Reference：
[1] Journal of Medicinal Chemistry, 2015, vol. 58, # 9, p. 3997 - 4015
[2] Recueil des Travaux Chimiques des Pays-Bas, 1927, vol. 46, p. 661,923
2
[ 57319-65-0 ]
[ 151-50-8 ]
[ 89877-62-3 ]
Reference：
[1] Chemische Berichte, 1934, vol. 67, p. 675,681
[2] Bulletin de la Societe Scientifique de Bretagne, 1951, vol. 26, p. Sonderheft 5, S. 7, 96[3] Comptes Rendus Hebdomadaires des Seances de l'Academie des Sciences, 1952, vol. 235, p. 962
3
[ 610-93-5 ]
[ 57319-65-0 ]
Yield
Reaction Conditions
Operation in experiment
87%
With hydrogen In tetrahydrofuran; methanol at 20℃; for 20 h;
Commercially available 6-nitro-1(3H)-isobenzofuranone (9.9 g, 55 mmol) was dissolved in a mixed solvent of tetrahydrofuran (20 ml)-methanol (60 ml), then 5percent palladium-charcoal catalyst (1.5 g) was added thereto, and the mixture was stirred at room temperature for 20 hours under an atmosphere of hydrogen gas. The reaction mixture was filtered, and the solid was washed successively with ethyl acetate and methanol. The filtrate and washings were combined, and the resulting solution was concentrated under reduced pressure. The obtained solid was washed with ethyl acetate to give the title compound (6.21 g) as a crystalline solid. The washings were concentrated, and the residue was crystallized from a mixed solvent of ethyl acetate-hexane to give an additional amount of the title compound (0.95 g, total yield 87percent). NMR spectrum (400 MHz, CD3OD) δ ppm: 5.225 (2H, s), 7.060 (1H, d-like, J=2 Hz), 7.071 (1H, dd-like, J=9, 2 Hz), 7.288 (1H, d, J=9 Hz) IR spectrum ν max KBr cm-1: 3473, 3372, 3278, 1735, 1631, 1504, 1330, 1059, 992.
86%
With palladium on carbon; hydrogen In methanol at 20℃; for 12 h;
6-Nitro-3H-isobenzofuran-1-one 1)> (2.00 g, 11.1 mmol) was dissolved in methanol (25 ml), and 20percent palladium/ carbon (200 mg) was added thereto, followed by stirring at room temperature for 12 hours in the presence of hydrogen gas (50 psi). The reaction solution was filtered and concentrated under reduced pressure to obtain the title compound (1.43 g, 86percent). [1326] 1H NMR (400 MHz, DMSO-d6): δ 7.30 (d, J=8.0 Hz, 1H), 6.96 (dd, J=8.0, 2.0 Hz, 1H), 6.91 (d, J=4.0 Hz, 1H), 5.56 (s, 2H), 5.21 (s, 2H)
78%
With hydrogenchloride; tin(ll) chloride In water for 4 h; Heating / reflux
Step b: 6-Aminoisobenzofuran-1(3H)-one To a solution of 6-nitroisobenzofuran-1(3H)-one (15 g, 0.080 mol) in HCl/H2O (375 mL/125 mL) was added SnCl2.2H2O (75 g, 0.33 mol). The reaction mixture was heated at reflux for 4 h before it was quenched with water and extracted with EtOAc (300 mL*3). The organics were dried over Na2SO4 and evaporated in vacuo to give 6-aminoisobenzofuran-1(3H)-one (10 g, 78percent). 1H NMR (300 MHz, CDCl3) δ 7.23 (d, J=8.1, 1H), 7.13 (d, J=2.1, 1H), 6.98 (dd, J=8.1, 2.1, 1H), 5.21 (s, 2H), 3.99 (br s, 2H).
