Synthesis of 2,2-[60]Fullerenoalkylamines via the Curtius Rearrangement

Tomoyuki Tada; Yasuhiro Ishida; Kazuhiko Saigo

doi:10.1055/s-2007-968017

LETTER

Synthesis of 2,2-[60]Fullerenoalkylamines via the Curtius Rearrangement

Tomoyuki Tada, Yasuhiro Ishida*, Kazuhiko Saigo*
Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
Fax: +81(3)58023348; e-Mail: saigo@chiral.t.u-tokyo.ac.jp;

Abstract

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Abstract

2,2-[60]Fullerenoalkylamines were easily and securely prepared from 2,2-[60]fullerenoalkanoyl azides, which were simply obtained from the corresponding 2,2-[60]fullerenoalkanoyl chlorides through the Curtius rearrangement in the presence of tert-butyl alcohol, followed by debutylation and decarboxylation under acidic conditions.

Key words

[60]fullerene - 2,2-[60]fullerenoalkanoyl chloride - 2,2-[60]fullerenoalkanoyl azide - 2,2-[60]fullerenoalkylamine - Curtius rearrangement

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References

References and Notes

1a Wudl F. Acc. Chem. Res. 1992, 25: 157

1b Diederich F. Isaacs L. Philip D. Chem. Soc. Rev. 1994, 23: 243

1c Nierengarten J.-F. Habicher T. Kessinger R. Cardullo F. Diederich F. Gramlich V. Gisselbrecht J.-P. Boudon C. Gross M. Helv. Chim. Acta 1997, 80: 2238

For selected examples of cyclopropanated [60]fullerene with functional group (s), see:

2a Bingel C. Chem. Ber. 1993, 126: 1957

2b Benito AM. Darwish AD. Kroto HW. Meidine MF. Taylor R. Walton DRM. Tetrahedron Lett. 1996, 37: 1085

2c Hino T. Kinbara K. Saigo K. Tetrahedron Lett. 2001, 42: 5065

2d Hamada M. Hino T. Kinbara K. Saigo K. Tetrahedron Lett. 2001, 42: 5069

3 Tada T. Ishida Y. Saigo K. Org. Lett. 2005, 7: 5897

4a Ito H. Tada T. Sudo M. Ishida Y. Hino T. Saigo K. Org. Lett. 2003, 5: 2643

4b Tada T. Ishida Y. Saigo K. J. Org. Chem. 2006, 71: 1633

5

The acyl chlorides 2b-g were synthesized by procedures similar to those reported in the literature [4b] (Scheme [2] ). Sulfonium Salts: The sulfonium tetrafluoroborates 5b-g were obtained from the corresponding tert-butyl 2-(methylthio)alkanoates by the reaction with trimethyl-oxonium tetrafluoroborate in CH₂Cl₂ at r.t. for 24 h, which were used without purification for further reactions.
tert -Butyl [60]Fullerenoalkanoates: The solutions of [60]fullerene and the sulfonium tetrafluoroborates 5b-g were allowed to react with DBU, which should generate in situ sulfonium ylides 6b-g, in toluene-CH₂Cl₂ at r.t. for 18 h to give the tert-butyl [60]fullerenoalkanoates 7b-g (21-65% yields).
[60]Fullerenoalkanoic Acids: The tert-butyl esters 7b-g thus-obtained were readily converted into the [60]fullereno-alkanoic acids 8b-g through the cleavage of the ester moiety promoted by p-toluenesulfonic acid monohydrate in toluene under reflux for 8 h (67-99% yield).
[60]Fullerenoalkanoyl Chlorides: The [60]fullereno-alkanoic acids 8b-g were easily transformed into the [60]fullerenoalkanoyl chlorides 2b-g by treatment with an excess amount of thionyl chloride in CH₂Cl₂-1,4-dioxane under reflux for 5 h (84-99% yield).

Scheme 2

6a Prato M. Li QC. Wudl F. J. Am. Chem. Soc. 1993, 115: 1148

6b Ishida T. Tanaka K. Nogami T. Chem. Lett. 1994, 561

6c Averdung J. Luftmann H. Mattay J. Claus K.-U. Abraham W. Tetrahedron Lett. 1995, 36: 2957

