2*Butenedioic acids, derivs

Mirbach, M.J., Mirbach, M.F., and Saus, A., The triplet energies of butenedioic acid derivatives,... 

Fumaric acid (2-butenedioic acid trans 1,2-ethylenedicarboxyHc acid) is a naturally occurring organic acid that is a key TCA cycle intermediate. It derives its name from the plant Fumaria officinalis, from which it was first isolated. 

Glovsky et al. observed an anticomplementary activity for levopimaric acid (45), a derivative of abietic acid, and prepared a number of synthetic derivatives such as maleopimaric acid (46) and fumaropimaric acid (47), being Diels-Alder substitution products of levopimaric acid v ith maleic anhydride or fumaric acid, respectively [28, 29]. Maleic acid is cis-butenedioic acid, fumaric acid is trans-butenedioic acid. Maleopimaric acid inhibited complement-mediated haemolysis via classical path-way activation (45% inhibition at a concentration of 500 iM), Fumaropimaic acid inhibited in vivo complement-dependent systemic Frossman, cutaneous Frossman, and reverse passive Arthus reactions. These pimaric acid derivatives have already been included in earlier reviews on complement-active compounds [8, 30]. The... 

The monomers discussed in this section are derived from maleic acid (MA, c -butenedioic acid) or fumaric acid (FA, tra 5-butenedioic acid). Whereas FA is present in the metabolism of mmierous plants, MA is not, but MA, in the form of its anhydride (MAH), is technically produced in large quantities in contrast to FA. The technical production of MAH (mp 52 to 53 °Q is based on the oxidation of benzene or butane with air in the presence of vanadium oxide-based catalysts. FA (mp 287 °Q is thermodynamically more stable than MA (mp 138 to 139 °C) by 22.8kJ/mol [915]. Therefore, FA is easily produced by catalytic isomerization of MA. 

Their common names again derive from their natural origins. For example, butanedioic (succinic) acid was discovered in the distillate from amber (succinum, Latin, amber), and trani -2-butenedioic (fumaric) acid is found in the plant Fumaria, which was burned in ancient times to ward off evil spirits (fumus, Latin, smoke). 

---