78%
With hydrogenchloride; tin(II) chloride dihdyrate In water for 4 h; Reflux
To a solution of 6-nitroisobenzofuran-1(3H)-one (15 g, 0.080 mol) in HCl/H2O (375 mL/125 mL) was added SnCl2.2H2O (75 g, 0.33 mol). The reaction mixture was heated at reflux for 4 h before it was quenched with water and extracted with EtOAc (300 mL*3). The organics were dried over Na2SO4 and evaporated in vacuo to give 6-aminoisobenzofuran-1(3H)-one (10 g, 78percent). 1H NMR (300 MHz, CDCl3) δ 7.23 (d, J=8.1, 1H), 7.13 (d, J=2.1, 1H), 6.98 (dd, J=8.1, 2.1, 1H), 5.21 (s, 2H), 3.99 (br s, 2H).
75%
With indium (III) iodide; 1,1,3,3-Tetramethyldisiloxane In toluene at 60℃; for 4 h; Inert atmosphere; Sealed tube
General procedure: To a screw top vial (5 mL) under N2 containing freshly distilled toluene (0.6 mL) were successively added an aromatic nitro compound (0.60 mmol), InI3 (14.9 mg, 0.030 mmol), and TMDS (318 μL, 1.80 mmol). After the vial was sealed with a cap that contained a PTFE septum, the mixture was stirred at 60 °C (bath temperature), and monitored via TLC analysis. Sat. aq NaHCO3 solution (5 mL) was added to the resultant mixture, which was then extracted with EtOAc (3 × 6 mL). The combined organic phases were dried over anhydrous Na2SO4, filtered, and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography (n-hexane–EtOAc, 9:1 to 4:1) to afford the corresponding aniline derivative.
Reference：
[1] Physical Chemistry Chemical Physics, 2005, vol. 7, # 24, p. 4070 - 4081
[2] Chemistry - A European Journal, 2016, vol. 22, # 13, p. 4600 - 4607
[3] ACS Catalysis, 2014, vol. 4, # 10, p. 3504 - 3511
[4] Patent: EP1362856, 2003, A1, . Location in patent: Page/Page column 159
[5] Journal of Heterocyclic Chemistry, 2006, vol. 43, # 5, p. 1195 - 1204
[6] Catalysis Letters, 2014, vol. 144, # 7, p. 1258 - 1267
[7] Patent: US2015/51395, 2015, A1, . Location in patent: Paragraph 1325-1326
[8] Journal of Heterocyclic Chemistry, 1992, vol. 29, # 6, p. 1519 - 1523
[9] Patent: US2008/9524, 2008, A1, . Location in patent: Page/Page column 409; 409-410
[10] Journal of Organic Chemistry, 2009, vol. 74, # 18, p. 6960 - 6964
[11] Patent: US2015/231142, 2015, A1, . Location in patent: Paragraph 1264
[12] European Journal of Medicinal Chemistry, 1987, vol. 22, p. 229 - 238
[13] Chemistry of Heterocyclic Compounds, 2010, vol. 46, # 2, p. 140 - 145
[14] Synthesis (Germany), 2015, vol. 47, # 20, p. 3179 - 3185
[15] Journal of the American Chemical Society, 1937, vol. 59, p. 864
[16] Patent: US2130480, 1935, ,
[17] Chemische Berichte, 1934, vol. 67, p. 675,681
[18] Tetrahedron, 1988, vol. 44, # 14, p. 4591 - 4604
[19] Journal of Medicinal Chemistry, 1993, vol. 36, # 22, p. 3417 - 3423
