Two-fragment α-adrenolytics. 4. Synthesis of phosphorylated derivatives of 2-aryloxyethylamines and N-phenylpiperazine

The reactions of 3-chloropropylphosphonates, 3-chloropropylthiophosphonates, or 3-chloropropylphosphinates with 2-aryloxyethylamines or N-phenylpiperazine afford the corresponding 3-(2-aryloxyethylamino)propylphosphonates and -phosphinates or 3-(4-phenylpiperazin-1-yl)propylphosphonates and -phosphinates. The compounds obtained exhibit -adrenolytic and hypotensive activities, the latter being found to depend on the substituents at the P atom.     

Reaction of aminoquinolines with unsaturated carboxylic acids. 2. Cyclization of N-quinolyl-β-alanines

The cyclization of N-(3-quinolyl)- and N-(6-quinolyl)--alanines was carried out to give uncondensed hexahydropyrimidine derivatives, while the cyclization of N-(5-quinolyl)- and N-(8-quinolyl)--alanines gave tetrahydrophenanthrolinone derivatives.Communication 1, see ref. [1].Kaunas Technological University, 3028 Kaunas, Lithuania, Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 653–657, May, 2000.     

2-Oxooxazolopyridines. 2. Synthesis of N′-alkyl-N-(2-oxo-3-pyridyl)ureas

In reactions with amines 2-oxo-7-trifluoromethyl-5-phenyl-(1H)-oxazolo[5,4-b]pyridines and alkyl N-(2-oxo-3-pyridyl)carbamates are converted into N-alkyl- and N,N-dialkyl-N-(2-oxo-3-pyridyl)ureas respectively.For Communication 1, see [1].Riga Technical University, Riga LV-1048, Latvia. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 385–391, March, 1998.     

Synthesis and properties of thiazole halohydrazones. 2. Interaction of 2-α-chlorobenzylidenehydrazino-4-ethoxy-carbonylthiazole with nucleophiles

In the interaction of 2--clzlorobenzylidenehydrazino-4-ethoxycarbonylthiazole with nucleophiles, two competing reactions take place. 1) nucleophilic replacement of the chlorine atom to form the corresponding substitution product; 2) elimination of a hydrogen chloride molecule, concluding in cyclization of the intermediate nitrilimine to form 3 phenyl-5-ethoxycarbonylthiazolo(2, 3-c]-1, 2, 4-triazole. The direction taken by the interaction depends on the nature of the nucleophile and is determined primarily by the ratio of basicity and nucleophilicity of the agent.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, 256–259, February, 1994. Original article submitted December 30, 1993.     

2-Benzopyrylium salts. 41. Intramolecular transformations of 4-1′-dimers of α-unsubstituted 2-benzopyrylium salts

Recyclization reactions of 4-1-dimers of 2-benzopyrylium salts leading to naphthalene derivatives are described. A new variant of the intramolecular Cannizzaro rearrangement has been discovered.For communication 40, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 175–180, February, 1991.     

Reactions of γ-Sultines with Electrophilic Reagents. 2. Bromination of 3,5-Diaryl-1,2-oxathiolane 2-Oxides in the Presence of Lewis Acids

The bromination of 3,5-diaryl-1,2-oxathiolane 2-oxides (-sultines) has been studied in the presence of added Lewis acids. It was discovered that -sultines with donor substituents react with bromine with ring fission and conjugated addition of the nucleophilic reactant. Possible mechanisms for the reaction are discussed based on the data obtained.     

Rearrangement of 1-oxa-2-azoles. 5. Synthesis and rearrangement of α-oximodimethyl-hydrazones of 1,2,4-oxadiazolyl-3-glyoxal

The acid halides of 1,2,4-oxadiazol-3-carbohydroxamic acids react with formaldehyde dimethylhydrazone to give the corresponding -oximohydrazones, which with hydrochloric acid rearrange to yield the dimethylhydrazone of 3-amino-4-formylfurazane. In the absence of an acid catalyst, the 5-trifluoromethyl derivative undergoes a rearrangement to give 1-dimethylamino-4-nitroso-3-trifluoroacetamidopyrazole.For Communication 4, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 976–978, July, 1991.     

Condensation reactions of α-lithio-imidazolines: Preparation and conjugate additions of 2-alkenyl-2-imidazolines.

Whereas 1-benzyl-2-lithiomethyl-2-imidazoline undergoes reversible 1,2-addition to aldehydes and ketones, a derived phosphonate salt affords the condensation products, 2-(1-alkenyl)-2-imidazolines; the latter undergo conjugate addition with carbon nucleophiles.     

Reaction of γ-Sultines with Electrophilic Reagents. 1. Bromination of 3,5-Diaryl-1,2-oxathiolane 2-Oxides

The effects of the nature of the aryl substituents and the reaction conditions on the bromination of 3,5-diaryl-1,2-oxathiolane 2-oxides (-sultines) have been studied. The possible mechanisms for the bromination of the -sultines are discussed on the basis of the experimental data.     

Reactions of γ-Sultines with Electrophilic Reagents. 3. Chlorination of 3,5-Diaryl-1,2-oxathiolane 2-Oxides

The influence of the nature of the aryl substituents and the reaction conditions for the chlorination of 3,5-diphenyl-1,2-oxathiolane 2-oxide and 3,5-bis(4-methoxyphenyl)-1,2-oxathiolane 2-oxide have been studied. Possible mechanisms for the chlorination of -sultines are discussed.     

