Issue in Honor of Prof. Richard Bartsch ARKIVOC 2010 (vii) 238-248
and evaporated in vacuo. Purification was accomplished by dissolving the residue in a minimum amount of CH2Cl2 and pre-sorbing the solution onto activated alumina (4:1 g/g adsorbent to product). The presorbed alumina was loaded onto a 20:1 adsorbent to product bed of activated alumina and the product was obtained by elution with ethyl acetate
Dibenzo-15-crown-5 (23). White crystalline solid obtained in 60% yield; mp 113-115 oC (lit.1 mp 113.5-115 oC). IR 1122 cm-1. 1H NMR (200 MHz, CDCl3) • 6.91 (m, 8H), 4.35 (m, 4H), 4.20 (m, 4H), 3.90 (m, 4H). 2,3,8,9-Dibenzo-18-crown-6 (24). White crystalline solid in 75% yield; mp 117-119 oC (lit.1 mp 117-118 oC). IR 1128 cm-1. •
1H NMR (200 MHz, CDCl3) • 6.89-6.99 (m, 8H), 4.42-4.57 (m, 4H), 4.16-4.20 (m, 4H), 3.82-3.93 (m, 8H). 2,3,8,9-Dibenzo-21-crown-7 (25). Tan oil (75%). IR 1125 cm-1. 1H NMR (200 MHz, CDCl3) • •
6.90 (m, 8H), 4.35 (m, 4H), 4.14 (m, 4H), 3.61-3.90 (m, 12H). Anal. calcd for C22H28O7: C, 64.80; H, 6.93. Found: C, 64.86; H, 6.86. 2,3,8,9-Dibenzo-24-crown-8 (26). Tan oil (78%). IR 1128 cm-1. 1H NMR (200 MHz, CDCl3) • • 6.90 (m, 8H), 4.35 (m, 4H), 4.14 (m, 4H), 3.50-3.90 (m, 16H). Anal. calcd for C24H32O8: C, 64.27; H, 7.19. Found: C, 64.60; H, 7.27. 2,3,11,12-Dibenzo-21-crown-7 (29). White crystalline solid (78%); mp 104-106 oC (lit.1 mp 106.5-107.5 oC); IR 1125 cm-1; 1H NMR (200 MHz, CDCl3) • 6.90 (m, 8H), 3.85-4.20 (m, 20H). 2,3,11,12-Dibenzo-24-crown-8 (30). White, crystalline solid (50%); mp 43-45 oC. IR 1126 cm-1. 1H NMR (200 MHz, CDCl3) • 6.90 (m, 8H), 3.65-4.20 (m, 24H). Anal. calcd for C24H32O8: C, 64.27; H, 7.19. Found: C, 64.23; H, 7.24. Dibenzo-16-crown-5 (34). After recrystallization from heptane was obtained in 56% yield; mp 117-118 oC (lit.1 mp 117-118 oC). IR 1253, 1122 cm-1. 1H NMR (200 MHz, CDCl3) • 6.81-6.87 (m, 8H) 4.25 (t, 6.5 Hz, 4H), 4.13-4.17 (m, 4H), 3.91-3.95 (m, 4H), 2.27 (p, 6.5 Hz, 2H). MS (DIP-EI) m/e 330.25 (330.15 calculated for C19H22O5) and 660.40 (660.30 calculated for C38H44O10). 2,3,9,10-Dibenzo-19-crown-6 (35). White crystalline solid (64%); mp 79-82 oC (lit.1 mp 84.586 oC). IR 1125 cm-1. 1H NMR (200 MHz, CDCl3) • 6.90 (m, 8H), 4.20 (m, 8H), 3.85 (m, 8H), 2.30 (m, 2H). 2,3,9,10-Dibenzo-25-crown-8 (36). Yellow oil. Yield 53%. IR 1256, 1125 cm-1. 1H NMR (200 MHz, CDCl3) • 6.88-6.95 (m, 8H), 4.23 (t, 6.4 Hz, 4H), 4.13-4.18 (m, 4H), 3.84-3.89 (m, 4H), 3.71-3.76 (m, 4H), 3.59-3.65 (m, 8H), 2.31 (p, 6.4 Hz, 2H). 13C NMR (50 MHz, CDCl3) • 149.0, 148.9, 148.7, 121.9, 121.3, 121.2, 115.3, 114.5, 114.1, 113.9, 70.9, 70.5, 69.5, 68.9, 67.1, 66.1, 65.7, 29.4. MS (DIP-EI) m/e 462.35 (462.23 calculated for C25H34O8). Anal. calcd for C25H34O8: C, 64.92; H, 7.41. Found: C, 65.35; H, 7.27. 2,3,9,10,18,19-Tribenzo-25-crown-8 (38). White solid. Yield 75%; mp 94-95 oC. IR 1255, 1124 cm-1. • 1H NMR (300 MHz, CDCl3) • 6.87-6.93 (m, 12H), 4.20 (t, 4.2 Hz, 4H), 4.09-4.16 (m, 8H), 3.88-3.92 (m, 8H), 2.23 (p, 4.2 Hz, 2H). 13C NMR (75 MHz, CDCl3) • 149.1, 149.0, 121.7,
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