The ultrasound promoted Knoevenagel condensation of aromatic aldehydes

Tetrahedron Letters

Volumn 39, Issue 44, 1998, Pages 8013-8016

  McNulty, James ^a   Steere, Jennifer A ^a   Wolf, Sonja ^a  

^a BROCK UNIVERSITY   (Canada)

Author keywords

Aldol reactions; Alkenes; Nitro compounds; Sonochemistry

Indexed keywords

ALDEHYDE; ALKENE; AROMATIC COMPOUND; NITRO DERIVATIVE;

ARTICLE; CATALYSIS; CHEMICAL REACTION; POLYMERIZATION; REACTION ANALYSIS; SYNTHESIS; ULTRASOUND;

EID: 0032578889     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/S0040-4039(98)01789-4     Document Type: Article

References (13)

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2. 3. Jones, G.; Organic Reactions Vol. 15; John Wiley: New York, 1967; p. 204.
3. 4. McNulty, J.; Mo, R. J. Chem. Soc., Chem. Commun. 1998, 933.
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5. 6. Monte, A.P.; Waldman, S.R.; Marona-Lewicka, D.; Wainscott, D.B.; Nelson, D.L.; Sanders-Bush, E.; Nichols, D.E. J. Med. Chem. 1997, 40, 2997.
6. 7. Ghosh, D.; Nichols, D.E. Synthesis 1996, 195.
7. 8. Lickiss, P.D.; McGrath, V.E. Chemistry in Britain, March 1996, p. 47.
8. 9. Ley, S.V.; Low, C.M.R. Ultrasound in Synthesis. Springer-Verlag, Berlin, 1989.
9. 10. General procedures. Nitromethane and pyridine (Aldrich) were freshly distilled. Ultrasound reactions were performed using a Branson 5510 ultrasound bath or a Crest Tru-Sweep ultrasonic cleaner with little difference. Method A: A mixture of aldehyde (20.0mmol), nitromethane (13.OmL), glacial acetic acid (3.3mL) and ammonium acetate (3.324g), sonicated at 22 °C for 3h. After removal of nitromethane, partition between dichloromethane and water then brine gave crude product which was recrystallized from aq. ethanol (except 5d, AcOH). Method B: A solution of aldehyde (1.00mmol), nitromethane (1.0 mL), ammonium acetate (2.5 mmol) and diisopropylethylamine (0.1 mmol) was sonicated at 22 °C for 3-6h, according to tlc. After removal of solvents, work-up as above gave the crude product which was purified on silica gel. Method C: A solution of aldehyde (1.00 mmol), malonic acid (2.18 mmol) in pyridine (5.7 mmol) and piperidine (0.20 mmol) was sonicated at 22°C for 3h. Solution added to 5% aq. HCl, chilled and filtered by suction. The precipitate was recrystallized from aq. ethanol.
10. 11. Zhao, H.; Neamati, N.; Mazumder, A.; Sunder, S.; Pommier, Y.; Burke, T.R.. Jr. J. Med. Chem. 1997, 40, 1186.
11. 12. Schafer, H.; Seebach, D. Tetrahedron 1995, 51, 2305.
12. 13. Evans, D.A.; Faul, M.M.; Bilodeau, M.T.; Anderson, B.A.; Barnes, D.M. J. Am. Chem. Soc. 1993, 115, 5328.
13. 14. Jacobsen, E.N.; Deng, L.; Furukawa, Y.; Martinez, L.E. Tetrahedron 1994, 50, 4323.