Efficient Demethylation of N,N-Dimethylanilines with Phenyl Chloroformate in Ionic Liquids

Satomi Imori; Hideo Togo

doi:10.1055/s-2006-951490

LETTER

Efficient Demethylation of N,N-Dimethylanilines with Phenyl Chloroformate in Ionic Liquids

Satomi Imori^a, Hideo Togo*^a,b
^a Graduate School of Science and Technology, Chiba University, Yayoi-cho 1-33, Inage-ku 263-8522, Japan
^b Department of Chemistry, Faculty of Science, Chiba University, Yayoi-cho 1-33, Inage-ku 263-8522, Japan
e-Mail: togo@faculty.chiba-u.jp;

Abstract

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Abstract

Demethylation of N,N-dimethylanilines was carried out in various ionic liquids and acetonitrile as well as under solvent-free conditions. We have demonstrated that their reactivity dramatically depends on the ionic liquid employed; [bmim]Cl showed the best reactivity.

Key words

N,N-dimethylaniline - demethylation - phenyl chloroformate - ionic liquid - phenyl N-methyl-N-arylcarbamate

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References and Notes

<A NAME="RU09106ST-1">1</A> Review: Cooley JH. Evain EJ. Synthesis 1989, 1 ; and references cited therein

<A NAME="RU09106ST-2">2</A> Hobson JD. McCluskey JG. J. Chem. Soc. C 1967, 2015

<A NAME="RU09106ST-3A">3a</A> Montzka TA. Matiskella JD. Partyka RA. Tetrahedron Lett. 1974, 1325

<A NAME="RU09106ST-3B">3b</A> Olofson RA. Schnur RC. Bunes L. Pepe JP. Tetrahedron Lett. 1977, 1567

<A NAME="RU09106ST-3C">3c</A> Olefson RA. Martz JT. Senet JP. Piteau M. Malfroot T. J. Org. Chem. 1984, 49: 2081

<A NAME="RU09106ST-3D">3d</A> Millan DS. Prager RF. Tetrahedron Lett. 1998, 39: 4387

<A NAME="RU09106ST-3E">3e</A> Dave PR. J. Org. Chem. 1996, 61: 5453

<A NAME="RU09106ST-4">4</A> Cossy J. Rakotoarisoa H. Tetrahedron Lett. 2000, 41: 2097

<A NAME="RU09106ST-5A">5a</A> Laurent P. Braekman J.-C. Daloze D. Eur. J. Org. Chem. 2000, 2057

<A NAME="RU09106ST-5B">5b</A> Jacquemard U. Beneteau V. Lofoix M. Routier S. Merour Y. Coudert G. Tetrahedron 2004, 60: 10039

Reviews:

<A NAME="RU09106ST-6A">6a</A> Welton T. Chem. Rev. 1999, 99: 2071

<A NAME="RU09106ST-6B">6b</A> Wasserscheid P. Keim W. Angew. Chem. Int. Ed. 2000, 39: 3772

<A NAME="RU09106ST-6C">6c</A> Sheldon R. Chem. Commun. 2001, 2399

<A NAME="RU09106ST-6D">6d</A> Sheldon RA. Pure Appl. Chem. 2002, 72: 1233

<A NAME="RU09106ST-6E">6e</A> Earle MJ. Seddon KR. Pure Appl. Chem. 2000, 72: 1391

<A NAME="RU09106ST-6F">6f</A> Zhao H. Malhotra SV. Aldrichimica Acta 2002, 35: 75

<A NAME="RU09106ST-6G">6g</A> Lee S. Chem. Commun. 2006, 1049

<A NAME="RU09106ST-6H">6h</A> Macfarlane DR. Pringle JM. Johansson KM. Forsyth SA. Forsyth M. Chem. Commun. 2006, 1905

<A NAME="RU09106ST-7A">7a</A> Surette JKD. Green L. Singer RD. Chem. Commun. 1996, 2753

<A NAME="RU09106ST-7B">7b</A> Adams CJ. Earle MJ. Roberts G. Seddon KR. Chem. Commun. 1998, 2097

<A NAME="RU09106ST-7C">7c</A> Jorapur YR. Lee C.-H. Chi DY. Org. Lett. 2005, 7: 1231

<A NAME="RU09106ST-8A">8a</A> Monteiro AL. Zinn FK. De Souza RF. Dupont J. Tetrahedron: Asymmetry 1997, 8: 177

<A NAME="RU09106ST-8B">8b</A> Dyson PJ. Ellis DL. Parker DG. Welton T. Chem. Commun. 1999, 25

<A NAME="RU09106ST-8C">8c</A> Adams CJ. Earle MJ. Seddon KR. Chem. Commun. 1999, 1043

