Synthesis of the diastereomeric 2-aryl-1-cyclohexyl-3-(2,3-epoxypropionyl)aziridines

The reaction of cinnamoyloxiranes with an iodine-cyclohexylamine complex in the presence of an excess of amine led to a mixture of the four diastereomeric epoxypropionylaziridines the ratio of which depended on steric and electronic factors in the substrate and reactants.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 456–459, April, 1986.     

Transformation of trans-4-aryl-3-chloro-1-(2-chloroethyl)azetidin-2-ones into 3-aryl-2-(ethylamino)propan-1-ols via intermediate 1-(1-aryl-2-chloro-3-hydroxypropyl)aziridines and trans-2-aryl-3-(hydroxymethyl)aziridines

trans-4-Aryl-3-chloro-1-(2-chloroethyl)azetidin-2-ones, prepared through cyclocondensation of chloroketene and the appropriate imines in a diastereoselective way, were unexpectedly transformed into 3-aryl-2-(ethylamino)propan-1-ols using LiAlH(4) in THF under reflux. A stepwise analysis showed that the initially formed 1-(1-aryl-2-chloro-3-hydroxypropyl)aziridines were converted into trans-2-aryl-3-(hydroxymethyl)aziridines, most probably via N-spiro bis-aziridinium intermediates, which were subsequently prone to undergo ring opening by LiAlH(4) to afford 3-aryl-2-(ethylamino)propan-1-ols.     

The interaction of cis and trans-1-cyclohexyl-2-phenyl-3-benzoylaziridine with lithium N-Methylanilide

A reaction pathway for the rearrangement-dehydrogenation of cis-1-cyclohexyl-2-phenyl-3-benzoylaziridine into 2-cyclohexylamino-3-phenylindenone can now be suggested. Furthermore, a competing degradation pathway involving C? C bond scission accounts for the major product in these reactions and leads to ω-cyclohexylaminoacetophenone and benzaldehyde. Observed also is the fact that trans-1-cyclohexyl-2-phenyl-3-benzoylaziridine fails to undergo the rearrangement-dehydrogenation reaction.     

Aziridinyl ketones. XVIII. The rearrangement-dehydrogenation of cis-1-cyclohexyl-2-phenyl-3-aroylaziridines

The sequential nature of the unique rearrangement-dehydrogenation of cis-1-alkyl-2-aryl-3-aroylaziridines ( 1a-d ) into 2-alkylamino-3-arylindenones ( 2a-d ) when treated with a lithium amide has been established. Furthermore, a competitive degradation pathway has been discovered which leads to ω-aminoacetophenones and benzaldehyde, thereby accounting for the major product of this reaction. trans-1-Alkyl-2-aryl-3-aroylaziridines do not react with the lithium amides employed in these studies. Although 1-cyclohexyl-2-methyl-3-benzoylaziridine reacts with lithium amide to produce a 3-carbanion, neither a rearrangement-dehydrogenation to a 2-aminoindenone nor a more extensive degradation involving carbon-carbon bond cleavage is observed. Mechanistic pathways for these base catalyzed reactions are discussed.     

Crystal and molecular structures of cis-1-phenyl-3-piperidinocyclohexan-1-ol hydrochloride

Mr = 295.84, triclinic, Pl, a = 6.786(1), b = 7.658(1), c = 8.561(1) Å, α = 108.17(1), β = 97.94(1), γ = 103.32(2)°, V = 400.6 ų, Z = 1,D_m = 1.23, D_x = 1.226 Mgm^?3, δ(Cu Kα) = 1.5418 Å, μ = 20.81 cm^?1, F(000) = 160. The structure has been solved by direct and Fourier methods and refined by a least-squares procedure to the final R = 0.043 for 1182 observed reflections (|F_o] >3σ(F_o)). cis-1-Phenyl-3-piperidinocyclohexan-1-ol possessing 1,3-diaxial positions between the piperidine and hydroxyl groups is converted to the isomer with 1,3-diequatorial positions in its hydrochloride. The hydrogen bond is formed between the chloride anion and the protonated nitrogen atom of piperidine instead of the intramolecular hydrogen bond in the free cis-base between the oxygen and nitrogen atoms.     

Mass spectra of cis- and trans-4-alkyl-3-phenyl-3,4-dihydrocoumarins

An analysis of the mass-spectrometric behavior of cis- and trans-4-alkyl-3-phenyl-3,4-dihydrocoumarins makes it possible to distinguish each of the isomers when the mass spectra of the two compounds are simultaneously present.Translated, from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 24–26, January, 1982.     