[20] Patent: US4409017, 1983, A,
[21] Bioorganic and Medicinal Chemistry, 2009, vol. 17, # 8, p. 3177 - 3188
[22] Chemical Biology and Drug Design, 2010, vol. 76, # 1, p. 25 - 33
[23] Organic Letters, 2012, vol. 14, # 14, p. 3748 - 3751
[24] Bioorganic and Medicinal Chemistry Letters, 2013, vol. 23, # 4, p. 1063 - 1069
[25] Bioorganic and Medicinal Chemistry Letters, 2013, vol. 23, # 5, p. 1269 - 1273
[26] Journal of Medicinal Chemistry, 2015, vol. 58, # 9, p. 3997 - 4015
[27] Bioorganic and Medicinal Chemistry, 2016, vol. 24, # 22, p. 5929 - 5940
[28] European Journal of Organic Chemistry, 2018, vol. 2018, # 2, p. 209 - 214
[29] Applied Catalysis A: General, 2018, vol. 559, p. 127 - 137
[30] Research on Chemical Intermediates, 2018, vol. 44, # 9, p. 5107 - 5122
4
[ 610-93-5 ]
[ 10025-69-1 ]
[ 57319-65-0 ]
Reference：
[1] Patent: US2011/98311, 2011, A1,
5
[ 87-41-2 ]
[ 57319-65-0 ]
Reference：
[1] Journal of Heterocyclic Chemistry, 2006, vol. 43, # 5, p. 1195 - 1204
[2] Journal of Medicinal Chemistry, 1993, vol. 36, # 22, p. 3417 - 3423
[3] Chemische Berichte, 1934, vol. 67, p. 675,681
[4] Chemical Biology and Drug Design, 2010, vol. 76, # 1, p. 25 - 33
[5] Patent: US2011/98311, 2011, A1,
[6] Bioorganic and Medicinal Chemistry Letters, 2013, vol. 23, # 4, p. 1063 - 1069
[7] Patent: US2015/51395, 2015, A1,
[8] Journal of Medicinal Chemistry, 2015, vol. 58, # 9, p. 3997 - 4015
[9] Patent: US2015/231142, 2015, A1,
6
[ 5466-84-2 ]
[ 57319-65-0 ]
Reference：
[1] European Journal of Medicinal Chemistry, 1987, vol. 22, p. 229 - 238
7
[ 85-44-9 ]
[ 57319-65-0 ]
Reference：
[1] Chemical Biology and Drug Design, 2010, vol. 76, # 1, p. 25 - 33
8
[ 57319-65-0 ]
[ 19477-73-7 ]
Yield
Reaction Conditions
Operation in experiment
84%
With hydrogen bromide; copper(I) bromide; sodium nitrite In water at 0℃; for 0.333333 h;
Step c: 6-Bromoisobenzofuran-1(3H)-one A solution of NaNO2 (2.2 g, 0.040 mol) in H2O (22 mL) was added to a mixture of 6-aminoisobenzofuran-1(3H)-one (5.0 g, 0.030 mol) in HBr (70 mL, 48percent) over 5 min at 0° C. The mixture was stirred for 20 minutes before it was pipetted into an ice cold solution of CuBr (22 g, 0.21 mol) in HBr (48percent, 23 mL). The resulting dark brown mixture was stirred for 20 min and was then diluted with H2O (200 mL) to produce an orange precipitate. The precipitate was filtered off, treated with sat. NaHCO3 solution, and extracted with EtOAc (20 mL*3). The organics were dried over Na2SO4 and evaporated in vacuo to give 6-bromoisobenzofuran-1(3H)-one (5.4 g, 84percent). 1H NMR (300 MHz, CDCl3) δ 8.05 (d, J=1.8, 1H), 7.80 (dd, J=8.1, 1.8, 1H), 7.39 (d, J=8.1, 1H), 5.28 (s, 2H).
