Orsellinoyl-_p_-hydroxybenzoic acid.
Protocatechuyl-_p_-hydroxybenzoic acid.
Galloyl-_p_-hydroxybenzoic acid.
Pyrogallolcarboy _p_-hydroxybenzoic acid.
Syringoyl-_p_-hydroxybenzoic acid.
_p_-Hydroxybenzoyl-syringic acid.
Pentamethyl-_m_-digallic acid.
Pentamethyl-_p_-digallic acid.
Vanilloyl vanillin.


Preparation of Tridepsides

Monohydroxybenzoic acids allow theoretically of tri-depsides of the type
HO.C_6H_4COO.C_6H_4.COO.C_6H_4.COOH only; if, on the other hand, di- or
trihydroxybenzoic acids are dealt with, two formulae are possible,
viz.:--

HO.C_6H_4.COO
} C_6H_3.COOH
HO.C_6H_4.COO

Of the former type, two compounds are known, _i.e._,
di-_p_-hydroxybenzoyl-_p_-hydroxybenzoic
acid and vanilloyl-_p_-hydroxybenzoyl-_p_-hydroxybenzoic acid--

HO
} C_6H_3.COO.C_6H_4.COO.C_6H_4.COOH
CH_3O