Quinones. Part 2. General synthetic routes to quinone derivatives with modified polyprenyl side chains and the inhibitory effects of these quinones on the generation of the slow reacting substance of anaphylaxis (SRS-A)

Abstract

General synthetic routes to quinone acids (8), quinone amides (9), quinone alcohols (10), and quinone methylketones (11) with polyprenyl side chains, in which allylic alcohols (3) are employed as the key intermediates, are described. The Claisen rearrangements and the Carrot reactions of the allylic alcohols (3) with ethyl orthoacetate and diketen produced the ethyl esters (4) and the methylketones (5), respectively. Quinone products (8), (10), and (11) were recovered by oxidative demethylation of hydroquinone dimethyl ethers (4), (5), and (7) or by acid hydrolysis of hydroquinone bis(methoxymethyl) ethers (4) and (5) followed by ferric chloride oxidation. Amidation of quinone acids (8) led to the formation of quinone amides (9). Inhibitory effects of these quinone derivatives on the generation of the slow reacting substance of anaphylaxis (SRS-A) in the lungs of sensitised guinea pigs are evaluated.