Synlett 2014; 25(19): 2773-2776
DOI: 10.1055/s-0034-1379238
letter
© Georg Thieme Verlag Stuttgart · New York

Synthesis of 2-Alkylidene-3-acylquinoxalines from N-Aryl-2-nitrosoanilines and 1,3-Diketones

Adam Trawczyński
Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44, 01-224, Poland   Fax: +48(22)6326681   Email: zbigniew.wrobel@icho.edu.pl
,
Zbigniew Wróbel*
Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44, 01-224, Poland   Fax: +48(22)6326681   Email: zbigniew.wrobel@icho.edu.pl
› Author Affiliations
Further Information

Publication History

Received: 20 August 2014

Accepted: 11 September 2014

Publication Date:
16 October 2014 (online)


Abstract

In the reaction of N-aryl-2-nitrosoanilines with β-diketones, a condensation of the nitroso group with diketone carbanion followed by condensation of the amino function with the less crowded carbonyl group leads to 2-alkylidene-3-acyl-1,2-dihydroquinoxalines under mild basic conditions.

 
  • References and Notes

  • 3 Kwast A, Stachowska K, Trawczyński A, Wróbel Z. Tetrahedron Lett. 2011; 52: 6484
    • 4a Wróbel Z, Stachowska K, Kwast A, Gościk A, Królikiewicz M, Pawłowski R, Turska I. Helv. Chim. Acta 2013; 96: 956
    • 4b Królikiewicz M, Cmoch P, Wróbel Z. Synlett 2013; 24: 973
    • 4c Wróbel Z, Królikiewicz M. J. Heterocycl. Chem. 2014; 51: 123
    • 4d Królikiewicz M, Błaziak K, Danikiewicz W, Wróbel Z. Synlett 2013; 24: 1945

