Synlett 2014; 25(13): 1909-1915
DOI: 10.1055/s-0034-1378335
letter
© Georg Thieme Verlag Stuttgart · New York

Facile Esterification of Alcohols with 2-Acyl-4,5-dichloropyridazin-3(2H)-ones under Friedel–Crafts Conditions

Bo Ram Kim
a   Department of Chemistry, Research Institute of Natural Sciences, Gyeongsang National University, Jinju 660-701, South Korea   Fax: +82(55)7721489   Email: yjyoon@gnu.ac.kr
,
Gi Hyeon Sung
a   Department of Chemistry, Research Institute of Natural Sciences, Gyeongsang National University, Jinju 660-701, South Korea   Fax: +82(55)7721489   Email: yjyoon@gnu.ac.kr
,
Ki Eun Ryu
a   Department of Chemistry, Research Institute of Natural Sciences, Gyeongsang National University, Jinju 660-701, South Korea   Fax: +82(55)7721489   Email: yjyoon@gnu.ac.kr
,
Hyo Jae Yoon*
b   Department of Chemistry, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 136-713, South Korea   Fax: +82(2)32903121   Email: hyoon@korea.ac.kr
,
Sang-Gyeong Lee
a   Department of Chemistry, Research Institute of Natural Sciences, Gyeongsang National University, Jinju 660-701, South Korea   Fax: +82(55)7721489   Email: yjyoon@gnu.ac.kr
,
Yong-Jin Yoon*
a   Department of Chemistry, Research Institute of Natural Sciences, Gyeongsang National University, Jinju 660-701, South Korea   Fax: +82(55)7721489   Email: yjyoon@gnu.ac.kr
› Author Affiliations
Further Information

Publication History

Received: 01 May 2014

Accepted after revision: 27 May 2014

Publication Date:
08 July 2014 (online)


Abstract

This paper describes the esterification of aromatic and aliphatic alcohols by using 2-acyl-4,5-dichloropyridazin-3(2H)-ones as an acyl source under Friedel–Crafts conditions. Twelve alcohols were reacted with four 2-acyl-4,5-dichloropyridazin-3(2H)-ones in the presence of AlCl3 in tetrahydrofuran at room temperature to give the corresponding esters in moderate to excellent yields. Thus, 2-acylpyridazin-3(2H)-ones serve as good and atom-economic acyl sources for the esterification of aromatic alcohols under Friedel–Crafts conditions, representing a rapid, practical, and efficient method of esterification.

Supporting Information

 
  • References and Notes

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    • 4a Hangx, G.; Kwant, G.; Maessen, H.; Markusse, P.; Urseanu, I. Reaction Kinetics of the Esterification of Ethanol and Acetic Acid Towards Ethyl Acetate, Deliverable 22, Intelligent Column Internals for Reactive Separations (INTINT), Technical Report to the European Commission, http://www.cpi.umist.ac.uk/intint/NonConf_Del/22.pdf (2001).
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  • 8 For some examples, see refs. 7d and 7j–m. See also: Anastas PT, Kirchhoff MM. Acc. Chem. Res. 2002; 35: 686
  • 9 Constable DJ. C, Dunn PJ, Hayler JD, Humphrey GR, Leazer JL, Linderman RJ. Jr, Lorenz K, Manley J, Pearlman BA, Wells A, Zaks A, Zhang TY. Green Chem. 2007; 9: 411
    • 14a Synthesis of 3 and 5a–d; General Procedure: To a solution of alcohol 2 (1 equiv, 2 mmol) in THF (20 mL), AlCl3 (1 equiv) was added followed by stirring for 1 min. 2-Acyl-4,5-pyridazin-3(2H)-one 1 (1 equiv) was then added and the mixture was stirred at room temperature until the alcohol was consumed. The reaction was quenched by the addition of H2O (20 mL), and the mixture was stirred for 10 min at room temperature. After the addition of CH2Cl2 (40 mL), the organic layer was separated and dried over anhydrous MgSO4. The solvent was evaporated under reduced pressure, and the resulting residue was applied to the top of an open-bed silica gel column. The column was eluted with CH2Cl2 (for 3ag, 5a and 5b), MeCN–CH2Cl2 (1:5 v/v for 3h), EtOAc–CH2Cl2 (1:1 v/v for 3i), n-hexane–CH2Cl2–EtOAc (4:2:1 v/v for 3j and 3k), or n-hexane–EtOAc (10:1 v/v for 5c and 5d). Fractions containing the product were combined and evaporated under reduced pressure to give the desired esters. Fractions containing 4,5-dichloropyridazin-3(2H)-one were combined and evaporated under reduced pressure to quantitatively give reusable 4,5-dichloropyridazin-3(2H)-one. (b) Synthesis of 5e–i; General Procedure: To a solution of alcohol 2 (1 equiv, 2 mmol) in THF (20 mL), AlCl3 (1 equiv) was added followed by stirring for 1 min. 2-Aroyl-4,5-dichloropyridazin-3(2H)-one 1 (1 equiv) was added and the mixture was stirred at room temperature until the alcohol was consumed. The reaction was quenched by the addition of H2O (20 mL), followed by stirring for 10 min at room temperature, and then neutralized with a saturated solution of NaHCO3. After the addition of further H2O (20 mL) and CH2Cl2 (40 mL), the resulting organic layer was separated, and H2O (10 mL) and a saturated solution of NaCl (20 mL) were added. The organic layer was then separated and dried over anhydrous MgSO4. The solvent was evaporated under reduced pressure and the resulting residue was applied to the top of an open-bed silica gel column. The column was eluted with CH2Cl2 (for 5gi) or n-hexane–EtOAc (3:1 v/v for 5e and 5f). Fractions containing the product were combined and evaporated under reduced pressure to give the desired esters. Fractions containing 4,5-dichloropyridazin-3(2H)-one were combined and evaporated under reduced pressure to quantitatively give reusable 4,5-dichloropyridazin-3(2H)-one.
  • 15 Procedures for Methods A–E in Scheme 3 Method A: To a solution of 1a (1 equiv) in THF (20 mL), 2b (1 equiv, 2 mmol) was added followed by stirring for 5 min. AlCl3 (1 equiv) was added and the mixture was stirred for 10 min at room temperature. Method B: To a solution of 2b (1 equiv, 2 mmol) in THF (20 mL), AlCl3 (1 equiv) was added followed by stirring for 30 min. 1a (1 equiv) was added and the mixture was stirred for 10 min at room temperature. Method C: To a solution of 1a (1 equiv) in THF (20 mL), AlCl3 (1 equiv) was added followed by stirring for 30 min. 2b (1 equiv, 2 mmol) was added and the mixture was stirred for 10 min at room temperature. Method D: To a solution of 2b (1 equiv, 2 mmol) in THF (20 mL), AlCl3 (1 equiv) was added followed by stirring for 30 min at room temperature. The solvent was evaporated under reduced pressure to give ROH–AlCl3 adducts. After drying by vacuum pump for 1 h at room temperature, the adduct was used without further purification. Crude salt was dissolved in THF (20 mL), 1a (1 equiv) was added, and the mixture was stirred at room temperature at 10 min. Method E: To a solution of 1a (1 equiv) in THF (20 mL), AlCl3 (1 equiv) was added followed by stirring for 30 min at room temperature. The solvent was evaporated under reduced pressure to give 1a–AlCl3 adducts. After drying by vacuum pump for 1 h at room temperature, the adduct was used without further purification. Crude salt was dissolved in THF (20 mL), 2b (1 equiv 2 mmol) was added, and the mixture was stirred at room temperature at 10 min.