Acetylenic Alcohols Research Articles

Structure‐Toxicity Relationships for α, β‐Unsaturated Alcohols in Fish

AbstractPrevious toxicity testing with fathead minnows (Pimephales promelas) indicated that some unsaturated acetylenic and allylic alcohols can be metabolically activated, via alcohol dehydrogenase, to highly toxic α, β‐unsaturated aldehydes and ketones or allene derivatives. Although several in vivo and in vitro toxicological and biochemical endpoints can differentiate these alcohols by toxic mechanism, the use of stereoelectronic molecular descriptors to discriminate these toxicants, and subsequently to predict potency, had not been previously attempted. Exploration of several descriptors indicated that soft electrophilic characteristics of acetylenic or allylic moieties in the suspected metabolites unambiguously discriminated reactive and narcotic toxicants. The acute toxicity of alcohols acting as narcotics was accurately predicted using an existing quantitative structure‐activity relationship for nonpolar narcosis. The toxicity of alcohols mediated by metabolic activation was estimated quantitatively using acceptor superdelocalizability of specific carbon atoms of the acetylenic or allylic moiety in the putative electrophilic intermediates.

Hydration of acetylenic compounds without using mercury

Copper(II), palladium(II) and silver(I), in conjunction with non-coordinating anion environments, have been found to catalyze the hydration of a variety of functionalized and nonfunctionalized alkynes. Suitable anions include trifluoromethane sulfonate, tetrafluoroborate, and sulfonate groups on perfluorinated ion-exchange resins. These catalyst systems are the first reported catalysts that are active for the hydration of acetylenic alcohols in high selectivity and do not contain mercury. The problems of dehydration and byproduct formation, observed when other catalysts are used with these alcohols, are minimized.

Direct Formation of Reactive Alkynyltrichlorotins from 1-Alkynes, SnCl4, and Bu3N. A Mild Alkynylation Reagent of Aldehydes, Acetals, and Enones

Abstract A reagent system of 1-alkyne, SnCl4, and Bu3N alkynylates aldehydes, acetals, and enones under mild reaction conditions giving acetylenic alcohols, acetylenic ethers, and acetylenic ketones, respectively, in high yields. Alkynyltrichlorotins are shown to be the reactive species for these reactions.

ChemInform Abstract: Inclusion by Acetylenic Alcohols and Some Other Novel Host Compounds

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.

The meyer‐schuster rearrangement and hydrohalide addition of 3‐alkynyl‐3‐hydroxy‐1H‐isoindol‐1‐ones

AbstractTreatment of N‐methyl and N‐phenylphthalimide with appropiate lithium acetylides in tetrahydrofuran obtained the acetylenic alcohols 2a through 2h. These compounds, when subjected to mildly acidic hydrolysis conditions in aqueous organic solvents, underwent Meyer‐Schuster rearrangement to yield the α,β‐unsaturated carbonyl compounds 4a through 4h which were determined to have the E configuration. The phenyl ethynyl analogs of series 4 underwent hydrohalide addition when treated with hydrogen halides in water solution.

An improved method for the introduction of carbon-carbon triple bond at C-13 in PG synthesis

An improved method for the introduction of carbon-carbon triple bond at C-13 in PG-synthesis is described. The efficient aldol reaction of aldehydes has been achieved by using α-chloro enolate anions derived from 1-bromo-1-chloro ketones, giving α-chloro enones after dehydration in good yields, the precursor of the acetylenic alcohols.

Preparation of polyfunctional allenic alcohols by the regioselective addition of functionalized propargylic chromium(III) organometallics to carbonyl compounds

The reaction of propargylic halides 1 (X=Cl, Br) with an aldehyde or ketone (0.67 equiv) in the presence of CrCl 2 (2 equiv) and LiI (2 equiv, necessary if X=Cl) affords allenic alcohols 3 with excellent reioselectivities (3-6% of the regioisomeric acetylenic alcohol 4 is formed) and in good yields (68-90%). Interestingly, this method allows the generation of highly functionalized intermediate propargylic chromium organometallics contains an ester, cyano, or chloride functionality