      For a review of recent advances in the synthesis of quinoxalines and medicinal compounds containing a quinoxaline moiety, see:
    • 5a Mamedov VA, Zhukova NA. Prog. Heterocycl. Chem. 2012; 24: 55
    • 5b Eary CT, Jones ZS, Groneberg RD, Burgess LE, Mareska DA, Drew MD, Blake JF, Laird ER, Balachari D, O’Sullivan M, Allen A, Marsh V. Bioorg. Med. Chem. Lett. 2007; 17: 2608
    • 5c Ohtake Y, Naito A, Hasegawa H, Kawano K, Morizono D, Taniguchi M, Tanaka Y, Matsukawa H, Naito K, Oguma T, Ezure Y, Tsuriya Y. Bioorg. Med. Chem. 1999; 7: 1247
    • 5d Torisu K, Kobayashi K, Iwahashi M, Nakai Y, Onoda T, Sugimoto I, Okada Y, Matsumoto R, Nanbu F, Ohuchida S, Nakai H, Toda M. Bioorg. Med. Chem. 2004; 12: 5361
    • 5e Sikorski JA. J. Med. Chem. 2006; 49: 1
    • 5f Jacobsen EJ, Stelzer LS, Belonga KL, Carter DB, Im WB, Sethy VH, Tang AH, VonVoigtlander PF, Petke JD. J. Med. Chem. 1996; 39: 3820
    • 5g Barrows TH, Farina PR, Chrzanowski RL, Benkovic PA, Benkovic SJ. J. Am. Chem. Soc. 1976; 98: 3678
  • 6 General Procedure for the Synthesis of Compounds 3 To a solution of N-aryl-2-nitrosobenzamine (0.5 mmol) and an appropriate 1,3-diketone (0.6 mmol) in dry DMF (5 mL) was added DBU (1 mmol). The mixture was stirred at r.t. for 24 h. The mixture was then poured into sat. NH4Cl solution and extracted with EtOAc, the combined extract was washed with H2O, dried (Na2SO4), and concentrated. The products were isolated by column chromatography (SiO2; hexane–toluene, 1:1).
  • 7 Analytical Data for New Compounds 1 and 3 Compound 1g: dark green solid; mp 90–92 °C. 1H NMR (400 MHz, CDCl3): δ = 1.20 (t, J = 7.6 Hz, 3 H), 2.57 (q, J = 7.6 Hz, 2 H), 6.81 (d, J = 2.0 Hz, 1 H), 6.92–6.95 (m, 1 H), 7.22–7.32 (m, 3 H), 7.33–7.37 (m, 1 H), 8.69 (br s, 1 H), 12.00 (br s, 1 H). 13C NMR (100 MHz, CDCl3): δ = 14.7, 24.7, 114.6, 118.6, 126.8, 127.2, 128.0, 130.0, 134.3, 140.1, 144.8, 155.3 (two C missing). ESI-MS (MeOH): m/z = 261 [M + H]+, 283 [M + Na]+. ESI-HRMS (MeOH): m/z calcd for C14H13N2ONaCl: 283.0614; found: 283.0604. Compound 1h: dark green solid; mp 69–71 °C. 1H NMR (400 MHz, CDCl3): δ = 1.37 (s, 9 H), 6.71–6.76 (m, 1 H), 6.90–6.93 (m, 1 H), 7.16–7.19 (m, 1 H), 7.21–7.33 (m, 2 H), 7.50–7.54 (m, 1 H), 8.70 (br s, 1 H), 12.26 (br s, 1 H). 13C NMR (100 MHz, CDCl3): δ = 14.7, 24.7, 114.6, 118.6, 126.8, 127.2, 128.0, 130.0, 134.3, 140.1, 144.8, 155.3 (two C missing). ESI-MS (MeOH): m/z = 289 [M + H]+, 311 [M + Na]+, 599 [2 M + Na]+. ESI-HRMS (MeOH): m/z calcd for C16H17N2ONaCl: 311.0927; found: 311.0923. Compound 3aa: yellow solid; mp 157–159 °C. 1H NMR (500 MHz, CDCl3): δ = 2.17 (s, 6 H), 3.52 (br s, 1 H), 3.98 (br s, 1 H), 5.98 (d, J = 1.7 Hz, 1 H), 6.83 (dd, J = 8.3, 1.9 Hz, 1 H), 7.25–7.30 (m, 3 H), 7.49–7.53 (m, 2 H), 7.34 (d, J = 8.3 Hz, 1 H), 7.62–7.66 (m, 1 H), 8.06–8.10 (m, 2 H). 