Next Article in Journal
4-Acetyl-2-hydroxy-2,5-dimethylfuran-3(2H)-one
Previous Article in Journal
(E)-1-(2-Aminophenyl)-3-(4-chlorophenyl)prop-2-en-1-one
 
 
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Short Note

Benzyl 2-((E)-Tosyliminomethyl)phenylcarbamate

Department of Chemistry, Kyonggi University, 154-42, Gwanggyosan-ro, Yeongtong-gu, Suwon 16227, Republic of Korea
*
Author to whom correspondence should be addressed.
Molbank 2016, 2016(4), M912; https://doi.org/10.3390/M912
Submission received: 8 September 2016 / Revised: 10 October 2016 / Accepted: 11 October 2016 / Published: 17 October 2016

Abstract

:
Benzyl 2-((E)-tosyliminomethyl)penylcarbamate was prepared in good yield and characterized by the condensation reaction of benzyl 2-formylphenylcarbamate with p-toluenesulfonyl amine. The structure of the newly synthesized compound was determined using 1H, 13C-NMR, IR and mass spectral data.

Graphical Abstract

1. Introduction

The Schiff base, structurally known as imine or azomethine, is a nitrogen analog of aldehyde or ketone in which the C=O group is replaced by C=N-R group after water molecular elimination [1]. Schiff bases are some of the most widely used organic compounds which used as pigments and dyes, catalysts and intermediates in organic synthesis [2]. Schiff bases have also been shown to exhibit a broad range of biological activities, including antibacterial, antimalarial, anti-inflammatory, antiviral, and anticancer properties [3,4,5]. In continuation of our research intefrest in 2-aminobenzaldehyde for the synthesis of highly functionalized chiral heterocylcles [6,7,8,9], we report here the preparation of a novel benzyl 2-((E)-tosyliminomethyl)phenylcarbamate.
The synthesis of the title compound 3 was achieved in one step, as presented in Scheme 1, which was performed by the condensation reaction of benzyl 2-formylphenylcarbamate (1) [10] with p-toluenesulfonyl amine (2). The reaction was carried out in toluene in the presence of 2 mol% of boron trifluoride diethyl etherate as a catalyst and provided the desired product in good yield. The structure of compound 3 was confirmed by 1H- and 13C-NMR, IR, mass spectral data, and all data are in accordance with the assumed structure.

2. Experimental Section

2.1. General Information

All reagents were used as received without further purification. Organic solutions were concentrated under reduced pressure using a Büchi rotary evaporator. Chromatographic purification of the title compound 3 was accomplished using forced-flow chromatography on ICN 60 32–64 mesh silica gel 63. Thin-layer chromatography (TLC) was performed on EM Reagents 0.25 mm silica gel 60-F plates. Developed chromatograms were visualized by fluorescence quenching and anisaldehyde stain. 1H and 13C-NMR spectra were recorded on a 400 MHz instrument as noted, and were internally referenced to residual protio solvent signals. Data for 1H-NMR were reported as follows: chemical shift (δ ppm), multiplicity (s = singlet, d = doublet, t = triplet, m = multiplet), integration, coupling constant (Hz) and assignment. Data for 13C-NMR were reported in terms of chemical shift. IR spectra were recorded on Perkin-Elmer 1600 FT-IR spectrometer (Waltham, MA, USA), and reported in terms of frequency of absorption (cm−1). High-resolution mass spectrometry data was recorded on a JEOL JMS-700 MStation mass spectrometer (JEOL, Tokyo, Japan).

2.2. Syntheis of Benzyl 2-((E)-Tosyliminomethyl)penylcarbamate (3)

p-Toluenesulfonyl amine (2, 94 mg, 0.55 mmol) was added to a solution of BF3·Et2O (1 μL, 0.01 mmol) and benzyl 2-formylphenylcarbamate (1, 128 mg, 0.50 mmol) in toluene (2 mL) at room temperature. The resulting mixture was refluxed for 60 h until complete consumption of benzyl 2-formylphenylcarbamate 1 was observed as determined by TLC. After being cooled to room temperature, water (2 mL) was added and the products were extracted with dichloromethane (3 × 5 mL). The organic phase was washed with aqueous saturated NaCl solution (2 × 5 mL), dried with anhydrous MgSO4, and concentrated in vacuo. The crude residue was purified by flash silica gel column chromatography using EtOAc/hexane (1/10) as eluent to afford the desired title compound 3 (64%, 154 mg).
White solid; m.p. 158–160 °C; 1H-NMR (400 MHz, CDCl3) δ 10.83 (s, 1H), 9.02 (s, 1H), 8.46 (d, J = 8.4 Hz, 1H), 7.89–7.77 (m, 2H), 7.64–7.52 (m, 2H), 7.47–7.33 (m, 5H), 7.14 (ddd, J = 8.4, 6.9, 3.0 Hz, 3H), 5.20 (s, 2H), 2.39 (s, 3H); 13C-NMR (100 MHz, CDCl3) δ 170.38, 153.17, 144.79, 142.28, 137.27, 136.43, 135.96, 135.33, 129.87, 128.61, 128.35, 128.21, 127.78, 122.37, 118.76, 117.46, 67.11, 21.67; IR (film) 3248, 2923, 2855, 1735, 1597, 1562, 1537, 1447, 1376, 1317, 1222, 1162, 1088, 1067, 1067 cm−1; HRMS (EI) m/z calcd for [M]+ C22H20N2O4S: 408.1144 Found: 408.1158.

