M524 - 2-[(2-Hydroxy-naphthalen-1-ylmethylene)-amino]- 5,6-dihydro-4H-cyclopenta [b] thiophene-3-carboxylic acid methyl ester

Molbank 2007, M524

http://www.mdpi.org/molbank/

2-[(2-Hydroxy-naphthalen-1-ylmethylene)-amino]- 5,6-dihydro-4H-cyclopenta [b] thiophene-3-carboxylic Acid Methyl Ester

Abdullah Mohamed Asiri *

Chemistry Department, Faculty of Science, King Abdul-Aziz University, Jeddah 21413, P.O. Box 9028, Saudi Arabia.

* Author to whom correspondence should be addressed. Tel: +966-2-6952293; Fax: +966-2-6952293; E-mail: [email protected]

Received: 3 January 2006 / Accepted: 24 June 2006 / Published: 31 May 2007

Keywords: 2-Aminothiophen, Anils, 2-hydroxy naphthaline, Schiff base

Schiff bases from 2-hydroxy-1-naphthaldehyde have often been used as chelating ligands in the field coordination chemistry [1]. The Schiff base compounds can be classified by their photochromic and thermochromic characteristics [2].

A solution of 2-Amino-5,6-dihydro-4H-cyclopenta[b]thiophene-3-carboxylic acid methyl ester 1 (5.0g, 0.025mol) and 2-hydroxynaphthaldehyde 2 (4.3g, 0.025 mol) in absolute ethanol (100 mL) was heated under reflux for 5 hrs. Cooling the mixture, filtering the precipitate and recrystallization from ethanol gave the Schiff base 3 as red crystals (6.4g, 72.88%).

Melting Point: 208-210ºC (EtOH).

IR (KBr; cm^-1): 1701.2 (C=O), 1560.6 (C=N), 1453.4 (C=C), 1308.4 (C-O) and 1046.2 (C-N).

¹H NMR (400 MHz; CDCl₃) δ, ppm: 14.93 (s, 1H, OH), 9.44 (s, 1H,=CH), 8.20- 7.27 (m, 6H, CH_aromatic 6H_aromatic), 3.99 (s, 3H,COOMe), 3.03-2.85 (t, 4H, 2 CH₂), 2.46-2.22 (m, 2H, CH₂).

¹³C NMR (100 MHz; CDCl₃) δ, ppm: 27.50, 28.81, 29.78, 30.72, 49.69, 51.14, 54.05, 109.93, 118.92, 120.44, 123.17, 124.79, 127.40, 128.83, 130.32, 136.64, 146.45, 153.55, 158.86, 164.71.

References

1. Garnovski, A.D.; Nivorozhkin, A.L.; Minkin, V.I. Coord. Chem. Rev. 1993, 126, 1.

2. Hadjoudis, E.; Vittorakis, M.; Maustakali-Mavridis, I. Tetrahedron 1987, 43, 1345.