Direct Transformation of Ethylarenes into Primary Aromatic Amides with N-Bromosuccinimide and I 2 -aq NH 3

Supporting Information Direct Transformation of Ethylarenes into Primary Aromatic Amides with N-Bromosuccinimide and I 2 -aq NH 3 Shohei Shimokawa, Yuhsuke Kawagoe, Katsuhiko Moriyama, Hideo Togo* Graduate School of Science, Chiba University, Yayoi-cho 1-33, Inage-ku, Chiba 263-8522, Japan togo@faculty.chiba-u.jp Table of Contents * General S1 * Typical Experimental Procedures for Direct Transformation of Ethylarenes into Primary Aromatic Amides and Their Characterization Data S1-S6 * 1 H- and 13 C-NMR Spectra of Compounds 2a-2z S7-S31 General: 1 H NMR spectra were measured on 500 MHz spectrometers. Chemical shifts were recorded as follows: chemical shift in ppm from internal tetramethylsilane on the δ scale, multiplicity (s = singlet; d = doublet; t = triplet; q = quartet; m = multiplet; br = broad), coupling constant (Hz), integration, and assignment. 13 C NMR spectra were measured on 125 MHz spectrometers. Chemical shifts were recorded in ppm from the solvent resonance employed as the internal standard (deuterochloroform at 77.0 ppm). Characteristic peaks in the infrared (IR) spectra were recorded in wave numbers, cm -1. Melting points were uncorrected. Thin-layer chromatography (TLC) was performed using 0.25 mm silica gel plates (60F-254). The products were purified by column chromatography on silica gel 60 (63 200 mesh). Typical Procedures for Direct Transformation of Ethylarenes into Primary Aromatic Amides and Their Characterization Data Conditions A; To a solution of ethylbenzene 1a (0.5 mmol, 53.1 mg) in AcOEt:water (5:1, 3.0 ml) were added NBS (1.75 mmol, 317.8 mg) and AIBN (0.05 mmol, 8.4 mg) at room temperature, and the mixture was stirred for 4 hours at 60 C. After cooling to S1

room temperature, CH 3 CN (1.0 ml), aq. NH 3 (concentration: 28-30%, 1.5 ml), and I 2 (1.25 mmol, 317.3 mg) were added to the mixture, and the obtained mixture was stirred for 12 hours at room temperature. The mixture was quenched by sat. aq. Na 2 SO 3 (10 ml), and extracted with AcOEt (20 ml 3). Then, the organic layer was washed with brine (20 ml), and dried over Na 2 SO 4. After removal of the solvent under reduced pressure, the residue was purified by short column chromatography on silica gel (AcOEt:hexane (1:1)) to afford benzamide 2a in 85% yield (51.5 mg). Benzamide (2a, commercially available): Yield: 51.5 mg (85%); white solid; Mp: 126-127 C; IR (neat): 1654, 3166, 3362 cm -1 ; 1 H-NMR (400 MHz, DMSO-d 6 ): δ = 7.38 (br, 1H), 7.43 (dd, 2H, J = 7.7, 6.9 Hz), 7.50 (t, 1H, J = 6.9 Hz), 7.87 (d, 2H, J = 7.7 Hz), 7.99 (br, 1H); 13 C-NMR (100 MHz, DMSO-d 6 ): δ = 127.48, 128.22, 131.24, 134.26, 167.92. 