Stereospecific synthesis of some tertiary homoallyl monoterpene alcohols

Conclusions Metallation of 2,2-dimethylcyclopropyl bromide and subsequent reaction with C₅ aldehydes yielded the corresponding C₁₀ cyclopropylcarbinols whose acid-catalyzed rearrangement gave trans-homoallyl tertiary monoterpene alcohols with high regio- and stereospecificity.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2545–2548, November, 1982.     

Reaction of tertiary diacetylenic alcohols with amino alcohols

Conclusions It was shown that nitrogen-containing ethynyl vinyl ethers can be synthesized from tertiary diacetylenic alcohols and amino alcohols in the presence of alkaline catalysts.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2604–2605, November, 1970.     

Improved synthesis of tertiary alcohols from reactions of organoboranes with 2-lithio-1,3-benzodithioles

Treatment of trialkylboranes with 2-lithio-1,3-benzodithioles and then mercuric chloride (or methyl fluorosulhonate) followed by oxidation gives tertiary alcohols in high yields. The method is applicable to reactions of hindered organoboranes that fail using 1-lithio-1,1-bis(phenylthio)alkanes.     

Selective ion-molecule reactions of lactams with dimethyl ether ions

The ion-molecule reactions of dimethyl ether ions CH₃OCH₃ ⁺ and (CH₃OCH₃)H⁺, and four- to seven-membered ring lactams with methyl substituents in various positions were characterized by using a quadrupole ion trap mass spectrometer and a triple-quadrupole mass spectrometer. In both instruments, the lactams were protonated by dimethyl ether ions and formed various combinations of [M + 13] ⁺, [M + 15] ⁺, and [M + 45] ⁺ adduct ions, as well as unusual [M + 3] ⁺ and [M + 16] ⁺ adduct ions. An additional [M + 47] ⁺ adduct ion was formed in the conventional chemical ionization source of the triple-quadrupole mass spectrometer. The product ions were isolated and collisionally activated in the quadrupole ion trap to understand formation pathways, structures, and characteristic dissociation pathways. Sequential activation experiments were performed to elucidate fragment ion structures and stepwise dissociation sequences. Protonated lactams dissociate by loss of water, ammonia, or methylamine; ammonia and carbon monoxide; and water and ammonia or methylamine. The [M + 16] ⁺ products, which are identified as protonated lactone structures, are only formed by those lactams that do not have an N-methyl substituent. The ion-molecule reactions of dimethyl ether ions with lactams were compared with those of analogous amides and lactones.     

Statistical theory of exothermic ion-molecule reactions

A statistical theory is presented for ion-molecule reactions of the type A₂+A⁺ ₂A⁺ ₃+A, with allowance for conservation of the total energy and of the angular momentum of the composite system A⁺ ₄. The conservation of the momentum greatly reduces the phase volume of the initial reaction channel; the probability of decomposition in the forward direction is less than one even for exothermic reactions. A reaction of this type is considered for hydrogen, for which the statistical theory gives a qualitative explanation of the observed relation of reaction cross-section to vibrational quantum number for H⁺ ₂.     

Microscopic cross section for ion-molecule reactions with polar molecules

Using Kapitsa's method of separating rapidly varying processes from slower translational motions, a microscopic capture cross section for gas phase ion-molecule reactions is derived (centrifugal barrier approximation), leading to rate coefficients lying between the values of Langevin's theory and those of the locked dipole approximation (LD).

---

, , - ( ), , , , LD-.

     

Exchange reactions of urethanes with proton-donating compounds: Kinetics of the reactions of phenyl-<Emphasis Type="Italic">N</Emphasis>-phenylurethane with butyl alcohols

The exchange reactions of phenyl-N-phenylurethane with aliphatic alcohols, namely, n-butyl, sec-butyl, and tert-butyl alcohols, in ortho-dichlorobenzene and in the media of the corresponding alcohols were studied. In the absence of a catalyst and proton-donating compounds, the monomolecular cleavage of phenyl-N-phenylurethane to isocyanate and alcohol proceeds at a noticeable rate starting only at 250°C. Between 40 and 80°C, the exchange reactions take place via direct exchange between urethane and the photon-donating compound and are second-order up to high conversions (until the almost complete disappearance of the initial urethane). Activation energies and apparent rate constants have been determined for the exchange reactions of phenyl-N-phenylurethane with butyl alcohols. The rates of the exchange reactions in the alcohol medium are compared with those in ortho-dichlorobenzene.     

Gas-phase ion-molecule reactions using regioselectively generated radical cations to model oxidative damage and probe radical sites in peptides