84%
With hydrogen bromide; copper(I) bromide; sodium nitrite In water at 0 - 80℃; for 0.333333 h;
6-Amino-1(3H)-isobenzofuranone (3.0 g, 20 mmol) obtained from Example 26-(1) was dissolved in a mixture of 47percent aqueous hydrobromic acid solution (15 ml) and water (15 ml), then the mixture was cooled to 0°C, and a solution of sodium nitrite (1.45 g, 21 mmol) in water (7 ml) was slowly added thereto. Further, a solution of copper (I) bromide (3.6 g, 25 mmol) dissolved in 47percent aqueous hydrobromic acid solution (10 ml) was added to the reaction mixture, and the resulting mixture was stirred at 80°C for 20 minutes. After cooling the mixture, the liberated product was collected by filtration and then washed with water. The obtained pale brown solid was dissolved in ethyl acetate, then the insoluble material was removed by filtration, and the filtrate was washed successively with a 1N aqueous solution of hydrochloric acid, an aqueous solution of sodium hydrogen carbonate, and an aqueous solution of sodium chloride, and then dried over anhydrous magnesium sulfate. After filtration, the filtrate was concentrated to afford the title compound (3.57 g, 84percent yield) as a crystalline solid. NMR spectrum (400 MHz, CDCl3) δ ppm: 5.289 (2H, s), 7.391 (1H, d, J=8 Hz), 7.808 (1H, dd, J=8, 2 Hz), 8.068 (1H, d, J=2 Hz) IR spectrum ν max KBr cm-1: 1778, 1458, 1359, 1191, 1046, 998, 768 Mass spectrum m/z (EI): 214, 212 (M+), 185, 183, 157, 155.
84%
Stage #1: With hydrogen bromide; sodium nitrite In water at 0℃; for 0.333333 h; Stage #2: With copper(I) bromide In water for 0.333333 h; Cooling with ice
A solution of NaNO2 (2.2 g, 0.040 mol) in H2O (22 mL) was added to a mixture of 6-aminoisobenzofuran-1(3H)-one (5.0 g, 0.030 mol) in HBr (70 mL, 48percent) over 5 min at 0° C. The mixture was stirred for 20 minutes before it was pipetted into an ice cold solution of CuBr (22 g, 0.21 mol) in HBr (48percent, 23 mL). The resulting dark brown mixture was stirred for 20 min and was then diluted with H2O (200 mL) to produce an orange precipitate. The precipitate was filtered off, treated with sat. NaHCO3 solution, and extracted with EtOAc (20 mL*3). The organics were dried over Na2SO4 and evaporated in vacuo to give 6-bromoisobenzofuran-1(3H)-one (5.4 g, 84percent). 1H NMR (300 MHz, CDCl3) δ 8.05 (d, J=1.8, 1H), 7.80 (dd, J=8.1, 1.8, 1H), 7.39 (d, J=8.1, 1H), 5.28 (s, 2H).
Reference：
[1] Patent: US2008/9524, 2008, A1, . Location in patent: Page/Page column 410
[2] Patent: EP1362856, 2003, A1, . Location in patent: Page/Page column 159
[3] Patent: US2015/231142, 2015, A1, . Location in patent: Paragraph 1265
[4] Chemistry of Heterocyclic Compounds, 2010, vol. 46, # 2, p. 140 - 145
[5] Journal of Medicinal Chemistry, 2015, vol. 58, # 9, p. 3997 - 4015
[6] Journal of Heterocyclic Chemistry, 2006, vol. 43, # 5, p. 1195 - 1204
[7] European Journal of Medicinal Chemistry, 2010, vol. 45, # 5, p. 1941 - 1946
[8] Patent: US2011/98311, 2011, A1,
9
[ 57319-65-0 ]
[ 53910-10-4 ]
Reference：
