, and dried over anhydrous Na2SO4. The solvent was removed under vacuo to yield the product (11.0 g, 51.0%) as a pale green solid. LOMS: (M-H) = 172.9
6-chloro-[1,2,5]oxadiazolo[3,4-b]pyridine 1-oxide[ No CAS ]
Yield
Reaction Conditions
Operation in experiment
77%
With [bis(acetoxy)iodo]benzene; In benzene; for 2h;Reflux;
General procedure: PhI(OAc)2 (1.93 g, 6 mmol) was added to a suspension ofcompound 9b-d (4.6 mmol) in PhH (40 ml). The mixturewas refluxed for 2 h. The solvent was removed underreduced pressure, and the residue was washed thoroughlywith hexane and dried on air.Methyl [1,2,5]oxadiazolo[3,4-b]pyridine-6-carboxylate1-oxide (12b). Yield 0.79 g (88%), yellow solid, mp 104-106C (mp 106.5-107.5C25). 1H NMR spectrum (DMSO-d6),δ, ppm: 9.21 (1H, br. s, H Ar); 8.69 (1H, br. s, H Ar); 3.94(3H, s, OCH3). Found, m/z: 196.0348 [M+H]+. C7H6N3O4.Calculated, m/z: 196.0353
With hydrogen bromide; bromine; sodium nitrite; In water; at 0 - 20℃; for 1h;
To a solution of intermediate 32a (10.0 g, 57.6 mmol) in HBr [(31 .0 mL (100%), 286.4 mmol)] at 0 00 sodium nitrite (13.8 g, 199.9 mmol) was added drop wise. To the stirred solution Br2 (10.0 mL, 197.1 mmol) was added in water and stirred at room temperature for 1 h. The reaction mixture was basified with NaHCO3 solution (pH=7) and extracted with ethyl acetate, washed with water, and dried over anhydrousNa2SO4 The solvent was removed under vacuo to yield the title product (10.0 g,73.0%) as a yellow solid.
73%
With hydrogen bromide; bromine; sodium nitrite; In water; at 0 - 20℃; for 1h;
To a solution of intermediate 32a (10.0 g, 57.6 mmol) in HBr [(31.0 mL (100%), 286.4 mmol)] at 0 00, sodium nitrite (13.8 g, 199.9 mmol) was added drop wise. To the stirred solution Br2 (10.0 mL, 197.1 mmol)in water was added and stirred at roomtemperature for 1 h. The reaction mixture was basified with NaHCO3 solution (PH=7) and extracted with ethyl acetate, washed with water, and dried over anhydrous Na2SO4 The solvent was removed under vacuo to yield the title product (10.0 g, 73.0%) as a yellow solid.
51.5%
With sodium hydroxide; hydrogen bromide; bromine; sodium nitrite; In ethanol; water;
2-Bromo-5-chloro-3-nitropyridine (103) To a stirred, ice bath cooled solution of HBr (48%, 214 mL, d=1.49, 1.89 mol) was added 2-amino-5-chloro-3-nitropyridine (2) (66.0 g, 376 mmol). The mixture was stirred until the internal temperature was less than 0 C., and then bromine (65 mL, d=3.102, 1.3 mol) was added dropwise. The resulting orange mixture was stirred at a temperature below 0 C. A solution of NaNO2 (91.3 g, 1.32 mol, used as received) in water (125 mL) was added slowly to the mixture so as to maintain the internal temperature below 0 C. The mixture was stirred for an additional 45 min at below 0 C., and then NaOH (139.3 g, 3.482 mol) in water (200 mL) was slowly added to the mixture to maintain the internal temperature below 20 C. The mixture was stirred at below 20 C. for an additional hour, and then gravity filtered. The recovered brown solid was dried at 25 C. under vacuum for 6 h. It was purified by recrystalization from 95% ethanol to obtain 103 as a yellow solid (46.0 g, 51.5%), mp 68-73 C. (Lit., 75 C., Berrie et al., J. Chem. Soc. 2042 (1952)); 1 H NMR (CDCl3): delta8.15 (d, J=2.1 Hz, 1H), 8,57 (d, J=2.1 Hz, 1H).
