4-Cyano-4,5-dihydroazepines, when treated with an acidic ion-exchange resin in aqueous alcohol, undergo hydrolytic cleavage to a cyanooctanedionediester. The cyanooctanedione-diester and its thermal cyclization product, a 4,7-dihydrofuro[2,3-b]pyridine, are shown to be intermediates in the rearrangement of cyanodihydroazepines to furo[2,3-b]pyridines by aqueous alcoholic silver nitrate. The mechanism of this rearrangement and the role of silver(I) are discussed. Ethyl 2-(2-cyanoethyl)acetoacetate cyclizes to a 1,2,3,4-tetrahydro-2-oxopyridine when refluxed with silver nitrate in aqueous ethanol.