[1] Journal of Medicinal Chemistry, 2015, vol. 58, # 9, p. 3997 - 4015
[2] Journal of Heterocyclic Chemistry, 2006, vol. 43, # 5, p. 1195 - 1204
[3] Bioorganic and Medicinal Chemistry Letters, 2013, vol. 23, # 4, p. 1063 - 1069
10
[ 57319-65-0 ]
[ 23932-84-5 ]
Reference：
[1] European Journal of Medicinal Chemistry, 2010, vol. 45, # 5, p. 1941 - 1946
11
[ 57319-65-0 ]
[ 4506-45-0 ]
Reference：
[1] Journal of Heterocyclic Chemistry, 2006, vol. 43, # 5, p. 1195 - 1204
[2] Chemistry of Heterocyclic Compounds, 2010, vol. 46, # 2, p. 140 - 145
12
[ 57319-65-0 ]
[ 2840-04-2 ]
Reference：
[1] Recueil des Travaux Chimiques des Pays-Bas, 1923, vol. 42, p. 37
With hydrogen;5%-palladium/activated carbon; In tetrahydrofuran; methanol; at 20℃; for 20h;
Commercially available 6-nitro-1(3H)-isobenzofuranone (9.9 g, 55 mmol) was dissolved in a mixed solvent of tetrahydrofuran (20 ml)-methanol (60 ml), then 5% palladium-charcoal catalyst (1.5 g) was added thereto, and the mixture was stirred at room temperature for 20 hours under an atmosphere of hydrogen gas. The reaction mixture was filtered, and the solid was washed successively with ethyl acetate and methanol. The filtrate and washings were combined, and the resulting solution was concentrated under reduced pressure. The obtained solid was washed with ethyl acetate to give the title compound (6.21 g) as a crystalline solid. The washings were concentrated, and the residue was crystallized from a mixed solvent of ethyl acetate-hexane to give an additional amount of the title compound (0.95 g, total yield 87%). NMR spectrum (400 MHz, CD3OD) delta ppm: 5.225 (2H, s), 7.060 (1H, d-like, J=2 Hz), 7.071 (1H, dd-like, J=9, 2 Hz), 7.288 (1H, d, J=9 Hz) IR spectrum nu max KBr cm-1: 3473, 3372, 3278, 1735, 1631, 1504, 1330, 1059, 992.
86%
With palladium on carbon; hydrogen; In methanol; at 20℃; under 2585.81 Torr; for 12h;
6-Nitro-3H-isobenzofuran-1-one 1)> (2.00 g, 11.1 mmol) was dissolved in methanol (25 ml), and 20% palladium/ carbon (200 mg) was added thereto, followed by stirring at room temperature for 12 hours in the presence of hydrogen gas (50 psi). The reaction solution was filtered and concentrated under reduced pressure to obtain the title compound (1.43 g, 86%). [1326] 1H NMR (400 MHz, DMSO-d6): delta 7.30 (d, J=8.0 Hz, 1H), 6.96 (dd, J=8.0, 2.0 Hz, 1H), 6.91 (d, J=4.0 Hz, 1H), 5.56 (s, 2H), 5.21 (s, 2H)
78%
With hydrogenchloride; tin(ll) chloride; In water; for 4h;Heating / reflux;
Step b: 6-Aminoisobenzofuran-1(3H)-one To a solution of <strong>[610-93-5]6-nitroisobenzofuran-1(3H)-one</strong> (15 g, 0.080 mol) in HCl/H2O (375 mL/125 mL) was added SnCl2.2H2O (75 g, 0.33 mol). The reaction mixture was heated at reflux for 4 h before it was quenched with water and extracted with EtOAc (300 mL*3). The organics were dried over Na2SO4 and evaporated in vacuo to give 6-aminoisobenzofuran-1(3H)-one (10 g, 78%). 1H NMR (300 MHz, CDCl3) delta 7.23 (d, J=8.1, 1H), 7.13 (d, J=2.1, 1H), 6.98 (dd, J=8.1, 2.1, 1H), 5.21 (s, 2H), 3.99 (br s, 2H).