13C NMR (125 MHz, CDCl3): δ = 17.7, 88.5, 111.3, 120.8, 128.8, 129.4, 130.0, 130.1, 130.4, 131.1, 134.1, 134.4, 134.5, 135.6, 136.4, 136.6, 159.5, 192.1 (one C missing). MS (EI): m/z (%) = 388 (44), 386 (100) [M+], 373 (20), 372 (15), 371 (56), 359 (19), 358 (17), 357 (51), 283 (28), 282 (18), 281 (84), 267 (12), 266 (26), 265 (17), 105 (49), 77 (44). HRMS (EI): m/z calcd for C24H19N2OCl: 386.1186; found: 386.1192. Compound 3ab: dark red solid; mp 66–68 °C. 1H NMR (500 MHz, CDCl3): δ = 2.10 (s, 6 H), 2.60 (s, 3 H), 3.55 (d, J = 1.5 Hz, 1 H), 4.84 (d, J = 1.5 Hz, 1 H), 5.84 (d, J = 1.9 Hz, 1 H), 6.77 (dd, J = 8.3, 1.9 Hz, 1 H), 7.23–7.29 (m, 3 H), 7.31 (d, J = 8.3 Hz, 1 H). 13C NMR (125 MHz, CDCl3): δ = 17.7, 27.7, 88.9, 111.2, 120.5, 129.2, 130.0, 130.7, 131.0, 134.0, 134.4, 136.5, 136.6, 137.6, 155.2, 199.2. MS (EI): m/z (%) = 326 (27), 324 (67) [M+], 311 (30), 310 (18), 309 (88), 283 (33), 282 (21), 281 (100), 268 (13), 267 (23), 266 (32), 265 (15), 252 (10), 77 (11), 44 (22). HRMS (EI): m/z calcd for C19H17N2OCl: 324.1029; found: 324.1028. Compound 3ba: orange solid; mp 202–204 °C (dec.). 1H NMR (500 MHz, CDCl3): δ = 2.21 (s, 6 H), 3.50 (d, J = 2.2 Hz, 1 H), 3.97 (d, J = 2.2 Hz, 1 H), 6.20 (d, J = 1.5 Hz, 1 H), 7.09 (dd, J = 8.0, 1.5 Hz, 1 H), 7.24–7.31 (m, 4 H), 7.32–7.38 (m, 4 H), 7.47–7.54 (m, 3 H), 7.61–7.65 (m, 1 H), 8.12 (m, 2 H). 13C NMR (125 MHz, CDCl3): δ = 17.8, 87.4, 109.8, 119.7, 127.0, 127.7, 128.7, 128.8, 129.1, 129.7, 129.9, 130.1, 131.9, 134.2, 134.6, 134.8, 134.9, 136.3, 136.8, 140.4, 143.7, 159.3, 192.4. MS (EI): m/z (%) = 428 (83) [M+], 414 (18), 413 (57), 400 (23), 399 (57), 324 (26), 323 (100), 308 (27), 307 (20), 297 (10), 214 (11), 105 (43), 77 (36). HRMS (EI): m/z calcd for C30H24N2O: 428.1889; found: 428.1886. Compound 3bb: dark red solid; mp 82–85 °C. 1H NMR (400 MHz, CDCl3): δ = 2.14 (s, 6 H), 2.63 (s, 3 H), 3.53 (d, J = 1.6 Hz, 1 H), 4.83 (d, J = 1.6 Hz, 1 H), 6.07 (d, J = 2.0 Hz, 1 H), 7.05 (dd, J = 8.0, 2.0 Hz, 1 H), 7.22–7.26 (m, 4 H), 7.33–7.36 (m, 4 H), 7.46 (d, J = 8.0 Hz, 1 H). 13C NMR (100 MHz, CDCl3): δ = 17.9, 27.9, 87.9, 109.8, 119.6, 127.1, 128.0, 128.8, 129.1, 130.0, 130.5, 131.7, 134.8, 135.0, 136.0, 136.9, 140.5, 144.9, 155.1, 199.6. MS (EI): m/z (%) = 366 (72) [M+], 352 (30), 351 (83), 324 (40), 323 (100), 321 (11), 309 (26), 308 (37), 307(27), 294 (15), 43 (12). HRMS (EI): m/z calcd for C25H22N2O: 366.1732; found: 366.1736. Compound 3bc: red solid; mp 151–154 °C. 1H NMR (400 MHz, CDCl3): δ = 1.23 (d, J = 7.2 Hz, 6 H), 2.14 (s, 6 H), 3.48 (d, J = 2.0 Hz, 1 H), 3.70 (sept, J = 7.2 Hz, 1 H), 4.42 (d, J = 2.0 Hz, 1 H), 6.10 (d, J = 1.6 Hz, 1 H), 7.06 (dd, J = 8.0, 1.6 Hz, 1 H), 7.22–7.27 (m, 4 H), 7.32–7.34 (m, 4 H), 7.45 (d, J = 8.0 Hz, 1 H). 