Demethoxydaunomycin The Desired Result, but not According

Devise an alternative mechanistic explanation for the conversion of 1 into 2. 

Three Isomeric Hexadienols Give the Same Bicyclic Lactone 

Treatment of 1-phenyl-2,4-hexadien-l-ol with the acid chloride of fumaric acid monomethyl ester in ether/triethylamine gave a quantitative yield of the crude ester as an oil. Attempted purification by Kugelrohr distillation at 180-190°C under high vacuum gave the bicyclic lactone 1 in 45% yield. It was subsequently found that the fumarate esters of the isomeric alcohols 1-phenyl-l,4-hexadien-3-ol and l-phenyl-l,3-hexadien-5-ol also gave compound 1 in 43 and 35% yield respectively when distilled in a Kugelrohr apparatus. 

Give reasonable explanations for the formation of 1 from the fumarate esters of the three isomeric alcohols. 

As part of a chemical study of the antibiotic X-537A, 1, the latter was treated with 5 equivalents of concentrated nitric acid in glacial acetic acid. The major product from this reaction was a dinitro derivative of 1 which, on treatment with dilute aqueous sodium hydroxide solution, gave a mixture of products one of which was shown to be 6-hydroxy-2,7-dimethyl-5-nitroquinoline. 

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