Unsaturated Primary Alcohols Research Articles

Compounds of the menthane series. Synthesis of unsaturated primary alcohols with the o- and p-menthane skeletons

Precursors to terpene alcohols of the o- and p-menthane series (o-cimen-7-ol and o- and p-cimen-9-ols) were synthesized, and their reduction with lithium in ethylenediamine was studied. The reduction of o- and p-cimen-9-ols in the presence of isopropyl alcohol selectively afforded the corresponding 1,4-dihydro derivatives. Under analogous conditions, o-cimen-7-ol was converted into a mixture of unsaturated hydrocarbons. The reduction with lithium in ethylenediamine in the absence of isopropyl alcohol in all cases gave mixtures of menthene alcohols.

ChemInform Abstract: Scope and Mechanism in Palladium‐Catalyzed Isomerizations of Highly Substituted Allylic, Homoallylic, and Alkenyl Alcohols.

AbstractThe intramolecular oxidation of unsaturated primary and secondary alcohols to aldehydes and ketones is achieved via Pd‐catalyzed olefin isomerization.

Chlorine atom-initiated low-temperature oxidation of prenol and isoprenol: The effect of C[dbnd]C double bonds on the peroxy radical chemistry in alcohol oxidation

The chlorine atom-initiated oxidation of two unsaturated primary C5 alcohols, prenol (3-methyl-2-buten-1-ol, (CH3)2CCHCH2OH) and isoprenol (3-methyl-3-buten-1-ol, CH2C(CH3)CH2CH2OH), is studied at 550K and low pressure (8Torr). The time- and isomer-resolved formation of products is probed with multiplexed photoionization mass spectrometry (MPIMS) using tunable vacuum ultraviolet ionizing synchrotron radiation. The peroxy radical chemistry of the unsaturated alcohols appears much less rich than that of saturated C4 and C5 alcohols. The main products observed are the corresponding unsaturated aldehydes – prenal (3-methyl-2-butenal) from prenol oxidation and isoprenal (3-methyl-3-butenal) from isoprenol oxidation. No significant products arising from QOOH chemistry are observed. These results can be qualitatively explained by the formation of resonance stabilized allylic radicals via H-abstraction in the Cl+prenol and Cl+isoprenol initiation reactions. The loss of resonance stabilization upon O2 addition causes the energies of the intermediate wells, saddle points, and products to increase relative to the energy of the initial radicals and O2. These energetic shifts make most product channels observed in the peroxy radical chemistry of saturated alcohols inaccessible for these unsaturated alcohols. The experimental findings are underpinned by quantum-chemical calculations for stationary points on the potential energy surfaces for the reactions of the initial radicals with O2. Under our conditions, the dominant channels in prenol and isoprenol oxidation are the chain-terminating HO2-forming channels arising from radicals, in which the unpaired electron and the –OH group are on the same carbon atom, with stable prenal and isoprenal co-products, respectively. These findings suggest that the presence of CC double bonds in alcohols will reduce low-temperature reactivity during autoignition.

Scientific Opinion on Flavouring Group Evaluation 06, Revision 4 (FGE.06Rev4): Straight‐ and branched‐chain aliphatic unsaturated primary alcohols, aldehydes, carboxylic acids and esters from chemical groups 1, 3 and 4

Scientific Opinion on Flavouring Group Evaluation 06, Revision 4 (FGE.06Rev4): Straight‐ and branched‐chain aliphatic unsaturated primary alcohols, aldehydes, carboxylic acids and esters from chemical groups 1, 3 and 4

One-pot β-alkylation of secondary alcohols with primary alcohols catalyzed by ruthenacycles

A ruthenacycle-catalyzed one-pot β-alkylation of secondary alcohols with primary alcohols is described. A survey of four C–N chelate ruthenacycles synthesized via the cyclometallation reaction of phenylmethanamine, N-methylphenylmethanamine, N,N-dimethylphenylmethanamine, and naphthalen-1-ylmethanamine with [(η6-C6H6)RuCl2]2 was undertaken. All four complexes were found to be active with the phenylmethanamine-based ruthenacycle showing the best combination of reactivity and product selectivity among the four. An expanded scope of substrates was also studied with the inclusion of unsaturated primary alcohols. The reactivity trend observed gave insights into the role of hydrogen bonding in the catalytic mechanism involving transfer hydrogenation between the substrates and the transition metal catalyst.