PREPARATION 62 5-Chloro-2,3-diaminopyridine A procedure similar to that described in Preparation 42 was repeated, except that 12.5 g of <strong>[5409-39-2]2-amino-5-chloro-3-nitropyridine</strong> (prepared as described in Preparation 61) 82.0 g of tin(II) chloride dihydrate, 1.35 g of sodium borohydride and 300 ml of a 9:1 by volume mixture of ethyl acetate and 2-methyl-2-propanol were used, to give the title compound as a crude product.
PREPARATION 61 2-Amino5-chloro-3-nitropyridine A procedure similar to that described in Preparation 56 was repeated, except that 25.0 g of 2-amino-5-chloropyridine, 100 ml of concentrated sulfuric acid and 12.5 ml of concentrated nitric acid were used, to give 18.5 g of the title compound, melting at 138-139 C.
To 150 mL of conc. H2 SO4 was added 42.96 g (334 mmol) of 2-amino-5-chloropyridine in portions with stirring and cooling (ice-water bath). To the resulting solution was added dropwise 22.5 mL of 69-71% HNO3 (355 mmol) at 50 C. (at such a rate that maintain the temperature within 50-55 C.) over 1 h. The resulting mixture was stirred at 60 C. for 3 h, poured into ice-water (about 1,500 mL) with stirring, then basified to pH 9 by the addition of 40% aq NaOH with stirring and cooling. The precipitate was filtered, washed with water (6*50 mL), and dried to give 32.47 g (56%) of 2 as a yellow powder, mp 190-191 C. (lit. 191-2 C. (Israel, M. & Day, A. R., J. Org. Chem. 24:1455-1460 (1959))). 1 H NMR (DMSO-d6), 8.044-8.055 (m, 3H), 8.054 (d, 1H, J=3.9).
2-Amino-5-chloro-3-nitropyridine (102) Concentrated H2 SO4 (97%, 300 mL) was placed in a 500 mL three-neck round-bottom flask. The flask was equipped with an internal thermometer, a glass funnel and stopper, and placed in a salt/ice bath. When the internal temperature reached 5 C., 2-amino-5-chloropyridine (101) (77.2 g, 0.600 mol) was added over 1 h with stirring. The suspension was then stirred at room temperature to dissolve the rest of the solid. The resulting solution was heated to 55 C. HNO3 (70%, 40.5 mL, d=1.41, 0.634 mol) was added dropwise through an addition funnel as to maintain the internal temperature at 57+-3 C. The reaction solution was poured over ice (1.5 kg), and the resulting mixture partially neutralized with 40% NaOH (~600 mL). The mixture was filtered to leave a yellow/orange solid. This solid was washed by resuspension in water (600 mL). The mixture was filtered, and the resulting solid was dried in the oven for 48 h to yield the title compound as an orange/yellow solid (66.3 g, 63.8%), mp 184-6 C. (Lit., 190-3 C., Vaughan et al., J. Amer. Chem. Soc. 71:1885 (1949)); 1 H NMR (CDCl3): δ6.69 (bs, 2H), 8.33 (d, J=1.5 Hz, 1H), 8.43 (d, J=1.5 Hz, 1H).
5-Chloro-3-nitro-2-aminopyridine is treated with pentafluoropropionic anhydride to obtain 5-chloro-3-nitro-2-(pentafluoropropionamido)pyridine, which when hydrogenated in the presence of palladium on carbon yields 6-chloro-1-hydroxy-2-(pentafluoroethyl)-1H-imidazo(4,5-b)pyridine, m.p., 240-42C.
palladium;
5-Chloro-3-nitro-2-aminopyridine is treated with pentafluoropropionic anhydride to obtain 5-chloro-3-nitro-2-(pentafluoropropionamido)pyridine, which when hydrogenated in the presence of palladium on carbon yields 6-chloro-1-hydroxy-2-(pentafluoroethyl)-1H-imidazo(4,5-b)pyridine, m.p., 240-42C.
palladium;
5-Chloro-3-nitro-2-aminopyridine is treated with pentafluoropropionic anhydride to obtain 5-chloro-3-nitro-2-(pentafluoropropionamido)pyridine, which when hydrogenated in the presence of palladium on carbon yields 6-chloro-1-hydroxy-2-(pentafluoroethyl)-1H-imidazo(4,5-b)pyridine, m.p., 240-42 C.
5-chloro-3-nitro-2-(heptafluorobutyramido)pyridine[ No CAS ]
[ 55989-44-1 ]
Yield
Reaction Conditions
Operation in experiment
5-Chloro-3-nitro-2-aminopyridine is reacted with heptafluorobutyric anhydride to obtain 5-chloro-3-nitro-2-(heptafluorobutyramido)pyridine which when hydrogenated yields 6-chloro-1-hydroxy-2-(heptafluoro-n-propyl)-1H-imidazo(4,5-b)-pyridine.
