- REACTION OF PERFLUOROTRIMETHYLAMINE WITH ANTIMONY PENTAFLUORIDE. SYNTHESIS AND X-RAY STRUCTURE OF A PERFLUORINATED HEXAHYDRO-TRIAZINEDIONE DERIVATIVE
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Perfluorotrimethylamine and SbF5 at an elevated temperature slowly eliminate CF4 to form the cation (III). (III) is also obtained from the reaction of CF3NCF2 with SbF5 in nearly quantitative yield.The hexahydrotriazinedione (IV) has been obtained by hydrolysis of (III).The constitution and structure of (IV) are established by X-ray crystallography.
- Buerger, H.,Koeplin, R.,Pawelke, G.,Krueger, C.
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- Arrhenius Parameters for the Reaction of Trifluoromethyl Radicals with Cyanogen Chloride
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The reaction of CF3 radicals with ClCN has been studied over a wide temperature range, 268-693 K, using CF3 radicals generated by the photolysis of CH3I.Over the range 408-473 K, CF3COCF3 was also used as a CF3 radical source.The radicals react with ClCN by addition followed by decomposition of the adduct and by chlorine abstraction: .The Arrhenius plot for this reaction is strongly curved.Using data from the low- and high-temperature regions, the following expressions for the rate constants for addition reaction (1) and chlorine abstraction (3) relative to CF3 recombination have been obtained: .The combination of E1 with the difference E-1-E2, which can be estimated, gives an upper limit for ΔH03 from which an approximate value of ΔH0f(CN) of 393.4 kJ mol-1 or less has been obtained.
- Cosa, Fernando,Oexler, Elena V.,Staricco, Eduardo H.
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Read Online
- Reactions of aromatic methyl ketimines with halonitriles as a new route to pyrimidines with two polyhaloalkyl groups
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N-Isopropyl-(1-phenylethylidene)amine reacts with trichloroacetonitrile to give 1-azabutadiene derivative, which undergoes a double addition reaction with a variety of halonitriles affording fluoro- and chloro-containing pyrimidines. Pyrimidines with two polyhaloalkyl groups were obtained by the reaction of methyl ketimines with an excess of trichloroacetonitrile, trifluoroacetonitrile and 2,2,3,3-tetrafluoropropionitrile.
- Sosnovskikh, Vyacheslav Ya,Usachev, Boris I,R?schenthaler, Gerd-Volker
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Read Online
- F-Ethylamine and F-Ethylimine
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The new compounds F-ethylamine, C2F5NH2, and F-ethylimine, CF3CF=NH, are readily prepared by the reaction of N,N-dichloro-F-ethylamine with trimethylsilane at -45 or -25 deg C, respectively.Both compounds are subject to dehydrofluorination.Thus, CF3CF=NH may be obtained by the loss of a single HF molecule from CF3CF2NH2 at -25 deg C.CF3CF2NH2 will react with SF4 to form CF3CF2N=SF2.Similarly, CF3CF=NH forms CF3CF=NCl with ClF in the presence of CsF.
- Kumar, Ramesh C.,Shreeve, Jean'ne M.
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- A Convenient Preparation of Trifluoroacetonitrile: Application to the Synthesis of a Novel Pyrimidinone Building Block
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The generation of trifluoroacetonitrile (1) under mild conditions and controlled rates from easily accessible starting materials is described. Dehydration of trifluoroacetamide (2) with trifluoroacetic anhydride in pyridine generates trifluoroacetonitrile at ambient temperatures. As the trifluoroacetonitrile is formed, it distills out of the pyridine reaction mixture and is bubbled into a primary reaction vessel. The rate at which the gas is formed is controlled by the rate of addition of the reactants. The practicality of this method is exemplified via the synthesis of multigram quantities of a novel pyrimidinone building block 3.
- Parker, Marshall H.
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Read Online
- Synthesis and characterization of perfluorinated nitriles and the corresponding sodium 5-perfluoroalkyltetrazolate salts
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The high-yield syntheses of trifluoroacetonitrile (1a), pentafluoropropionitrile (1b) and heptafluorobutyronitrile (1c) under mild reaction conditions using readily available starting materials (trifluoroacetamide, pentafluoropropionamide, heptafluorobutanamide) are described. Furthermore, the reactions of the perfluoroalkyl nitriles with sodium azide in acetonitrile forming sodium 5-trifluoromethyltetrazolate (2a), sodium 5-pentafluoroethyltetrazolate (2b) and sodium 5-heptafluoropropyltetrazolate (2c) were undertaken. The 5-perfluoroalkyltetrazolate salts were characterized using vibrational (Raman and infrared) and multinuclear (13C, 14/15N, 19F) NMR spectroscopy, differential scanning calorimetry, mass spectrometry and elemental analysis. Additionally, the single crystal X-ray structure of the monohydrate of 2a was determined. Crystal data: 2a·H2O: monoclinic, C2/m, a = 18.8588(6) A?, b = 7.1857(2) A?, c = 9.3731(3) A?, β = 102.938(3)°, V = 1237.94(7) A?3, Z = 8, Dcalc = 1.911 g cm-3.