4-Methylbenzamide (2b, commercially available): Yield: 46.6 mg (69%); white solid; Mp: 157-158 C; IR (neat): 1666, 3157, 3338 cm -1 ; 1 H-NMR (400 MHz, DMSO-d 6 ): δ = 2.33 (s, 3H), 7.23 (d, 2H, J = 8.2 Hz), 7.27 (br, 1H), 7.76 (d, 2H, J = 8.2 Hz), 7.89 (br, 1H); 13 C-NMR (100 MHz, DMSO-d 6 ): δ = 20.95, 127.51, 128.74, 131.47, 141.06, 167.80. 4-tert-Butylbenzamide (2c, commercially available): Yield: 67.4 mg (76%); white solid; Mp: 171-172 C; IR (neat): 1650, 3221, 3389 cm -1 ; 1 H-NMR (400 MHz, DMSO-d 6 ): δ = 1.28 (s, 9H), 7.26 (br, 1H), 7.44 (d, 2H, J = 8.2 Hz), 7.79 (d, 2H, J = 8.2 Hz), 7.89 (br, 1H); 13 C-NMR (100 MHz, DMSO-d 6 ): δ = 30.95, 34.59, 124.96, 127.32, 131.54, 153.94, 167.80. [1,1 -Biphenyl]-4-carboxamide (2d, commercially available): Yield: 89.8 mg (91%); white solid; Mp: 234-235 C; IR (neat): 1645, 3178, 3407 cm -1 ; 1 H-NMR (400 MHz, DMSO-d 6 ): δ = 7.37-7.41 (m, 2H), 7.48 (dd, 2H, J = 8.0, 7.3 Hz), 7.71-7.75 (m, 4H), 7.96 (d, 2H, J = 8.5 Hz), 8.03 (br, 1H); 13 C-NMR (100 MHz, DMSO-d 6 ): δ = 126.45, 126.88, 128.03, 128.17, 129.03, 133.08, 139.22, 142.75, 167.56. 4-Bromobenzamide (2e, commercially available): Yield: 83.0 mg (83%) a, 76.0 mg (76%) b ; white solid; Mp: 191-192 C; IR (neat): 1654, 3170, 3356 cm -1 ; 1 H-NMR (400 MHz, DMSO-d 6 ): δ = 7.46 (br, 1H), 7.65 (d, 2H, J = 8.7 Hz), 7.80 (d, 2H, J = 8.7 Hz), 8.04 (br, 1H); 13 C-NMR (100 MHz, DMSO-d 6 ): δ = 125.02, 129.61, 131.24, 133.39, S2

166.93. a S.M. was 1-bromo-4-ethylbenzene. b S.M. was 4-ethylphenylboronic acid. 4-Iodobenzamide (2f, commercially available): Yield: 106.2 mg (86%); white solid; Mp: 215-217 C; IR (neat): 1654, 3168, 3353 cm -1 ; 1 H-NMR (400 MHz, DMSO-d 6 ): δ = 7.45 (br, 1H), 7.64 (d, 2H, J = 8.0 Hz), 7.82 (d, 2H, J = 8.0 Hz), 8.03 (br, 1H); 13 C-NMR (100 MHz, DMSO-d 6 ): δ = 98.96, 129.50, 133.70, 137.13, 167.24. 2,5-Dibromothiophene-3-carboxamide (2g, commercially available): Yield: 98.3 mg (69%); white solid; Mp: 136 C; IR (neat): 1649, 3182, 3372 cm -1 ; 1 H-NMR (400 MHz, DMSO-d 6 ): δ = 7.41 (s, 1H), 7.57 (br, 1H), 7.75 (br, 1H); 13 C-NMR (100 MHz, DMSO-d 6 ): δ = 110.83, 113.46, 130.98, 136.95, 162.44. 3-Bromobenzo[b]thiophene-2-carboxamide (2h): Yield: 98.6 mg (77%); yellow solid; Mp: 213-215 C; IR (neat): 1655, 3127, 3238 cm -1 ; 1 H-NMR (400 MHz, DMSO-d 6 ): δ = 7.53-7.60 (m, 2H), 7.82-7.88 (m, 2H), 8.04 (br, 1H), 8.06-8.10 (m, 1H); 13 C-NMR (100 MHz, DMSO-d 6 ): δ = 107.10, 123.23, 123.91, 126.04, 127.35, 134.36, 137.25, 137.73, 162.31; HRMS (APCI): Calcd for C 9 H 7 ON 79 BrS [M+H] + = 255.9426, Found = 255.9427. Conditions B; To a solution of 4-cyano-1-ethylbenzene 1j (0.5 mmol, 65.6 mg) in CH 3 CN:water (5:1, 3.0 ml) were added NBS (1.75 mmol, 317.8 mg) and AIBN (0.05 mmol, 8.4 mg) at room temperature, and the mixture was stirred for 8 hours at 80 C. After cooling to room temperature, CH 3 CN (1.0 ml), aq. NH 3 (concentration: 28-30%, 1.5 ml), and I 2 (1.5 mmol, 380.8 mg) were added to the mixture, and the obtained mixture was stirred for 12 hours at 60 C. The mixture was quenched by sat. aq. Na 2 SO 3 (10 ml), and extracted with AcOEt (20 ml 3). Then, the organic layer was washed with brine (20 ml), and dried over Na 2 SO 4. After removal of the solvent under reduced pressure, the residue was purified by short column chromatography on silica gel (AcOEt:hexane (1:1)) to afford 4-cyanobenzamide 2j in 91% yield (66.5 mg). 4-Cyanobenzamide (2j, commercially available): Yield: 66.5 mg (91%); white solid; Mp: 224-225 C; IR (neat): 1696, 2229, 3166, 3439 cm -1 ; 1 H-NMR (400 MHz, DMSO-d 6 ): δ = 7.68 (br, 1H), 7.92 (d, 2H, J = 8.6 Hz), 8.01 (d, 2H, J = 8.6 Hz), 8.21 (br, 1H); 13 C-NMR (100 MHz, DMSO-d 6 ): δ = 113.70, 118.42, 128.30, 132.42, 138.31, 166.53. S3

Methyl 4-carbamoylbenzoate (2k, commercially available): Yield: 56.4 mg (63%); white solid; Mp: 206-207 C; IR (neat): 1112, 1276, 1654, 1721, 3182, 3403 cm -1 ; 1 H-NMR (400 MHz, DMSO-d 6 ): δ = 3.86 (s, 3H), 7.57 (br, 1H), 7.97-8.02 (m, 4H), 8.15 (br, 1H); 13 C-NMR (100 MHz, DMSO-d 6 ): δ = 52.37, 127.84, 129.08, 131.80, 138.43, 165.75, 167.05. 4-Nitrobenzamide (2l, commercially available): Yield: 70.6 mg (85%); white solid; Mp: 197-199 C; IR (neat): 1341, 1520, 1672, 3161, 3474 cm -1 ; 1 H-NMR (400 MHz, DMSO-d 6 ): δ = 7.73 (br, 1H), 8.07 (d, 2H, J = 8.7 Hz), 8.25 (br, 1H), 8.26 (d, 2H, J = 8.7 Hz); 13 C-NMR (100 MHz, DMSO-d 6 ): δ = 123.47, 128.96, 140.01, 149.08, 166.31. 4-(Methylsulfonyl)benzamide (2m, commercially available): Yield: 71.7 mg (72%); white solid; Mp: 214-215 C; IR (neat): 1153, 1286, 1682, 3173, 3386 cm -1 ; 1 H-NMR (400 MHz, DMSO-d 6 ): δ = 3.25 (s, 3H), 7.66 (br, 1H), 8.00 (d, 2H, J = 8.7 Hz), 8.08 (d, 2H, J = 8.7 Hz), 8.21 (br, 1H); 13 C-NMR (100 MHz, DMSO-d 6 ): δ = 43.28, 127.00, 128.42, 138.79, 142.95, 166.62. 2-Carbamoylphenyl methanesulfonate (2n, commercially available): Yield: 97.9 mg (91%); white solid; Mp: 125-126 C; IR (neat): 1161, 1341, 1662, 3152, 3327 cm -1 ; 1 H-NMR (400 MHz, DMSO-d 6 ): δ = 3.36 (s, 3H), 7.39-7.43 (m, 2H), 7.52-7.57 (m, 1H), 7.60 (dd, 1H, J = 7.6, 1.8 Hz), 7.61 (br, 1H), 7.83 (br, 1H); 13 C-NMR (100 MHz, DMSO-d 6 ): δ = 37.97, 123.11, 127.20, 129.64, 130.84, 131.38, 145.68, 166.84. 