顺式和反式-2-氨基-3-氰基-4-苯基-1-(4'-甲基苯基)-2-环戊烯-1-醇的合成和晶体结构

用低价钛试剂(TiCl4-Zn)与4, 4-二氰基-3-苯基-1-(4'-甲基苯基)-1-丁酮反应合成了顺式和反式-2-氨基-3-氰基-4-苯基-1-(4'-甲基苯基)-2-环戊烯-1-醇, 并用X射线衍射分析确定了这两个异构体的构型。     

The SO2(3B1) photosensitized isomerization of cis- and trans-1,2-difluoroethylene

Quantum yield measurements for the SO₂(³B₁) photosensitized isomerization of cis-1,2-difluoroethylene have been made at 3712 Å and 22°C. The [SO₂]/[cis-C₂F₂H₂] ratio was varied from 47.4 to 455 and the quantum yield measurements over this variation of concentration ratios were consistent with a mechanism in which SO₂(³B₁) molecules and the cis isomer form a collision intermediate which decomposes with a probability of 0.42 ± 0.17 and 0.58 ± 0.17 of producing trans- and cis-1,2-difluoroethylene, respectively. When SO₂ was subjected to prolonged irradiations in the presence of initially either pure cis- or pure trans-1,2-difluoroethylene, a photostationary composition, [cis]/[trans] = 1.0 ± 0.2, was obtained. The rate constant at 22°C for removal of SO₂(³B₁) molecules by cis-1,2-difluoroethylene was estimated to be (1.72 ± 0.72) × 10¹⁰ 1./mole · sec.     

Resolution and conformational analysis of diastereoisomeric esters of cis- and trans-2-(aminomethyl)-1-carboxycyclopropanes

(1R,2S)-, (1S,2R)-, (1R,2R)- and (1S,2S)-2-(Aminomethyl)-1-carboxycyclopropanes, conformationally restricted analogues of the neurotransmitter γ-aminobutyric acid (GABA), have been resolved by chromatographic separation of the corresponding diastereoisomeric esters which were formed between the cis- and trans-2-(acetamidomethyl)-1-carboxycyclopropanes with (R)-(−)-pantolactone. ¹H NMR, semi-empirical conformational analysis, ab initio (DFT) structure and NMR shielding tensor calculations of the cis-diastereoisomers allowed the absolute configuration assignments of the cis-amino acids.     

The SO2(3B1) photosensitized isomerization of cis- and trans-1,2-dichloroethylene

The photolysis of SO₂ at 3712 Å in the presence of the 1,2-dichloroethylenes has been investigated at 22deg;C. The data are consistent with the SO₂(³B₁) photosensitized isomerization of the 1,2-dichloroethylene isomer. A kinetic treatment of the initial quantum yield data was consistent with the formation of a polarized charge-transfer intermediate whenever SO₂(³B₁) molecules and one of the 1,2-dichloroethylene isomers collide which ultimately decays unimolecularly to the cis-isomer with a probability of 0.70 ± 0.26 and to the trans-isomer with a 0.37 ± 0.16 probability. Quenching rate constants for removal of SO₂(³B₁) molecules by cis- and trans-1,2-dichloroethylene have been estimated from quantum yield data and from laser excited phosphorescence lifetimes using an excitation wavelength of 3130 Å. Estimates of the quenching rate constant (units of 1./mole ± sec) are for the cis-isomer, (1.63 ± 0.71) × 10¹⁰, quantum yield data, and (2.44 ± 0.11) × 10¹⁰, lifetime data; and for the trans-isomer,(2.59 ± 0.09)×10¹⁰, lifetime data, and (2.35 ±0.89) × 10¹⁰, quantum yield data. An experimentally determined photostationary composition,[cis-C₂Cl₂H₂]/[trans-C₂Cl₂H₂] = 1.8 - 0.1, was in good agreement with a value of 2.00 - 1.15 which was predicted from rate constants derived in this study.     

Synthesis and structure assignments of cis- and trans-2-(diethylaminomethyl)cyclohexanols

The synthesis of cis- and trans-2-(diethylaminomethyl)-cyclohexanols and their structural assignments by NMR using the shift reagent Eu(dpm)₃ are described. The correlation of the induced shifts with the equation Δν = K(3 cos²θ – 1)r^?3, assuming an Eu? O distance of 2·4 Å and θ less than 30°, suggests that the interactions are pseudocontact. The values of K are 452 and 420 for the two cyclohexanols, respectively.     

Prototropic isomerization of trans-4-benzamido-3-hydroxy-2-(4-carbomethoxybutylidene)thiophan to cis- and trans-4-benza mido-3-oxo-2-(4-carbomethoxybutyl) thiophan

trans-4-Benzamido-3-hydroxy-2-(4-carbomethoxybutylidene)thiophan (I) was prototropically isomerized in the presence of hydrogen chloride. It is shown that the two possible isomers cis- and trans-4-benzamido-3-oxo-2-(4-carbomethoxybutyl)thiophan — are formed in the process.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No, 2, pp. 175–177, February, 1973.