Synthesis and transformations of 1,1,1-trifluoro-2-benzylthiopropene

Conclusions 1,1,1-Trifluoro-2-benzylthiopropene was synthesized and the reactions of this sulfide with electrophiles and nucleophiles (H₂SO₂, SO₂C₁₂ and NHEt₂) leading 1,1,1-trifluoroacetone, 1,1,1-trifluoro-2,3-dichloro-2-benzylthiopropane and 1-trifluoromethy1-2-(N,N-diethylamino)-ethyl benzyl sulfide, respectively, were studied.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 209–211, January, 1987.     

The Competitive dehydrohalogenation of 1,1,1-trifluoro-2-chloroethane in reflected shock waves

The thermal decomposition of 1,1,1-trifluoro-2-chloroethane has been investigated in the single-pulse shock tube between 1120° and 1300deg;K at total reflected shock pressures from ～2610 to 3350 torr. Under these conditions, the major reaction is the α,α-elimination of hydrogen chloride, with The decomposition also involves the slower α,β-elimination of hydrogen fluoride, with the first-order rate constant given by At temperatures above 1270°K, two additional minor products were observed. These were identified as CF₂CFCl and CF₃CHCl₂ and suggest C? Cl rupture as a third reaction channel leading to complicated kinetics.     

Light-induced reactions of 1,1,1-trifluoro-3-decyn-2-one with olefins

Irradiation ( λ = 300 nm) of 1,1,1-trifluoro-3-decyn-2-one in the presence of olefins affords RH-reduction products (tertiary alcohols) in addition to [2+2] -(oxetans) and [3+2] -(dihydrofurans) cycloadducts.     

Crystal and Molecular Structure of Nickel(II) trans-Bis-(1,1,1-trifluoro-4-iminopentan-2-onate)

A method of synthesis and the structure of the -iminoketonate complex of Ni(II) based on 1,1,1-trifluoro-4-iminopentan-2-one (CF₃–CO–CH₂–C(NH)–CH₃) are described.     

Structure of Two Crystal Modifications of Cu(II) trans-Bis-(1,1,1-trifluoro-4-iminopentan-2-onate)

Two crystal modifications of the volatile Cu(II) complex prepared from fluorinated -ketoimine (1,1,1-trifluoro-4-iminopentanon-2-one), CH₃(NH)CCH₂COCF₃, were studied by X-ray crystallography (CAD-4 Enraf-Nonius automatic diffractometer, MoK radiation, graphite monochromator). The phases have molecular structures consisting of trans complexes. In both cases, the square plane around the Cu atom is completed to a tetragonal bipyramid by the carbon atoms of the chelate rings of the neighboring complexes; the Cu...C distance equals 3.36-3.39 . For Cu–O and Cu–N distances, an anomalously large difference between the centrosymmetric and noncentrosymmetric complexes has been found.     

Efficient One-Pot Synthesis of 2-Chloro-1,1, 1-trifluoro-2-alkenes Under Solvent-Free Conditions

The improved one-pot Wittig reaction had been used to prepare trifluoromethyl-containing olefins under solvent-free conditions. Treatment of aldehydes with PPh₃ and CF₃CCl₃ in the presence of K₂CO₃ at 100 °C afforded 2-chloro-1,1,1-trifluoro-2-alkenes in good to moderate yields.     

Indium-mediated diastereoselective allylation of D- and L-glyceraldimines with 4-bromo-1,1,1-trifluoro-2-butene: highly stereoselective synthesis of 4,4,4-trifluoroisoleucines and 4,4,4-trifluorovaline

A practical and efficient route for the stereoselective synthesis of (2R,3S)- and (2S,3R)-4,4,4-trifluoroisoleucines and (2R,3S)-4,4,4-trifluorovaline was developed. Indium-mediated allylation of (R)-N-benzyl-2,3-O-isopropylideneglyceraldimine 7 with 4-bromo-1,1,1-trifluoro-2-butene 4 gave the desired homoallylic amine 8 in high diastereoselectivity (>95% de) with moderate yield. The Cbz-protected (2R,3S)-4,4,4-trifluoroisoleucine 14 and Boc-protected (2R,3S)-4,4,4-trifluorovaline 21 were then readily prepared from 8. In addition, following the same procedure, Cbz-protected (2S,3R)-4,4,4-trifluoroisoleucine 28, the enantiomer of 14, was prepared starting from (S)-N-benzyl-2,3-O-isopropylideneglyceraldimine 24.     

Synthesis Of CF3-Heterocycles Based on 4-Dimethylamino-1,1,1-trifluoro-3-buten-2-one

Novel heterocyclizations have been investigated based on the reaction of the complex between trifluoromethanesulfonic anhydride and 4-dimethylamino-1,1,1-trifluoro-3-buten-2-one with 2,2'-biindolyl and N,N'-dipyrrolylmethane leading to closure of 6- or 7-membered rings.     