78%
With hydrogenchloride; tin(II) chloride dihdyrate; In water; for 4h;Reflux;
To a solution of <strong>[610-93-5]6-nitroisobenzofuran-1(3H)-one</strong> (15 g, 0.080 mol) in HCl/H2O (375 mL/125 mL) was added SnCl2.2H2O (75 g, 0.33 mol). The reaction mixture was heated at reflux for 4 h before it was quenched with water and extracted with EtOAc (300 mL*3). The organics were dried over Na2SO4 and evaporated in vacuo to give 6-aminoisobenzofuran-1(3H)-one (10 g, 78%). 1H NMR (300 MHz, CDCl3) delta 7.23 (d, J=8.1, 1H), 7.13 (d, J=2.1, 1H), 6.98 (dd, J=8.1, 2.1, 1H), 5.21 (s, 2H), 3.99 (br s, 2H).
75%
With indium (III) iodide; 1,1,3,3-Tetramethyldisiloxane; In toluene; at 60℃; for 4h;Inert atmosphere; Sealed tube;
General procedure: To a screw top vial (5 mL) under N2 containing freshly distilled toluene (0.6 mL) were successively added an aromatic nitro compound (0.60 mmol), InI3 (14.9 mg, 0.030 mmol), and TMDS (318 muL, 1.80 mmol). After the vial was sealed with a cap that contained a PTFE septum, the mixture was stirred at 60 C (bath temperature), and monitored via TLC analysis. Sat. aq NaHCO3 solution (5 mL) was added to the resultant mixture, which was then extracted with EtOAc (3 × 6 mL). The combined organic phases were dried over anhydrous Na2SO4, filtered, and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography (n-hexane-EtOAc, 9:1 to 4:1) to afford the corresponding aniline derivative.
palladium; In acetic acid;
(a) <strong>[610-93-5]6-Nitrophthalide</strong> (14.0 g; J A Houbion, J A Miles and J A Paton, Organic Preparations and Procedures International, 11 (1), 27, 1979) in solution in acetic acid was hydrogenated over a palladium on carbon catalyst to give 6-aminophthalide (12.0 g; W R Vaughan and S L Baird, J. Amer. Chem. Soc. 68, 1314, 1946).
With palladium 10% on activated carbon; hydrogen; In ethyl acetate; for 18h;
<strong>[610-93-5]6-Nitrophthalide</strong> (20 mmol) was dissolved in ethyl acetate (200 mL) and methanol (50 mL) and hydrogenated at atmospheric pressure in the presence of 10% Pd/C (0.3 g). After 18 h the reaction mmixture was filtered through a bed of celite and the filtrate was removed under reduced pressure. The residue was washed with cold ethyl acetate (20 mL) to yield 6-aminophthalide.5
With palladium 10% on activated carbon; hydrogen; In methanol; ethyl acetate; for 24h;
<strong>[610-93-5]6-Nitrophthalide</strong> (10 mmol) was dissolved in ethyl acetate (100 mL) and methanol (25 mL) and hydrogenated at atmospheric pressure in the presence of 10% Pd/C (0.2 g). After 24 h the reaction mixture was filtered through a bed of celite and the filtrate was removed under reduced pressure.The residue was washed with cold ethyl acetate (20 mL) to yield 6-aminophthalide. 6-Hydroxyphthalide was synthesized by reacting a cold suspension of 6-aminophthalide (3 mmol) in 10 mL H2SO4 (50%) with a cold solution of NaNO2 (3.5 mmol in 3 mL H2O) to yield the diazonium salt. The resulting solution was added to boiling (125 C) H2SO4 (50%, 20 mL) and the reaction mixture was boiled for 5 min. The reaction was rapidly cooled in an ice bath, and subsequently extracted to diethyl ether (3x20 mL). The ether portions were combined, washed with a saturated solution of NaHCO3 (25 mL) and dried over anhydrous Na2SO4. The ether was removed under reduced pressure, leaving the brown 6-hydroxyphthalide residue. Yield 65%; m.p. 198-200 C; 1H NMR (300MHz, DMSO) delta 5.25 (s, 2H), 7.15-7.18 (m, 2H), 7.39 (d, J=9.0 Hz, 1H); ESI-MS m/z: 150.9 [M+H]+.