<A NAME="RU09106ST-9A">9a</A> Howarth J. Hanlon K. Fayne D. McCormac P. Tetrahedron Lett. 1997, 38: 3097

<A NAME="RU09106ST-9B">9b</A> Huddleston JG. Rogers RD. Chem. Commun. 1998, 1765

<A NAME="RU09106ST-9C">9c</A> Lee CW. Tetrahedron Lett. 1999, 40: 2461

<A NAME="RU09106ST-10A">10a</A> Carmichael AJ. Earle MJ. Holbrey JD. McCormac PB. Seddon KR. Org. Lett. 1999, 1: 997

<A NAME="RU09106ST-10B">10b</A> Calo V. Nacci A. Lopez L. Mannarini N. Tetrahedron Lett. 2000, 41: 8973

<A NAME="RU09106ST-10C">10c</A> Mathews CJ. Smith PJ. Welton T. Chem. Commun. 2000, 1249

<A NAME="RU09106ST-10D">10d</A> Fukuyama T. Shinmen M. Nishitani S. Sato M. Ryu I. Org. Lett. 2002, 4: 1691

<A NAME="RU09106ST-10E">10e</A> Mayo KG. Nearhoof EH. Kiddle JJ. Org. Lett. 2002, 4: 1567

<A NAME="RU09106ST-11">11</A> Calo V. Nacci A. Lopez L. Lerario VL. Tetrahedron Lett. 2000, 41: 8977

<A NAME="RU09106ST-12A">12a</A> Owens GS. Abu-Omar MM. Chem. Commun. 2000, 1165

<A NAME="RU09106ST-12B">12b</A> Howarth J. Tetrahedron Lett. 2000, 41: 6627

<A NAME="RU09106ST-12C">12c</A> Ansari IA. Gree R. Org. Lett. 2002, 4: 1507

<A NAME="RU09106ST-12D">12d</A> Yanada R. Takemoto Y. Tetrahedron Lett. 2002, 43: 6849

<A NAME="RU09106ST-12E">12e</A> Liu Z. Chen Z.-C. Zheng Q.-G. Org. Lett. 2003, 5: 3321

<A NAME="RU09106ST-12F">12f</A> Yadav JS. Reddy BVS. Basak AK. Narsaiah AV. Tetrahedron 2004, 60: 2131

<A NAME="RU09106ST-12G">12g</A> Chhikara BS. Tehlan S. Kumar A. Synlett 2005, 63

<A NAME="RU09106ST-12H">12h</A> Wu X.-E. Ma L. Ding M.- X. Gao L.-X. Chem. Lett. 2005, 34: 312

<A NAME="RU09106ST-12I">12i</A> Wu X.-E. Ma L. Ding M.-X. Gao L.-X. Synlett 2005, 607

<A NAME="RU09106ST-13A">13a</A> Morrison DW. Forbes DC. Davis JH. Tetrahedron Lett. 2001, 42: 6053

<A NAME="RU09106ST-13B">13b</A> Xie Y.-Y. Chen Z.-C. Zheng Q.-G. Synthesis 2002, 1505

<A NAME="RU09106ST-13C">13c</A> Su C. Chen Z.-C. Zheng Q.-G. Synthesis 2003, 555

<A NAME="RU09106ST-13D">13d</A> Kitaoka S. Nobuoka K. Ishikawa Y. Chem. Commun. 2004, 1902

<A NAME="RU09106ST-13E">13e</A> Sato A. Nakamura Y. Maki T. Ishihara K. Yamamoto A. Adv. Synth. Catal. 2005, 347: 1337

<A NAME="RU09106ST-14">14</A> Andrade CKZ. Takeda SCS. Alves LM. Rodrigues JP. Suarez PAZ. Brandao RF. Soares VCD. Synlett 2004, 2135

<A NAME="RU09106ST-15">15</A> Ren RX. Zueva LD. Ou W. Tetrahedron Lett. 2001, 42: 8441

<A NAME="RU09106ST-16A">16a</A> Deng Y. Shi F. Beng J. Quio K. J. Mol. Catal. A: Chem. 2001, 165: 33

<A NAME="RU09106ST-16B">16b</A> Fraga-Dubreuil J. Bourahla K. Rahmouni M. Bazureau JP. Hamelin J. Catal. Commun. 2002, 3: 185

<A NAME="RU09106ST-16C">16c</A> Brinchi L. Germani R. Savelli G. Tetrahedron Lett. 2003, 44: 2027

<A NAME="RU09106ST-16D">16d</A> McNulty J. Cheekoori S. Nair JJ. Larichev V. Capretta A. Robertson AJ. Tetrahedron Lett. 2005, 46: 3641

<A NAME="RU09106ST-17A">17a</A> Kim DW. Song CE. Chi DY. J. Am. Chem. Soc. 2002, 124: 10278

