Synlett 2015; 26(11): 1625-1627
DOI: 10.1055/s-0034-1379925
letter
© Georg Thieme Verlag Stuttgart · New York

Cyclotribenzoin

Qing Ji
Department of Chemistry, University of Houston, 112 Fleming Building, Houston, Texas 77204-5003, USA   Email: miljanic@uh.edu
,
Loi H. Do
Department of Chemistry, University of Houston, 112 Fleming Building, Houston, Texas 77204-5003, USA   Email: miljanic@uh.edu
,
Ognjen Š. Miljanić*
Department of Chemistry, University of Houston, 112 Fleming Building, Houston, Texas 77204-5003, USA   Email: miljanic@uh.edu
› Author Affiliations
Further Information

Publication History

Received: 23 March 2015

Accepted after revision: 07 May 2015

Publication Date:
08 June 2015 (online)


Dedicated to Peter Vollhardt, for fifteen years of chemistry- and lifestyle-related inspiration

Abstract

Using cyanide-assisted benzoin condensation of isophthaldehyde, we prepared cyclotribenzoin: a cone-shaped macrocycle whose three benzene rings define a cuplike cavity, while six of its C–H bonds convergently point in the opposite direction. This combination of convergently oriented cation- and anion-binding groups, coupled with an exceedingly simple synthesis, promises to make cyclotribenzoin an appealing platform for supramolecular chemistry studies.

Supporting Information

 
  • References and Notes

  • 1 Macrocycles: Davis F, Higson S. Construction, Chemistry and Nanotechnology Applications. Wiley; Chichester: 2011
  • 7 Wöhler F, Liebig J. Ann. Pharm. (Lemgo, Ger.) 1832; 3: 249
  • 9 Jones JI, Tinker PB. J. Chem. Soc. 1955; 1286
  • 10 Johnson JS. Angew. Chem. Int. Ed. 2004; 43: 1326
  • 12 Synthesis of Macrocycle 2 Isophthaldehyde (1, 684 mg, 5.10 mmol), EtOH (5 mL), and deionized H2O (5 mL) were added to a round-bottom flask equipped with a stirring bar, and the mixture was heated at reflux under nitrogen until all of 1 dissolved. At that time, NaCN (25 mg, 0.51 mmol) was added into the round-bottom flask and heating was continued for 48 h. The precipitate obtained was filtered and then washed with deionized H2O (10 mL), EtOH (10 mL), and Et2O (10 mL). After recrystallization from 2-methoxyethanol, pure 2 was obtained (280 mg, 41%) as a white solid; mp 245 °C (decomp.). UV/vis (THF): λmax (log ε) = 248 (4.29), 288 (3.46) nm. IR (neat): 3456 (w, νO–H), 3070 (w, νC–H), 2925 (w, νC–H), 1682 (s, νC=O), 1583 (s), 1432 (s), 1395 (s), 1274 (m), 1182 (m), 1083 (m), 796 (s), 743 (s), 692 (s) cm–1. 1H NMR (400 MHz, DMSO-d 6): δ = 8.78 (s, 3 H), 7.63 (d, 3 J H–H = 7.8 Hz, 3 H), 7.45 (d, 3 J H–H = 7.8 Hz, 3 H), 7.35 (dd, 3 J H–H = 7.8, 7.3 Hz, 3 H), 6.42 (d, 3 J H–H = 5.5 Hz, 3 H), 6.01 (d, 3 J H–H = 5.5 Hz, 3 H) ppm. 13C NMR (100 MHz, DMSO-d 6): δ = 198.4, 140.8, 134.9, 132.4, 130.2, 130.0, 128.2, 74.7 ppm. ESI-LRMS: m/z [M – H] calcd for C24H18O6: 401.11; found: 401.13. Single crystals of 2 were obtained over 7 d by vapor diffusion of CHCl3 into its solution in THF (0.5 mg mL–1).
  • 13 Crystallographic information file (CIF) for compound 2 has been deposited with Cambridge Structural Database under deposition code CCDC 1055400.
  • 14 Hua Y, Flood AH. Chem. Soc. Rev. 2010; 39: 1262 ; and the references cited therein.
  • 15 Synthesis of Macrocycle 3 Compound 2 (128 mg, 0.32 mmol), imidazole (1.30 g, 19.1 mmol), and dry CH2Cl2 (15 mL) were added to a thick-walled 20 mL microwave vial. The mixture was stirred under nitrogen for 10 min. The reagent TBDMSCl (2.90 g, 19.1 mmol) was then added to the mixture. The vial was sealed, and then placed into a Biotage microwave reactor, where it was heated for 10 h at 40 °C. The reaction mixture was diluted with CHCl3 (50 mL), washed with H2O (50 mL), and the organic layer was separated and dried over anhydrous MgSO4. After removal of solvent, the crude product was isolated as a light yellow oil. Pure compound 3 was obtained after recrystallization from pentane at –78 °C (142 mg, 60%); mp 167 °C. UV/vis (THF): λmax (log ε) = 286 (3.61), 326 (3.18) nm. IR (neat): 3070 (w, νC–H), 2929 (w, νC–H), 1713 (s, νC=O), 1674 (s), 1581 (s), 1471 (s), 1362 (s), 1257 (m), 1120 (m), 1028 (m), 862 (m), 781 (s), 735 (s), 698 (s) cm–1. 1H NMR (500 MHz, CDCl3): δ = 7.88 (s, 3 H), 7.72 (d, 3 J H–H = 8.0 Hz, 3 H), 7.73 (d, 3 J H–H = 7.6 Hz, 3 H), 7.33 (dd, 3 J H–H = 8.0, 7.4 Hz, 3 H), 5.82 (s, 3 H), 0.87 (s, 27 H), 0.09 (s, 9 H), 0.08 (s, 9 H) ppm. 13C NMR (125 MHz, CDCl3): δ = 198.3, 139.2, 135.7, 131.6, 129.5, 128.9, 127.0, 79.4, 25.9, 18.5, –4.6, –4.7 ppm. ESI-LRMS: m/z [M + Na+] calcd for C42H60O6Si3: 767.36; found: 767.38; m/z [2M + Na+] calcd: 1511.73; found: 1511.09.