5-Chloro-3-nitro-2-aminopyridine is reacted with heptafluorobutyric anhydride to obtain 5-chloro-3-nitro-2-(heptafluorobutyramido)pyridine which when hydrogenated yields 6-chloro-1-hydroxy-2-(heptafluoro-n-propyl)-1H-imidazo(4,5-b)pyridine.
With pyridine; trifluoroacetic anhydride; In chloroform; trifluoroacetic acid;
EXAMPLE 2: 5-CHLORO-3-NITRO-2-(TRIFLUOROACETAMIDO)PYRIDINE The compound of Example 1 was also synthesised by dissolving the 5-chloro-3-nitro-2-aminopyridine (5.0 grams) in a minimum amount of warm trifluoroacetic acid, and then adding 1.5 equivalents of trifluoroacetic anhydride and 0.5 milliliters of pyridine and refluxing for about an hour. The reaction mixture was then poured onto ice to precipitate the 5-chloro-3-nitro-2-(trifluoroacetamido)pyridine compound, which was separated, dissolved in chloroform, and washed twice with water. Thereafter, the solution was shaken with activated carbon and filtered, and chloroform removed under vacuum to obtain a purified product. It was further recrystallized from a low boiling (40-50C.) petroleum ether, m.p., 104-05C.
With pyridine; trifluoroacetic anhydride; In chloroform; trifluoroacetic acid;
EXAMPLE 2 5-CHLORO-3-NITRO-2-(TRIFLUOROACETAMIDO)PYRIDINE The compound of Example 1 was also synthesised by dissolving the 5-chloro-3-nitro-2-aminopyridine (5.0 grams) in a minimum amount of warm trifluoroacetic acid, and then adding 1.5 equivalents of trifluoroacetic anhydride and 0.5 milliliters of pyridine and refluxing for about an hour. The reaction mixture was then poured onto ice to precipitate the 5-chloro-3-nitro-2-(trifluoroacetamido)pyridine compound, which was separated, dissolved in chloroform, and washed twice with water. Thereafter, the solution was shaken with activated carbon and filtered, and chloroform removed under vacuum to obtain a purified product. It was further recrystallized from a low boiling (40-50C.) petroleum ether, m.p., 104-05C.
With pyridine; trifluoroacetic anhydride; In chloroform; trifluoroacetic acid;
EXAMPLE 2 5-CHLORO-3-NITRO-2-(TRIFLUOROACETAMIDO)PYRIDINE The compound of Example 1 was also synthesised by dissolving the 5-chloro-3-nitro-2-aminopyridine (5.0 grams) in a minimum amount of warm trifluoroacetic acid, and then adding 1.5 equivalents of trifluoroacetic anhydride and 0.5 milliliters of pyridine and refluxing for about an hour. The reaction mixture was then poured onto ice to precipitate the 5-chloro-3-nitro-2-(trifluoroacetamido)pyridine compound, which was separated, dissolved in chloroform, and washed twice with water. Thereafter, the solution was shaken with activated carbon and filtered, and chloroform removed under vacuum to obtain a purified product. It was further recrystallized from a low boiling (40-50 C.) petroleum ether, m.p., 104-05 C.
EXAMPLE 1: 5-CHLORO-3-NITRO-2-(TRIFLUOROACETAMIDO)PYRIDINE 5-Chloro-3-nitro-2-aminopyridine (5.0 grams) and excess trifluoroacetic anhydride were refluxed together for 24 hours. TLC showed no reaction had taken place. Pyridine (2.0 ml.) was then added. After fifteen minutes the solution solidified. The product was dissolved in chloroform and washed twice with water, and the chloroform was then evaporated under vacuum. The resulting product residue was recrystallized from a mixture of benzene and aliphatic naphtha: m.p., 104-05C., yield 6.0 g.
With pyridine; In chloroform;
EXAMPLE 1 5-CHLORO-3-NITRO-2-(TRIFLUOROACETAMIDO)PYRIDINE 5-Chloro-3-nitro-2-aminopyridine (5.0 grams) and excess trifluoroacetic anhydride were refluxed together for 24 hours. TLC showed no reaction had taken place. Pyridine (2.0 ml.) was then added. After fifteen minutes the solution solidified. The product was dissolved in chloroform and washed twice with water, and the chloroform was then evaporated under vacuum. The resulting product residue was recrystallized from a mixture of benzene and aliphatic naphtha: m.p., 104-05C., yield 6.0 g.
