Synthesis Of Ambrox Research Articles

Engineering Escherichia coli for effective and economic production of cis-abienol by optimizing isopentenol utilization pathway

Efficient and economical supply of cis-abienol has attracted extensive attention due to its use as a precursor in the synthesis of ambrox (a cardinal odor of rare ambergris). Increasing awareness in environmental issues and advantages of microbial production–sustainable and green manufacture, have motivated efforts to advance the cis-abienol biosynthesis in more affordable ways. Herein, Escherichia coli cells were employed to scale up cis-abienol production via expressing the concise isopentenol utilization pathway (IUP). Alcohol kinases and isopentenyl phosphate kinases (IPKs) were screened and coordinated to increase dimethylallyl diphosphate (DMAPP) supply, which resulted in approximately 37-fold improvements in the cis-abienol yield, compared with the titer obtained by endogenous MEP pathway. Next, we constructed a double-phosphatase-deficient strain (BD203), resulting in a 40% increase in the cis-abienol titer relative to wild-type strains. By optimization of addition strategies, a cis-abienol titer of 311.8 ± 1.0 mg/L was obtained in strain BD203, which is the highest cis-abienol titer reported in shake flasks and 14.7% of the maximum theoretical yield. Finally, further optimization of the fed-batch fermentation process enabled a cis-abienol titer of 1375.7 mg/L in a 1.3 L bioreactor. Overall, BD203 achieved a substantial increase in the cis-abienol titer in this study and engineering microbes were expected to facilitate progress toward industrial production.

Synthesis of Ambrox ® from labdanolic acid

A synthesis of the valuable amber-type odorant Ambrox ® from labdanolic acid (main diterpenoid of the acid fraction of non-polar extracts of Cistus ladaniferus L.) is reported. The conversion is based on (a) the α,β-dehydrogenation of methyl labdanolate using an organoselenium reagent, (b) subsequent oxidative degradations of the side chain, and (c) final acid-promoted cyclization of the resulting tetranorlabdan-8α,12-diol. The influence of the temperature and solvent in the cyclization of the diol with p-toluenesulfonic acid is also described. Thus, Ambrox ® has been obtained by a six-step procedure in 33% overall yield from methyl labdanolate.

The synthesis of Ambrox®-like compounds starting from (+)-larixol. Part 2

Several Ambrox®-like compounds were synthesized in an enantiomerically pure form, and in relatively short procedures, starting from (+)-larixol. Triol 5 and enone 6 are important intermediates in these syntheses. The formation of Δ6-Ambrox®-type ethers was achieved by a new cyclization approach via ionization of the C(6)-allylic alcohol in ring B.

The synthesis of Ambrox ®-like compounds starting from (+)-larixol

The oxidation of the (3-hydroxy-3-methyl-4-pentenyl)-side chain at C(9) of some labdanic diterpenoids with potassium permanganate was investigated. Triols, ketones, or cyclic enol ethers are the main reaction products, strongly influenced by the substituent at C(8). Further degradation of the methyl ketones by the Baeyer–Villiger reaction and modification of the exocyclic 8(17) double bond lead to suitable intermediates, which have been transformed into Ambrox ®-like compounds. Synthetic routes using palladium catalyzed elimination or isomerization of allylic acetates, followed by ozonolysis have been developed as well for shortening of the side chain of (+)-larixol. Products from both routes have been cyclized to 6α-hydroxy Ambrox ®. This compound was used as the key intermediate for the synthesis of several other Ambrox ®-like compounds of which some showed pleasant odour properties.

A PRACTICAL SYNTHESIS OF AMBROX® FROM SCLAREOL USING NO METALLIC OXIDANT

The commercial synthesis of Ambrox® is modified so thatthe key intermediate, the sclareolide, results from an indirect oxidativedegradation of sclareol. This method allows to greatly alleviate the wastedisposal problem and to raise the overall yield of Ambrox® to 75%.

Ambergris: perfume e síntese

Rules for the occurence of the ambergris odor is presented and discussed in terms of the relationship between chemical structure and odor. A general overview of the major approaches in the synthesis of Ambrox® , the key ambergris-type compound, is also presented.

Formal Synthesis of Ambrox® and 9-Epiambrox

Abstract (-)-Drimenol (5) was used as starting material for the synthesis of diastereoisomeric diols 3 and 4, through the nitrile 7, Compounds 3 and 4 are the direct precursors of Ambrox® (1) and 9-epiambrox (2).

ChemInform Abstract: Synthesis of Ambrox® (‐)‐(V) from (‐)‐Sclareol (I) and (+)‐cis‐ Abienol (VI).

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform Abstract: Synthesis of Ambrox from Communic Acids.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Synthesis of Ambrox® from communic acids

Two routes for preparing Ambrox® ( 1) from the methyl esters of trans-communic acid ( 2b) and/or cis-communic acid ( 3b), via selective degradation of their side chains, stereoselective formation of the tetrahydrofurane ring, and reduction of the axial methoxycarbonyl group, are described.

ChemInform Abstract: A New Synthesis of Ambrox and Related Compounds.

AbstractThe alcohol (IVb), prepared from (‐)‐drimenol (Ia), is converted into the dihydroxy acetate (V).

A New Synthesis of Ambrox and Related Compounds

A New Synthesis of Ambrox and Related Compounds