A convenient synthesis of pyridine and 2,2′-bipyridine derivatives |
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Authors: | Marta Altuna-Urquijo Stephen P Stanforth Brian Tarbit |
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Institution: | a School of Applied Sciences, Northumbria University, Newcastle upon Tyne NE1 8ST, UK b Vertellus Specialities UK Ltd, Seal Sands Road, Seal Sands, Middlesbrough TS2 1UB, UK |
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Abstract: | α-Chloro-α-acetoxy-β-keto-esters 9 were readily prepared from β-keto-esters 6 in good overall yields. These compounds reacted as α,β-diketo-ester equivalents 2 with amidrazones 1 yielding triazines 3, generally in good yields. Picolinates 10 provided an alternative source of α,β-diketo-ester equivalents 2 when treated with copper(II) acetate. A ‘one-pot’ reaction of the α,β-diketo-ester equivalents 2 with amidrazones 1 in the presence of 2,5-norbornadiene 5 in boiling ethanol yielded the pyridines 4 and 2,2′-bipyridines 4 (R1=2-pyridyl) directly without the need to isolate the corresponding triazines 3. Triazine 3c reacted with the aza-dienophiles 13 and 17 affording the products 16 and 18, respectively, in good yields. |
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Keywords: | Pyridines 2 2&prime -Bipyridines 1 2 4-Triazines α β-Diketo-esters Aza Diels-Alder reaction |
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