Intramolecular oxypalladation and cross-coupling of acetylenic alkoxides

Stereodefined 2-alkylidenetetrahydrofurans and pyrans were synthesized by treatment of alkyl or aryl acetylenic alcohols with n-BuLi in THF at 0 o C followed by addition of a solution of 10 mol % of Pd(OAc) 2 or PdCl 2 and PPh 3 in THF and 1 equiv of an organic halide

ChemInform Abstract: Hydratizing Trimerization of Acetylene in Superalkaline Media. Part 3. Vinylation of Acetylene Alcohols as an Intermediate State of this Process.

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.

Ellipsometric investigation of the adsorption of acetylenic alcohols on iron

The adsorption kinetics of nine alkynols and four other related compounds on iron in H 2SO 4 were examined by in situ time-resolved automatic ellipsometry. The time, concentration and potential dependences of the adsorption, the subsequent orientation transition and polymer growth of the adsorbed layers formed by these compounds were determined. A new method based upon the Lorentz-Lorenz equation is deduced for the calculation of surface packing density of an adsorbed organic compound with a certain orientation on an electrode surface from ellipsometric data. Using this method, useful correlation between the molecular structure and the saturated surface packing density is obtained. In addition, the polarizabilities of an organic compound with different orientations on the surface are also obtained.

Determination of the Absolute Configuration and Enantiomeric Purity of Allylic and Acetylenic Alcohols

Abstract The relative magnitude of steric bulk of saturated vs. unsaturated substituents in the title compounds has been estimated by a lanthanoid induced shift (LIS) study of these (R)-(+)-α-methoxy-α-(trifluoromethyl)phenylacetate esters [(R)-(+)-MTPA esters] by 1H NMR spectroscopy: CH2=C(Me)−>Pentyl>n−Pr>Et\simeqCH2=CH−>Me>CH≡C−;Ph>Cyclohexyl These results allow the assignment of the absolute configurations of both cyclic and acyclic unsaturated alcohols. Furthermore, the relative intensity of well-separated OMe signals for those diastereomeric MTPA esters can be used for the determination of the %ee of the original alcohols.

Inhibition of alcohol dehydrogenase activity by acetylenic and allylic alcohols: Concordance with in vivo electrophile reactivity in fish

Acetylenic and allylic alcohols have been reported to be 20 to 5,000 times more acutely toxic to fathead minnows (Pimephales promelas) than would be expected from a narcosis-based mechanism of action. The greater-than-expected toxicity of these alcohols has been proposed to be a result of metabolic activation to the corresponding reactive α,β-unsaturated aldehydes or allene derivatives. Using purified horse liver and rainbow trout (Oncorhynchus mykiss) hepatic cytosol alcohol dehydrogenase (ADH) preparations, the propensity of a series of acetylenic and allylic alcohols to inhibit enzyme activity, in both the presence and the absence of reduced glutathione, was ascertained. Those alcohols classified as reactive toxicants in acute toxicity tests were generally effective inhibitors of ADH activity, whereas those alcohols classified as narcotics were generally ineffective inhibitors. The results from this study suggest that (a) acetylenic and allylic alcohols may be metabolically activated to reactive species and (b) to compare and ultimately predict the toxicity of these unsaturated alcohols, their rates of metabolic activation and the reactivity of the subsequently produced aldehydes must be quantified.

The Mechanism of Corrosion Inhibition of Iron in Acid Solution by Acetylenic Alcohols

The mechanism of corrosion inhibition of iron by acetylenic alcohols in acid solutions was established by relating the interfacial structure obtained from spectroscopic measurements with the corrosion reaction kinetics obtained from electrochemical measurements. A modified adsorption interaction model was found to be applicable for describing the hydrogen evolution reaction on an inhibitor‐covered iron electrode. For the iron dissolution reaction, a parallel dissolution model was found to be applicable. The parallel dissolution model was further justified by constructing the two‐dimensional potential energy diagrams for iron dissolution on a free Fe surface and an inhibitor‐covered surface with the use of Morse functions. A comprehensive analysis of the mechanism of corrosion inhibition in general is given. It is suggested that formation of a compact three‐dimensional protective layer on the electrode surface is key for effective inhibition of corrosion.