13C NMR (100 MHz, CDCl3): δ = 17.8, 17.9, 37.4, 87.3, 109.8, 119.6, 127.1, 127.9, 128.4, 129.1, 130.0, 130.1, 131.8, 135.1, 135.5, 135.6, 136.9, 140.5, 144.3, 157.5, 205.3. MS (EI): m/z (%) = 394 (100) [M+], 393 (31), 380 (17), 379 (58), 324 (28), 323 (90), 309 (17), 308 (20), 307 (14), 44 (13). HRMS (EI): m/z calcd for C27H26N2O: 394.2045; found: 394.2048. Compound 3bd (1:1 mixture of E and Z isomers): dark red solid; mp 120–122 °C. 1H NMR (400 MHz, CDCl3): δ = 0.85 (d, J = 8.0 Hz, 3 H), 1.20 (t, J = 7.2 Hz, 3 H), 1.25 (t, J = 7.2 Hz, 3 H), 1.37 (d, J = 7.6 Hz, 3 H), 2.13 (s, 6 H), 2.28 (s, 6 H), 2.97 (q, J = 7.2 Hz, 2 H), 3.10 (q, J = 7.2 Hz, 2 H), 4.19 (q, J = 7.6 Hz, 1 H), 4.69 (q, J = 8.0 Hz, 1 H), 6.08 (d, J = 2.0 Hz, 1 H), 6.13 (d, J = 2.0 Hz, 1 H), 6.99 (dd, J = 6.0, 1.6 Hz, 1 H), 7.01 (dd, J = 6.4, 2.0 Hz, 1 H), 7.13–7.17 (m, 2 H), 7.21–7.30 (m, 6 H), 7.30–7.36 (m, 9 H), 7.46 (d, J = 8.0 Hz, 1 H). 13C NMR (100 MHz, CDCl3): δ = 7.7, 7.8, 10.8, 14.0, 29.8, 31.7, 33.1, 34.1, 100.6, 102.6, 109.5, 109.8, 118.6, 119.6, 127.0, 127.1, 127.7, 127.8, 128.8, 129.0, 129.3, 129.8, 129.9, 130.0, 131.8, 132.1, 136.0, 136.1, 136.3, 137.5, 137.8, 138.4, 140.7, 143.1, 143.9, 156.7, 161.3, 203.4, 204.4. MS (EI): m/z (%) = 394 (100) [M+], 380 (10), 379 (21), 366 (22), 365 (51), 338 (26), 337 (98), 323 (19), 322 (24), 321 (17), 309 (14), 308 (17), 307 (15), 57 (16). HRMS (EI): m/z calcd for C27H26N2O: 394.2045; found: 394.2050. Compound 3ca: yellow solid; mp 179–181 °C (dec.). 1H NMR (400 MHz, CDCl3): δ = 2.15 (s, 6 H), 3.55 (d, J = 2.8 Hz, 1 H), 4.07 (d, J = 2.8 Hz, 1 H), 5.86 (d, J = 2.0 Hz, 1 H), 6.92 (d, J = 2.0 Hz, 1 H), 7.28 (m, 3 H), 7.50 (m, 2 H), 7.63 (m, 1 H), 8.09 (m, 2 H). 13C NMR (100 MHz, CDCl3): δ = 17.9, 89.9, 11.2, 121.7, 128.4, 128.9, 129.7, 130.2, 130.3, 134.2, 134.5, 134.7, 135.2, 135.4, 136.3, 136.6, 137.0, 159.6, 191.6. MS (EI): m/z (%) = 422 (77), 420 (100) [M+], 407 (46), 405 (67), 393 (36), 391 (52), 317 (67), 315 (97), 300 (33). HRMS (EI): m/z calcd for C24H18N2OCl2: 420.0796; found: 420.0800. Compound 3cc: brown solid; mp 90–92 °C. 1H NMR (400 MHz, CDCl3): δ = 1.22 (d, J = 6.8 Hz, 6 H), 2.10 (s, 6 H), 3.56 (d, J = 2.0 Hz, 1 H), 3.74 (sept, J = 6.8 Hz, 1 H), 4.66 (d, J = 2.0 Hz, 1 H), 5.75 (d, J = 2.0 Hz, 1 H), 6.88 (d, J = 2.0 Hz, 1 H), 7.23–7.31 (m, 3 H). 