- Crawford, Margaret-J.,Klap?tke, Thomas M.,Radies, Hendrik
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- KINETICS OF THE HYDROGEN ABSTRACTION FROM HYDROGEN CYANIDE BY TRIFLUOROMETHYL RADICALS.
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The reaction of CF//3 radicals with HCN in the gas phase has been studied in the temperature range 573-673 K using CF//3 radicals generated by thermal decomposition of CF//3I. Arrhenius parameters. Rate parameters are compared with those for reactions of CF//3 with polar and non-polar substrates.
- Lane,Oexler,Staricco
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Read Online
- 2,2,2-Trifluoroacetaldehyde O-(Aryl)oxime: A Precursor of Trifluoroacetonitrile
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The preparation of 2,2,2-trifluoroacetaldehyde O-(aryl)oxime, a previously inaccessible precursor of trifluoroacetonitrile, via reaction of hydroxylamine and trifluoroacetaldehyde hydrate is reported. This precursor released CF3CN in quantitative yield under mildly basic conditions. The precursor was successfully used in the synthesis of trifluoromethylated oxadiazoles. The facile, cost-effective, scalable, and recyclable procedure makes these trifluoroacetonitrile precursors generally applicable.
- Lin, Bo,Yao, Yunfei,Huang, Yangjie,Weng, Zhiqiang
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supporting information
p. 2055 - 2058
(2022/03/31)
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- Preparation method of trifluoroacetamidine
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The invention discloses a preparation method of trifluoroacetamidine, and belongs to the technical field of organic synthesis. Trifluoroacetamide is used as a raw material, gas-state trifluoroacetonitrile is collected through reflux and water diversion under the action of a catalyst, then trifluoroacetonitrile is introduced into DBU/liquid ammonia for a reaction, a polymerization inhibitor is added, distillation is performed, and trifluoroacetamidine is obtained. The method is coherent in reaction steps, simple and convenient to operate and high in yield; three wastes are reduced, the catalyst can be repeatedly utilized for more than 10 times in the dehydration process, the content of the obtained product is more than 99%, and the method has a potential industrial amplification prospect.
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Paragraph 0023-0031
(2021/04/17)
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- Process for fluorinating inorganic or organic compounds by direct fluorination
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The invention relates to the use of a fluorinated gas, wherein the elemental fluorine (F2) is present at a high concentration, the present invention relates to a process for producing fluorinated compounds by direct fluorination using a fluorination gas in which elemental fluorine (F2) is present at a high concentration, such as a concentration of elemental fluorine (F2), in particular equal to much higher than 15 vol% or even 20 vol% (i.e., at least 15 vol% or even 20 vol%), and to a process for producing fluorinated compounds by direct fluorination using a fluorination gas. The process of the present invention relates to the manufacture of fluorinated compounds other than fluorinated benzene by direct fluorination, in particular to the preparation of fluorinated organic compounds, end products and intermediates for use in agricultural, pharmaceutical, electronic, catalyst, solvent and other functional chemical applications. The fluorination process of the invention can be carried outin batches or in a continuous manner. If the process of the invention is carried out in batches, a column (tower) reactor may be used. If the process of the invention is continuous, a microreactor may be used.
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Paragraph 0259-0260; 0265-0274
(2020/07/14)
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- A METHOD FOR THE PREPARATION OF FLUOROALKYL NITRILES AND THEIR USE TO PREPARE RELATED FLUOROALKYL TETRAZOLES
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The present invention relates to a method for the preparation of fluoroalkyl nitrile of Formula I and their use to prepare related fluoroalkyl tetrazole of Formula II in the presence of the dehydrating agent, wherein, x1 and x2 have the same meaning as defined in the description. The present invention also relates to an apparatus for the preparation of fluoroalkyl nitrile of Formula I and fluoroalkyl tetrazole of Formula II.
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Page/Page column 10-11
(2020/03/29)
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- Method for preparing perfluorinated nitrile through gas phase catalysis
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The invention discloses a method for preparing perfluorinated nitrile through gas phase catalysis. The method comprises the following steps: a, in the absence of a catalyst, enabling acyl fluoride R1COF or perfluor substituted ethylene oxide Cyclo-CF2-CR2R3-O- to perform a gas phase amination reaction with an ammonia gas or a primary amine compound, to obtain amide of which a general formula is R1CONH2 or CR2R3FCONH2, wherein general formulas of R1, R2 and R3 are CnF[2n+1], CxF[2x+1], and CyF[2y+1], wherein x and y are non-negative integer sets, x+y=n, and n is a positive integer set; and b, in the presence of the catalyst, dehydrating the amide R1CONH2, to obtain the perfluorinated nitrile R1CN. The method is short in reaction route, and the perfluor substituted ethylene oxide or the acylfluoride is easily obtained. A total yield of the perfluorinated nitrile is high, and the route is easy for continuous industrialization.
