- A facile synthesis of pyrimidin-4-ones
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A facile synthesis of 2,6-disubstituted pyrimidin-4-ones and 2,5,6-trisubstituted pyrimidin-4-ones from commercially available materials with application of microwave technology in key steps is described.
- Guo, Cheng
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scheme or table
p. 548 - 549
(2010/10/02)
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- Onium Salt-catalyzed Acylations with Diketene
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Weak NH- and CH-acids can be acylated advantageously by diketene (1) in the presence of a quarternary ammonium chloride.Carboxamides yield with one or two moles of 1 the products 3 or 10 selectively. β-Keto esters and β-diketones lead to 12a, b or 13, respectively, and acetoacetamides give 5 or 8.The polymer 16 and/or 17 is formed by self-condensation of 1.
- Dehmlow, Eckehard V.,Shamout, Abdul Rahman
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p. 2062 - 2067
(2007/10/02)
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- 1,3-Oxazines and Related Compounds. V. N-Acylacetylation of Carboxamides with the Diketene-Halotrimethylsilane System or Acyl Meldrum's Acids
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Various aliphatic and aromatic carboxamides smoothly underwent N-acetoacetylation by means of the diketene-iodotrimethylsilane system to give the corresponding N-acetoacetyl derivatives.The diketene-bromotrimethylsilane system was found to be very efficient for N-acetoacetylation of unsaturated carboxamides such as acrylamide and methacrylamide.In addition, acyl Meldrum's acids proved effective for N-acylacetylation of carboxamides, especially heterocyclic carboxamides such as picolinamides.Keywords: carboxamide; acylacetylation; diketene; iodotrimethylsilane; bromotrimethylsilane; acyl Meldrum's acid
- Yamamoto, Yutaka,Ohnishi, Shuhei,Azuma, Yutaka
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p. 3505 - 3512
(2007/10/02)
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- Synthesis of N-Acylacetoacetamide using 2,2,6-Trimethyl-1,3-dioxin-4-one
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Diketene-acetone adduct (2,2,6-trimethyl-1,3-dioxin-4-one) 1 reacts with amide NH to give the corresponding N-acetoacetates 2.Formamide and basic amides such as picolinamide, on treatment with the adduct, are transformed to the N-acyl-2,6-dimethyl-4-oxo-4H-pyran-3-carboxamide (4a and 4p) together with the corresponding N-acetoacetates.Keywords--diketene-acetone adduct; 1,3-dioxin-4-one; acetylketene; diketene; acetoacetylation; 4-pyrone derivatives; N-acylacetoacetamide
- Sato, Masayuki,Kanuma, Norio,Kato, Tetsuzo
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p. 1315 - 1321
(2007/10/02)
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