7

2c: IR (KBr): 2923, 1776, 1509, 1453, 1428, 1185, 987, 794, 754, 694, 575, 525 cm^-1. ¹H NMR [300 MHz, CDCl₃-CS₂ (1:1)]: δ = 1.61 (t, J = 7.4 Hz, 3 H), 3.10 (q, J = 7.4 Hz, 2 H). MS (MALDI-TOF; dithranol): m/z [M]⁺ calcd for C₆₄H₅ClO: 824.00; found: 824.11.
2f: IR (KBr): 2925, 1779, 1509, 1427, 1252, 1172, 1044, 1030, 754, 698, 575, 526 cm^-1. ¹H NMR [300 MHz, CDCl₃-CS₂ (1:1)]: δ = 3.91 (s, 3 H), 7.10 (d, J = 8.7 Hz, 2 H), 8.03 (d, J = 8.7 Hz, 2 H). MS (MALDI-TOF; dithranol): m/z [M]⁺ calcd for C₆₉H₇ClO₂: 902.01; found: 902.02.
2g: IR (KBr): 2955, 1778, 1495, 1426, 1210, 1185, 1044, 819, 807, 754, 697, 576, 525 cm^-1. ¹H NMR (300 MHz, CDCl₃): δ = 1.29 (d, J = 6.6 Hz, 6 H), 2.94-2.98 (br, 1 H), 7.31-7.34 (br, 2 H), 7.60-7.62 (br, 2 H), 7.79-7.82 (br, 2 H), 8.16-8.18 (br, 2 H). ¹³C NMR (75 MHz, CDCl₃): δ = 23.94, 33.74, 62.56, 75.23, 127.03, 127.09, 127.44, 127.79, 133.23, 137.03, 137.70, 138.40, 140.90, 140.98, 141.78, 141.96, 142.01, 142.07, 142.68, 142.77, 142.83, 142.87, 143.47, 143.68, 144.23, 144.35, 144.39, 144.50, 144.53, 144.63, 144.69, 144.76, 145.02, 145.06, 145.09, 145.16, 145.56, 148.76, 166.80. MS (MALDI-TOF; dithranol): m/z [M]⁺ calcd for C₇₇H₁₅ClO: 990.08; found: 989.74.
3b: IR (KBr): 2925, 2135, 1709, 1509, 1428, 1230, 1173, 1024, 576, 526 cm^-1. ¹H NMR [300 MHz, CDCl₃-CS₂ (1:1)]: δ = 2.50 (s, 3 H). ¹³C NMR [75 MHz, 1,2-C₆D₄Cl₂-CS₂ (1:1)]: δ = 17.57, 32.26, 78.60, 140.20, 140.36, 142.84, 143.02, 143.92, 144.14, 144.84, 144.92, 144.97, 145.16, 145.54, 145.77, 146.24, 146.52, 146.57, 146.67, 147.07, 147.11, 147.34, 147.59, 148.73, 176.11. MS (MALDI-TOF; dithranol): m/z [M - N₂ + H]⁺ calcd for C₆₃H₄NO: 790.03; found: 790.19.
3c: IR (KBr): 2922, 2136, 1709, 1427, 1217, 1172, 1043, 575, 525 cm^-1. ¹H NMR [300 MHz, CDCl₃-CS₂ (1:1)]: δ = 1.57 (t, J = 7.5 Hz, 3 H), 2.92 (q, J = 7.5 Hz, 2 H). MS (MALDI-TOF; dithranol): m/z [M - N₂ + H]⁺ calcd for C₆₄H₆NO: 804.04; found: 804.13.
3d: IR (KBr): 2918, 2132, 1714, 1509, 1427, 1169, 1040, 575, 525 cm^-1. ¹H NMR [300 MHz, CDCl₃-CS₂ (1:1)]: δ = 4.27 (s, 2 H), 7.39-7.51 (m, 3 H), 7.67 (d, J = 6.9 Hz, 2 H). MS (MALDI-TOF; dithranol): m/z [M - N₂ + H]⁺ calcd for C₆₆H₈NO: 866.06; found: 866.09.
3e: IR (KBr): 2244, 2135, 1701, 1427, 1212, 1176, 754, 698, 573, 525 cm^-1. ¹H NMR [300 MHz, CDCl₃-CS₂ (1:1)]: δ = 7.53-7.58 (m, 3 H), 8.04-8.07 (m, 2 H). MS (MALDI-TOF; dithranol): m/z [M - N₂ + H]⁺ calcd for C₆₈H₆NO: 852.04; found: 852.22.