Crystal structure of nickel(II) bis-(1,1,1,-trifluoro-5,5-dimethyl-2,4-hexanedionate)-1,3-diaminopropane

The structure of the complex of nickel(II) bis-(1,1,1-trifluoro-5,5-dimethyl-2,4-hexanedionate) with 1,3-diaminopropane is determined by single crystal X-ray diffraction at a temperature of 150 K. Crystallographic data for C₂₀H₃₄F₆N₂NiO₅: a = 17.5446(8) ?, b = 18.1171(10) ?, c = 18.6654(7) ?, β = 115.4150(10)°, space group C2/c, V = 5358.8(4) ?³, Z = 8, d _calc = 1.376 g/cm³, R = 0.0435. The structure is molecular; the metal atom coordinates four oxygen atoms of two β-diketonate ligands and two nitrogen atoms of propylenediamine. In the crystal, the molecules are bonded only by van der Vaals interactions.     

Synthesis and reactions of (E)-1,1,1-trifluoro-2-methyl-2-penten-4-ylidene-malonodinitrile

Condensation of (E)-1,1,1-trifluoro-2-methyl-2-penten-4-one with malonodinitrile affords mixtures of unsaturated nitriles. Attempted cyclization of these nitriles in concentrated sulfuric acid furnishes derivatives of alkylidenecyanoacetamides and alkylidenemalonodiamide.     

Highly sensitive laser fluorimetry of europium(III) with1,1,1-trifluoro-4-(2-thienyl)-2,4-butanedione

The detection limit for tris(1,1,1-trifluoro-4-(2-thienyl)-2,4-butanediono)-europium(III) is established as 2 pg l^-1. A highly sensitive fluorimetric system consisting of a nitrogen laser and a pulse-gated photon counter is used.     

Cyclocondensation reaction of 4-aryl-4-methoxy-1,1,1-trifluoro-3-buten-2-ones with urea: Synthesis of novel 6-aryl(5-methyl)-4-trifluoromethyl-2(1H)-pyrimidinones

The synthesis of a novel series of eleven 6-aryl(5-methyl)-4-trifluoromethyl-2(1H)-pyrimidinones, where aryl=Ph, 4-CH₃Ph, 4-FPh, 4-ClPh, 4-BrPh, 4-OCH₃Ph and alkyl=H, CH₃, from the reaction of 4-aryl-4-methoxy-1,1,1-trifluoro-3-buten-2-ones with urea in the presence of hydrochloric acid, is reported. Trifluoroacetylation of acetophenone- and propiophenone-dimethylacetals derived from phenones, was employed to obtain the precursors.     

Synthesis of 2-pyridones, pyrimidines, and pyrazoles from 1,1,1-trifluoro-4,4-bis(methylthio)but-3-en-2-one

Reactions of 1,1,1-trifluoro-4,4-bis(methylthio)but-3-en-2-one with cyanoacetamide, malonamide, acetoacetamide, amidines, hydrazines, and hydroxylamine gave a number of novel trifluoromethylated heterocyclic compounds containing the methylthio group.     

Cyclocondensation between fatty acid hydrazides and 1,1,1-trifluoro-4-alkoxy-3-alken-2-ones: Introducing a trifluoromethylated head onto fatty acid moieties

This paper reports the regioselective synthesis of new trifluoromethylated lipid derivatives, namely, 1-(5-hydroxy-5-trifluoromethyl-3-alkyl-4,5-dihydro-1H-pyrazol-1-yl)alkan-1-ones, through cyclocondensation reactions between a series of fatty hydrazides (palmitoyl, stearoyl, and oleoyl hydrazides) obtained from fatty acids from renewable resources (1,1,1-trifluoro-4-alkoxy-3-alken-2-ones [F₃CC(O)CH?C(R¹)OR, where R¹?=?H and R?Et; R¹?=?–(CH₂)₆CH₃, –(CH₂)₆CH₃, –(CH₂)₈CH₃, –(CH₂)₉CH₃, –(CH₂)₁₀CH₃, –(CH₂)₁₂CH₃, –(CH₂)₂Ph], and R?Me). Experimental observations showed that the lipophilic characteristic of 5-hydroxy-5-trifluoromethyl-4,5-dihydro-1H-pyrazoles (5–7) prevent the acid catalyzed dehydration to aromatization of 1H-pyrazole ring, although in some cyclocondensations a proportion of the aromatic derivative 1-(5-trifluoromethyl-3-alkyl-1H-pyrazol-1-yl)alkan-1-one was obtained. All products were characterized using multinuclear (¹H, ¹³C, ¹⁹F) NMR spectroscopy.     

