818-92-8Relevant articles and documents
Displacement Dynamics of Fluorine Atoms Reacting with Allyl Bromide Molecules
Zhu, Z. Z.,Smith, D. J.,Grice, R.
, p. 4008 - 4011 (1994)
Reactive scattering of F atoms with C3H5Br molecules leading to Br atom displacement has been studied at an initial translational energy E ca. 40 kJ mol-1 using a supersonic beam of F atoms seed in He buffer gas.The center-of-mass angular distribution of C3H5F scattering shows a broad peak in the forward direction with roughly constant relative intensity ca. 0.4 in the backward hemisphere.The product translational energy distribution peaks at a low fraction f'pk ca. 0.1 of the total available energy with a tail extending up to higher energy.The reaction dinamics involve a stripping mechanism whereby the F atom adds to the C=C double bond, forming either the secondary fluorobromopropyl radical which dissociates directly to form allyl fluoride reaction product by bonding to the terminal CH2 group or the primary fluorobromopropyl radical which may dissociate by ring closure to form fluorocyclopropane reaction product by bonding to the intermediate CH group.The suggested occurence of two reaction pathways is inferred from the absence of H atom or CH2Br radical displacement pathways since the mass spectrometer detector does not distinguish between the proposed reaction products.
Conformational stability of 3-fiuoropropene in rare gas solutions from temperature-dependent FT-IR spectra and ab initio calculations
Van Der Veken
, p. 1976 - 1985 (1999)
The infrared spectra (3500-400 cm-1) of 3-fluoropropene (allyl fluoride), CH2=C(H)CH2F, dissolved in liquid argon, krypton, and xenon have been recorded at various temperatures ranging from -180 to -65 °C. From these studies, the enthalpy difference between the more stable cis conformer and the high-energy gauche rotamer has been determined to range from 60 ± 8 cm-1 (718 ±96 J/mol) in liquid xenon to 81 ±1 cm-1 (969 ±12 J/mol) in liquid argon. These values have been extrapolated utilizing a linear relationship between the Kirkwood function of the solvent and the enthalpy differences in the solvents to give a value of 130 ± 25 cm-1 (1.56 ±.30 kJ/mol) for the vapor. From the experimental enthalpy value, the gauche dihedral angle, torsional transitions for both retainers, and better structural parameters, the potential function governing the conformational interchange has been recalculated. Ab initio calculations utilizing the 6-31G(d,p) and 6-311G(d,p) basis sets with electron correlation at the MP2 level predict the cis conformer to be the more stable rotamer, but from the MP2/6-311 ++G(d,p) calculation the gauche conformer is predicted to be more stable by 117 cm-1 (1.40 kJ/mol). By combination of the ab initio predictions of the structural parameters with the previously reported microwave rotational constants for 11 different isotopic species of both conformers, complete ro parameters have been obtained for both rotamers. The results of these structural parameter determinations are compared to those previously reported.
Efficient protocol for the SO2F2-mediated deoxyfluorination of aliphatic alcohols
Epifanov, Maxim,Lai, Joey,Lee, Cayo,Sammis, Glenn M.,Wang, Cindy Xinyun
supporting information, (2021/09/28)
Alkyl fluorides are prevalent in both the pharmaceutical and agrochemical industries. As such, there has been significant interest over the past 40 years in the development of new synthetic methods to access these important fluorinated motifs. Herein we report the sulfuryl fluoride-mediated deoxyfluorination of alcohols using room temperature reaction conditions in only an hour. A wide range of primary aliphatic alcohols were efficiently converted to the corresponding fluoride in 46-70% isolated yields. Secondary alcohols were also effectively deoxyfluorinated in 50–92% yields. Chiral secondary alcohols were cleanly converted to the corresponding alkyl fluoride with only a minor deterioration of the enantioenrichment. A steroid derivative also underwent deoxyfluorination in 50% yield and 5.9:1 dr, with the major product resulting from net inversion of the stereocenter.
Targeting cyclic nucleotide phosphodiesterase 5 (PDE5) in brain: Toward the development of a PET radioligand labeled with fluorine-18
Wenzel, Barbara,Liu, Jianrong,Dukic-Stefanovic, Sladjana,Deuther-Conrad, Winnie,Teodoro, Rodrigo,Ludwig, Friedrich-Alexander,Chezal, Jean-Michel,Moreau, Emmanuel,Brust, Peter,Maisonial-Besset, Aurelie
, p. 346 - 362 (2019/02/14)
With the aim to develop a specific radioligand for imaging the cyclic nucleotide phosphodiesterase 5 (PDE5) in brain by positron emission tomography (PET), seven new fluorinated inhibitors (3–9) were synthesized on the basis of a quinoline core. The inhibitory activity for PDE5 together with a panel of other PDEs was determined in vitro and two derivatives were selected for IC50 value determination. The most promising compound 7 (IC50 = 5.92 nM for PDE5A), containing a 3-fluoroazetidine moiety, was further radiolabeled by aliphatic nucleophilic substitution of two different leaving groups (nosylate and tosylate) using [18F]fluoride. The use of the nosylate precursor and tetra-n-butyl ammonium [18F]fluoride ([18F]TBAF) in 3-methyl-3-pentanol combined with the addition of a small amount of water proved to be the best radiolabeling conditions achieving a RCY of 4.9 ± 1.5% in an automated procedure. Preliminary biological investigations in vitro and in vivo were performed to characterize this new PDE5 radioligand. Metabolism studies of [18F]7 in mice revealed a fast metabolic degradation with the formation of radiometabolites which have been detected in the brain.