3f: IR (KBr): 2925, 2135, 1705, 1509, 1427, 1251, 1214, 1170, 754, 526 cm^-1. ¹H NMR [300 MHz, CDCl₃-CS₂ (1:1)]: δ = 3.92 (s, 3 H), 7.09 (d, J = 8.4 Hz, 2 H), 8.00 (d, J = 8.4 Hz, 2 H). ¹³C NMR [125 MHz, CDCl₃-CS₂ (1:1)]: δ = 29.79, 55.22, 75.46, 114.26, 123.01, 131.85, 133.66, 137.86, 138.37, 140.90, 140.94, 141.87, 142.01, 142.07, 142.10, 142.16, 142.81, 142.89, 142.93, 142.95, 143.02, 143.05, 143.57, 143.79, 144.35, 144.42, 144.56, 144.61, 144.70, 144.94, 145.00, 145.05, 145.12, 145.17, 145.18, 145.24, 145.64, 146.53, 160.44, 172.87. MS (MALDI-TOF; dithranol): m/z [M - N₂ + H]⁺ calcd for C₆₉H₈NO₂: 882.06; found: 882.06.
3g: IR (KBr): 2954, 2135, 1707, 1496, 1457, 1427, 1214, 1169, 799, 738, 557, 526 cm^-1. ¹H NMR (300 MHz, CDCl₃): δ = 1.30 (d, J = 6.9 Hz, 6 H), 2.92-3.06 (m, 1 H), 7.33 (d, J = 8.4 Hz, 2 H), 7.61 (d, J = 8.4 Hz, 2 H), 7.78 (d, J = 8.7 Hz, 2 H), 8.11 (d, J = 8.7 Hz, 2 H). ¹³C NMR (75 MHz, CDCl₃): δ = 23.99, 33.79, 56.35, 75.33, 127.04, 127.11, 127.30, 129.80, 132.81, 137.34, 137.96, 138.36, 140.92, 140.95, 141.93, 142.03, 142.09, 142.19, 142.32, 142.78, 142.82, 142.89, 142.96, 143.04, 143.57, 143.80, 144.32, 144.37, 144.44, 144.60, 144.64, 144.97, 145.06, 145.13, 145.31, 145.63, 146.44, 148.68, 173.07. MS (MALDI-TOF; dithranol): m/z [M - N₂ + H]⁺ calcd for C₇₇H₁₆NO: 970.12; found: 969.97.
4b: IR (KBr): 3413, 2972, 2927, 1703, 1511, 1428, 1365, 1249, 1161, 1054, 577, 526 cm^-1. ¹H NMR [300 MHz, 1,2-C₆D₄Cl₂-CS₂ (1:1)]: δ = 1.67 (s, 9 H), 2.60 (s, 3 H), 5.95 (br, 1 H). MS (MALDI-TOF; dithranol): m/z [M - C₄H₈ - CO₂ + 2 × H]⁺ calcd for C₆₂H₆N: 764.05; found: 764.22.
4c: IR (KBr): 3410, 2969, 2927, 1704, 1513, 1427, 1365, 1246, 1159, 1051, 572, 525 cm^-1. ¹H NMR [300 MHz, 1,2-C₆D₄Cl₂-CS₂ (1:1)]: δ = 1.33 (br, 2 H), 1.64 (br, 14 H, overlapped with internal H₂O), 2.98 (br, 3 H), 5.95 (br, 1 H). MS (MALDI-TOF; dithranol): m/z [M - C₄H₈ - CO₂ + 2 × H]⁺ calcd for C₆₃H₈N: 778.07; found: 778.16.
4d: IR (KBr): 3408, 2972, 1704, 1475, 1428, 1365, 1242, 1159, 1051, 754, 574, 525 cm^-1. ¹H NMR [300 MHz, CDCl₃-CS₂ (1:1)]: δ = 1.54 (br, 9 H), 4.18 (br, 2 H), 5.58 (br, 1 H), 7.32-7.58 (m, 5 H). ¹³C NMR [75 MHz, 1,2-C₆D₄Cl₂-CS₂ (1:1)]: δ = 28.26, 34.63, 53.61, 79.52, 80.15, 129.00, 129.70, 136.76, 137.08, 137.83, 137.97, 140.90, 141.04, 142.01, 142.09, 142.15, 142.36, 142.70, 142.92, 143.05, 143.58, 143.64, 144.24, 144.36, 144.56, 144.66, 144.84, 145.02, 145.07, 145.09, 145.30, 145.47, 146.13, 146.54, 154.20. MS (MALDI-TOF; dithranol): m/z [M - C₄H₈ - CO₂ + 2 × H]⁺ calcd for C₆₈H₁₀N: 840.08; found: 840.19.
4e: IR (KBr): 3407, 2972, 1700, 1474, 1428, 1365, 1239, 1157, 701, 574, 526 cm^-1. ¹H NMR [300 MHz, CDCl₃-CS₂ (1:1)]: δ = 1.48 (br, 17 H, overlapped with internal H₂O), 6.10 (br, 1 H), 7.47-7.53 (m, 3 H), 8.13 (br, 2 H). MS (MALDI-TOF; dithranol): m/z [M - C₄H₈ - CO₂ + 2 × H]⁺ calcd for C₆₇H₈N: 826.07; found: 826.22.