The photochemical Wolff rearrangement of 3-diazo-1,1,1-trifluoro-2-oxopropane revisited

Ethyl 2-diazo-4,4,4-trifluoroacetoacetate (1a) and 3-diazo-1,1,1-trifluoro-2-oxopropane (1b) exhibit a deviating behavior in solution photolysis (hydrogen abstraction for 1a; Wolff rearrangement for 1b) [(a) F. Weygand, W. Schwenke and H. J. Bestmann, Angew. Chem., 1958, 70, 506; (b) F. Weygand, H. Dworschak, K. Koch and S. Konstas, Angew. Chem., 1961, 73, 409]. As shown by 13C-labelling of 1b this difference is not caused by rearrangement of the primarily formed alpha-oxocarbene to an isomeric alpha-oxocarbene presenting a hydrogen atom as a migrating substituent for the Wolff rearrangement. It is discussed that the singlet alpha-oxocarbene generated from 1a rapidly undergoes spin equilibration followed by hydrogen abstraction of the triplet alpha-oxocarbene. In contrast, due to a larger singlet-triplet splitting in the singlet alpha-oxocarbene generated from 1b, the intramolecular Wolff rearrangement on the singlet surface can efficiently compete with the singlet-triplet interconversion.     

Reactions of 1,1,1-trihalo-3-nitrobut-2-enes with enamines derived from cycloalkanones. Rearrangement of trifluoromethylated 1,2-oxazine N-oxide into 1-pyrroline N-oxides and stereochemistry of the products

1,2-Oxazine N-oxides derived from (E)-1,1,1-trifluoro-3-nitrobut-2-ene and cyclohexanone enamines underwent spontaneous rearrangement with ring contraction to give 1-pyrroline N-oxides. Reactions of (E)-1,1,1-trifluoro(trichloro)-3-nitrobut-2-enes with N-cyclopent-enylmorpholine resulted in a series of novel CX₃-containing nitroalkyl enamines and g-nitro ketones; the stereochemistry of the synthesized compounds were studied by NMR spectroscopy and X-ray diffraction.     

Crystal structure of platinum(II) chloro(1,1,1-trifluoro-4-imino-2-pentanononate(Hydrate)) [PtCl(ktf)H2O]

This paper reports on our study of the mixedligand βiminoketonate complex [PtCl(ktf)H₂O] including 1,1,1-trifluoro-4-imino-2-pentanone as a ligand. An X-ray diffraction analysis was performed on a CAD-4 diffractometer (MoK_α radiation, ω/2θ scan mode). Crystal data ofPtClF₃O₂NC₅H₇: a = 26.264(5), b = 4.750(1), c = 15.955(3) Å, β = 108.16(3)°, V = 1891.3ų, space group C2/c, Z = 8, d_calc = 2.82 g/cm³. The Pt atom has a distorted square planar environment. The Pt-Cl, Pt-O(H₂O), Pt-N, and Pt-O bonds are 2.29, 2.07, 1.97, and 1.98 Å in length, respectively. The chelate angle is 93.7°. The environment of Pt is completed to pyramidal due to interactions with the C_γ atom of the neighboring molecule at a distance of 3.57 Å. The compound has a molecular structure. The molecules of the complex are stacked along the Y direction.     

Rotational spectrum of 1,1,1-trifluoro-2-butanone using chirped-pulse Fourier transform microwave spectroscopy

The pure rotational spectra of 1,1,1-trifluoro-2-butanone and its four (13)C isotopologues have been studied using the new chirped-pulsed Fourier transform microwave spectrometer at the University of Manitoba in combination with a conventional Balle-Flygare-type instrument. Quantum chemical calculations, at the MP2/6-311++G(d,p) level, were carried out to obtain information about the structure, relative stability, and difference in populations of the three lowest energy conformers corresponding to dihedral angles of 0°, 82.8°, and 119.2° along the carbon backbone. The observed spectra are that of conformer I (dihedral angle 0°), and, based on analysis of the observed splitting, the V(3) barrier to internal rotation of the methyl group has been determined to be 9.380(5) kJ mol(-1). The spectroscopic constants of the five isotopologues were used to precisely derive the r(s) and partial r(0) geometries of this conformer based on an assumed planar carbon backbone (as supported by the spectra and ab initio calculations).     

氟烷麻醉剂中的毒性物质研究

1,1,1-三氟-2-溴-2-氯乙烷(4)(简称氟烷)是1956年问世的一个高效低毒内吸入麻醉剂,我国于六十年代初期开始生产并供临床使用。七十年代初,长海医院发现某批氟烷麻醉剂在临床使用时有明显毒性,要求对毒性物质进行鉴定。该麻醉剂是经下述工艺生产的:     

(N-Isocyanimino)triphenylphosphorane-Mediated,One-Pot,Efficient Synthesis of Sterically Congested 1,1,1-Trifluoro-2-(5-aryl-1,3,4-oxadiazol-2-yl)-2-propanol Derivatives via Intramolecular Aza-Wittig Reaction

Reactions of (N-isocyanimino)triphenylphosphorane with 1,1,1-trifluoroacetone in the presence of aromatic (or heteroaromatic) carboxylic acids (3-methylbenzoic acid, 1-naphthalenecarboxylic acid, 2-naphthalenecarboxylic acid, 2-furancarboxylic acid, and 2-thiophenecarboxylic acid) proceed smoothly at room temperature and in neutral conditions to afford sterically congested 1,1,1-trifluoro-2-(5-aryl-1,3,4-oxadiazol-2-yl)-2-propanol derivatives in high yields. The reaction proceeds smoothly and cleanly under mild conditions, and no side reactions were observed.

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