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Paragraph 0083; 0084
(2019/02/21)
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- METHOD FOR PREPARING FLUOROALKYLNITRILES AND THE CORRESPONDING FLUOROALKYLTETRAZOLES
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The present invention relates to a method for preparing fluoroalkylnitriles and the corresponding fluoroalkyltetrazoles by reacting fluorinated carboxamides with phosphorus trichloride (PCl3) or phosphorus oxychloride (POCl3) in the presence of a base.
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Paragraph 0039; 0040; 0041; 0042
(2019/08/02)
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- MACROCYCLIC COMPOUNDS AS PROTEASOME INHIBITORS
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The compounds of the present invention are represented by the following compounds having Formula I and Formula (I'): where the substituents R1, R2, R2', R3, R4, R5, R', R", X, Y, and Z are as defined herein and where the substituents R1, R2, R3, R4, R5, R', R", X, Y, and Z are as defined herein. These compounds are used in the treatment of bacterial infections, parasite infections, fungal infections, cancer, immunologic disorders, autoimmune disorders, neurodegenerative diseases and disorders, inflammatory disorders, or muscular dystrophy or for providing immunosuppression for transplanted organs or tissues.
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Paragraph 0428
(2019/05/02)
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- PROCESS FOR THE PREPARATION OF FLUOROALKYLNITRILES AND THE CORRESPONDING FLUOROALKYLTETRAZOLES
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The present invention relates to a process for the preparation of fluoroalkylnitriles and the corresponding fluoroalkyltetrazoles starting from fluorinated carboxamides.
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Paragraph 0062-0070
(2020/01/02)
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- A NOVEL PROCESS FOR THE PREPARATION OF ANTHRANILIC DIAMIDES
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The present invention relates to a novel process for the preparation of a compound of formula (II) and anthranilic diamides of formula (I) therefrom: wherein, R1a, R1b, R2, R3, R4, A, m, n, p, Q, and T are as defined in the description.
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(2019/12/15)
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- METHOD FOR PRODUCING FLUOROALKYL NITRILE
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PROBLEM TO BE SOLVED: To provide a method for producing fluoroalkyl nitrile that makes it possible to obtain fluoroalkyl nitrile in high yields, in a conveniently and safe manner. SOLUTION: The present invention provides a method for producing a compound represented by the general formula (IV). The method includes reacting at least one compound selected from the group consisting of compounds represented by the general formulae (I)-(III) with a fluorinating agent in solvent. [In the general formulae (I)-(III), R1 is a branched or linear fluoroalkyl group with a carbon number of n+1. In the general formula (IV), R2 is a branched or linear fluoroalkyl group with a carbon number of n. n is an integer to meet 1≤n≤19]. SELECTED DRAWING: None COPYRIGHT: (C)2019,JPOandINPIT
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Paragraph 0033; 0034
(2019/04/03)
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- Design, Synthesis and Evaluation of Oxazaborine Inhibitors of the NLRP3 Inflammasome
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The NLRP3 inflammasome is an important regulator of the sterile inflammatory response, and its activation by host-derived sterile molecules leads to the intracellular activation of caspase-1, processing of the pro-inflammatory cytokines interleukin-1β (IL-1β)/IL-18, and pyroptotic cell death. Inappropriate activation of NLRP3 drives a chronic inflammatory response and is implicated in several non-communicable diseases, including gout, atherosclerosis, type II diabetes and Alzheimer's disease. In this study, we report the design, synthesis and biological evaluation of novel boron compounds (NBCs) as NLRP3 inflammasome inhibitors. Structure–activity relationships (SAR) show that 4-fluoro substituents on the phenyl rings retain NLRP3 inhibitory activity, whereas more steric and lipophilic substituents diminish activity. Loss of inhibitory activity is also observed if the CCl3 group on the oxazaborine ring is replaced by a CF3 group. These findings provide additional understanding of the NBC series and will aid in the development of these NLRP3 inhibitors as tool compounds or therapeutic candidates for sterile inflammatory diseases.
