Synthesis of 2H-pyrano[2,3-b]quinolines. Part I

3,4-Dihydro-2H-pyrano[2,3-b]quinolines 5a-e and 2H-pyrano[2,3- b ]quinolines 10a-c were synthesised starting from the appropriate ω-chloro-n-valeroylanilides 2a-e . Compounds 10a-c were transformed to analogs of the novel antihypertensive agent Cromakalim ( 1 ).