Scientific Opinion on Flavouring Group Evaluation 06, Revision 3 (FGE.06Rev3): Straight‐ and branched‐chain aliphatic unsaturated primary alcohols, aldehydes, carboxylic acids, and esters from chemical groups 1 and 4

Scientific Opinion on Flavouring Group Evaluation 06, Revision 3 (FGE.06Rev3): Straight‐ and branched‐chain aliphatic unsaturated primary alcohols, aldehydes, carboxylic acids, and esters from chemical groups 1 and 4

Scientific Opinion on Flavouring Group Evaluation 06, Revision 2 (FGE.06Rev2): Straight‐ and branched‐chain aliphatic unsaturated primary alcohols, aldehydes, carboxylic acids, and esters from chemical groups 1 and 4

Scientific Opinion on Flavouring Group Evaluation 06, Revision 2 (FGE.06Rev2): Straight‐ and branched‐chain aliphatic unsaturated primary alcohols, aldehydes, carboxylic acids, and esters from chemical groups 1 and 4

Oxidation of Unsaturated Primary Alcohols and ω‐Haloalkanols with 4‐Acetylamino‐2,2,6,6‐tetramethylpiperidine‐1‐oxoammonium Tetrafluoroborate

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Potential application of palladium nanoparticles as selective recyclable hydrogenation catalysts

The search for more efficient catalytic systems that might combine the advantages of both homogeneous (catalyst modulation) and heterogeneous (catalyst recycling) catalysis is one of the most exciting challenges of modern chemistry. More recently with the advances of nanochemistry, it has been possible to prepare soluble analogues of heterogeneous catalysts. These nanoparticles are generally stabilized against aggregation into larger particles by electrostatic or steric protection. Herein we demonstrate the use of room temperature ionic liquid for the stabilization of palladium nanoparticles that are recyclable catalysts for the hydrogenation of carbon–carbon double bonds and application of these catalysts to the selective hydrogenation of internal or terminal C=C bonds in unsaturated primary alcohols. The particles suspended in room temperature ionic liquid show no metal aggregation or loss of catalytic activity even on prolonged use.

Oxidation of Unsaturated Primary Alcohols and ω-Haloalkanols with 4-Acetylamino-2,2,6,6-tetramethylpiperidine-1-oxoammonium Tetrafluoroborate

Unsaturated primary alcohols and ω-haloalkanols, all applied in pheromone synthesis, are oxidized to the corresponding aldehydes using 4-acetylamino-2,2,6,6-tetramethylpiperidine-1-oxo--ammonium tetrafluoroborate ( 1A). Three methods are compared with one another; oxidations with 1A and silica gel, oxidations with 1A in the presence of pyridine, and pyridinium chlorochromate (PCC).

Spectral and catalytic properties of aryl-alcohol oxidase, a fungal flavoenzyme acting on polyunsaturated alcohols.

Spectral and catalytic properties of the flavoenzyme AAO (aryl-alcohol oxidase) from Pleurotus eryngii were investigated using recombinant enzyme. Unlike most flavoprotein oxidases, AAO does not thermodynamically stabilize a flavin semiquinone radical and forms no sulphite adduct. AAO catalyses the oxidative dehydrogenation of a wide range of unsaturated primary alcohols with hydrogen peroxide production. This differentiates the enzyme from VAO (vanillyl-alcohol oxidase), which is specific for phenolic compounds. Moreover, AAO is optimally active in the pH range of 5-6, whereas VAO has an optimum at pH 10. Kinetic studies showed that AAO is most active with p-anisyl alcohol and 2,4-hexadien-1-ol. AAO converts m- and p-chlorinated benzyl alcohols at a similar rate as it does benzyl alcohol, but introduction of a p-methoxy substituent in benzyl alcohol increases the reaction rate approx. 5-fold. AAO also exhibits low activity on aromatic aldehydes. 19F NMR analysis showed that fluorinated benzaldehydes are converted into the corresponding benzoic acids. Inhibition studies revealed that the AAO active site can bind a wide range of aromatic ligands, chavicol (4-allylphenol) and p-anisic (4-methoxybenzoic) acid being the best competitive inhibitors. Uncompetitive inhibition was observed with 4-methoxybenzylamine. The properties described above render AAO a unique oxidase. The possible mechanism of AAO binding and oxidation of substrates is discussed in the light of the results of the inhibition and kinetic studies.