- Baldwin, Alex G.,Tapia, Victor S.,Swanton, Tessa,White, Claire S.,Beswick, James A.,Brough, David,Freeman, Sally
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p. 312 - 320
(2018/02/09)
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- METHOD FOR PRODUCING OXADIAZOLE DERIVATIVE SUBSTITUTED WITH AMINO GROUP
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PROBLEM TO BE SOLVED: To provide an intermediate and a production method of an oxadiazole derivative substituted with an amino group, the derivative having NPY Y5 receptor antagonism. SOLUTION: Provided is an intermediate which is a salt of a compound represented by formula (I) and one basic compound selected from a substituted or unsubstituted imidazole, substituted triazole, substituted pyrazole, substituted pyrrole, substituted or unsubstituted bezimidazole, substituted benzotriazole, and substituted benzopyrazole. Also provided is a method for producing an oxadiazole derivative substituted with an amino group, comprising reacting the salt with a halogenating agent or a base, if desired, in the presence of a basic compound which forms the salt, the derivative having NPY Y5 receptor antagonism. SELECTED DRAWING: None COPYRIGHT: (C)2018,JPOandINPIT
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Paragraph 0038
(2018/06/15)
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- Drug synthesis intermediates for the preparation method of the (by machine translation)
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The invention relates to the synthesis intermediate for the preparation method. In particular, the invention relates to a preparation under mild conditions the following formula 2 compound of preparation method, the states the equation below 2 of the cycloalkene compound 1 in the preparation of the compounds of use is necessary, the states the equation below 1 compound is used for the synthesis of inhibiting DPP - IV of the therapeutic agent for diabetes of the intermediate, the final high yield and purity of the formula 1 compound. Wherein R1, R2, R3, R4, R5 and P1 such as defined in the specification. (by machine translation)
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Paragraph 0085-0087
(2018/11/22)
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- COMPLEXES FOR NUCLEOPHILIC, RADICAL, AND ELECTROPHILIC POLYFLUOROALKYLATION
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Disclosed herein are borazine complexes and use of the same in perfluoroalkylation reactions.
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Paragraph 00135
(2018/04/11)
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- Stereoselective synthesis of oxazolidinonyl-fused piperidines of interest as selective muscarinic (M1) receptor agonists: A novel M1 allosteric modulator
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Syntheses of (1RS,2SR,6SR)-2-alkoxymethyl-, 2-hetaryl-, and 2-(hetarylmethyl)-7-arylmethyl-4,7-diaza-9-oxabicyclo[4.3.0]nonan-8-ones, of interest as potential muscarinic M1 receptor agonists, are described. A key step in the synthesis of (1RS,2SR,6SR)-7-benzyl-6-cyclobutyl-2-methoxymethyl-4,7-diaza-9-oxabicyclo[4.3.0]nonan-8-one, was the addition of isopropenylmagnesium bromide to 2-benzyloxycarbonylamino-3-tert-butyldimethylsilyloxy-2-cyclobutylpropanal. This gave the 4-tert-butyldimethylsilyloxymethyl-4-cyclobutyl-5-isopropenyloxazolidinone with the 5-isopropenyl and 4-tert-butyldimethylsilyloxymethyl groups cis-disposed about the five-membered ring by chelation controlled addition and in situ cyclisation. This reaction was useful for a range of organometallic reagents. The hydroboration-oxidation of (4SR,5RS)-3-benzyl-4-(tert-butyldimethylsilyloxymethyl)-4-cyclobutyl-5-(1-methoxyprop-2-en-2-yl)-1,3-oxazolidin-2-one gave (4SR,5RS)-3-benzyl-4-(tert-butyldimethylsilyloxymethyl)-4-cyclobutyl-5-[(SR)-1-hydroxy-3-methoxyprop-2-yl]-1,3-oxazolidin-2-one stereoselectively. 4,7-Diaza-9-oxabicyclo[4.3.0]nonan-8-ones with substituents at C2 that could facilitate C2 deprotonation were unstable with respect to oxazolidinone ring-opening and this restricted both the synthetic approach and choice of 2-heteroaryl substituent. The bicyclic system with a 2-furyl substituent at C2 was therefore identified as an important target. The addition of 1-lithio-1-(2-furyl)ethene to 2-benzyloxycarbonylamino-3-tert-butyldimethylsilyloxy-2-cyclobutylpropanal gave (4SR,5RS)-4-tert-butyldimethylsilyloxymethyl-4-cyclobutyl-5-[1-(2-furyl)ethenyl]-1,3-oxazolidinone after chelation controlled addition and in situ cyclisation. Following oxazolidinone N-benzylation, hydroboration at 35 °C, since hydroboration at 0 °C was unexpectedly selective for the undesired isomer, followed by oxidation gave a mixture of side-chain epimeric alcohols that were separated after SEM-protection and selective desilylation. Conversion of the neopentylic alcohols into the corresponding primary amines by reductive amination, was followed by N-nosylation, removal of the SEM-groups and cyclisation using a Mitsunobu reaction. Denosylation then gave the 2-furyloxazolidinonyl-fused piperidines, the (1RS,2SR,6SR)-epimer showing an allosteric agonistic effect on M1 receptors. Further studies resulted in the synthesis of other 2-substituted 4,7-diaza-9-oxabicyclo[4.3.0]nonan-8-ones and an analogous tetrahydropyran.
- Broadley, Kenneth J.,Buffat, Maxime G. P.,Burnell, Erica,Davies, Robin H.,Moreau, Xavier,Snee, Stephen,Thomas, Eric J.
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p. 2057 - 2089
(2016/02/18)
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- Process For Preparing Fluoroalkyl Nitriles
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The present invention relates to a process for preparing fluoroalkyl nitriles by reacting fluorinated carboxamides with halides and fluorinated carboxylic acids.
