Synthetic Transformation of Abietic Acid I. Addition of Dienophiles

Abstract

Addition of acetylene dicarboxylic acid dimethylester to abietic acid is an en-reaction. The structure of the resulting product was determined. Compounds formally derived from addition of acetylene to levopimaric acid have been synthesized. By a retro-Diels-Alder reaction, the B-ring is cleaved and an aromatic system is formed. Diels-Alder addition of 2-chloroacrylonitrile to abietic acid gives a tetracyclic -chloronitrile (10). Further transformations of this product are described.

Synthetic Transformation of Abietic Acid IIIa. Photoconversion of Diene Adducts

“…After three days, only resin acids could be detected. ÐÐÐÐ a For part I see [1], for part II see [2].…”

“…In previous publications we have described the synthesis of ,-enone 1 by DielsAlder addition of 2-chloroacrylonitrile to abietic acid methyl ester and subsequent treatment of the adduct with NaOH [1,2]. ,-Enones have two chromophores and are capable of undergoing a variety of photochemical reactions, e.g.…”

Synthesis of new chiral phosphorous- and nitrogen-containing ligands from resin acids

“…Dehydroabietic acid (21) (1R,4aR,10aR )-1,4a-Dimethyl-7-isopropyl-1,2, 3,4,4a,9,10,10a-octahydrophenanthrene-1-isocyanate (24) was prepared according to the literature procedure: 24 (1R,4aR,10aR )-1,4a-Dimethyl-7-isopropyl-1,2,3,4, 4a,9,10,10a-octahydrophenanthrene-1-amine (25). To a solution of compound 24 (2 g, 6.7 mmol) in benzene (50 mL), 35% HCl (5 mL) was added.…”

“…15,17 Thus, the methods of selective decarboxylation and oxidative cleavage of the double bond of the levopimaric acid adducts formed with a variety of dienophiles, including catalytic methods followed by the retro-Diels-Alder reaction, were developed. 21,22 To search biologically active compounds, amides and imides of maleopimaric acid formed with aliphatic and aromatic amines as well as with amino acids were synthesized. 3,4 The chemistry of dehydroabietic acid including classical transformations of the aromatic ring has been studied, and reaction products were used for preparation of bioactive nitrogen-containing heterocyclic compounds.…”