Total synthesis of (+)-Leukotriene B 4 methyl ester and its 5-epimer from (R)-glycidol

The PdCu coupling reaction of a chiral hydroxy-(E,E)-iododiene with a racemic acetylenic alcohol followed by reduction of the dienyne leads to the desired (Z,E,E) geometry and allows synthesis of LTB 4 and its 5-epimer after separation of diastereomers.

ChemInform Abstract: Synthesis of Carbamates from Amine, Acetylenic Alcohol, and CO2 Using Lanthanoid as Catalyst.

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.

Conversion of Hydroxyl Groups in Alcohols to Other Functional Groups with N-Hydroxy-2-thiopyridone, and Its Application to Dialkylamines and Thiols

Abstract The radical decarboxylation reaction of N-alkoxyoxalyloxy-2-thiopyridone which was prepared by the reaction of alcohol, oxalyl chloride, and N-hydroxy-2-thiopyridone was studied both in the absence and presence of olefinic compounds. The same reactions with olefinic and acetylenic alcohols gave the corresponding lactone derivatives. On the other hand the unsymmetrical alkyl 2-pyridyl disulfides were obtained by the same reaction with aliphatic thiols.

New acetylenic alcohols from the sponge Cribrochalina vasculum

We have isolated five new acetylenic alcohols from a sponge Cribrochaline vasculum collected in Belize. These terminal mono acetylenic compounds are simpler in structure and differ from the previously reported polyacetylenic compounds from sponges belonging to genera Cribrochaline, Siphonochaline, Petrosia, and Xestospongia. We report here their isolation and structure determination

ChemInform Abstract: Allylsilanes in Organic Synthesis. Convenient Preparation of Synthetic Intermediates by Catalytic Hydrogenation of Acetylenic Alcohols.

ChemInform Abstract: Allylsilanes in Organic Synthesis. Convenient Preparation of Synthetic Intermediates by Catalytic Hydrogenation of Acetylenic Alcohols.

ChemInform Abstract: Ready Access to α‐(Triorganosilyl)methylene β‐Lactones by Means of Rhodium‐Catalyzed Cyclocarbonylation of Substituted Propargyl Alcohols.

AbstractThe carbonylation of an equimolar mixture of the acetylenic alcohols (I), (VI), and (VIII), a silane e.g. (II) or (IX), and a base in the presence of a catalytic amount of Ru4(CO)12 results in the formation of α‐(triorganylsilyl)methylene β‐, γ‐, and δ‐lactones (IV), (VII), and (X), respectively.

Effects of abscisic acid and its acetylenic alcohol on dormancy, root development and transpiration in three conifer species

Abscisic acid (ABA) and a synthetic analog, the 2‐cis acetylenic alcohol, were compared to evaluate their effectiveness in conditioning seedlings of Douglas‐fir [Pseudotsuga menziesii (Mirb.) Franco], Engelmann spruce (Picea engelmannii Parry) and lodgepole pine (Pinus contorta Dougl.). Following preconditioning with ABA and the analog, seedlings were water stressed with the osmoticum polyethylene glycol (PEG) 3350. The effects of the growth regulators on transpiration, net photosynthesis, their ratio, called water use efficiency, and cell water relations parameters were then compared in stressed and unstressed plants. The antitranspirant action of these compounds varied depending on the species, the growth regulator, and the level of stress. ABA promoted transpiration in unstressed seedlings for all 3 species seven days after application. The analog was superior to ABA as an antitranspirant in osmotically‐stressed lodgepole pine and Engelmann spruce, but neither compound was effective in Douglas‐fir. For Douglas‐fir and Engelmann spruce, net photosynthesis remained consistently higher in ABA‐treated plants during the two levels of osmotic stress, relative to control and analog treatments. Neither compound had any effect on root development or cell water relations. ABA, and to a lesser extent its analog, hastened terminal bud formation in seedlings exposed to short days and low temperatures.