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Page/Page column 3
(2010/12/29)
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- Asymmetric induction in thia-Diels-Alder reactions of chiral polyfluoroalkylthionocarboxylates
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A series of chiral S- or O-alkyl thionoesters have been synthesized by treatment of trifluorothioacetyl- or 2,2,3,3-tetrafluorothiopropionyl chloride with corresponding thiols or alcohols. The thia-Diels-Alder reaction of the thionoesters with symmetrical 1,3-dienes proceeds with diastereoselectivity up to 60%. Structures of cycloaddition products and corresponding transition states have been studied at the DFT level of approximation. The experimentally observed diastereomeric excess has been referred to differences in activation energies of transition states, preceding formation of the diastereomeric cycloaducts.
- Timoshenko, Vadim M.,Siry, Sergiy A.,Rozhenko, Alexander B.,Shermolovich, Yuriy G.
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experimental part
p. 172 - 183
(2010/04/30)
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- GASEOUS DIELECTRICS WITH LOW GLOBAL WARMING POTENTIALS
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A dielectric gaseous compound which exhibits the following properties: a boiling point in the range between about ?20° C. to about ?273° C.; non-ozone depleting; a GWP less than about 22,200; chemical stability, as measured by a negative standard enthalpy of formation (dHf0); a toxicity level such that when the dielectric gas leaks, the effective diluted concentration does not exceed its PEL; and a dielectric strength greater than air.
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- Synthesis and antifungal activity of β mrifluoroalkyl aminovinyl ketone derivatives
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Ten β-trifluoroalkyl aminovinyl ketone derivatives were synthesized, and their inhibitory effects on several phytopathogenic fungi, an oomycete and plants were assessed. The various compounds were fungitoxic at the 10-100 μM range, with (Z)-3-amino-4,4,4-trifluoro-1-(4-chlorophenyl)but-2-en1-one exhibiting the highest inhibitory effect on most of the test pathogens. Alternarla alternata and Neurospora crassa were the most tolerant and sensitive fungi to the compounds, respectively. We propose that (Z)-3-amino-4,4,4- trifluoro-1-phenylbut-2-en-1-one is the minimal structural requirement for a β-trifluoroalkyl aminovinyl ketone fungitoxic derivative. 2009 American Chemical Society.
- Gellerman, Gary,Pariente, Natali,Zahi, Paz,Shnaiderman, Anat,Yarden, Oded
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experimental part
p. 8303 - 8307
(2010/07/15)
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- Microwave accelerated aza-claisen rearrangement
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A study of microwave-induced and standard thermal Overman rearrangement of selected allylic trichloroacetimidates 1a-1f, 6-8 to the corresponding acetamides 2a-2f, 9-11 is reported. The microwave-assisted rearrangement of trifluoroacetimidate 13 is also described. Using this methodology, an efficient access to versatile allylic trihaloacetamides building synthons was established.
- Gajdosikova, Eva,Martinkova, Miroslava,Gonda, Jozef,Conka, Patrik
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experimental part
p. 2837 - 2847
(2009/04/05)
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- NOVEL PHARMACEUTICALS
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The present invention relates to immune response modifiers of formula (I), which act selectively through agonism, of Toll-Like Receptors (TLRs), uses thereof, processes for the preparation thereof, intermediates used in the preparation thereof and compositions containing said inhibitors. These inhibitors have utility in a variety of therapeutic areas including the treatment of infectious disease such as Hepatitis (e.g. HCV, HBV), genetically related viral infection and cancer.
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Page/Page column 71-72
(2010/11/28)
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- Aza-Wittig reaction of fluoroalkylated N-vinylic phosphazenes with carbonyl compounds. Usefulness of 2-azadienes for the preparation of fluoroalkyl pyridine derivatives
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A method for the preparation of 3-fluoroalkyl substituted 2-aza-butadienes 6 by aza-Wittig reaction of 3-fluoroalkyl-N-vinylic phosphazenes 4 and aldehydes 5 is reported. [4+2] Cycloaddition reaction of these heterodienes 6 with enamines 9 gives fluoroalkyl substituted pyridine 15, 16, 24-27 and isoquinoline 12-14, 20 derivatives.
- Palacios, Francisco,Alonso, Concepción,Rubiales, Gloria,Villegas, Maite
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p. 2779 - 2794
(2007/10/03)
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- Reactions of 1,3,3-trimethyl-3,4-dihydroisoquinolines with polyhaloalkanonitriles
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The reactions of 1,3,3-trimethyl-3,4-dihydroisoquinolines with halogenated nitriles afford β-aminovinylimines, which undergo acid hydrolysis to form 1-(polyhaloacylmethylene)-3,3-dimethyl-3,4-dihydroisoquinolines.
- Sosnovskikh,Usachev,Shklyaev
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p. 1248 - 1252
(2007/10/03)
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- Preparation and characterization of bicyclic amide acetals and monothioacetals
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We have prepared and characterized new examples of 5-substituted-1-aza-4,6- dioxabicyclo[3.3.0]octanes (bicyclic amide acetals) and examples of the new heterocyclic system, 5-substituted-1-aza-4-oxa-6-thiabicyclo[3.3.0]octanes (bicyclic amide monothioacetals). Detailed analysis of NMR coupling constants and X-ray structure determination for an example of each class of compound established the stereochemistry and conformation of these ring systems.
