Synlett 2003(14): 2249-2251  
DOI: 10.1055/s-2003-42058
LETTER
© Georg Thieme Verlag Stuttgart · New York

An Ionic Liquid Mediated Efficient Oxidation of Alcohols Using o-Iodoxy­benzoic Acid (IBX) - a Simple and Eco-friendly Protocol

Ganesan Karthikeyan, Paramasivan T. Perumal*
Organic Chemistry Division, Central Leather Research Institute, Adyar, Chennai-600 020, India
Fax: +91(44)24911589; e-Mail: ptperumal@hotmail.com;;
Further Information

Publication History

Received 25 July 2003
Publication Date:
07 October 2003 (online)

Abstract

An environmentally benign ionic liquid is shown to be for the first time an excellent medium for mild and selective oxidation­ of alcohols using IBX at room temperature.

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Representative Experimental Procedure of Compound 7: To 1 g of molten bmimCl was added 1 mmol of tetrahydro-1-naphthol and 1.2 mmol of IBX and the reaction mixture was stirred at r.t. TLC monitoring shows the completion of reaction in 15 min, after which 10 mL of water was added to the reaction mixture and extracted with EtOAc (3 × 15mL). The organic layer was separated, dried over anhyd Na2SO4, filtered and then evaporated under reduced pressure. The crude product thus obtained was purified by column chromatography (EtOAc/petroleum ether 1:9) to yield 0.133 g (91%) of tetralone.

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1H NMR (500 MHz, CDCl3) data of N-Fmoc Valinal: δ = 9.64 (s, 1 H, CHO), 7.78-7.25 (m, 8 H), 5.47 (d, 1 H, J = 7.5 Hz, NH), 4.42-4.33 (m, 3 H, Fmoc-9-H, Fmoc-CH2), 4.23-4.21 (m, 1 H, 2-H), 2.29 (m, 1 H, 3-H), 1.03 [2 d, 6 H, CH(CH3)2, J CH3,3 = 6.9 Hz].