Ionic-Liquid-Supported 1,3-Dimethylimidazolidin-2-one: Application as a Reusable Halogenation Reagent

Abstract

We describe the synthesis of ionic-liquid-supported 1,3-dimethylimidazolidin-2-one, together with the halogenation of alcohols in a reaction system in which this reagent is combined with oxalyl chloride. A new method was established that does not require additives such as bases, and which permits the ready isolation and purification of the product. Good conversions were obtained, and good reusability of the reagent was observed.

Key words

ionic liquid - chlorination - alcohols - dimethylimidazolidinone - supported reagent

• References and Notes

• 1a Fujii S. Yuki Gosei Kagaku Kyokaishi 1994; 52: 778
• 1b Zhao L.-M, Zhang S.-Q, Jin H.-S, Wan L.-J, Dou F. Org. Lett. 2012; 14: 886
• 1c Kitamura T, Gondo K, Katagiri T. J. Org. Chem. 2013; 78: 3421
• 2 Akiyama A, Hanamura H, Imatomi S, Yamada S, Itou H, Kondou H, Maeshima Y. JP 2018024818, 2018
• 3a Isobe T, Ishikawa T. J. Org. Chem. 1999; 64: 6984
• 3b Isobe T, Ishikawa T. J. Org. Chem. 1999; 64: 6989
• 3c Isobe T, Ishikawa T. J. Org. Chem. 1999; 64: 5832
• 4 Disadee W, Watanabe T, Ishikawa T. Synlett 2003; 115
• 5a Hallett JP, Welton T. Chem. Rev. 2011; 111: 3508
• 5b Wasserscheid P, Welton T. Ionic Liquids in Synthesis . Wiley-VCH; Weinheim, Germany: 2007
• 5c Wasserscheid P, Keim W. Angew. Chem. Int. Ed. 2000; 39: 3772
• 5d Welton T. Chem. Rev. 1999; 99: 2071
• 6a Marra A, Chiappe C, Mele A. Chimia 2011; 65: 76
• 6b Xue H, Shreeve JM. Eur. J. Inorg. Chem. 2005; 2573
• 7 Cao H, McNamee L, Alper H. J. Org. Chem. 2008; 73: 3530
• 8a Koguchi S. Trans. Mater. Res. Soc. Jpn. 2013; 38: 35
• 8b Matsumoto H, Yanagida M, Tanimoto K, Nomura M, Kitagawa Y, Miyazaki Y. Chem. Lett. 2000; 29: 922
• 8c Sakaebe H, Matsumoto H. Electrochem. Commun. 2003; 5: 594
• 9a Koguchi S, Izawa K. ACS Comb. Sci. 2014; 16: 381
• 9b Koguchi S, Mihoya A, Mimura M. Tetrahedron 2016; 72: 7633
• 9c Koguchi S, Nakamura K. Synlett 2013; 24: 2305
• 10 Chlorination of Alcohols (Table 2); General ProcedureThe solution of ionic-liquid-supported DMI 7 (2.2 mmol) in [bmim]PF₆ (2 mL) was added to oxalyl chloride (2.0 mmol), and the mixture was stirred at 60 °C for 2 h. The mixture was then added to the appropriate alcohol (1.5 mmol), and the resulting mixture was stirred at r.t. overnight. Finally, the mixture was extracted with hexane 10 mL x 3, and the organic layer was concentrated.1-(2-hydroxyethyl)imidazolidin-2-one (2)The solution of 2-((2-aminoethyl) amino) ethanol (6.24g, 60mmol) in ethylene glycol (4 ml) was added to ureal (3.60g, 60 ml). The mixture was stirred at 130 °C for 24 h. The mixture extracted with ethyl acetate, and organic layer was washed with H₂O, dried (MgSO₄) and evaporated. The product was isolated by silica gel column chromatography to give the title compound 2 (6.94 g, 89%) as white solid; mp 45 °C. ¹H NMR (500 MHz, CDCl₃): δ =3.30–3.77 (9H, m), 5.80 (1H, s). ¹³C NMR (CDCl₃) δ = 38.4, 46.0, 46.3, 60.2, 164.0. HRMS (APCI): m/z [M + H]⁺ calcd for C₅H₁₁N₂O₂, 131.08205; found: 131.08390.1-(2-chloroethyl)imidazolidin-2-one (3)The solution of 1-(2-hydroxyethyl) imidazolidin-2-one (5.07g, 39.1mmol) in chloroform (10 ml) was added to thionyl chloride (5.70ml, 78.2mmol). The mixture was stirred at 50 °C for 3 h. The mixture was evaporated, and the product was isolated by silica gel column chromatography to give the title compound 3 (5.50 g, 95%) as white solid; mp 85–88 °C. ¹H NMR (500 MHz, CDCl₃): δ = 3.45–3.64 (8H, m), 5.60 (1H, s). ¹³C NMR (CDCl₃) δ = 38.3, 42.5, 45.6, 46.0, 163.0. HRMS (APCI): m/z [M + Na]⁺ calcd for C₅H₉ClN₂NaO, 171.03011; found: 170.03091.1-(2-chloroethyl)-3-methylimidazolidin-2-one (4)The solution of 1-(2-chloroethyl) imidazolidin-2-one (4.00g, 26mmol) in THF (56 ml) was added to sodium hydride (1.86g, 45mmol) at 0 °C. And then the mixture was added to iodomethane (3.4ml, 53.8mmol) and stirred at room temperature for 24 h. The mixture extracted with chloroform, and organic layer was washed with H₂O, dried (MgSO₄) and evaporated. The product was isolated by silica gel column chromatography to give the title compound 3 (4.03 g, 92%) as yellow liquid. ¹H NMR (500 MHz, CDCl₃): δ = 2.80 (3H, s), 3.32–3.63 (8H, m). ¹³C NMR (CDCl₃) δ = 31.2, 42.5, 43.5, 45.0, 46.3, 161.2. HRMS (APCI): m/z [M + H]⁺ calcd for C₆H₁₂ClN₂O, 163.06382; found: 163.06851.1-methyl-3-(2-(3-methyl-2-oxoimidazolidin-1-yl)ethyl)-1H-imidazol-3-ium chloride (5)The solution of 1-(2-chloroethyl)-3-methylimidazolidin-2-one (4.00 g, 24.6mmol) in toluene (30 ml) was added to 1-methylimidazole (2.02g, 24.4 ml). The mixture was stirred at 110 °C for 24 h. The mixture was washed with hexane and evaporated to give the title compound 5 (5.11 g, 85%) as yellow liquid. ¹H NMR (500 MHz, DMSO): δ = 2.59 (3H, s), 7.13 (1H, s), 3.15–3.88 (6H, m), 3.88 (3H, s), 4.37 (2H, m), 7.77 (1H, s), 7.86 (1H, s), 9.47 (1H, s). ¹³C NMR (CDCl₃) δ = 31.4, 36.2, 42.7, 44.7, 44.9, 47.3, 123.1, 123.9, 137.3, 161.2. HRMS (APCI): m/z [M]⁺ calcd for C₁₀H₁₇N₄O, 209.1402; found: 209.14283.1-methyl-3-(2-(3-methyl-2-oxoimidazolidin-1-yl)ethyl)-1H-imidazol-3-ium tetrafluoroborate (6)The solution of 1-methyl-3-(2-(3-methyl-2-oxoimidazolidin-1-yl) ethyl)-1H-imidazol-3-ium chloride (0.54 g, 2.2 mmol) in methanol (2 ml) was added to sodium tetrafluoroborate (0.24 g, 2.2 mmol). The mixture was stirred at room temperature for 24 h. The mixture was filtered and evaporated to give the title compound 6 (0.65 g, quant.) as yellow liquid.¹H NMR (500 MHz, DMSO): δ = 2.60(3H, s), 3.24–3.28(4H, m), 3.47(2H, t, J=6), 3.85(3H, s), 4.30(2H, t, J=6), 7.68(1H, s), 7.75(1H, s), 9.10(1H, s). ¹³C-NMR(125 MHz, DMSO): δ =31.4, 36.2, 42.7, 44.7, 44.9, 47.4, 123.1, 123.9, 137.2, 161.3. HRMS (APCI): m/z [M]⁺ calcd for C₁₀H₁₇N₄O, 209.1402; found: 209.13960.1-methyl-3-(2-(3-methyl-2-oxoimidazolidin-1-yl)ethyl)-1H-imidazol-3-ium hexafluorophosphate (7)The solution of 1-methyl-3-(2-(3-methyl-2-oxoimidazolidin-1-yl) ethyl)-1H-imidazol-3-ium chloride (0.75 g, 3.0 mmol) in methanol (2 ml) was added to potassium hexafluorophosphate (0.55 g, 3.0 mmol). The mixture was stirred at room temperature for 24 h. The mixture was filtered and evaporated to give the title compound 7 (1.06 g, quant.) as white solid. mp 85–102 °C.¹H NMR (500 MHz, DMSO): δ = 2.60 (3H, s), 3.22–3.30 (4H, m), 3.47 (2H, t, J=6), 3.85 (3H, s), 4.29 (2H, t, J=6), 7.68 (1H, s), 7.75 (1H, s), 9.10 (1H, s). ¹³C-NMR (125 MHz, DMSO): δ =31.4, 36.2, 42.7, 44.7, 44.9, 47.4, 123.1, 123.9, 137.3, 161.3. HRMS (APCI): m/z [M]⁺ calcd for C₁₀H₁₇N₄O, 209.1402; found: 209.13975.