- Guthrie, J. Peter,Gallant, Roger T.,Jennings, Michael C.
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p. 268 - 278
(2007/10/03)
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- Toward the assignment of liposidomycin stereochemistry: Synthesis of 1,4-diazepan-3-one analogues by reductive amination approach
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Toward the assignment of liposidomycin stereochemistry, a stereocontrolled synthesis of the liposidomycin diazepanone ring system and two precursors, has been achieved. The NMR coupling constants of a 5-phenyl model compound closely related to the liposidomycin diazepanone degradation product.
- Nakajima, Noriyuki,Isobe, Takahiro,Irisa, Shiro,Ubukata, Makoto
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p. 107 - 113
(2007/10/03)
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- Activated dimethyl sulfoxide dehydration of amide and its application to one-pot preparation of benzyl-type perfluoroimidates
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Various types of primary amides were treated under an activated dimethyl sulfoxide (DMSO) species, (COCl)2-DMSO and Et3N, as a dehydrating agent to obtain nitriles in excellent yield. This dehydration system was extended to a one-pot preparation of perfluoroimidates via volatile perfluoronitriles from perfluoroamides. Fifteen benzyl-type perfluoroimidates can be prepared in 70-90% yield as more stable imidates than the trichloro analogue. MPM- and DMPM-perfluoroimidates can be used to protect alcohols in place of the trichloroacetimidate with excellent chemical properties and in comparable yields.
- Nakajima, Noriyuki,Saito, Miho,Ubukata, Makoto
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p. 3561 - 3577
(2007/10/03)
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- Allyl, epoxy and glycosyl perfluoroimidates. One-pot preparation and reaction
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The one-pot preparation of allyl, epoxy and glycosyl perfluoroimidates and their reaction are described. Volatile perfluoronitriles were generated from perfluoroamides with an 'activated' dimethyl sulfoxide (DMSO) species at -78°C. Allyl, epoxy and glycosyl perfluoroimidates were prepared in 44-92% yield following in situ nucleophilic addition of alcohol and sugar derivatives to nitriles. The obtained trifluoroacetimidates were more stable than the trichloro analogue and were easily purified by SiO2 column chromatography and/or distillation. The 3,3-sigmatropic rearrangement of allylic analogues, acid-catalyzed cyclization of the epoxy analogues and glycosylation of sugar analogues were studied comparing with their corresponding trichloroacetimidates. The trifluoroacetimidates were considerably less reactive than trichloroacetimidates due to their electron-withdrawing substituents on the imidate carbon.
- Nakajima, Noriyuki,Saito, Miho,Kudo, Masabumi,Ubukata, Makoto
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p. 3579 - 3588
(2007/10/03)
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- Stereoselective synthesis of allylic amines by rearrangement of allylic trifluoroacetimidates: Stereoselective synthesis of polyoxamic acid and derivatives of other α-amino acids
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On heating in xylene under reflux, allylic trifluoroacetimidates undergo [3,3] sigmatropic rearrangement to regioisomeric allylic trifluoroacetamides. Examples include the rearrangements of the trifluoroacetimidates 16 and 73 to the trifluoroacetamides 17 and 74, which were incorporated into stereoselective syntheses of polyoxamic acid 1, and the rearrangement of the trifluoroacetimidate 26. The rearrangement was the key step in asymmetric syntheses of the (S)- and (R)-valine derivatives 37 and 48. Other examples include rearrangements of the trifluoroacetimidates 52, 54 and 56 prepared from geraniol, cinnamyl alcohol and sorbyl alcohol, respectively, and the more complex trifluoroacetimidates 62 and 69. The stereoselectivity of these rearrangements, which are somewhat faster than rearrangements of analogous allylic trichloroacetimidates, is consistent with the participation of chair-like, six-membered, transition structures. The Royal Society of Chemistry 1999.
- Savage, Ian,Thomas, Eric J.,Wilson, Peter D.
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p. 3291 - 3303
(2007/10/03)
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- Stereoselective synthesis of thymine polyoxin C using an allylic trifluoroacetimidate-trifluoroacetamide rearrangement
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A stereoselective synthesis of thymine polyoxin C 3 is described in which the key step is the [3,3] sigmatropic rearrangement of the trifluoroacetimidate 12 to the trifluoroacetamide 13. Exchange of the protecting groups followed by ozonolysis and further oxidation then gave the methyl ester 20 which was converted into thymine polyoxin C 3 by introduction of the pyrimidine followed by final deprotection. The Royal Society of Chemistry 1999.
- Chen, Anqi,Thomas, Eric J.,Wilson, Peter D.
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p. 3305 - 3310
(2007/10/03)
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- Combined experimental and theoretical study of the protonation of polyfluorobenzenes [C6H(6-n)F(n)] (n = 0-6)
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In a recent high-pressure mass spectrometric revision to the gas-phase basicity scale (J. E. Szulejko and T. B. McMahon, J. Am. Chem. Sec. 115, 7839 (1993)), it was observed that the proton affinity for hexafluorobenzene was 24 kcal mol-1 (1 kcal = 4.184 kJ) lower than the accepted National Institute of Science and Technology (NIST) database value of 177.7 kcal mol-1 (S. G. Lias et al., J. Phys. Chem. Ref. Data 17, Suppl. 1 (1988)). Furthermore, the proton affinities for most other polyfluorobenzenes were also found to differ substantially from the NIST values. For many of the polyfluorobenzenes large protonation entropy changes were noted, which were substantially greater than then those expected from rotational symmetry number changes alone. In view of these observations, MP2/6-31G**/HF/6-31G** ab initio calculations were undertaken to investigate further the proton affinity and entropy changes with respect to the degree of fluorine substitution. The present proton affinity variations found for the polyfluorobenzenes (hexaflorobenzene excepted) can be interpreted with the aid of the ab initio results in terms of a simple additivity scheme. Each fluorine substituent para, meta, ortho or ipso to the ring protonation site will induce an incremental proton affinity change with respect to benzene of 1.5, -7.0, -1.5 and -19.0 kcal mol-1, respectively. This additivity scheme can also be used to rationalize the re-evaluated proton affinities for the polymethylbenzenes and m- and o-fluorotoluenes. The corresponding methyl increments are 7.5, 5.5, 2.5 and 1.0 kcal mol-l for para, meta, ortho and ipso protonation respectively. From the present ab initio statistical thermodynamic analysis of the various protonation entropy components, it was concluded that the low frequency vibrations are almost exclusively responsible for the large excess entropy changes observed experimentally. Ab initio calculated barriers for 1,2 proton shifts in arenium species available in the literature are concluded to be too large to allow the existence of a so-called dynamic proton. Large excess protonation entropies are noted from the literature for polymethylbenzenes, naphthalene and 1-methylnaphthalene.
- Szulejko,Hrusak,McMahon
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p. 494 - 506
(2007/10/03)
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- Preparation of fluorinated imides
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A direct method for the preparation of trifluoroacetimides has been extended to the preparation of trifluoroacetyl trifluoracetimide and the new compound trifluoromethylsulfuryl trifluoroacetimide. Points concerning previously reported syntheses of trifluoroacetyl isocyanate have also been clarified.
- Ye,Noftle
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p. 193 - 196
(2007/10/03)
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- 114. Aza-claisen rearrangement: Synthesis of 5'-branched 5'- aminothymidines
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The syntheses of both diastereoisomers of 5'-ethyl-substituted thymidine dimers, the (5'R)- and (5'S)-configurated 33a and 33b, respectively, in which the natural phosphodiester linkage is replaced by an amide group (C(3')- CH2CONH-CH(5')(Et)), are described. Their fully protected derivatives 35a and 35b, respectively, are suitable for incorporation into antisense oligonucleotides. Unexpectedly, an attempted Pd(II)-catalysed aza-Claisen rearrangement of trichloroacetimidate 7 provided the diastereoisomerically pure cyclopropane derivative 17, whose structure was confirmed by X-ray analysis.
- Ammenn, Jochen,Altmann, Karl-Heinz,Bellus, Daniel
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p. 1589 - 1606
(2007/10/03)
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- Microwave Spectra, Hyperfine Splittings and Average Structures of 3,3,3-Trifluoropropyne, CF3CCH and Trifluoroacetonitrile, CF3CN
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The J = 1 -- 0 and J = 2 -- 1 microwave transitions of eight isotopomers of CF3CCH and six isotopomers of CF3CN have been investigated under high resolution using a pulsed-nozzle Fourier-transform spectrometer.High-precition isotopic measurements including the previously unobserved species (13)CF3CCH have enabled a complete calculation of the zero-point average structure of CF3CCH: r(C-C) = 1.201 (1) Angstroem ; r(C-C) = 1.474(5) Angstroem; r(C-H) = 1.051 (2) Angstroem; angle FCF = 108.3(2) deg; r(C-F) = 1.337 (2) Angstroem.For CF3CCD deuterium quadrupole hyperfine structure was resolved and measured at the J = 1 --0 transition, giving eqQ(D) = 201.9(5.2)kHz.The zero-point average structure of CF3CN has also been calculated from the high-resolution isotopic data after the necessary vibrational corrections: r(CN) = 1.154 (1) Angstroem; r(C-C) = 1.492 (5) Angstroem; angle FCF = 109.2 (2) deg; r(C-F) = 1.328 (2) Angstroem.Measurements at the J = 1 -- 0 transition give an improved value for the nitrogen quadrupole coupling constant, eQq((14)N) = -4.666 (4) MHz, in CF3CN.
