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Abstract
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There has been considerable interest in the 2oxo-2Hchromene (coumarine) and 4H chromene ring systems as a resuft ‘of their toxicity, carcinogenicty and photodynamic effects. There have been many reported studies on the synthesis 2oxo-2Hchromene and 4Hchromene ring structures. As part of our current studies on the development of new routes to heterocyclic and carbocyclic systems, we now report the reaction between tertbutyl isocyanide and dialkyl acetylenedicarboxylates (1) in the presence of 2..hydroxybenzaldehyde (2a), 3.methoxy.2hydroxybenzaldehyde (2b), 4methoxy2- hydroxybenzaldehyde (2c), or 5.methoxy2hydrexybenzaldehyde (2d). Thus, reaction of1 and terrbutyl isocyanide in the presence of 2a or 2b, leads to 2-oxo2Hchromenes 3.
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