<A NAME="RU09106ST-17B">17b</A> Chiappe C. Pieraccini D. Saullo P. J. Org. Chem. 2003, 68: 6710

<A NAME="RU09106ST-17C">17c</A> Brinchi L. Germani R. Savelli G. Tetrahedron Lett. 2003, 44: 6583

<A NAME="RU09106ST-17D">17d</A> Brinchi L. Germani R. Savelli G. Tetrahedron Lett. 2003, 44: 2027

<A NAME="RU09106ST-17E">17e</A> Mohile SS. Potdar MK. Salunkhe MM. Tetrahedron Lett. 2003, 44: 1255

<A NAME="RU09106ST-17F">17f</A> Yadav JS. Reddy BVS. Basak AK. Venkat Narsaiah A. Tetrahedron Lett. 2003, 44: 2217

<A NAME="RU09106ST-17G">17g</A> Kotti SRSS. Xu X. Li G. Headly AD. Tetrahedron Lett. 2004, 45: 1427

<A NAME="RU09106ST-18A">18a</A> Handy ST. J. Org. Chem. 2006, 71: 4659

<A NAME="RU09106ST-18B">18b</A> Law MC. Wong K. Chen TH. Chem. Commun. 2006, 2457

<A NAME="RU09106ST-19">19</A> Yoshino T. Imori S. Togo H. Tetrahedron 2006, 62: 1309