Collision induced dissociation (CID) of sodiated peptide derivatives containing a nitrate ester functionality was used to regiospecifically generate three isomeric radicals of the model peptide Bz-Ala-Gly-OMe corresponding to radicals formed at: C(α) of the alanine residue [4+Na](+); C(α) of the glycine residue [5+Na](+); and the side chain of alanine [6+Na](+). The ion-molecule reactions of these peptide radicals were examined to model oxidative damage to peptides and to probe whether the radical sites maintain their integrity or whether they isomerise via intramolecular hydrogen atom transfer (HAT). Only [6+Na](+) is reactive towards O(2), forming the peroxyl radical [7+Na](+), which loses O(2), HO˙ and HO(2)˙ under CID. The radical ion [7 + Na](+) abstracts a hydrogen atom from 4-fluorothiophenol to form the hydroperoxide [8+Na](+), which upon CID fragments via the combined loss of HO˙ and CH(2)O. In contrast, all three of the isomeric sodiated radicals react with NO˙ and NO(2)˙ to form adducts. CID of the NO adducts only regenerates the radicals via NO˙ loss, thus providing no structural information. In contrast, CID of the NO(2) adducts gives rise to a range of product ions and the spectra are different for each of the three adducts, suggesting that the isomeric radicals [4+Na](+), [5+Na](+) and [6+Na](+) are produced as discrete species. Finally, CID of the NO(2) adducts was used to probe the rearrangement of the radicals [4+Na](+), [5+Na](+) and [6+Na](+) prior to their reaction with NO(2)˙: [6 + Na](+) rearranges to a mixture of [4+Na](+) and [5+Na](+) while [5+Na](+) rearranges to [4+Na](+).     

Ruthenium-catalyzed direct amination of alcohols with tertiary amines

A highly selective phosphine-based ruthenium catalyst system efficiently catalyzes the direct amination of alcohols with aliphatic tertiary amines, yielding unsymmetric tertiary amines in yields up to 87%. Ligand and solvent both affect the reaction yields significantly. The reaction can be performed with a wide variety of functionalities.     

The role of ion-molecule pairs in solvolysis reactions. Nucleophilic addition of water to a tertiary allylic carbocation.

The acid-catalyzed solvolysis of 2-methoxy-2-phenyl-3-butene (1-OMe) in 9.09 vol % acetonitrile in water provides 2-hydroxy-2-phenyl-3-butene (1-OH) as the predominant product under kinetic control along with the rearranged alcohol 1-hydroxy-3-phenyl-2-butene (2-OH) and a small amount of the rearranged ether 2-OMe. The more stable isomer 2-OH is the predominant product after long reaction time, K(eq) = [2-OH](eq)/[1-OH](eq) = 16. The ether 2-OMe reacts to give 2-OH and a trace of 1-OH. Solvolysis of 1-OMe in (18)O-labeled water/acetonitrile shows complete incorporation of (18)O in the product 1-OH, confirming that the reaction involves cleavage of the carbon-oxygen bond to the allylic carbon. A completely solvent-equilibrated allylic carbocation is not formed since the solvolysis of the corresponding chloride 1-chloro-3-phenyl-2-butene (2-Cl) yields a larger fraction of 1-OH. This may be attributed to a shielding effect from the chloride leaving group. Quantum chemical calculations of the geometry and charge distribution show that the cation should rather be described as a vinyl-substituted benzyl cation than as an allyl cation, which is in accord with its higher reactivity at the tertiary carbon.     

Reaction of tertiary cyanoacetylenic alcohols with hydrogen bromide

Conclusions The addition of HBr to tertiary cyanoacetylenic alcohols is accompanied by intramolecular cyclization, which leads to the hydrobromides of bromiminodihydrofurans.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1646–1647, July, 1983.     

Radical deoxygenation of tertiary alcohols

The thioformates of tertiary alcohols are smoothly reduced by tributyl tin hydride to the corresponding hydrocarbon in a radical chain reaction.     

Generation of alkoxide anions from a series of aliphatic diols and alcohols and their ion-molecule reactions with carbon dioxide in the gas phase

Alkoxide anions, [M-H](-) from a series of aliphatic diols and alcohols are generated in the source under negative ion electrospray ionisation conditions by cone-voltage fragmentation of the corresponding [M + F](-) ions. The collision-induced dissociation (CID) spectra of [M-H](-) ions consist of [M-H-2H](-) ions, in addition to the other characteristic fragment ions, and the relative abundance of [M-H-2H(-) ions among the series of diols varies as a function of chain length that could be explained based on their stabilities through intramolecular hydrogen bonding. The reactivity of alkoxide anions is studied through ion-molecule reactions with CO(2) in the collision cell of a triple quadrupole mass spectrometer. All the alkoxide anions reacted with CO(2) and formed corresponding carbonate anions, [M-H + CO(2)](-) ions. The reactivity of alkoxide anions within the series of diols also reflected the stability of their [M-H](-) ions.     

Acylation of steroid alcohols with 3-carboxypropanamido acids

Using N-(3-carboxypropanoyl)--phenyl--alanine as a model it has been established that when steroid alcohols are esterified with 3-carboxypropanamido acids, the carboxy group of the succinic acid residue takes part in the esterification reaction. In order to obtain a steroid ester of a 3-carboxypropanamido acid in which the carboxyl of the amino acid is the esterifying group, the carboxy group of the succinic acid residue must first be esterified.Khar'kov Scientific-Research Institute of Endocrinology and Hormone Chemistry. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 700–704, September–October, 1985.     

Acylation of steroid alcohols with 3-carboxypropanamido acids

Chemistry of Natural Compounds - Using N-(3-carboxypropanoyl)-β-phenyl-α-alanine as a model it has been established that when steroid alcohols are esterified with 3-carboxypropanamido...     

Thermal reactions of benzosilacyclobutenes with alcohols

In the thermal reaction with alcohols, benzosilacyclobutenes underwent both benzyl-silicon and aryl-silicon bond rupture to yield (dialkyl)alkoxy-$\text{o}$-tolylsilanes and (dialkyl)-alkoxybenzylsilanes, respectively.