Indole from adrenochromes

The non-oxidative formation of melanin from adrenochrome in acid solution, reported by Harley-Mason,6 has recently been shown by Bu Lock to be controlled by a second-order reaction between adrenochrome and acid.107 It was suggested that the initial product (not isolated) was probably l-methylindole-5,6-quinone, which polymerized rapidly to melanin via dimers and oligomers.107 (The intermediate monomer quinone also gave a melanin-like copolymer with indole.107)... 

A number of psychotomimetic substances—including adrenochrome and adrenolutin which are derived from adrenaline —are indole compounds and are therefore structurally related to 5-hydroxytryptamine. The most extensively studied member of the group—LSD25—is, however, less closely related to 5-hydroxytryptamine than are compounds such as bufotenine. 

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