Acetate esters of saturated and unsaturated alcohols (C 12–C 20) are major components in Dufour glands of Bracon cephi and Bracon lissogaster (Hymenoptera: Braconidae), parasitoids of the wheat stem sawfly, Cephus cinctus (Hymenoptera: Cephidae)

Chemistry of Dufour glands associated with the venom complex in Bracon cephi (Gahan) and Bracon lissogaster Muesebeck (Hymenoptera; Braconidae), two parasitoids of the wheat stem sawfly, Cephus cinctus Norton (Hymenoptera: Cephidae), was examined by solid phase micro-extraction (SPME) and gas chromatography/mass spectrometry. Homologous series of five chemical classes were detected in individual glands from each species. Major classes included: (1) acetate esters of saturated and unsaturated primary alcohols with parent chain lengths from C 12 to C 20. Hexadecanyl acetate, octadecanyl acetate, and octadecenyl acetate were major components in B. cephi. The composition of the acetate series in B. lissogaster was similar except that the octadecanyl acetate was only a minor component. (2) A homologous series of monoenes from C 23:1 to C 35:1 were detected in both species, with C 29:1, C 31:1 and C 33:1 being the major components. Dienes from C 31:2 to C 35:2 and trienes (C 33:3–C 35:3) were also detected in both species. (3) A homologous series of n-alkanes from C 19 to C 31 was detected in both species. n-Tricosane was the major component. Minor components in both species included homologous series of both mono- and dimethyl branched alkanes. The Dufour gland hydrocarbon components in both B. cephi and B. lissogaster have some similarities to the composition of cuticular hydrocarbons of their host C. cinctus, a species with a complex pheromonal signaling system.

Liquid-phase oxidation of alcohols by oxygen and nitrous oxide catalysed by Ru–Co oxide

Chemoselective catalysts in bulk or supported on γ-Al 2O 3 binary oxides Ru IV–Co III (Ru/Co = 1:1–1:2), prepared by co-precipitation, were used for liquid-phase oxidation of saturated and unsaturated primary and secondary alcohols to aldehydes and ketones with O 2 or N 2O. The catalysts can be separated by filtration and reused. No leaching of Ru or Co in solution was observed. The oxidation is enhanced by the presence of hydration water in the Ru–Co catalyst, which indicates the participation of active Ru IV hydroxo species in the reaction. From XRD and TGA, the Ru–Co oxide can be approximated as a hydrous binary oxide comprising the amorphous RuO 2 and heterogenite-3R cobaltic acid CoO(OH). The alcohol oxidation appears to occur by a nonradical mechanism, which may be viewed as an oxidative dehydrogenation of alcohols to form an aldehyde or ketone. H 2-TPR shows that Co III practically does not affect the oxidising ability of RuO 2. This suggests that the cobalt is likely to enhance catalyst reoxidation by O 2 rather than to play a significant role in the alcohol dehydrogenation. The alcohol oxidation by N 2O exhibits a close similarity to the oxidation by O 2 but is much less efficient. Much more active catalysts are required to make the oxidation with N 2O synthetically useful.

Surface organometallic chemistry on metals: influence of organometallic fragments grafted to the surface of Rh particles on the competitive hydrogenation of terminal and internal double bonds of unsaturated primary alcohols

Hydrophobic organotin fragments, grafted to the surface of a rhodium particle can strongly modify the rate of the hydrogenation of internal or terminal carbon–carbon (C–C) double bonds of unsaturated primary alcohols. In this work, the rate of hydrogenation of trans-2-hexenol and 5-hexenol was determined at room temperature under 20 bar of hydrogen in butanol+water (30+10) solution for Rh/SiO 2 catalysts which were either used unmodified or modified with Sn( n-C 4H 9) 4. It was found that the presence of alkyl groups decreases the ratio between the rate of hydrogenation of the terminal and internal double bond by a factor of 4. These results are explained by the formation of a hydrophobic layer around the modified particle which inhibits the adsorption of the unsaturated alcohol by its internal double bond.

