Synthesis and reactions of some new hydroxymethylene spirofurobenzopyran derivatives

Claisen condensation of furochromanone derivatives with ethyl formate yield ed 6-(hydroxymethylene)furobenzopyran derivatives; these with hydrazine hyd rate, phenylhydrazine, hydroxylammonium chloride, malononitrile, and ethyl cyanoacetate afforded furopyrazolobenzopyran, furoisoxazolobenzopyran, and furopyranobenzopyran derivatives. Condensation reaction of furobenzopyran-6-carbaldehyde derivatives with ind an-1,3-dione gave furobenzopyranylmethyleneindan-1,3-dione derivatives whic h gave indanopyridine derivatives on treatment with ammonia. Moreover, cond ensation reaction with dimedone, pyrazolone, barbituric acid, and thiobarbi turic acid yielded oxanthenylfurobenzopyran derivatives, furobenzopyranylme thylenepyrazolones, and furobenzopyranylmethylenebarbituric resp. -thiobarb ituric acid.