On the Nature of Pyroabietic Acids

Abstract

ON THE: NATURE gravity at 15/15, 0.7954, optical rotation, -0.7', and refractive index a t Z O O , 1.4705. These figures are close to those recorded for myrcene.This fraction boils at 164-166' at atmospheric pressure with partial polymerization.Oxidation with permanganate gave succinic acid, m. p.186 ' . Reduction with sodium in alcohol yielded dihydromyrcene (tetrabromide m. p. 89-90"), and hydration with acetic acid and 50% sulfuric acid a t low temperature gave myrcenol, having a lavender odor and giving a phenylurethan melting at 71-72'.(Enklaarz reported a melting point of 68" for myrcenol phenylurethan.) The phenylurethan from the myrcenol gave sharp depressions in melting point when mixed with both I-linalool and i-linalool phenylurethans.The small higher boiling fraction remaining after distillation of the myrcene was redistilled a t 10 mm. from a small flask provided with a Vigreux column yielding the following products: (1) a very small fraction, 85-90";(2) a small fraction, 90-100°; (3) the main fraction, 100-110"; (4) a small fraction, 110-140"; leaving a thick, viscous residue in the flask.Fraction 1 gave a negative reaction for alcohols on treatment with phenyl isocyanate, but gave a positive reaction for the carbonyl group on treatment with semicarbazide, as did also fractions 2 and 3, which gave copious yields of semicarbazone. On decomposition of the semicarbazones an odor suggesting methyl nonyl ketone was observed.The semicarbazone from fraction 1 melted a t 114.5". The semicarbazones from fractions 2 and 3 melted at 123-124 ' , and gave no depression in melting point when mixed with the semicarbazone of methyl It-nonyl ketone. While (2) Enklaar, "Over Ocimeen en hlyrceen," Inaugural Dissertation, Utrecht, 1905 OF PYROABIET~C ACIDS 92 1 indices of refraction were not measurable in either case, optical crystallographic examination showed identical crystalline form and interference figures.'Fraction 3, boiling a t 10C)-llOo, had an odor suggesting geraniol. When a portion of this fraction was oxidized with potassium dichromate, an odor of citral was detected. However, attempts to isolate geraniol as the diphenylurethan, or the semicarbazone of citral, were unsuccessful, due no doubt to the predominance of methyl It-nonyl ketone.From the distillation residue a non-volatile oil was extracted which gives a lasting tingling sensation to the tongue and lips. Alkaloidal material was found only in traces, so this physiological effect is not due to aconitine. This substance is being further investigated. SummaryThe volatile oil of Amur cork tree fruit coiitains over 92% of the aliphatic terpene, myrcene.The higher boiling portion of the oil contains methyl n-nonyl ketone, with possibly a small amount of a lower homolog such as methyl nheptyl ketone.Evidence was obtained of the presence of a small amount of geraniol in the fraction boiling at 100-llOo at 10 mm.The slight optical activity of the myrcene fraction is probably due to a small amount of an optically active terpene.(3) Optical crystallographic e...

Synthesis and antimicrobial evaluation of novel analogues of dehydroabietic acid prepared by C H-Activation

“…1 9 General procedure of the C-H-Arylation: Nickel acetate tetrahydrate (1 eq.) and anhydrous sodium carbonate (2 eq.)…”

“…in dimethylformamide (0.2 ml) afforded after purification by preparative thin layer chromatography (silica, 20% ethylacetate in heptane) 35 mg (70%) of product as yellow oil. 1 10 Amide 9a (62.0 mg, 0.1 mmol) was dissolved in a mixture of toluene/water/triflic acid (2 mL, 6:1:1) and stirred for 4 days at 100 °C. The product was extracted from aqueous hydrochloric acid (1 N, 10 mL) with dichloromethane (3 x 10 mL), the combined organic layers were dried with MgSO 4 and concentrated in vacuo.…”

“…Indeed, derivatization of these natural products and biological evaluation of the generated compounds has been a topic of interest over the last decades. Abietic (1) and Dehydroabietic acid (DHAA) (2) can be considered as leading representatives of resin acids in drug discovery ( Figure 1). In particular, DHAA can be isolated from disproportionated rosin [1] and an aromatic C-ring endows the compound with enhanced chemical stability compared to its saturated analogue 1.…”

“…Abietic (1) and Dehydroabietic acid (DHAA) (2) can be considered as leading representatives of resin acids in drug discovery ( Figure 1). In particular, DHAA can be isolated from disproportionated rosin [1] and an aromatic C-ring endows the compound with enhanced chemical stability compared to its saturated analogue 1. In prior studies, DHAA was shown to have antimicrobial, antiinflammatory or anti-cancer activity [2].…”

The use of palladium nanoparticles supported on active carbon for synthesis of disproportionate rosin (DPR)

“…At the present time, palladium catalysts have been of great interest, in part because of the good properties that the DPR feature regarding light color, low odor, medium softening-point, and excellent resistance to oxidation [1,2,[12][13][14][15]. In the continuation of our research [16][17][18][19][20][21], the disproportionation of rosin with Pd nanoparticles supported on activated carbon (AC) was studied in this work.…”