13C NMR (100 MHz, CDCl3): δ = 17.8, 18.1, 37.3, 90.1, 110.1, 121.3, 128.0, 129.2, 129.6, 130.2, 134.5, 135.4, 136.6, 137.0, 137.6, 156.7, 204.6. MS (EI): m/z (%) = 388 (63), 386 (89) [M+], 373 (48), 371 (72), 317 (69), 315 (100), 300 (29). HRMS (EI): m/z calcd for C21H20N2OCl2: 386.0953; found: 386.0959. Compound 3da: yellow-green solid; mp 144–146 °C. 1H NMR (400 MHz, CDCl3): δ = 2.21 (s, 3 H), 3.53 (d, J = 2.8 Hz, 1 H), 4.01 (d, J = 2.8 Hz, 1 H), 6.00 (d, J = 2.0 Hz, 1 H), 6.81 (dd, J = 8.4, 2.0 Hz, 1 H), 7.17–7.22 (m, 1 H), 7.32 (d, J = 8.4 Hz, 1 H), 7.41–7.45 (m, 2 H), 7.46–7.54 (m, 3 H), 7.64 (m, 1 H), 8.01 (m, 2 H). 13C NMR (100 MHz, CDCl3): δ = 17.6, 89.5, 112.1, 120.8, 128.9, 129.2, 129.4, 129.8, 130.3, 130.5, 131.2, 132.9, 134.5, 134.8, 136.0, 136.3, 136.7, 136.9, 137.3, 159.4, 192.3. MS (EI): m/z (%) = 374 (49), 372 (100) [M+], 359 (42), 345 (36), 269 (20), 267 (55), 105 (66), 91 (14), 77 (56). HRMS (EI): m/z calcd for C23H17N2OCl: 372.1029; found: 372.1028. Compound 3ea: dark brown oil. 1H NMR (400 MHz, CDCl3): δ = 2.17 (s, 6 H), 3.53 (d, J = 2.4 Hz, 1 H), 3.99 (d, J = 2.4 Hz, 1 H), 5.71 (dd, J = 10.4, 2.4 Hz, 1 H), 6.51–6.57 (m, 1 H), 7.36–7.41 (m, 1 H), 7.44–7.47 (m, 1 H), 7.40–7.53 (m, 3 H), 7.61–7.66 (m, 1 H), 7.86–7.89 (m, 1 H), 8.07–8.10 (m, 2 H). 13C NMR (100 MHz, CDCl3): δ = 17.8, 26.0, 88.3, 96.8, 98.9 (d, J CF = 29 Hz), 107.5 (d, J CF = 23 Hz), 127.1, 128.9, 129.5, 130.1 (d, J CF = 13 Hz), 131.1 (d, J CF = 11 Hz), 132.4, 134.5 (d, J CF = 10 Hz), 134.9, 135.7, 136.4 (d, J CF = 12 Hz), 136.8, 158.5, 163.2, 165.7, 192.4. ESI-MS (MeOH): m/z = 371 [M + H]+. ESI-HRMS (MeOH): m/z calcd for C24H20N2OF: 371.1560; found: 371.1552. Compound 3eb: dark red solid; mp 105–108 °C. 1H NMR (400 MHz, CDCl3): δ = 2.11 (s, 6 H), 2.60 (s, 3 H), 3.56 (d, J = 1.6 Hz, 1 H), 4.89 (d, J = 1.6 Hz, 1 H), 5.57 (dd, J = 10.4, 2.4 Hz, 1 H), 6.47–6.53 (m, 1 H), 7.22–7.30 (m, 3 H), 7.35–7.39 (m, 1 H). 13C NMR (100 MHz, CDCl3): δ = 17.8, 27.8, 88.8, 98.7 (d, J CF = 28 Hz), 107.4 (d, J CF = 23 Hz), 128.8 (d, J CF = 2 Hz),, 129.3, 130.1, 131.9 (d, J CF = 11 Hz),, 134.0, 134.8, 136.8, 137.4 (d, J CF = 10 Hz), 154.0 (d, J CF = 3 Hz), 165.4 (d, J CF = 248 Hz), 199.4. MS (EI): m/z (%) = 308 (50) [M+], 293 (93), 265 (100), 250 (56), 236 (18). HRMS (EI): m/z calcd for C19H17N2OF: 308.1325; found: 308.1321. Compound 3fa: dark brown solid; mp 89–91 °C. 1H NMR (400 MHz, CDCl3): δ = 2.17 (s, 6 H), 3.46 (d, J = 2.0 Hz, 1 H), 3.66 (s, 3 H), 3.95 (d, J = 2.0 Hz, 1 H), 5.55 (d, J = 2.8 Hz, 1 H), 6.42 (dd, J = 8.8, 2.8 Hz, 1 H), 7.13–7.18 (m, 2 H), 7.36 (d, J = 8.8 Hz, 1 H), 7.59–7.64 (m, 1 H), 7.42–7.52 (m, 2 H), 7.86–7.90 (m, 1 H), 8.07–8.11 (m, 2 H). 13C NMR (100 MHz, CDCl3): δ = 17.8, 55.5, 87.0, 96.8, 97.8, 105.3, 125.4, 127.1, 128.4, 128.8, 129.2, 129.9, 130.3, 130.8, 134.2, 136.1, 136.9, 156.5, 162.0, 192.8. MS (EI): m/z (%) = 382 (66) [M+], 367 (62), 353 (62), 277 (81), 248 (56), 105 (100), 77 (60). HRMS (EI): m/z calcd for C25H22N2O2: 382.1681; found: 382.1685. Compound 3gb: dark red solid; mp 70–73 °C. 1H NMR (400 MHz, CDCl3): δ = 1.17 (t, J = 7.6 Hz, 3 H), 2.45–2.53 (m, 2 H), 2.59 (s, 3 H), 3.56 (d, J = 1.6 Hz, 1 H), 4.81 (d, J = 1.6 Hz, 1 H), 5.88 (d, J = 2.0 Hz, 1 H), 6.76 (dd, J = 8.4, 2.0 Hz, 1 H), 7.09 (dd, J = 7.6, 1.2 Hz, 1 H), 7.29 (d, J = 8.4 Hz, 1 H), 7.39–7.54 (m, 3 H). 