Pyrogallolarenes are related macrocycles derived from the condensation of pyrogallol (1,2,3-trihydroxybenzene) with an aldehyde. The developing chemistry is similar to that of catechol or pyrogallol. Gallacetophenone is the acetyl derivative of pyrogallol. It is a dimethyl ether of pyrogallol. Another developer mainly based on pyrogallol was formulated by Jay DeFehr. Adolf von Baeyer had experimented with phenols and formaldehydes in 1872, particularly Pyrogallol and benzaldehyde. The bark and especially the fruit yield pyrogallol and catechol to dye and tan leather. The other two isomers are hydroxyquinol (1,2,4-benzenetriol) and pyrogallol (1,2,3-benzenetriol). Pyrogallol and pyrocatechin are among the oldest photographic developers. In 1969, he began experimenting with the forgotten photographic developing agent Pyrogallol. Other developing agents in use are p-aminophenol, glycin (N-(4-hydroxyphenyl)glycine), pyrogallol, and catechol. Berkeley's formula contained pyrogallol, sulfite, and citric acid. From 1969 to 1977, Wimberley experimented with the Pyrogallol developing agent. Chestnut tannin is one of the pyrogallol class of tannins (also known as hydrolysable tannin). It can be synthesized from pyrogallol using zinc chloride and acetic anhydride.