Fumaropimaric acid

In some applications, it is desirable to enhance the hydrophilic portion of colophony. This is achieved by reaction of colophony with maleic acid, maleic anhydride or fumaric acid in a so-called Diels-Alder addition. Maleopimaric acid is formed in reactions with maleic anhydride, while both fumaropimaric acid... 

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... 

---