13C NMR (100 MHz, CDCl3): δ = 13.7, 23.6, 27.8, 90.5, 112.4, 120.6, 128.4, 129.2, 129.5, 129.8, 130.9, 131.0, 135.8, 136.3, 137.3, 137.9, 142.5, 155.3, 199.4. MS (EI): m/z (%) = 326 (24), 324 (37) [M+], 311 (44), 309 (100), 283 (23), 281 (44), 266 (39), 255 (32). HRMS (EI): m/z calcd for C19H17N2OCl: 324.1029; found: 324.1027. Compound 3ha: brown solid; mp 156–159 °C. 1H NMR (400 MHz, CDCl3): δ = 1.37 (s, 9 H), 3.54 (d, J = 2.4 Hz, 1 H), 4.15 (d, J = 2.4 Hz, 1 H), 5.98 (d, J = 2.0 Hz, 1 H), 6.81 (dd, J = 8.4, 2.0 Hz, 1 H), 7.03–7.06 (m, 1 H), 7.31 (d, J = 8.4 Hz, 1 H), 7.40–7.53 (m, 4 H), 7.61–7.66 (m, 1 H), 7.69–7.72 (m, 1 H), 8.05–8.09 (m, 2 H). 13C NMR (100 MHz, CDCl3): δ = 32.0, 36.3, 91.9, 113.9, 120.8, 127.2, 128.8, 128.9, 129.7, 130.2, 130.3, 131.1, 131.5, 131.9, 132.4, 134.5, 134.7, 135.2, 136.0, 138.4, 139.5, 148.4, 159.2, 192.2. MS (EI): m/z (%) = 416 (11), 414 (71) [M+], 402 (13), 400 (37), 359 (20), 357 (49), 311 (47), 309 (99), 105 (100), 91 (41), 77 (81). HRMS (EI): m/z calcd for C26H23N2OCl: 414.1499; found: 414.1489. Compound 6: green solid; mp 116–118 °C. 1H NMR (400 MHz, CDCl3): δ = 1.10 (s, 3 H), 1.12 (d, J = 6.8 Hz, 6 H), 2.34 (s, 3 H), 4.10 (sept, J = 6.8 Hz, 1 H), 5.23 (s, 1 H), 5.89 (d, J = 2.0 Hz, 1 H), 6.75 (dd, J = 8.4, 2.0 Hz, 1 H), 6.85 (dd, J = 7.2, 2.0 Hz, 1 H), 7.09–7.23 (m, 7 H), 7.48 (d, J = 8.4 Hz, 1 H). 13C NMR (100 MHz, CDCl3): δ = 17.9, 18.3, 19.2, 19.9, 34.5, 84.2, 112.4, 118.6, 125.7, 127.2, 128.2, 128.7, 129.1, 132.1, 134.5, 137.4, 138.8, 139.4, 141.2, 143.6, 150.7, 208.3. MS (EI): m/z (%) = 432 (5) [M+•], 416 (13), 391 (11), 389 (30), 364 (11), 363 (41), 362 (33), 361 (88), 357 (26), 356 (17), 355 (67), 337 (12), 333 (13), 327 (13), 257 (12), 255 (11), 106 (12), 105 (100), 77 (43), 44 (20). HRMS (EI): m/z calcd for C26H25N2O2Cl: 432.1605; found: 432.1588. Compound 7: orange solid; mp 156–158 °C. 1H NMR (500 MHz, CDCl3): δ = 1.39 (s, 3 H), 2.46 (s, 3 H), 4.93 (s, 1 H), 6.05 (d, J = 2.0 Hz, 1 H), 6.80–6.83 (m, 2 H), 7.06–7.15 (m, 5 H), 7.26–7.29 (m, 2 H), 7.47–7.52 (m, 3 H), 7.60–7.64 (m, 1 H), 8.13–8.17 (m, 2 H). 13C NMR (125 MHz, CDCl3): δ = 18.3, 20.0, 84.3, 113.2, 119.0, 126.2, 127.8, 128.2, 128.3, 128.5, 129.1, 131.1, 131.6, 133.7, 135.4, 135.5, 136.6, 138.2, 138.5, 140.7, 142.0, 153.4, 193.3. ESI-MS (MeOH): m/z = 489 [M + Na]+, 955 [2 M + Na]+, 1421 [3 M + Na]+. ESI-HRMS (MeOH): m/z calcd for C29H23N2O2NaCl: 489.1346; found: 489.1338.