Synthesis and structures of partially unsaturated thiacrown ethers with hydroxyl groups

Abstract

Partially unsaturated 14- and 28-membered thiacrown ethers possessing hydroxyl groups were synthesised. The crystal structures of some geometrical isomers of the macrocycles were determined by X-ray crystallographic analysis and six oxygen atoms of the 14-membered trans-thiacrown ether were found to gather through hydrogen bonds in the crystalline state. The redox behaviours of the 14-membered thiacrown ethers were examined and the Z,E-isomerisation reactions were found to occur upon heating.

Keywords:

• thiacrown ether
• unsaturated cyclic compound
• crystal structure
• cyclic voltammetry
• Z,E-isomerisation

Acknowledgements

The authors are grateful to Associate Professor Wataru Fujita and Assistant Professor Ken-ichi Yamashita for the measurements of X-ray diffraction.

Notes

^1. (Z,Z)-cis-1,4,8,11-Tetrathia-6,13-dihydroxycyclotetradec-2,9-diene (cis- 3): mp 148°C (decomp., colourless needles from hexane-dichloromethane); ¹H NMR (500 MHz, CDCl₃) δ 2.58 (dd, J = 14.0, 9.0 Hz, 4H), 2.95 (dd, J = 14.0, 3.5 Hz, 4H), 3.56–3.59 (m, 2H), 3.63 (d, J = 3.0 Hz, 2H), 6.39 (s, 4H); ¹³C NMR (125 MHz, CDCl₃) δ 39.3, 68.9, 130.0; MS (EI, 70 eV) m/z 296 (M⁺, 73%), 130 (39%), 103 (100%), 73 (66%); IR (KBr) ν_max 3426, 2908, 2365, 2346, 1686, 1522, 1412, 1271, 1230, 1027, 996, 808, 756, 687 cm^− 1. Anal. Calcd for C₁₀H₁₆O₂S₄, 40.51; H, 5.44. Found: C, 40.37; H, 5.45

^2. (Z,Z)-trans-1,4,8,11-Tetrathia-6,13-dihydroxycyclotetradec-2,9-diene (trans- 3): mp 128°C (decomp., pale yellow blocks from hexane-dichloromethane); ¹H NMR (500 MHz, CDCl₃) δ 2.71 (dd, J = 14.0, 8.0 Hz, 4H), 2.91 (dd, J = 14.0, 4.8 Hz, 4H), 3.27 (d, J = 3.0 Hz, 2H), 3.75–3.80 (m, 2H), 6.43 (s, 4H); ¹³C NMR (125 MHz, CDCl₃) δ 39.5, 69.7, 129.8; MS (EI, 70 eV) m/z 295 (M⁺ − 1, 69%), 130 (70%), 103 (100%), 73 (99%); IR (KBr) ν_max 3179, 2916, 2369, 2346, 1684, 1541, 1415, 1300, 1070, 1034, 991, 865, 815, 689, 676 cm^− 1. Anal. Calcd for C₁₀H₁₆O₂S₄, 40.51; H, 5.44. Found: C, 40.67; H, 5.52

^3. Cis- 3: Compound cis- 3 crystallised in the monoclinic space group P2₁, with a = 9.9681(17) Å, b = 4.9997(6) Å, c = 13.2482(19) Å, b = 94.215(7)^o, V = 658.47(17) Å³, Z = 2, and Dc = 1.495 g cm^− 3. 5059 data collected with Mo Kα radiation (λ = 0.71070 Å) and Fo >2.0σ (I) were used in the least-squares refinement to yield R = 0.076, R _w = 0.213. Crystallographic data have been deposited with Cambridge Crystallographic Data Centre as supplementary publication no. CCDC-780250

^4. Trans- 3: Compound trans- 3 crystallised in the trigonal space group R-3, with a = 20.4290(13) Å, b = 20.4290(13) Å, c = 8.5863(7) Å, V = 3103.3(4) Å³, Z = 9, and Dc = 1.428g cm^− 3. 7623 data collected with Mo Kα radiation (λ = 0.71070 Å) and Fo>2.0σ (I) were used in the least-squares refinement to yield R = 0.040, R _w = 0.099. Crystallographic data have been deposited with Cambridge Crystallographic Data Centre as supplementary publication no. CCDC-780684

^5. (Z,Z,Z,Z)-1,2-alternate-1,4,8,11,15,18,22,25-Octathia-6,13,20,27-tetrahydroxycyclooctacos-2,9,16,23-tetraene (1,2-alternate- 4): ¹H NMR (270 MHz, DMSO-d ₆) δ 2.78 (dd, J = 13.5, 6.2 Hz, 8H), 2.78–2.89 (m, 8H), 3.61–3.72 (m, 4H), 5.27 (d, J = 5.1 Hz, 4H), 6.09 (s, 8H)

^6. 1,2-Alternate- 4: Compound 1,2-alternate- 4 crystallised in the monoclinic space group P2₁/n, with a = 7.234(2) Å, b = 9.968(3) Å, c = 19.387(5) Å, β = 98.563(5)^o, V = 1382.4(7) Å³, Z = 2, and Dc = 1.425 g cm^− 3. 7519 data collected with Mo Kα radiation (λ = 0.71073 Å) and Fo>2.0σ (I) were used in the least-squares refinement to yield R = 0.105, R _w = 0.284. Crystallographic data have been deposited with Cambridge Crystallographic Data Centre as supplementary publication no. CCDC-780685