Oxymercuration-demercuration of car-3-ene

The composition of the products of the oxymercuration-demercuration reaction of car-3-ene according to the degree of its transformation has been studied. It has been established that this reaction forms trans-caran-3-ol, -terpineol, m-menth-6-en-8-ol, 3,4-epoxy-trans-carane, p- and m-1, 8-cineoles, p- and m-1,8-terpins, and terpene esters. It has been shown that the double bond of car-3-ene possesses a higher reactivity than the cyclopropane ring, and the opening of the latter takes place equally at both external bonds.Institute of Physical Organic Chemistry of the Academy of Sciences of the Belorussian SSR, Minsk. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 646–650, September–October, 1979.     

Pyrolysis of homoadamant-3-ene

Pyrolysis of homoadamant-3-ene ($\text{5}$), generated from 1-adamantylcarbene ($\text{7}$), leads to the same three olefins ($\text{2}$, $\text{3}$, and $\text{4}$) that are produced from pyrolysis of 3-homoadamantyl acetate ($\text{1}$).     

Oxymercuration-demercuration of car-3-ene

The composition of the products of the oxymercuration-demercuration reaction of car-3-ene according to the degree of its transformation has been studied. It has been established that this reaction forms trans-caran-3-ol, α-terpineol, m-menth-6-en-8-ol, 3,4-epoxy-trans-carane, p- and m-1, 8-cineoles, p- and m-1,8-terpins, and terpene esters. It has been shown that the double bond of car-3-ene possesses a higher reactivity than the cyclopropane ring, and the opening of the latter takes place equally at both external bonds.     

Gas-phase rate coefficients for the reactions of nitrate radicals with (Z)-pent-2-ene, (E)-pent-2-ene, (Z)-hex-2-ene, (E)-hex-2-ene, (Z)-hex-3-ene, (E)-hex-3-ene and (E)-3-methylpent-2-ene at room temperature

Rate coefficients for reactions of nitrate radicals (NO3) with (Z)-pent-2-ene, (E)-pent-2-ene, (Z)-hex-2-ene, (E)-hex-2-ene, (Z)-hex-3-ene, (E)-hex-3-ene and (E)-3-methylpent-2-ene were determined to be (6.55 +/- 0.78)x 10(-13) cm3 molecule(-1) s(-1), (3.78 +/- 0.45)x 10(-13) cm3 molecule(-1) s(-1), (5.30 +/- 0.73)x 10(-13) cm(3) molecule(-1) s(-1), (3.83 +/- 0.47)x 10(-13) cm(3) molecule(-1) s(-1), (4.37 +/- 0.49)x 10(-13) cm(3) molecule(-1) s(-1), (3.61 +/- 0.40)x 10(-13) cm3 molecule(-1) s(-1) and (8.9 +/- 1.5)x 10(-12) cm3 molecule(-1) s(-1), respectively. We performed kinetic experiments at room temperature and atmospheric pressure using a relative-rate technique with GC-FID analysis. The experimental results demonstrate a surprisingly large cis-trans(Z-E) effect, particularly in the case of the pent-2-enes, where the ratio of rate coefficients is ca. 1.7. Rate coefficients are discussed in terms of electronic and steric influences, and our results give some insight into the effects of chain length and position of the double bond on the reaction of NO3 with unsaturated hydrocarbons. Atmospheric lifetimes were calculated with respect to important oxidants in the troposphere for the alkenes studied, and NO3-initiated oxidation is found to be the dominant degradation route for (Z)-pent-2-ene, (Z)-hex-3-ene and (E)-3-methylpent-2-ene.     

New highly strained bridgehead imines, 2-azaadamant-1-ene and 4-azaprotoadamant-3-ene

An azaanalog of adamantene, 2-azaadamant-1-ene ($\text{1}$) and 4-azaprotoadamant-3-ene ($\text{7}$) were generated in the nonstatistical ratio via photolysis of 3-azidonoradamantane ($\text{2}$). The highly strained $\text{1}$ and $\text{7}$ could not be isolable but were trapped by MeOH. Acidolysis of $\text{2}$ was also reported, and discussed in comparison with the photolysis.     

Derivatives of 3-thienylphosphonic acid and 1,2-oxaphosphol-3-ene

Alkylsulfenyl chlorides react with 5-methyl-1,3,4-hexatrienyl-3-phosphonic esters giving derivatives of 3-thienylphosphonic acid and 1,2-oxaphosphol-3-ene.     

Ruthenium complexes of 3-hydroxy-4-pyranones and of 3-hydroxy-4-pyridinones

Reactions of hydrated ruthenium chloride with 2-methyl-3-hydroxy-4-pyranone, ethylmaltol (etmaltH) and with 1,2-dimethyl-3-hydroxy-4-pyridinone (dmppH) are described. The former results in the formation of Ru(etmalt)₃, but the course of the latter depends on conditions, producing the earlier-characterised Ru(dmmp)₃Cl in ethanol–water solution, Ru(dmmp)₃ in aqueous solution under mild conditions, and Ru(dmpp)₂(H₂O)₂ after extended refluxing. EXAFS studies established ruthenium-oxygen distances in Ru(etmalt)₃ and in Ru(dmmp)₃ · 6H₂O. Solubilities of Ru(dmmp)₃ in methanol–water mixtures reveal greater solubility in methanol than in water, and indications of a modest solubility maximum, and thus synergic solvation, in methanol-rich mixtures.     

Synthesis of novel 5-hydroxy-3-alkoxy- and 5-hydroxy-3-alkylthioindole-2-carboxamides

The preparation of several novel 5-hydroxyindole-2-carboxamides is described. A 5-benzyloxyindole ester was elaborated to the 3-bromo, 3-hydroxy, and 3-alkoxy ester intermediates followed by conversion to the amide and debenzylation. A related 5-acetyloxy indole ester was converted to 3-sulfinyl and 3-alkylthio intermediates before simultaneous amidation and removal of the 5-hydroxy protecting group.     

A convenient stereoselective synthesis of 5-hydroxy-3-oxoesters and 3-hydroxy-5-oxoesters

A biocatalytic approach was employed for the asymmetric reduction of sterically demanding ketones to prepare 3-hydroxy-5-oxo-5-phenylpentanoates and 5-hydroxy-3-oxo-5-phenylpentanoates. Screening a collection of microorganisms led to the identification of stereocomplementary microbial strains that provide access to both enantiomers of 3-hydroxy-5-oxo-5-phenylpentanoates and 5-hydroxy-3-oxo-5-phenylpentanoates with high enantiomeric excess (up to 99% ee). Moreover, the application of Saccharomyces cerevisiae gave two diastereomers of 3,5-dihydroxy-5-phenylpentanoates with high enantiomeric excess (up to 99% ee). The applicability of the identified strains was demonstrated by transforming the obtained dihydroxy ester into the chemically valuable lactone (4S,6R)-tetrahydro-4-hydroxy-6-phenyl-pyran-2-one.     

3-羟基-2-吡啶亚胺异构反应的机理

在RHF-6-31G,MP2/6-31G和MP2/6-31G水平上,对3-羟基-2-吡啶亚胺的气相、水分子作为催化剂的异构化反应进行了研究,结果表明,气象异构难于进行,水分子作为催化剂参与反应过程是目标反应所循的反应路径。