Synthesis and stereochemistry of chiral azetidin-2-ones and azetidine-2-thiones. 3. Stereodirected construction of theβ-lactam fragment of the thienamycin molecule

It has been shown possible to introduce an -hydroxyethyl group trans-stereospecifically into position 3 of 4-methyl-1-(-methyl-benzl)azetidin-2-one. The stereochemistry of the asymmetric centers C₍₃₎, C₍₃₎, and C₍₄₎ of the diastereoisomers of the 3--hydroxyethyl derivative obtained in larger amount and of the corresponding three adjacent chiral centers C₍₈₎, C₍₆₎, and C₍₅₎ in thienamycin are the same.For part 2 see [1].M. V. Lomonosov Moscow State University, Moscow, 119899. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 254–257, February, 1995. Original article submitted December 14, 1994.     

Copolymers from α-Pinene. 2. Cationic Copolymerization of Styrene and α-Pinene

A study of the copolymerization of α-pinene and styrene has been carried out at 10°C using anhydrous AlCl₃ as the initiator. It is found that styrene forms copolymer with α-pinene at all mono-meric ratios. A copolymer of 2320–3080 molecular weight is obtained. The softening range of the copolymer is 82 to 85°C. The copolymers are of commercial value.     

Reductive cleavage of highly substituted Δ2-isoxazolines. Synthesis of crispatic acid

The preparation of highly substituted β-hydroxy carbonyl compounds from isoxazolines is featured in a synthesis of crispatic acid. A β-hydroxy imine, the proposed intermediate in this transformation, is isolated for the first time and a stereoselective hydroboration of a 5-vinyl substituted isoxazoline is also reported.     

Synthesis and reactions of metallocycles. 6. Stereoselective synthesis of 3,4-dialkyl-substituted aluminocyclopentanes by cyclometallation of α-olefins using trialkylalanes in the presence of Cp2ZrCl2

An efficient method has been developed for the synthesis of a new class of organoaluminum compounds, trans-3,4-dialkyl-substituted aluminocyclopentanes, via the cyclometallation of -olefins using R₃A1 in the presence of catalytic amounts of Cp₂ZrCl₂. Hydrolysis, deuterolysis, and oxidation of the resulting aluminocy-clopentanes generate the corresponding transformation products having exclusively the threo-configuration.For previous communication see [1].Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1141–1144, May, 1991.     

Pressure–temperature phase diagram of SeO2. Characterization of new phases

We have investigated SeO₂ at high pressures and high temperatures. Two new phases (β-SeO₂ and γ-SeO₂) and the boundary separating them have been found, following experimental runs performed at pressures up to 15 GPa and temperatures up to 820°C. The two phases crystallize in the orthorhombic system in space group Pmc2₁ (no. 26) with a=5.0722(1) Å, b=4.4704(1) Å, c=7.5309(2) Å, V=170.760(9) Å³ and Z=4 for the β-phase, and with a=5.0710(2) Å, b=4.4832(2) Å, c=14.9672(6) Å, V=340.27(3) Å³ and Z=8 for the γ-phase. Both phases are stable at ambient pressure and temperature below −30°C. At ambient temperature the phases return to the starting phase (α-SeO₂) in a few days. We discuss our findings in relation to a previous report of in-situ measurements at high pressures and ambient temperature.     

The enthalpy of solution of MgCl2 and MgCl2·6H2O in water at 25°C. I. The integral molar enthalpy of solution

The data for the relative apparent and integral molar enthalpy of solution, L and H _sol ⁱⁿ , respectively, were critically reviewed, for the magnesium chloride-water system at 25°C. The concentration dependence L(m) and the enthalpy of solution at infinite dilution H _sol ^o were determined calorimetrically at 25°C. Both results are in agreement with most of the small amount of data published previously. From the results of our measurements, and from the most reliable value for H _sol ^o of MgCl₂, the concentration dependence H _sol ⁱⁿ (m) at 25°C was derived, for MgCl₂·6H₂O. The enthalpy of the hydration

ChemInform Abstract: The B2.epsilon.+ ← X2.epsilon.+ Transition of HgI

ChemInform 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.     

Infrared spectroscopy and modeling of co-crystalline CO2·C2H2 aerosol particles. I. The formation and decomposition of co-crystalline CO2·C2H2 aerosol particles

Aerosol particles composed of co-crystalline CO(2)·C(2)H(2) were generated in a bath gas cooling cell at cryogenic temperatures and investigated with infrared spectroscopy between 600 and 4000 cm(-1). Similar to results obtained for thin films of the co-crystal [T. E. Gough and T. E. Rowat, J. Chem. Phys. 109, 6809 (1998)], this phase was found to be metastable and decomposed into pure CO(2) and pure C(2)H(2). These decomposed aerosols were characterized through (i) a comparison to experimentally prepared aerosols of mixed CO(2) and C(2)H(2) of known architectures and (ii) the modeling of infrared spectra. A likely architecture after decomposition are C(2)H(2)-CO(2) core-shell particles with a disk-like shape. The co-crystalline CO(2)·C(2)H(2) aerosols prior to decomposition are modeled and analyzed in detail in the subsequent paper (Part II).