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Synlett 2011(20): 2947-2950  
DOI: 10.1055/s-0031-1289906
LETTER
© Georg Thieme Verlag Stuttgart ˙ New York

[MeC(OH)2]+ClO4 -: A New Efficient Organocatalyst for the Preparation of 1-Amido- and 1-Carbamato-alkyl Naphthols

Fatemeh Tamaddon*, Javad Moazeni Bistgani
Department of Chemistry, Yazd University, P. O. Box 89195-741, Yazd, Iran
Fax: +98(351)8210644; e-Mail: ftamaddon@yazduni.ac.ir;
Further Information

Publication History

Received 28 June 2011
Publication Date:
23 November 2011 (online)

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Abstract

[MeC(OH)2]+ClO4 - as a super acidic ionic liquid is found to be a new and highly efficient catalyst in the synthesis of amidoalkyl naphthols via three-component condensation of β-naphthol and aldehydes with nitriles, amides, or carbamates.

Key words

multicomponent reactions - amidoalkyl naphthols - ionic liquids - super acids

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Tamaddon, F.; Tavakoli, F. manuscript submitted for publication.

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General Procedure for the [MeC(OH) 2 ] + ClO 4 - -Catalyzed Synthesis of Amidoalkyl Naphthols
A mixture of an aldehyde (1 mmol), β-naphthol (1 mmol) with amide, nitrile, urea, or carbamate (1 mmol) in the presence of [MeC(OH)2]+ClO4 - (1 mol%) was stirred in EtOAc (1 mL) at r.t. (or at 80 ˚C under solvent-free conditions) for the given times. After completion of the reaction (TLC monitoring), H2O was added, and the precipitate was filtered off to give the corresponding amidoalkyl naphthols. Most of the products were known and characterized by comparison of their melting points and spectral data with those reported in the literature without further purification. In some cases the products were recrystallized from EtOH-H2O (60:40).