With pyridine; In chloroform;
EXAMPLE 1 5-CHLORO-3-NITRO-2-(TRIFLUOROACETAMIDO)PYRIDINE 5-Chloro-3-nitro-2-aminopyridine (5.0 grams) and excess trifluoroacetic anhydride were refluxed together for 24 hours. TLC showed no reaction had taken place. Pyridine (2.0 ml.) was then added. After fifteen minutes the solution solidified. The product was dissolved in chloroform and washed twice with water, and the chloroform was then evaporated under vacuum. The resulting product residue was recrystallized from a mixture of benzene and aliphatic naphtha: m.p., 104-05 C., yield 6.0 g.
5-chloro-3-nitro-2-(2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-pentafluorooctanamido)pyridine[ No CAS ]
[ 55989-36-1 ]
Yield
Reaction Conditions
Operation in experiment
5-Chloro-3-nitro-2-aminopyridine is reacted with perfluorooctanoic anhydride to obtain 5-chloro-3-nitro-2-(2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-pentafluorooctanamido)pyridine, which on hydrogenation yields 6-chloro-1-hydroxy-2-(perfluoro-n-heptyl)-1H-imidazo(4,5-b)pyridine.
6-chloro-1-hydroxy-2-(1,1-difluoroethyl)-1H-imidazo(4,5-b)pyridine[ No CAS ]
5-chloro-3-nitro-2-(2,2-difluoropropionamido)pyridine[ No CAS ]
Yield
Reaction Conditions
Operation in experiment
palladium;
5-Chloro-3-nitro-2-aminopyridine is reacted with 2,2-difluoropropionic anhydride to obtain 5-chloro-3-nitro-2-(2,2-difluoropropionamido)pyridine, which on hydrogenation in the presence of palladium on calcium sulfate yields 6-chloro-1-hydroxy-2-(1,1-difluoroethyl)-1H-imidazo(4,5-b)pyridine.
INTERMEDIATE 16-οΜθΓθ-5-οο-2-( 6ν3^ηγ1>-1Η-^8ζο f4,5-b1 pyridineStep A 5, 6-dichloro-3 -nitropyridin-2-amine. To a solution of <strong>[5409-39-2]5-chloro-3-nitropyridin-2-amine</strong> (16 g, 92 mmol) in AcOH (70 mL) was added N-chlorosuccinimide (14.8 g i l l mmol). The mixture was stirred overnight at 80 C for 3 h, cooled to rt, diluted with MeOH (30 mL) and filtered. The solid residue was washed with AcOH, water, and then dried to afford the desired product as a white solid, which was used in the next step without further purification. LC-MS: calculated for C5H3Cl2N302 208.0, observed m/e: 208.07 (M+H)+ (Rt 1.48/5 min).
With N-chloro-succinimide; acetic acid; at 80℃; for 3h;
To a solution of <strong>[5409-39-2]5-chloro-3-nitropyridin-2-amine</strong> (16 g, 92 mmol) in AcOH (70 mL) was added N-chlorosuccinimide (14.8 g 111 mmol). The mixture was stirred overnight at 80 C. for 3 h, cooled to rt, diluted with MeOH (30 mL) and filtered. The solid residue was washed with AcOH, water, and then dried to afford the desired product as a white solid, which was used in the next step without further purification. LC-MS: calculated for C5H3Cl2N3O2 208.0, observed m/e: 208.07 (M+H)+ (Rt 1.48/5 min).
With N-chloro-succinimide; acetic acid; at 80℃; for 3h;
Step A 5,6-dichioro-3-nitropyridin-2-amine10552] To a solution of <strong>[5409-39-2]5-chloro-3-nitropyridin-2-amine</strong> (16 g, 92 mmol) in AcOR (70 mE) was added N-chlorosuccinimide (14.8 g 111 mmol). The mixture was stirred overnight at 80 C. for 3 h, cooled to rt, diluted with MeOR (30 mE) and filtered. The solid residue was washed with AcOR, water, and then dried to afford the desired product as a white solid, which was used in the next step without thrther purification. EC-MS: calculated for C5H3C12N302 208.0. observed mle: 208.07 (M+H) (Rt 1.48/5 mm).