2-Bromobenzamide (2o, commercially available): Yield: 76.0 mg (76%); white solid; Mp: 160-162 C; IR (neat): 1621, 3177, 3354 cm -1 ; 1 H-NMR (400 MHz, DMSO-d 6 ): δ = 7.30-7.35 (m, 1H), 7.38-7.42 (m, 2H), 7.56 (br, 1H), 7.63 (d, 1H, J = 8.0 Hz), 7.86 (br, 1H); 13 C-NMR (100 MHz, DMSO-d 6 ): δ = 118.61, 127.49, 128.54, 130.64, 132.70, 139.36, 169.06. 2-Iodobenzamide (2p, commercially available): Yield: 90.2 mg (73%); white solid; Mp: 183-184 C; IR (neat): 1645, 3177, 3359 cm -1 ; 1 H-NMR (400 MHz, DMSO-d 6 ): δ = 7.13 (t, 1H, J = 7.7 Hz), 7.33 (d, 1H, J = 7.7 Hz), 7.41 (t, 1H, J = 7.7 Hz), 7.51 (br, 1H), 7.82 (br, 1H), 7.86 (d, 1H, J = 7.7 Hz); 13 C-NMR (100 MHz, DMSO-d 6 ): δ = 93.14, 127.78, 127.94, 130.60, 139.16, 143.14, 170.73. S4

3,5-Dibromobenzamide (2q, commercially available): Yield: 121.3 mg (87%); white solid; Mp: 190-191 C; IR (neat): 1644, 3168, 3368 cm -1 ; 1 H-NMR (400 MHz, DMSO-d 6 ): δ = 7.67 (br, 1H), 8.00 (s, 1H), 8.04 (s, 2H), 8.17 (br, 1H); 13 C-NMR (100 MHz, DMSO-d 6 ): δ = 122.58, 129.52, 135.96, 137.85, 164.89. Anthraquinone-2-carboxamide (2r, commercially available): Yield: 85.4 mg (68%); brown solid; Mp: 274-276 C; IR (neat): 1660, 1668, 3206, 3327 cm -1 ; 1 H-NMR (400 MHz, DMSO-d 6 ): δ = 7.74 (br, 1H), 7.87~7.93 (m, 2H), 8.16 (d, 1H, J = 8.4 Hz), 8.18 (d, 1H, J = 8.8 Hz), 8.21 (d, 1H, J = 8.0 Hz), 8.31 (d, 1H, J = 8.0 Hz), 8.41 (br, 1H), 8.62 (s, 1H); 13 C-NMR (100 MHz, DMSO-d 6 ): δ = 125.87, 126.80, 126.83, 127.01, 132.96, 133.00, 133.06 (2C), 134.59, 134.64, 139.23 (2C), 166.35, 182.11 (2C). Isonicotinamide (2s, commercially available): Yield: 40.3 mg (66%); white solid; Mp: 153-154 C; IR (neat): 1677, 3059, 3320 cm -1 ; 1 H-NMR (400 MHz, DMSO-d 6 ): δ = 7.79 (d, 2H, J = 6.1 Hz), 7.85 (br, 1H), 8.36 (br, 1H), 8.69 (d, 2H, J = 6.1 Hz); 13 C-NMR (100 MHz, DMSO-d 6 ): δ = 121.75, 141.54, 150.41, 167.02. Conditions C; To a solution of 4-methoxy-1-ethylbenzene 1t (0.5 mmol, 68.1 mg) in CHCl 3 :water (5:1, 3.0 ml) were added NBS (2.5 mmol, 454.0 mg) and AIBN (0.05 mmol, 8.4 mg) at room temperature, and the mixture was stirred for 10 hours at 60 C. After cooling to room temperature and removal of solvent, which was mostly CHCl 3, under reduced pressure, CH 3 CN (2.0 ml), aq. NH 3 (concentration: 28-30%, 1.5 ml), and I 2 (1.75 mmol, 444.2 mg) were added to the mixture, and the obtained mixture was stirred for 12 hours at 60 C. The mixture was quenched by sat. aq. Na 2 SO 3 (10 ml), and extracted with AcOEt (20 ml 3). Then, the organic layer was washed with brine (20 ml), and dried over Na 2 SO 4. After removal of the solvent under reduced pressure, the residue was purified by short column chromatography on silica gel (AcOEt:hexane (1:1)) to afford 3-bromo-4-methoxybenzamide 2t in 83% yield (95.5 mg). 3-Bromo-4-methoxybenzamide (2t, commercially available): Yield: 95.5 mg (83%); white solid; Mp: 180-183 C; IR (neat): 1650, 3164, 3364 cm -1 ; 1 H-NMR (400 MHz, DMSO-d 6 ): δ = 3.89 (s, 3H), 7.17 (d, 1H, J = 8.7 Hz), 7.32 (br, 1H), 7.89 (d, 1H, J = 8.6 Hz), 7.94 (br, 1H), 8.09 (s, 1H); 13 C-NMR (100 MHz, DMSO-d 6 ): δ = 56.50, 110.24, 112.00, 127.74, 128.81, 132.22, 157.62, 166.15. 3-Bromo-4-isopropoxybenzamide (2u, commercially available): Yield: 93.0 mg S5