Surface organometallic chemistry on metals: Influence of the presence of functional groups grafted at the surface of Rh particles on the competitive hydrogenation of terminal and internal double bonds of unsaturated primary alcohols

Careful hydrogenolysis of organometallic compounds with group VIII metallic surfaces lead to surface organometallic fragments directly grafted on the metallic particles with well-defined structures. The presence of such surface organometallic fragments was demonstrated by various physical and chemical techniques (EXAFS, magnetic measurements, IR spectroscopy, Mössbauer, thermoreduction, etc.). Surface organometallic complexes with an average formula M s[M′R x ] y (M: Rh, Pt, Ni; M′: Sn, Ge, Si, Se; R: Me, Et, Bu) were proposed. It was recently demonstrated that organometallic fragments with functional groups can also be grafted on a platinum or rhodium surface. In this work, we demonstrate that organo-tin fragments with functional groups, grafted on a silica-supported rhodium surface can strongly modify the regio-selectivity of the hydrogenation of unsaturated primary alcohols. The rate of hydrogenation of trans-2-hexenol and 5-hexenol was determined at room temperature under 20 bar of hydrogen in heptane solution for Rh/SiO 2 catalysts which were either used as they were or were modified with Bu 3Sn(CH 2) 3OH or Bu 2Sn[(CH 2) 2(O(CH 2) 2) 2OMe] 2. The rate of hydrogenation of the terminal double bond is slightly modified by the presence of functional groups, while that of the internal unsaturation decreases by a factor of 4. These results are explained by the formation of a hydrophilic layer around the metallic particle which inhibits the adsorption of the unsaturated alcohol by its internal double bond.

New entry to alicyclic amines via alkylative fragmentation of cyclic aminoaldehyde tosylhydrazones

Tosylhydrazones of cyclic aminoaldehydes when exposed to aromatic and aliphatic Grignard reagents produce ring-opened acyclic unsaturated primary carbamates and carbamate alcohols in good yields.

A Three-Step-One-Pot Chemo-enzymatic Synthesis of Epoxyalkanolacylates

Using the ability of Novozym 435 ® to catalyze both the perhydrolysis and the interesterification of esters, unsaturated primary alcohols are converted with an ester and hydrogen peroxide to give esters of epoxidized alcohols directly in a convenient three-step-one-pot synthesis with yields of 66–89 %.

Gas-liquid chromatography-mass spectrometry of primary and secondary fatty alcohols and diols as their tert.-butyldimethylsilyl derivatives

The use of gas-liquid chromatography (GLC) and mass spectrometry (MS) with derivatizing agents which give stable derivatives and informative fragmentation patterns allows for accurate identification of a variety of compounds. In this comprehensive study, the tert.-butyldimethylsilyl ( tBDMS) derivatives of saturated and unsaturated primary alcohols, iso-and anteiso-primary alcohols, branched alcohols, secondary alcohols and primary diols were produced and analyzed by GLC-MS. Most derivatized alcohols produced prominent mass minus 57 [M-57] + fragment ions, which, combined with their respective retention data and other key fragment ions, allows for their identification and analysis.

Oxidation of Alcohols by Sodium Percarbonate Catalyzed by the Association of Potassium Dichromate and a Phase Transfer Agent

Abstract Catalytic amounts of both potassium dichromate and Adogen 464 are effective in promoting the oxidation by sodium percarbonate of various unsaturated primary and secondary alcohols to the corresponding carbonyl compounds at 80°C in 1,2-dichloroethane, the reaction of saturated alcohols being sluggish.

ChemInform Abstract: Diene, Alkyne, Alkene and Alkyl Complexes of Early Transition Metals: Structures and Synthetic Applications in Organic and Polymer Chemistry

An unprecedented series of highly reactive alkene-and diene-complexes of the early transition metals (Groups 3A–5A of the periodic system) have been isolated recently. Diene complexes of this sort (M Ti, Zr, Hf, Nb, Ta) prefer, besides the (η4-s-cis-diene)metal structure, either a novel bent η4-metallacyclo-3-pentene structure or the unique (η4-s-trans-diene)metal structure. In bis(diene)metal complexes of Nb and Ta the η4-s-cis-dienes assume an unusual exo-endo (supine-prone) geometry. The MC bonds in these diene-metal complexes generally exhibit highly polarized σ-bonding along with π-bonding character. The complexes therefore undergo a variety of regio- and stereoselective carbometalations with substrates containing CC, CO, or CN multiple bonds. Examples of the products that can be obtained include ketones, vinyl ketones, unsaturated primary, secondary, and tertiary alcohols, as well as diols and unsaturated acids. Mechanistic studies on the stoichiometric and catalytic conversions of unsaturated hydrocarbons provides, inter alia, some insights into the course of polymerization reactions.