With N-chloro-succinimide; acetic acid; at 80℃;
To a solution of <strong>[5409-39-2]5-chloro-3-nitropyridin-2-amine</strong> (16 g, 92 mmol) in AcOH (70 mL) was added N-chlorosuccinimide (14.8 g 111 mmol). The mixture was stirred overnight at 80 C. for 3 h, cooled to rt, diluted with MeOH (30 mL) and filtered. The solid residue was washed with AcOH, water, and then dried to afford the desired product as a white solid, which was used in the next step without further purification. LC-MS: calculated for C5H3Cl2N3O2 208.0, observed m/e: 208.07 (M+H)+ (Rt 1.48/5 min)
With N-chloro-succinimide; acetic acid; at 80℃; for 3h;
To a solution of <strong>[5409-39-2]5-chloro-3-nitropyridin-2-amine</strong> (16 g, 92 mmol) in AcOH (70 mL) was added N-chlorosuccinimide (14.8 g 111 mmol). The mixture was stirred overnight at 80 C. for 3 h, cooled to rt, diluted with MeOH (30 mL) and filtered. The solid residue was washed with AcOH, water, and then dried to afford the desired product as a white solid, which was used in the next step without further purification. LC-MS: calculated for C5H3Cl2N3O2 208.0, observed m/e: 208.07 (M+H)+ (Rt 1.48/5 min).
With N-chloro-succinimide; acetic acid; at 80℃; for 3h;
To a solution of <strong>[5409-39-2]5-chloro-3-nitropyridin-2-amine</strong> (16 g, 92mmol) in AcOR (70 mE) was added N-chlorosuccinimide(14.8 g 111 mmol). The mixture was stirred overnight at 80 C. for 3 h, cooled to rt, diluted with MeOR (30 mE) and filtered. The solid residue was washed with AcOR, water, and then dried to afford the desired product as a white solid,which was used in the next step without further purification. EC-MS: calculated for C5H3C12N302 208.0. observed mle:208.07 (M+H) (Rt 1.48/5 mm).
(R)-(4′-(6-chloro-2-(methylsulfonyl)-1-((2 (trimethylsilyl)ethoxy)methyl)-1H-imidazo[4,5-b]pyridin-5-yl)[1,1′-biphenyl]-4-yl)(3-((2-(trimethylsilyl)ethoxy)methoxy)pyrrolidin-1-yl)methanone[ No CAS ]
Multi-step reaction with 9 steps
1.1: acetic acid; N-chloro-succinimide / 18 h / 80 °C
2.1: acetic acid; sodium iodide / 2 h / 90 °C
3.1: tin(II) chloride dihdyrate / ethanol / 0.5 h / 70 °C
4.1: dmap / tetrahydrofuran / 1 h / 22 °C / Inert atmosphere
5.1: potassium hydroxide / ethanol / 0.5 h / 22 °C
5.2: 1 h / 22 °C
6.1: Oxone / acetonitrile; water / 18 h / 22 °C
7.1: potassium phosphate; palladium diacetate; di(adamantan-1-yl)(butyl)phosphine / tetrahydrofuran; water / 18 h / 45 °C
8.1: triethylamine / tetrahydrofuran / 0.25 h / 0 - 22 °C
9.1: 1,8-diazabicyclo[5.4.0]undec-7-ene / N,N-dimethyl acetamide / 18 h / 22 °C
9.2: 18 h / 22 °C
9.3: 18 h / 0 - 22 °C
4-(6-amino-5-nitropyridin-3-yl)-1-fluorenylmethoxycarbonylpiperazine[ No CAS ]
Yield
Reaction Conditions
Operation in experiment
89.8%
With N-ethyl-N,N-diisopropylamine; In N,N-dimethyl-formamide; at 20℃; for 8h;
Will be dissolved in the compound monoterpene methoxycarbonyl piperazine (3.39g, 11mmol)2-Amino-3-nitro-5-chloropyridine (1.73 g, 10 mmol) and diisopropylethylamine (1.55 g, 12 mmol) were added to dimethylformamide (10 mL).After reacting for 8 hours at room temperature, the solvent was removed under reduced pressure and the residue was separated by flash column chromatography.(dichloromethane:methanol = 50:1) gave solid compound II-3 (4.0 g,The yield was 89.8%).