(72%); white solid; Mp: 127-128 C; IR (neat): 1644, 3177, 3359 cm -1 ; 1 H-NMR (400 MHz, DMSO-d 6 ): δ = 1.28 (d, 6H, J = 6.0 Hz), 4.75 (septet, 1H, J = 6.0 Hz), 7.17 (dd, 1H, J = 8.5, 3.2 Hz), 7.32 (br, 1H), 7.85 (d, 1H, J = 8.5 Hz), 7.93 (br, 1H), 8.09 (d, 1H, J = 3.2 Hz); 13 C-NMR (100 MHz, DMSO-d 6 ): δ = 21.71, 71.29, 111.55, 114.10, 127.49, 128.62, 132.44, 156.11, 166.13. 5-Bromo-2-methoxybenzamide (2v, commercially available): Yield: 73.6 mg (64%); white solid; Mp: 151-152 C; IR (neat): 1638, 3175, 3440 cm -1 ; 1 H-NMR (400 MHz, DMSO-d 6 ): δ = 3.86 (s, 3H), 7.10 (d, 1H, J = 9.0 Hz), 7.62, (dd, 1H, J = 9.0, 2.7 Hz), 7.67 (br, 2H), 7.83 (d, 1H, J = 2.7 Hz); 13 C-NMR (100 MHz, DMSO-d 6 ): δ = 56.21, 111.85, 114.61, 125.03, 132.71, 134.65, 156.43, 164.94. 5-Bromo-2-ethoxybenzamide (2w, commercially available): Yield: 74.5 mg (61%); white solid; Mp: 128 C; IR (neat): 1645, 3173, 3370 cm -1 ; 1 H-NMR (400 MHz, DMSO-d 6 ): δ = 1.36 (t, 3H, J = 7.0 Hz), 4.14 (q, 2H, J = 7.0 Hz), 7.09 (d, 1H, J = 8.9 Hz), 7.59 (dd, 1H, J = 8.9, 2.7 Hz), 7.61 (br, 1H), 7.69 (br, 1H), 7.84 (d, 1H, J = 2.7 Hz); 13 C-NMR (100 MHz, DMSO-d 6 ): δ = 14.35, 64.70, 111.84, 115.47, 125.07, 132.80, 134.67, 155.65, 165.00. 5-Bromothiophene-2-carboxamide (2x, commercially available): Yield: 89.6 mg (87%); white solid; Mp: 164-166 C; IR (neat): 1650, 3171, 3350 cm -1 ; 1 H-NMR (400 MHz, DMSO-d 6 ): δ = 7.26 (d, 1H, J = 4.1 Hz), 7.53 (br, 1H), 7.56 (d, 1H, J = 4.1 Hz), 8.03 (br, 1H); 13 C-NMR (100 MHz, DMSO-d 6 ): δ = 116.90, 129.34, 131.56, 142.23, 161.83. 1-Naphthamide (2y, commercially available): Yield: 67.6 mg (79%); white solid; Mp: 199 C; IR (neat): 1659, 3164, 3327 cm -1 ; 1 H-NMR (400 MHz, DMSO-d 6 ): δ = 7.50-7.60 (m, 4H), 7.63 (dd, 1H, J = 7.0, 1.4 Hz), 7.94-8.01 (m, 3H), 8.28-8.31 (m, 1H); 13 C-NMR (100 MHz, DMSO-d 6 ): δ = 124.95, 125.14, 125.58, 126.14, 126.61, 128.18, 129.71, 129.78, 133.20, 134.65, 170.61. 2-Naphthamide (2z, commercially available): Yield: 59.0 mg (69%); white solid; Mp: 191-192 C; IR (neat): 1652, 3195, 3378 cm -1 ; 1 H-NMR (400 MHz, DMSO-d 6 ): δ = 7.48 (br, 1H), 7.55-7.62 (m, 2H), 7.95-8.01 (m, 4H), 8.14 (br, 1H), 8.48 (s, 1H); 13 C-NMR (100 MHz, DMSO-d 6 ): δ = 124.39, 126.65, 127.59 (2C), 127.76, 127.81, 128.87, 131.63, 132.15, 134.16, 167.95. S6

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