Neoabietic acid

Fig. 1. Abietic-type acids include abietic acid [514-10-3] (1), levopimaiic acid [79-54-9] (2), neoabietic acid [471-77-2] (3), palustiic acid [1945-53-5] (4), and dehydroabietic acid [1740-19-8] (5). Pimaric-type acids are pimaric acid [127-27-5] (6) and isopimaric acid [5835-26-7] (7).

The structures and nomenclature for the common pine resin acids based on the abietane skeleton (abietic-type acids) are given in Fig. 8. The abietic, neoabietic, palustric and levopimaric acids differ only in tbe location of tbeir two double bonds. All double bonds are endocyclic, except in the neoabietic acid in which one is exocyclic. 

Fig. 5-5. Examples of resin acids. 1, Pimaric acid 2, sandaracopimaric acid 3, isopimaric acid 4, abietic acid 5, levopimaric acid 6, palustric acid 7, neoabietic acid 8, dehydroabietic acid.

C20H16O 5-methoxy-10-methyl-1,2-benzanthracene 63020-61-1 445.65 38.688 2 32358 C20H3002 neoabietic acid 471-77-2 579.33 51.556 2... 

Chemistry of the Tricyclic Diterpenoids.—The addition of chlorosulphonyl isocyanate to the methyl esters of levopimaric and neoabietic acids with the formation of C-12 carboxyamides has been described.63 The well documented aromatic substitution reactions of dehydroabietic acid continue to be examined,64 together... 

Loeblich and Lawrence1 describe a method for isolating neoabietic acid from pine oleoresin or rosin in 8-12% yield by recrystallization of the 2-amino-2-methyl-1,3-propanediol salt. 

Naphthyridine, 391 Nebularine, 29, 411 Neoabietic acid, 24, 156, 190 Neopentyl alcohol, 446 Nepetic acids, 149, 150 Nepetonic acid, 234 Nerol, 260... 

Phenanthrenequinone 152) has been reported to sensitize the photooxidation of neoabietic acid. 

Abietic acid Neoabietic acid Levopimaric acid... 

The Chemistry of Ringc.—The modification of ring c has centred on making available relays that are suitable for elaboration into more complex diterpenoids, the diterpenoid alkaloids, and triterpenoids. The unsaturated ketone (53) has proved to be a valuable relay for synthesis. It had been prepared previously from neoabietic acid, which is difficult to obtain pure. It has now been obtained from the levopimaric acid-formaldehyde adduct (50). Oxidation of the adduct with potassium permanganate not only formed the glycol but in an unusual step converted the cyclic ether into the (5-lactone (51). Dehydration, ozonolysis of the newly formed double bond, and then treatment of the keto-acetate (52) with chromous chloride afforded the a -unsaturated ketone (53). The last step involved hydrogenolysis, / -elimination. and decarboxylation. 

Neoabietic acid, T32.il Levopimaric acid, T32.il Palustric acid, T32.il Abietic acid, T32.il, T"33, D"4 Pimaric acid, T32.14, T"32 Isopimaric acid, T32.18 Cyathin A2, T 13.7 Isoagatholactone, T 14.2, T"39 Sandaracopimaric acid, T32.18 Trachylobanic acid, T35.6 3-Hydroxy-7-kemp-8-en-6-one, T"37.15 C20H30O3... 

Resin acids, resinic adds hydroaromatic diter-penes, the acid components of resins. Colophony (rosin) consists of up to 90% R.a. The most important representatives are abietic acid, neoabietic acid, dex-tro-pimaric acid and neopimaric acid. Salts and esters of the R. are called resinates. The alkali salts are also called resin soaps. 

Isol. from resins of Firms spp., Abies spp. and Agathis microstachys. Cryst. (EtOH aq.). Mp 173-173.5° (167-169°) (sealed tube under N2). [a] +161.6° (c, 2.5 in 95% EtOH). Air-sensitive. Dextrosapinic acid was a mixt. of Abietic and Neoabietic acids. 

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