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Heterocyclic β‐Enamino Esters, 48 1) Heterocondensed Pyridines by Cycloaddition‐Extrusion Sequence of Bi‐ and Tricyclic 1,3‐Oxazinones with N,N ‐Diethyl‐1‐propynylamine
Author(s) -
Ming YangFu,
Horlemann Norbert,
Wamhoff Heinrich
Publication year - 1987
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19871200821
Subject(s) - chemistry , cycloaddition , pyridine , oxazole , stereochemistry , medicinal chemistry , pyrrole , acetylene , reagent , isoindole , organic chemistry , catalysis
Dihalotriphenylphosphoranes convert the N ‐benzoylated ethyl 2‐amino‐4,5‐dihydrofuran‐ ( 5b ), ‐pyrrole‐ ( 7b ), ‐isoxazole‐ ( 9b ), and ‐oxazole‐3‐ or‐4‐carboxylates ( 11b ) into heterocondensed 1,3‐oxazinones 6, 8, 10 , and 12 . Treatment with N,N ‐diethyl‐1‐propynylamine of these compounds as well as the already known 1,3‐oxazinones 1a,b, 2a,b , and 3 results in a regiospecific cycloaddition‐extrusion sequence to afford the corresponding heterocondensed pyridines 13a,b, 14a,b, 15a,b , and 16–21 . Of these 15b and the 4‐oxonaphthyridines 16, 17 represent examples of insertion of the acetylene reagent.