4f: IR (KBr): 3407, 2925, 1700, 1511, 1459, 1365, 1249, 1172, 1158, 754, 572, 526 cm^-1. ¹H NMR [300 MHz, CDCl₃-CS₂ (1:1)]: δ = 1.51-1.57 (br, 10 H, overlapped with internal H₂O), 3.90 (s, 3 H), 6.27-6.59 (br, 1 H), 7.03-7.08 (m, 2 H), 8.09 (br, 2 H). MS (MALDI-TOF; dithranol): m/z [M - C₄H₈ - CO₂ + 2 × H]⁺ calcd for C₆₈H₁₀NO: 856.08; found: 856.08.
4g: IR (KBr): 3406, 2957, 1701, 1463, 1427, 1365, 1238, 1158, 820, 755, 574, 526 cm^-1. ¹H NMR [300 MHz, CDCl₃-CS₂ (1:1)]: δ = 1.30 (d, J = 6.6 Hz, 6 H), 1.47-1.58 (br, 9 H), 2.90-2.99 (m, 1 H), 6.31 (br, 1 H), 7.29 (d, J = 8.4 Hz, 2 H), 7.56 (d, J = 8.4 Hz, 2 H), 7.69 (d, J = 8.4 Hz, 2 H), 8.14-8.18 (br, 2 H). MS (MALDI-TOF; dithranol): m/z [M - C₄H₈ - CO₂ + 2 × H]⁺ calcd for C₇₆H₁₈N: 944.14; found: 944.16.
1b: IR (KBr): 3466, 1635, 1427, 1400, 1258, 1176, 1031, 764, 642, 577, 525 cm^-1.
1c: IR (KBr): 3435, 2945, 2861, 1608, 1533, 1458, 1428, 1252, 1175, 1029, 764, 637, 572, 526 cm^-1.
1d: IR (KBr): 3127, 2916, 1635, 1495, 1453, 1428, 1400, 1258, 1177, 1033, 765, 643, 576, 526 cm^-1.
1e: IR (KBr): 3158, 1626, 1494, 1448, 1428, 1401, 1253, 1175, 1034, 764, 644, 578, 526 cm^-1.
1f: IR (KBr): 3435, 2927, 1636, 1597, 1513, 1459, 1428, 1256, 1175, 1032, 765, 642, 573, 525 cm^-1.
1g: IR (KBr): 3450, 2956, 1636, 1523, 1498, 1428, 1398, 1255, 1177, 1031, 820, 764, 642, 574, 525 cm^-1.
7c: IR (KBr): 2970, 2926, 1731, 1454, 1427, 1366, 1251, 1160, 1138, 848, 574, 525 cm^-1. ¹H NMR [300 MHz, CDCl₃-CS₂ (1:1)]: δ = 1.54 (t, J = 7.2 Hz, 3 H), 1.67 (s, 9 H), 2.89 (q, J = 7.2 Hz, 2 H). ¹³C NMR [75 MHz, CDCl₃-CS₂ (1:1)]: δ = 11.65, 23.36, 28.13, 52.17, 76.88, 83.44, 142.91, 143.00, 143.53, 143.70, 144.03, 144.34, 144.38, 144.50, 144.66, 144.73, 144.97, 145.02, 145.04, 145.19, 145.60, 146.26, 148.11, 166.33. MS (MALDI-TOF; dithranol): m/z [M + H]⁺ calcd for C₆₈H₁₅O₂: 863.11; found: 863.18.
7f: IR (KBr): 2973, 2926, 1732, 1509, 1457, 1427, 1367, 1250, 1172, 1151, 1034, 800, 753, 526 cm^-1. ¹H NMR [300 MHz, CDCl₃-CS₂ (1:1)]: δ = 1.55 (s, 9 H), 3.89 (s, 3 H), 7.02 (d, J = 8.7 Hz, 2 H), 7.96 (d, J = 8.7 Hz, 2 H). ¹³C NMR (75 MHz, CDCl₃-CS₂ (1:1)]: δ = 27.82, 55.06, 56.48, 76.20, 83.34, 113.85, 124.58, 133.09, 137.43, 138.10, 140.76, 141.92, 141.95, 142.03, 142.20, 142.72, 142.77, 142.80, 142.82, 142.93, 143.53, 143.71, 144.16, 144.20, 144.44, 144.47, 144.52, 144.58, 144.93, 144.97, 144.99, 145.12, 145.35, 146.35, 147.76, 159.84, 165.27. MS (MALDI-TOF; dithranol): m/z [M + H]⁺ calcd for C₇₃H₁₇O₃: 941.12; found: 941.04.