With hydrazine hydrate; In ethanol; at 30℃; for 1.33333h;Autoclave;
General procedure: The catalytic reduction of nitro aromatics was conducted in a 25 mlTelfon-lined stainless steel autoclave with magnetic stirring. In a typicalprocess, 6 mmol nitroarene, and desired amounts of reducing agent andsolvents were introduced in the reactor. The autoclave was transferredinto a water bath at the set temperature with an accuracy of better than0.2 C for ?0.5 h. Then, 10 mg catalyst was added into the reactionmixture and started the reduction at a stirring rate of 450 rpm. After thereaction, the catalyst was rapidly separated by ltration. n-Decane(500 muL) as standard was added into the ltrate and was dried withanhydrous Na 2 SO 4 . The products were analyzed by gas chromato-graphy-mass spectrometry (GC-MS) (Shimadzu GCMS-QP2010 Plus)and GC (Varian CP-3800) with a capillary column (column VF-1 ms,15 m, 0.25 mm, 0.25 mum) and a ame ionization detector (FID).
With palladium 10% on activated carbon; hydrogen; In methanol; at 20℃;
A mixture of compounds 12 (10 mmol) and 10% (mass fraction) Pd/C (0.20 g) in MeOH (20 mL) was subjected to standard hydrogenolysis condition at atmospheric pressure (balloon) and room temperature. The progress of the reaction was monitored by TLC. After completion of the reactions, the reaction mixture was filtered off and the filtrate was evaporated on a rotary evaporator to afford the crude products 13, which were used directly in the next step without further purification. Yield: 87%, Mp: 186-187 C. 1H-NMR (CDCl3, 600 MHz), d: 7.28(s, 1H, ArH), 7.11-7.07(m, 1H, ArH), 7.05(dd, J = 8.1Hz, 2.1Hz, 1H, ArH), 5.25(s, 2H), 3.95(s, 2H, NH2). 5110 X. Hu et al. 123
With hydrogen bromide; copper(I) bromide; sodium nitrite; In water; at 0℃; for 0.333333h;
Step c: 6-Bromoisobenzofuran-1(3H)-one A solution of NaNO2 (2.2 g, 0.040 mol) in H2O (22 mL) was added to a mixture of 6-aminoisobenzofuran-1(3H)-one (5.0 g, 0.030 mol) in HBr (70 mL, 48%) over 5 min at 0 C. The mixture was stirred for 20 minutes before it was pipetted into an ice cold solution of CuBr (22 g, 0.21 mol) in HBr (48%, 23 mL). The resulting dark brown mixture was stirred for 20 min and was then diluted with H2O (200 mL) to produce an orange precipitate. The precipitate was filtered off, treated with sat. NaHCO3 solution, and extracted with EtOAc (20 mL*3). The organics were dried over Na2SO4 and evaporated in vacuo to give 6-bromoisobenzofuran-1(3H)-one (5.4 g, 84%). 1H NMR (300 MHz, CDCl3) delta 8.05 (d, J=1.8, 1H), 7.80 (dd, J=8.1, 1.8, 1H), 7.39 (d, J=8.1, 1H), 5.28 (s, 2H).