Supplementary Materials

1H- and 13C-NMR spectra for compound 3 are available online at https://www.mdpi.com/1422-8599/2016/4/M912.
Supplementary File 1Supplementary File 2Supplementary File 3Supplementary File 4

Acknowledgments

This work was supported by Kyonggi University’s Graduate Research Assistantship 2016.

Author Contributions

Both authors contributed equally to this work.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Quin, W.; Long, S.; Panunzio, M.; Biondi, S. Schiff Bases: A short survey on an evergreen chemistry tool. Molecules 2013, 18, 12264–12289. [Google Scholar] [CrossRef] [PubMed]
  2. Dhar, D.N.; Taploo, C.L. Schiff bases and their applications. J. Sci. Ind. Res. 1982, 41, 501–506. [Google Scholar]
  3. Zoubi, W.A. Biological Activities of Schiff Bases and Their Complexes: A Review of Recent Works. Int. J. Org. Chem. 2013, 3, 73–95. [Google Scholar] [CrossRef]
  4. Anand, P.; Patil, V.M.; Sharma, V.K.; Khosa, R.L.; Masand, N. Schiff bases: A review on biological insights. Int. J. Drug Discov. 2012, 3, 851–868. [Google Scholar]
  5. Da Silva, C.M.; da Silva, D.L.; Modolo, L.V.; Alves, R.B.; de Resende, M.A.; Marins, C.V.B.; de Fátima, A. Schiff bases: A short review of their antimicrobial activities. J. Adv. Res. 2011, 2, 1–8. [Google Scholar] [CrossRef]
  6. Lee, Y.; Heo, S.; Kim, S.-G. Asymmetric one-pot synthesis of 1,4-dihydroquinolines via an organocatalytic aza-Michael/Michael cascade strategy. Adv. Synth. Catal. 2015, 357, 1545–1550. [Google Scholar] [CrossRef]
  7. Kim, H.; Kim, S.-G. One-pot organocatalytic enantioselective Michael addition and aza-cyclization/dehydration cascade reaction strategy: Asymmetric synthesis of highly functionalized 1,4-dihydroquinolines. Tetrahedron Lett. 2015, 56, 4819–4823. [Google Scholar] [CrossRef]
  8. Yu, M.; Kim, S.-G. Asymmetric organocatalytic Michael addition/aza-cyclization coupled with sequential Michael addition for synthesizing densely polycyclic-fused dihydroquinolines. Tetrahedron Lett. 2015, 56, 4159–4162. [Google Scholar] [CrossRef]
  9. Lee, Y.; Kim, S.-G. Asymmetric organocatalytic cascade reaction of aldehydes with 2-amino-β-nitrostyrenes: Synthesis of chiral tetrahydroquinolines and dihydroquinolines. J. Org. Chem. 2014, 79, 8234–8243. [Google Scholar] [CrossRef] [PubMed]
  10. Wagner, A.M.; Knezevic, C.E.; Wall, J.L.; Sun, V.L.; Buss, J.A.; Allen, L.T.; Wenzel, A.G. A copper(II)-catalyzed, sequential Michael-aldol reaction for the preparation of 1,2-dihydroquinolines. Tetrahedron Lett. 2012, 53, 833–836. [Google Scholar] [CrossRef]
Scheme 1. Synthesis of benzyl 2-((E)-tosyliminomethyl)penylcarbamate (3).
Scheme 1. Synthesis of benzyl 2-((E)-tosyliminomethyl)penylcarbamate (3).
Molbank 2016 m912 sch001

Share and Cite

MDPI and ACS Style

Ko, K.M.; Kim, S.-G. Benzyl 2-((E)-Tosyliminomethyl)phenylcarbamate. Molbank 2016, 2016, M912. https://doi.org/10.3390/M912

AMA Style

Ko KM, Kim S-G. Benzyl 2-((E)-Tosyliminomethyl)phenylcarbamate. Molbank. 2016; 2016(4):M912. https://doi.org/10.3390/M912

Chicago/Turabian Style

Ko, Kwang Min, and Sung-Gon Kim. 2016. "Benzyl 2-((E)-Tosyliminomethyl)phenylcarbamate" Molbank 2016, no. 4: M912. https://doi.org/10.3390/M912

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop