Tetronic Acids and Derivatives Part VIII (1) o-Alkylation of 3-Unsubstituted Tetronic Acids

References

• Pollet , P. and Gelin , S. 1978 . Tetrahedron , 34 : 1453 Part V
   Web of Science ®Google Scholar
• Pattenden , G. 1978 . Forsch. Chem. Org. Naturstoffe , 35 : 133 for a review see For more recent examples see A. Pelter, M. Ayoub, J. Schutz, R. Hansel and D. Reinhardt, Tetrahedron Letters, 1627, (1979) and T. Reffstrup and P. M. Boll, Phytochem., 18, 325, (1979)
   Google Scholar
• Compounds 5 are easily detected by a characteristic purple coloration with aqueous sodium nitrite or by brown spots in T.L.C. by iodine staining
   Google Scholar
• Schnedler-Wengel , A. , Reffstrup , T. and Boll , P. M. 1979 . Tetrahedron , 35 : 2181
   Web of Science ®Google Scholar
• Kumler , W. D. 1938 . J. Amer. Chem. Soc. , 60 : 2532 A. W. Nineham and R. A. Raphael, J. Chem. Soc., 118, (1949)
   Google Scholar
• Jones , E. R. H. and Whiting , M. C. 1949 . J. Chem. Soc. , : 1423
   Web of Science ®Google Scholar
• Jacobsen , J. P. , Reffstrup , T. , Cox , S. , Holker , J. S. E. and Boll , P. M. 1978 . Tetrahedron Letters , : 1081 For a definitive revision of carolic acid structure see
   Google Scholar
• Goel , O. P. and Seamans , R. E. 1973 . Synthesis , : 538
   Google Scholar
• All new compounds give spectral and microanalytical data in agreement with the proposed structure. Typical data for compounds 1–3 were previously described1,4
   Google Scholar
• After dilution of the reaction mixture with water, etheral extractive work-up and distillation (for 8a) or chromatography over silicagel with ether-hexane 1–1 (for 8b)
   Google Scholar
• 8a: b.p.:171–2°C (1 torr). I.R. (neat):2980, 2960, 1770 (COO) 1745 (COOEt), 1640 (C=C). 1H NMR (CDCl3): 1.45 (3H, t, J=7) 1.5 (3H, d, J=7), 2.25 (2H, m), 2.5 (2H, t, J=6), 4.2 (4H, 7 lines) 4.9 (1H, dq, J=7, J=1.5), 5.14 (1H, d, J=1.5). 8b: I. R. (neat):2980, 2960, 1770 (COO), 1735 (COOtBu), 1635 (C[dbnd]C). 1H NMR (CDCl3): 1.45 (3H, d, J=7), 1.5 (6H, s), 2.0–2.6 (4H, m) 4.2 (2H, t, J=6), 4.84 (1H, dq, J=7, J=1.5), 5.08 (1H, d, J=1.5). 9: 85% from 8a and 1N NaOH (25°C, 12h). 20% from 8b and P. T. S. A. in boiling toluene. m. p.: 108–9°C (EtOAc-hexane) I. R. (CHCl3): 3200–2900 (COOH), 1750 (COO), 1745 (COOH), 1645 (C[dbnd]C) 1H NMR (CDCl3): 1.5 (3H, d, J=7), 2.58 (2H, t, J=6), 2.28 (2H, m) 4.2 (2H, t, J=6), 4.9 (1H, dq, J=7, J=1.5), 5.16 (1H, d, J=1.5) 10.64 (1H, s)
   Google Scholar
• Gelin , S. and Pollet , P. 1975 . Bull. Soc. Chim. Fr. , : 307 Prepared along a previously described procedure
   Google Scholar
• Gelin , S. and Pollet , P. 1979 . J. Heterocyclic Chem. , 16 : 505 Compounds 1 are easily converted, as tetronic acids 5, to 3-hydroxyalkyl 5-hydroxypyrazoles by reaction with mono substituted hydrazines
   Web of Science ®Google Scholar
• Gillespie , J. F. and Price , C. C. 1957 . J. Org. Chem. , 22 : 780
   Web of Science ®Google Scholar