84%
With hydrogen bromide; copper(I) bromide; sodium nitrite; In water; at 0 - 80℃; for 0.333333h;
6-Amino-1(3H)-isobenzofuranone (3.0 g, 20 mmol) obtained from Example 26-(1) was dissolved in a mixture of 47% aqueous hydrobromic acid solution (15 ml) and water (15 ml), then the mixture was cooled to 0C, and a solution of sodium nitrite (1.45 g, 21 mmol) in water (7 ml) was slowly added thereto. Further, a solution of copper (I) bromide (3.6 g, 25 mmol) dissolved in 47% aqueous hydrobromic acid solution (10 ml) was added to the reaction mixture, and the resulting mixture was stirred at 80C for 20 minutes. After cooling the mixture, the liberated product was collected by filtration and then washed with water. The obtained pale brown solid was dissolved in ethyl acetate, then the insoluble material was removed by filtration, and the filtrate was washed successively with a 1N aqueous solution of hydrochloric acid, an aqueous solution of sodium hydrogen carbonate, and an aqueous solution of sodium chloride, and then dried over anhydrous magnesium sulfate. After filtration, the filtrate was concentrated to afford the title compound (3.57 g, 84% yield) as a crystalline solid. NMR spectrum (400 MHz, CDCl3) delta ppm: 5.289 (2H, s), 7.391 (1H, d, J=8 Hz), 7.808 (1H, dd, J=8, 2 Hz), 8.068 (1H, d, J=2 Hz) IR spectrum nu max KBr cm-1: 1778, 1458, 1359, 1191, 1046, 998, 768 Mass spectrum m/z (EI): 214, 212 (M+), 185, 183, 157, 155.
84%
A solution of NaNO2 (2.2 g, 0.040 mol) in H2O (22 mL) was added to a mixture of 6-aminoisobenzofuran-1(3H)-one (5.0 g, 0.030 mol) in HBr (70 mL, 48%) over 5 min at 0 C. The mixture was stirred for 20 minutes before it was pipetted into an ice cold solution of CuBr (22 g, 0.21 mol) in HBr (48%, 23 mL). The resulting dark brown mixture was stirred for 20 min and was then diluted with H2O (200 mL) to produce an orange precipitate. The precipitate was filtered off, treated with sat. NaHCO3 solution, and extracted with EtOAc (20 mL*3). The organics were dried over Na2SO4 and evaporated in vacuo to give 6-bromoisobenzofuran-1(3H)-one (5.4 g, 84%). 1H NMR (300 MHz, CDCl3) delta 8.05 (d, J=1.8, 1H), 7.80 (dd, J=8.1, 1.8, 1H), 7.39 (d, J=8.1, 1H), 5.28 (s, 2H).
copper(I) bromide; In water; hydrogen bromide;
Step c: 6-Bromoisobenzofuran-1(3H)-one A solution of NaNO2 (2.2 g, 0.040 mol) in H2O (22 mL) was added to a mixture of 6-aminoisobenzofuran-1(3H)-one (5.0 g, 0.030 mol) in HBr (70 mL, 48%) over 5 min at 0 C. The mixture was stirred for 20 minutes before it was pipetted into an ice cold solution of CuBr (22 g, 0.21 mol) in HBr (48%, 23 mL). The resulting dark brown mixture was stirred for 20 min and was then diluted with H2O (200 mL) to produce an orange precipitate. The precipitate was filtered off, treated with sat. NaHCO3 solution, and extracted with EtOAc (20 mL*3). The organics were dried over Na2SO4 and evaporated in vacuo to give 6-bromoisobenzofuran-1(3H)-one (5.4 g, 84%). 1H NMR (300 MHz, CDCl3) delta 8.05 (d, J=1.8, 1H), 7.80 (dd, J=8.1, 1.8, 1H), 7.39 (d, J=8.1, 1H), 5.28 (s, 2H).
Step b: 6-Aminoisobenzofuran-1(3H)-one To a solution of <strong>[610-93-5]6-nitroisobenzofuran-1(3H)-one</strong> (15 g, 0.080 mol) in HCl/H2O (375 mL/125 mL) was added SnCl2.2H2O (75 g, 0.33 mol). The reaction mixture was heated at reflux for 4 h before it was quenched with water and extracted with EtOAc (300 mL*3). The organics were dried over Na2SO4 and evaporated in vacuo to give 6-aminoisobenzofuran-1(3H)-one (10 g, 78%). 1H NMR (300 MHz, CDCl3) delta 7.23 (d, J=8.1, 1H), 7.13 (d, J=2.1, 1H), 6.98 (dd, J=8.1, 2.1, 1H), 5.21 (s, 2H), 3.99 (br s, 2H).
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