7g: IR (KBr): 2956, 1733, 1496, 1426, 1367, 1150, 823, 800, 754, 525 cm^-1. ¹H NMR (300 MHz, CDCl₃): δ = 1.30 (d, J = 6.9 Hz, 6 H), 1.57 (s, 9 H), 2.89-3.03 (m, 1 H), 7.32 (d, J = 8.1 Hz, 2 H), 7.63 (d, J = 8.1 Hz, 2 H), 7.76 (d, J = 8.4 Hz, 2 H), 8.12 (d, J = 8.4 Hz, 2 H). ¹³C NMR (75 MHz, CDCl₃): δ = 23.98, 27.99, 33.75, 56.82, 76.05, 83.89, 126.88, 126.94, 126.99, 131.34, 132.25, 137.50, 138.09, 140.76, 140.79, 141.42, 141.98, 141.99, 142.02, 142.20, 142.73, 142.77, 142.80, 142.82, 142.93, 143.51, 143.70, 144.12, 144.25, 144.41, 144.46, 144.47, 144.51, 144.62, 144.94, 144.97, 145.00, 145.16, 145.38, 146.32, 147.69, 148.39, 165.44. MS (MALDI-TOF; dithranol): m/z [M + H]⁺ calcd for C₈₁H₂₅O₂: 1029.19; found: 1029.16.
8c: IR (KBr): 2919, 2847, 1727, 1427, 1251, 1231, 1184, 1117, 1079, 872, 573, 526 cm^-1. ¹H NMR [300 MHz, THF-d ₈-CS₂ (1:1)]: δ = 1.73 (t, J = 7.5 Hz, 3 H), 3.10 (q, J = 7.5 Hz, 2 H). The carboxyl proton could not be detected probably due to the broadening of the signal. MS (MALDI-TOF; dithranol): m/z [M]⁺ calcd for C₆₄H₆O₂: 806.04; found: 806.14.
8f: IR (KBr): 2955, 1733, 1509, 1427, 1251, 1231, 1174, 1034, 824, 526 cm^-1. ¹H NMR (300 MHz, THF-d ₈-CS₂ (1:1)]: δ = 3.80 (s, 3 H), 6.98 (d, J = 8.1 Hz, 2 H), 7.93 (d, J = 8.1 Hz, 2 H). The carboxyl proton could not be detected probably due to the broadening of the signal. ¹³C NMR [75 MHz, THF-d ₈-CS₂ (1:1)]: δ = 30.81, 55.53, 77.51, 114.69, 125.42, 125.96, 134.15, 138.66, 139.02, 141.49, 141.55, 142.83, 142.90, 143.09, 143.56, 143.61, 143.64, 143.71, 144.39, 144.61, 144.98, 145.27, 145.37, 145.53, 145.78, 145.83, 146.15, 146.37, 147.72, 149.21, 161.00, 167.33. MS (MALDI-TOF; dithranol): m/z [M]⁺ calcd for C₆₉H₈O₃: 884.05; found: 883.96.
8g: IR (KBr): 2954, 1734, 1496, 1427, 1252, 1225, 1185, 1119, 870, 816, 575, 526 cm^-1. ¹H NMR [300 MHz, THF-d ₈-CS₂ (1:1)]: δ = 1.25 (d, J = 7.2 Hz, 6 H), 2.82-2.96 (m, 1 H), 7.24 (d, J = 8.1 Hz, 2 H), 7.52 (d, J = 8.1 Hz, 2 H), 7.67 (d, J = 8.1 Hz, 2 H), 8.08 (d, J = 8.1 Hz, 2 H). The carboxyl proton could not be detected probably due to the broadening of the signal. ¹³C NMR [75 MHz, THF-d ₈-CS₂ (1:1)]: δ = 30.77, 34.72, 57.25, 77.01, 125.91, 127.59, 127.76, 132.14, 133.28, 137.16, 138.38, 138.59, 138.90, 141.38, 141.46, 142.47, 142.67, 142.70, 142.76, 142.89, 143.43, 143.46, 143.50, 143.58, 143.63, 144.24, 144.46, 144.87, 144.90, 145.14, 145.18, 145.21, 145.38, 145.62, 145.65, 145.66, 145.96, 146.18, 147.30, 148.70, 148.80, 166.92. MS (MALDI-TOF; dithranol): m/z [M]⁺ calcd for C₇₇H₁₆O₂: 972.12; found: 971.87.