Phenyl N -Methyl- N -phenylcarbamate; Typical Procedure: A flask containing [bmim]Cl (2.0 mL) was dried under reduced pressure by a vacuum pump for 2 h at 80 °C. Then, N,N-dimethylaniline (1.0 mmol) and phenyl chloroformate (1.2 equiv) were added to the flask. The resulting mixture was stirred and heated at 80 °C for 3 h. Then H₂O (3 mL) was added and the reaction mixture was extracted with EtOAc (20 × 5 mL). The combined extract was condensed to give a residue; the purity of the product was about 50% due to the presence of phenyl chloroformate and a little ionic liquid. The residue was purified by preparative TLC (hexane-EtOAc, 7:1) to give pure phenyl N-methyl-N-phenylcarbamate in 95% yield; colorless oil; bp 155 °C (1 mmHg). IR (neat): 1730, 1600, 1205, 740, 695 cm^-1. ¹H NMR (CDCl₃, TMS): δ = 7.39-7.09 (10 H, m), 3.39 (3 H, s). The following abbreviations are used in ¹³C spectral data: p, s, t, q, for primary, secondary, tertiary, and quarternary carbon, respectively. ¹³C NMR (CDCl₃, TMS): δ = 153.9 (q), 151.2 (q), 142.8 (q), 129.1 (2 t), 128.9 (2 t), 126.5 (t), 125.8 (t), 125.3 (2 t), 121.5 (2 t), 38.1 (p). HRMS (FAB): m/z calcd for C₁₄H₁₄NO₂ (M + H): 228.1025; found: 228.1012. Phenyl N -Methyl- N -phenylcarbamate; Distillation Method: A flask containing [bmim]Cl (4.0 mL) was dried under reduced pressure by a vacuum pump for 2 h at 80 °C. Then, N,N-dimethylaniline (20.0 mmol)and phenyl chloroformate (1.2 equiv) were added to the flask. The resulting mixture was stirred and heated at 80 °C for 3 h. Then the reaction mixture was distilled to give pure phenyl N-methyl-N-phenylcarbamate in 90% yield; bp 155 °C (1 mmHg).Phenyl N -Methyl- N-p -bromophenylcarbamate: Colorless oil; bp 210 °C (1 mmHg). IR (neat): 1720, 1590, 1200, 830, 740, 690 cm^-1. ¹H NMR (CDCl₃, TMS): δ = 7.49-7.45 (2 H, m), 7.34-7.09 (7 H, m), 3.38 (3 H, s). ¹³C NMR (CDCl₃, TMS): δ = 153.5 (q), 151.0 (q), 141.8 (q), 131.9 (2 t), 129.1 (2 t), 127.2 (t), 125.3 (2 t), 121.4 (2 t), 121.4 (q), 38.1 (p). HRMS (FAB): m/z calcd for C₁₄H₁₃BrNO₂ (M + H): 306.0130; found: 306.0137. Phenyl N -Methyl- N-p -methylphenylcarbamate: Colorless oil; bp 170 °C (1 mmHg). IR (neat): 1720, 1595, 1205, 820, 740, 690 cm^-1. ¹H NMR (CDCl₃, TMS): δ = 7.33-7.08 (9 H, m), 3.38 (3 H, s), 2.34 (3 H, s). ¹³C NMR (CDCl₃, TMS): δ = 154.0 (q), 151.3 (q), 140.3 (q), 136.4 (q), 129.6 (2 t), 129.1 (2 t), 125.7 (t), 125.2 (2 t), 121.6 (2 t), 38.2 (p), 20.9 (p). HRMS (FAB): m/z calcd for C₁₅H₁₆NO₂ (M + H): 242.1181; found: 242.1190. Phenyl N -Methyl -N-m -nitrophenylcarbamate: Colorless oil; bp 240 °C (1 mmHg). IR (neat): 1740, 1600, 1200, 810, 750, 695 cm^-1. ¹H NMR (CDCl₃, TMS): δ = 8.27-8.26 (1 H, m), 8.07-8.05 (1 H, m), 7.75-7.73 (1 H, m), 7.54-7.50 (1 H, m), 7.37-7.33 (2 H, m), 7.20-7.13 (3 H, m), 3.48 (3 H, s). ¹³C NMR (CDCl₃, TMS): δ = 153.3 (q), 150.6 (q), 148.3 (q), 143.8 (q), 131.3 (t), 129.5 (t), 129.2 (2 t), 125.6 (t), 121.3 (2 t), 120.7 (t), 120.1 (t), 37.5 (p). HRMS (FAB): m/z calcd for C₁₄H₁₃N₂O₄ (M + H): 273.0875; found: 273.0879. Phenyl N -Methyl- N -naphthylcarbamate: White solid; mp 86-87 °C. IR (paraffin): 1720, 1595, 1200, 695 cm^-1. ¹H NMR (CDCl₃, TMS): δ = 8.00-6.92 (12 H), 3.49-3.41 (3 H). ¹³C NMR (CDCl₃, TMS): δ = 154.6 (q), 151.2 (q), 139.1 (q), 134.4 (q), 130.0 (q), 128.9 (2 t), 128.4 (t), 128.1 (t), 126.8 (t), 126.2 (t), 125.6 (t), 125.1 (t), 124.7 (t), 122.2 (t), 121.4 (2 t), 38.4 (p). HRMS (FAB): m/z calcd for C₁₈H₁₆NO₂ (M + H): 278.1181; found: 278.1165. Phenyl N -Butyl- N -phenylcarbamate: Colorless oil; bp 150 °C (1 mmHg). IR (neat): 1720, 1595, 1200, 745, 690 cm^-1. ¹H NMR (CDCl₃, TMS): δ = 7.42-7.09 (10 H, m), 3.78-3.74 (2 H, m), 1.66-1.59 (2 H, m), 1.40-1.31 (2 H, m), 0.93-0.89 (3 H, t, J = 7.3 Hz). ¹³C NMR (CDCl₃, TMS): δ = 153.8 (q), 151.3 (q), 141.5 (q), 129.1 (2 t), 129.0 (2 t), 127.3 (t), 126.9 (t), 125.1 (2 t), 121.5 (2 t), 50.6 (s), 30.2 (s), 19.8 (s), 13.7 (p). HRMS (FAB): m/z calcd for C₁₇H₂₀NO₂ (M + H): 270.1494; found: 270.1488.Phenyl N -Ethyl- N -phenylcarbamate: Colorless oil; bp 160 °C (1 mmHg). IR (neat): 1720, 1595, 1200, 750, 690 cm^-1. ¹H NMR (CDCl₃, TMS): δ = 7.42-7.08 (10 H, m), 3.83-3.79 (2 H, m), 1.24-1.21 (3 H, m). ¹³C NMR (CDCl₃, TMS): δ = 153.6 (q), 151.3 (q), 142.8 (q), 129.1 (2 t), 129.0 (2 t), 127.3 (t), 126.9 (t), 125.1 (2 t), 121.5 (2 t), 45.8 (s), 13.8 (p). HRMS (FAB): m/z calcd for C₁₅H₁₆NO₂ (M + H): 242.1181; found: 242.1170. Phenyl N -Methyl- N -dodecylcarbamate: Colorless oil; bp 180 °C (1 mmHg). IR (neat): 1730, 750, 690 cm^-1. ¹H NMR (CDCl₃, TMS): δ = 7.36-7.37 (2 H, m), 7.20-7.09 (3 H, m), 3.43-3.31 (2 H), 3.06-2.98 (3 H), 1.63 (2 H), 1.32-1.26 (18 H, m), 0.91-0.86 (3 H, m). ¹³C NMR (CDCl₃, TMS): δ = 153.6 (q), 151.3 (q), 142.8 (q), 129.1 (2 t), 129.0 (2 t), 127.3 (t), 126.9 (t), 125.1 (2 t), 121.5 (2 t), 45.8 (s), 13.8 (p). HRMS (FAB): m/z calcd for C₂₀H₃₄NO₂ (M + H): 320.2590; found: 320.2596.