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Selected Characterization Data N -[(2-Hydroxynaphthalen-1-yl)(phenyl)methyl]-benzamide (Table 2, Entry 1) 9,¹8 White solid; mp 235-237 ˚C. IR (KBr): νmax = 1625, 3065, 3418 cm-¹. ¹H NMR (300 MHz, DMSO-d 6): δ = 7.20-7.90 (m, 16 H), 8.10-8.13 (d, 1 H, J = 8.4 Hz), 9.02 (d, 1 H, J = 8.4 Hz), 10.33 (s, 1 H, NH) ppm. ¹³C NMR (75 MHz, DMSO-d 6): δ = 50.0, 119.1, 119.4, 123.4, 127.1, 127.2, 127.5, 127.8, 128.9, 129.1, 129.2, 129.3, 130.1, 132.1, 133.0, 135.0, 142.7, 147.0, 153.9, 166.4 ppm.
N -[(2-Hydroxynaphthalen-1-yl)(4-nitrophenyl)methyl]-benzamide (Table 2, Entry 2) ²9,8 Yellow solid; mp 247-249 ˚C. IR (KBr): νmax = 1641, 3234, 3410 cm-¹. ¹H NMR (300 MHz, DMSO-d 6): δ = 7.22-7.56 (m, 9 H), 7.82-7.91 (m, 4 H), 8.06 (d, 1 H, J = 8.4 Hz), 8.14 (d, 2 H, J = 8.4 Hz), 9.04 (d, 1 H, J = 8.1 Hz), 10.35 (s, 1 H, NH) ppm. ¹³C NMR (75 MHz, DMSO-d 6): δ = 49.1, 117.4, 118.6, 122.6, 122.8, 123.4, 127.0, 127.4, 127.5, 128.4, 128.7, 130.0, 131.6, 132.2, 134.0, 146.2, 150.2, 153.4, 166.3 ppm.
N -[(2-Hydroxynaphthalen-1-yl)( p -tolyl)methyl]-benzamide (Table 2, Entry 3) 8,9 White solid; mp 223-225 ˚C. IR (KBr): νmax = 1627, 3043, 3413 cm-¹. ¹H NMR (300 MHz, DMSO-d 6): δ = 1.97 (s, 3 H, CH3), 2.23 (s, 3 H, CH3), 7.05-7.38 (m, 8 H), 7.74-7.81 (m, 2 H), 7.85 (d, 1 H, J = 8.4 Hz), 8.38 (d, 1 H, J = 8.4 Hz), 9.94 (s, 1 H, NH) ppm. ¹³C NMR (75 MHz, DMSO-d 6): δ = 20.5, 22.6, 47.6, 118.4, 119.0, 122.3, 126.0, 126.2, 128.5, 129.0, 132.3, 135.0, 139.5, 153.0, 169.0 ppm.
N -[1-(2-Hydroxynaphthalen-1-yl)butyl]benzamide (Table 2, Entry 6) ³0 White solid; mp 240-242 ˚C. IR (KBr): νmax = 3415, 3222, 3204, 1633, 1575, 1528, 1342, 1074, 815, 747, 716 cm-¹. ¹H NMR (300 MHz, DMSO-d 6): δ = 10.09 (s, 1 H), 8.60 (d, 1 H, J = 6.3 Hz), 8.23 (d, 1 H, J = 7.6 Hz), 7.81 (t, 3 H, J = 7.2 Hz), 7.71 (d, 1 H, J = 8.8 Hz), 7.53-7.44 (m, 4 H), 7.31 (t, 1 H, J = 7.3 Hz), 7.20 (d, 1 H, J = 8.8 Hz), 6.04 (q, 1 H, J = 7.1 Hz), 2.15-2.10 (m, 1 H), 1.90-1.80 (m, 1 H), 1.51-1.42 (m, 1 H), 1.30-1.20 (m, 1 H), 0.95 (t, 3 H, J = 7.3 Hz) ppm. ¹³C NMR (75 MHz, DMSO-d 6): δ = 165.2, 152.8, 134.7, 132.1, 131.1, 128.5, 128.4, 128.3, 128.2, 126.9, 126.3, 122.3, 119.8, 118.6, 118.5, 46.6, 36.0, 19.6, 13.8 ppm.
N -[Phenyl-(2-hydroxy-naphthalen-1-yl)-methyl]-acetamide (Table 2, Entry 7) ¹¹,²8 White solid; mp 232-233 ˚C. IR (KBr): νmax = 3390, 3246, 3062, 1640, 1582, 1514, 1372, 1337, 1060, 808, 742, 696, 623 cm-¹. ¹H NMR (300 MHz, CDCl3): δ = 1.95 (s, 3 H), 7.10 (m, 1 H), 7.12 (m, 1 H), 7.15 (m, 1 H), 7.17 (m, 1 H), 7.20 (m, 2 H), 7.21 (m, 1 H), 7.25 (m, 1 H), 7.35 (t, 1 H, J = 7.5 Hz), 7.70 (d, 1 H, J = 9.1 Hz) ppm. ¹³C NMR (75 MHz, DMSO-d 6): δ = 23.2, 40.3, 119.2, 122.9, 123.8, 126.6, 126.8, 128.5, 128.8, 128.9, 129.1, 129.8, 132.8, 143.1, 153.7, 169.0 ppm.
4-Bromo- N -[(2-hydroxynaphthalen-1-yl)(phenyl)-methyl]benzamide (Table 2, Entry 10) Yellow solid; mp 239-242 ˚C. IR (KBr): νmax = 3408, 3246, 3146, 1626 cm-¹. ¹H NMR (400 MHz, DMSO-d 6): δ = 7.22 (m, 7 H), 7.41 (t, 2 H, J = 8.0 Hz), 7.66 (t, 2 H, J = 4.4 Hz), 7.78 (m, 4 H), 8.02 (d, 1 H, J = 8.0 Hz), 7.20 (m, 2 H), 9.08 (d, J = 4.0 Hz, 1 H), 10.26 (s, 1 H) ppm. ¹³C NMR (100 MHz, DMSO-d 6): δ = 49.7, 115.5, 118.2, 122.6, 126.8, 128.3, 128.8, 128.9, 133.1, 142.8, 153.6, 167.8 ppm. Anal. Calcd for C24H18BrNO2: C, 66.68; H, 4.20; Br, 18.48; N, 3.24; O, 7.40. Found: C, 66.75; H, 4.11; N, 3.15.