PRODUCTION OF COMPOUNDS COMPRISING CF30 GROUPS
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Page/Page column 5, (2011/04/24)
The present invention relates to a process for the preparation of compounds containing CF3O groups using compounds containing at least one group Y, in which Y=—Hal, —OSO2(CF2)zF, —OSO2CzH2z+1 (z=1-10), —OSO2F, —OSO2Cl, —OC(O)CF3— or —OSO2Ar, to a process for the preparation of compounds containing CF3O groups using KOCF3 and/or RbOCF3, and to novel compounds containing CF3O groups, and to the use thereof.
Stereospecific rhenium catalyzed desulfurization of thiiranes
Jacob, Josemon,Espenson, James H.
, p. 1003 - 1004 (2007/10/03)
Methyltrioxorhenium catalyzes the efficient and stereospecific desulfurization of thiiranes by triphenylphosphine at room temperature, moreso when MTO has been pretreated with hydrogen sulfide, with a Re(v) species as the active form of the catalyst.
Catalytic deoxygenation of epoxides with (Cp*ReO)2(μ-O)2 and catalyst deactivation
Gable, Kevin P.,Zhuravlev, Fedor A.,Yokochi, Alexandre F.T.
, p. 799 - 800 (2007/10/03)
In situ reduction of Cp*ReO3 by PPh3 to form (Cp*ReO)2(μ-O)2 allows catalytic deoxygenation of epoxides, however, conproportionation between the ReV and ReVII species to form clusters of {(Cp*Re)3(μ-O)6}2+(ReO 4-)2 and new compound {(Cp*Re)3(μ2-O)3(μ 3-O)3ReO3}+(ReO4 -) leads to removal of rhenium from the catalytic cycle and loss of activity.
The carbonylation of allylic halides and prop-2-en-1-ol catalysed by triethylphosphine complexes of rhodium
Payne, Marc J.,Cole-Hamilton, David J.
, p. 3167 - 3175 (2007/10/03)
In ethanol, [RhX(CO)(PEt3)2] added directly or formed in situ from [Rh2(OAc)4]·2MeOH (OAc = O2CMe) and PEt3 or [Rh(OAc)(CO)(PEt3)2] catalysed the carbonylation of CH2=CHCH2X (X = Cl, Br or I) to ethyl but-3-enoate with CH2=CHCH2OEt as a side product. Small amounts of the isomerisation product, ethyl but-2-enoate were produced but no base was required for the reaction. The selectivity of the reaction is in the order Cl > Br > I and prop-2-en-1-ol can be successfully carbonylated to prop-2-enyl but-3-enoate by the same system using 3-chloroprop-1-ene as a promoter. 3-Fluoropropene was not carbonylated, but in the presence of H2 underwent hydroformylation to produce acetals. 3-Chlorobut-1-ene and 1-chlorobut-2-ene both produced ethyl pent-3-enoate and 3-ethoxybut-1-ene. In situ and ex situ NMR and IR spectroscopic studies have been used to show that the first step of the reaction is oxidative addition to give [Rh(CH2CH=CH2)Cl2(CO)(PEt3) 2] for which thermodynamic parameters have been obtained. Both 3-chlorobut-1-ene and 1-chlorobut-2-ene give [Rh(CH2CH=CHMe)Cl2-(CO)(PEt3)2] but with different E:Z ratios. The detailed mechanism of the oxidative addition is discussed. The CO inserts into the Rh-C bond to give [Rh(COCH2CH=CH2)Cl2(CO)(PEt3) 2], from which but-3-enoyl chloride reductively eliminates to react with ethanol to give the observed products. High-pressure IR and high-pressure NMR studies reveal that [RhX(CO)(PEt3)2] (X = Cl or Br) reacts with CO to give [RhX(CO)2(PEt3)2], which exists as two isomeric forms. The compound [Rh(OAc)(CO)(PEt3)2] catalyses the formation of prop-2-enyl ethanoate from 1-chloroprop-2-ene and sodium ethanoate. A mechanism is proposed.
Utilisation of ammonium and phosphonium perfluorocyclobutane ylides as fluoride anion source
Pasenok, Sergej V.,De Roos, Marijn E.,Appel, Wolfgang K.
, p. 9755 - 9758 (2007/10/03)
Ammonium- and phosphoniumperfluorocyclobutane glides 1 and 2, prepared from perfluorocyclobutene and tertiary amines or phosphines can be used as a masked fluoride anion source. These properties have been demonstrated in several reactions. Ylides 1 and 2 cleave C-Si or O-Si bonds, cause dimerisation of fluoroolefins or react with acid chlorides or activated aromatic compounds under halogen exchange.
New method of preparation of fluoro compounds via utilisation of ammonium and phosphonium perfluorocyclobutane ylides as fluorination reagents
Pasenok, Sergej V.,De Roos, Marijn E.,Appel, Wolfgang K.
, p. 2977 - 2982 (2007/10/03)
Ammonium- and phosphoniumperfluorocyclobutane ylides (7-11), easily prepared from perfluorocyclobutene (1) and tertiary amines (2-4) or phosphines (5,6), smoothly react with primary or secondary alcohols (12-18) and carboxylic acids (19, 20) with formation of alkyl fluorides (21-26) or acyl fluorides (27, 28), respectively. A mechanism for the reaction is proposed.