tert-butyl 4-(6-amino-5-nitropyridin-3-yl)piperazine-1-carboxylate[ No CAS ]
Yield
Reaction Conditions
Operation in experiment
86.7%
With N-ethyl-N,N-diisopropylamine; In N,N-dimethyl-formamide; at 20℃; for 8h;
Will dissolveMono-tert-butoxycarbonylpiperazine(2.05 g, 11 mmol) of dimethylformamide(10 mL) was added <strong>[5409-39-2]2-amino-3-nitro-5-chloropyridine</strong> (1.73 g, 10 mmol) andDiisopropylethylamine (1.55 g, 12 mmol) was reacted at room temperature for 8 hours, then the solvent was evaporated under reduced pressure. 2.8 g, yield 86.7%).
N-(5-chloro-3-nitropyridin-2-yl)chloracetamide[ No CAS ]
Yield
Reaction Conditions
Operation in experiment
92%
In N,N-dimethyl-formamide; at 20℃; for 16h;Cooling with ice;
Nitroaminopyridine 1 (1.00g, 5.76mmol) was suspended in anhydrous DMF (1mL) and a solution of chloroacetyl chloride (1.83mL, 23.04mmol) in DMF (1mL) was added dropwise under stirring and cooling with an ice bath. After the addition was completed the reaction mixture was allowed to stir at room temperature for 16h and then poured into ice and diluted with water. The resulting precipitate was filtered, washed with water and dried to yield pure compound 7 (1.32g, 92%). mp 111-112C (EtOAc/pentane); 1H NMR (600MHz, CDCl3) δ 4.35 (s, 2H, H-2), 8.52 (d, J=2.2Hz, 1H, H-4), 8.68 (d, J=2.2Hz, 1H, H-6), 10.73 (br s, 1H, D2O exchangeable, NH); 13C NMR (50MHz, CDCl3) δ 43.6 (C-2), 127.50 (C-5), 133.6 (C-3), 134.3 (C-4), 143.0 (C-2), 152.7 (C-6), 164.6 (C-1); HR-MS (ESI) m/z: Calcd for C7H4Cl2N3O3: [M-H]-=247.9635, found 247.9632.
N-(5-chloro-3-nitropyridin-2-yl)-3-chloropropanamide[ No CAS ]
Yield
Reaction Conditions
Operation in experiment
82%
In N,N-dimethyl-formamide; at 20℃; for 16h;Cooling with ice;
General procedure: Nitroaminopyridine 1 (1.00g, 5.76mmol) was suspended in anhydrous DMF (1mL) and a solution of chloroacetyl chloride (1.83mL, 23.04mmol) in DMF (1mL) was added dropwise under stirring and cooling with an ice bath. After the addition was completed the reaction mixture was allowed to stir at room temperature for 16h and then poured into ice and diluted with water. The resulting precipitate was filtered, washed with water and dried to yield pure compound 7 (1.32g, 92%). mp 111-112C (EtOAc/pentane); 1H NMR (600MHz, CDCl3) δ 4.35 (s, 2H, H-2), 8.52 (d, J=2.2Hz, 1H, H-4), 8.68 (d, J=2.2Hz, 1H, H-6), 10.73 (br s, 1H, D2O exchangeable, NH); 13C NMR (50MHz, CDCl3) δ 43.6 (C-2), 127.50 (C-5), 133.6 (C-3), 134.3 (C-4), 143.0 (C-2), 152.7 (C-6), 164.6 (C-1); HR-MS (ESI) m/z: Calcd for C7H4Cl2N3O3: [M-H]-=247.9635, found 247.9632.
With tin dioxide; iodine; In toluene; at 110℃; for 12h;
General procedure: A mixture of 2-aminopyridine (1a, 1 mmol), 1,3-diphenyl-2-propen-1-one (2a, 1 mmol), SnO2 (10 mol %) and I2 (0.5 equivalent) were refluxed in toluene for 12 h. The reaction was monitored by TLC. After completion of the reaction, the resulting reaction mixture was cooled to room temperature and dissolved in ethyl acetate and the catalyst was separated using centrifugation. The obtained filtrate containing the product was washed using a saturated Na2S2O3 solution (15 mL) and then acidified with the 1N HCl (3 × 7 mL). After that, the aqueous acidic layer was separated and neutralized using a 1N NaOH solution. The precipitated product was filtered off and then confirmed by 1H and 13C NMR spectroscopic methods. .
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