Development of a new traceless aniline linker for combinatorial solid-phase parallel synthesis of rod-shaped liquid crystals with an azomethine linkage

Tetrahedron Letters

Volumn 45, Issue 41, 2004, Pages 7591-7594

  Hioki, Hideaki ^a   Fukutaka, Mizuki ^a   Takahashi, Hideki ^a   Kodama, Mitsuaki ^a   Kubo, Kanji ^b   Ideta, Keiko ^b   Mori, Akira ^b  

^a TOKUSHIMA BUNRI UNIVERSITY   (Japan)

^b KYUSHU UNIVERSITY   (Japan)

Author keywords

Azomethines; Combinatorial synthesis; Liquid crystals; Traceless linker

Indexed keywords

ANILINE DERIVATIVE; AZOMETHINE YLIDE; IMINE;

ARTICLE; CHEMICAL REACTION; COMBINATORIAL CHEMISTRY; HIGH TEMPERATURE; PHASE TRANSITION; SOLID; SYNTHESIS; X RAY DIFFRACTION;

EID: 4544285315     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/j.tetlet.2004.08.106     Document Type: Article

References (15)

1. M. Wagner, and H. Kunz Angew. Chem., Int. Ed. 41 2002 317 320
2. P. Blaney, R. Grigg, and V. Sridharan Chem. Rev. 102 2002 2607 2624
3. T. Takahashi, H. Inoue, Y. Yamamura, and T. Doi Angew. Chem., Int. Ed. 40 2001 3230 3233
4. A. Mori, I. Akahoshi, M. Hashimoto, T. Doi, and T. Takahashi Tetrahedron Lett. 45 2004 813 815
5. M. Hashimoto, A. Mori, H. Inoue, H. Nagamiya, T. Doi, and T. Takahashi Tetrahedron Lett. 44 2003 1251 1254
6. T. Haino, M. Tanaka, K. Ideta, K. Kubo, A. Mori, and Y. Fukazawa Tetrahedron Lett. 45 2004 2277 2279
7. Combinatorial syntheis of liquid crystals in solution phase has been reported see: O. Deeg, P. Kirsch, D. Pauluth, and P. Bäuerle Chem. Commun. 2002 2762 2763
8. O. Deeg, and P. Bäuerle Org. Biomol. Chem. 1 2003 1609 1624
9. D. Demus, J. Goodby, G.W. Gray, H.-W. Spiess, and V. Vill Handbook of Liquid Crystals 1998 VCH Weinheim
10. Condensation of resin-bound aniline and aromatic aldehydes was reported see: C. Patteux, V. Levacher, and G. Dupas Org. Lett. 5 2003 3061 3063
11. General procedures for the synthesis of the library are shown as follows: Synthesis of 13 on solid support 11: Eighty four pieces of the solid supported aniline 11 (D-series, loading: 38 μmol × 84, 3.19 mmol) were reacted with 4-carboxybenzaldehyde (2.54 g, 16.9 mmol, 5.3 equiv) in DMF solution (80 mL) at room temperature for 24 h. The solution was removed by decantation and the resulting resins were washed with DMF (3 × 0.5 min) and DCM (3 × 0.5 min). Synthesis of 14a on solid support 13 with n-nonanol: Twenty eight pieces of the solid supported azomethine 13 (D-series, loading: 38 μmol × 28, 1.06 mmol) were reacted with 4-N,N-dimethylaminopyridine (32.5 mg, 0.266 mmol, 0.25 equiv), n-nonanol (0.74 mL, 4.2 mmol, 4 equiv), and 1,3-diisopropyl-carbodiimide (1.3 mL, 8.5 mmol, 8 equiv) in DCM at room temperature for 3 h. The solution was removed by decantation and the resulting resins were washed with DMF (3 × 0.5 min) and DCM (3 × 0.5 min). Cleavage from the solid support: Four pieces of the solid supported ester 14a (D-series, loading: 38 μmol × 4, 152 μmol) were reacted with 4-n-octyloxyaniline (168.2 mg, 0.76 mmol, 5 equiv) in DMF (5 mL) at 50°C for 3 h. The the resulting resins were washed with DMF (3 × 3 min). The combined DMF solution was evaporated and purified by HPLC (hexane/EtOAc = 9/1) to give 1a8 in 66% yield (48.3 mg, 107 μmol) as pale yellow solid. All 28 library members have been fully characterized by analytical and spectroscopic means
12. The yield of the second cycle was almost half of the first one
13. The X-ray diffraction measurements were carried out using Ni-filtered Cu-Kα radiation at various temperatures
14. E. Taffin De Givenchy, F. Guittard, F. Bracon, and A. Cambon Liq. Cryst. 26 1999 1163 1170
15. Compounds 1a1 and 1c1 were chosen as model compounds for 1a4-1a10 and 1c4-1c10. Hundred and eight conformers for each compound were generated systematically and individual conformers were optimized at the HF3-21G* level using pc spartan 02 program. Only four conformers were found for 1a1 and 1c1. The dipole moments calculated from the sum of the Boltzmann factors of each conformation at 298 K