- Cox, A. Peter,Ellis, Mark C.,Legon, A. C.,Wallwork, Andrew
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p. 2937 - 2944
(2007/10/02)
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- UNSATURATED NITROGEN COMPOUNDS CONTAINING FLUORINE. PART 8. THE REACTION OF 2,5-DICHLORO-1,1,1,6,6,6-HEXAFLUORO-3,4-DIAZAHEXA-2,4-DIENE WITH TRIETHYLAMINE AND RELATED REACTIONS
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Exposure of a mixture of the title azine (1) and triethylamine (1:2 molar ratio) to daylight gives as major products, triethylamine hydrochloride and the Δ2-azetine (3), together with trifluoroacetonitrile and tar; a single electron transfer (SET) mechanism is proposed involving the intermediacy of the enamine Et2NCH=CH2.In contrast the reaction of azine (1) with tri-n-propylamine in light affords the amine hydrochloride, the substituted azine CF3CCl=N-N=C(NPrn2)CF3 (14) and tar.Treatment of the heterocycle (3) with diethylamine results in replacement of Cl by NEt2 to give the azetine (6) which is also formed when the azine CF3CCl=N-N=C(NEt2)CF3 (7) is heated with triethylamine.
- Benomar, Salim M.,O'Reilly, Neil J.,Tipping, Anthony E.
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p. 207 - 216
(2007/10/02)
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- Push-Pull Carbenes: Methoxytrifluoromethylcarbene
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Despite the possibility of 'push-pull' carbene stabilization by substituents of opposing electronic properties, absolute rate studies show methoxytrifluoromethylcarbene to be highly reactive and electronically indiscriminant in its reactions with alkenes.
- Moss, Robert A.,Zdrojewski, Tadeusz,Ho, Guo-Jie
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p. 946 - 947
(2007/10/02)
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- OXADIAZOLES WITH NF2-CONTAINING SUBSTITUENTS
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Oxalyl chloride was reacted with sodium-5-(difluoroamino)-difluoromethyltetrazolate or sodium-5-pentafluoroethyltetrazolate to form f = NF2CF2 (7)>, and with F2NCF2C(NH2)=NOH to give 2 (5) which may be dehydrated to the 1,2,4-oxadiazole (6).Both sodium salts can be reacted with perfluoroacyl acid chlorides to form 2,5-disubstituted 1,3,4-oxadiazoles, where Rf'=NF2CF2 and Rf = CF3 (8), C2F5 (9) or C3F7 (10); Rf'= C2F5 and Rf = CF3 (11) or C2F5 (12).
- John, Earnest Obed,Kirchmeier, Robert L.,Shreeve, Jean'ne M.
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p. 333 - 343
(2007/10/02)
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- Fluoride-promoted competitive reactions of cyanogen fluoride, perfluoromethanimine, and pentafluoro-2-azapropene
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Competitive reactions of cyanogen fluoride (FC≡N), perfluoromethanimine (CF2=NF), and pentafluoro-2-azapropene (CF3N=CF2) were performed by combining pairs of the substrates over KF or CsF. These reactions establish the order of reactivity with fluoride ion as CF2=NF > CF3N=CF2 ? F - C≡N. Subsequent reactions of the addition products with fluoride ion, CIF, and Br2/CsF are discussed. Seven new compounds, including a novel diaziridine, were characterized by IR, NMR, MS, and physical properties.
- Bauknight Jr., Charles W.,DesMarteau, Darryl D.
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p. 728 - 733
(2007/10/02)
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- A Study of Solvent Effects on the Rates of Solvolyses of Pinacolyl Derivatives
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The solvolysis rates of RCH(O3SAr)C(CH3)3 (4a, R = Et, Ar = p-BrPh; 4b, R = i-Pr, Ar = p-BrPh; 4c, R = t-Bu, Ar = p-Tol) and CF3CH(O3SR)C(CH3)3 (6-OBs, R = p-BrPh; 6-OTf, R = CF3) have been determined in mixtures of ethanol and water (the E-W solvent series) and acetic acid and formic acid (the A-F solvent series).Correlations of the rate data by eq 1 neophyl-OTs + c> showed that 4a,b responded similarly to pinacolyl brosylate (1) to the examined solvent effect, yielding separate E-W, A-F regression lines, but with decreased dispersion with increased steric bulk of R.For compound 4c a linear correlation with eq 1 was obtained.These results are interpreted in terms of steric hindrance to electrostatic solvation of the incipient carbocation.The reactivity of the CF3-substituted sulfonate 6-OBs is greatly depressed.The substrate failed to react in the E-W solvent series.Added salt produced enhanced rates of solvolysis of 6-OBs in 25percent AcOH-75percent HCOOH.These results suggest an SN2-like mechanism with very strong electrophilic solvent assistance in the transition state.However, since the solvolysis reactions of 6-OBs are attended with kinetic complexities, the data do not allow a detailed mechanistic interpretation.The solvolytic behavior of 6-OTf stands in sharp contrast to that of 6-OBs.For example, added nucleophilic salts cause only small increases in the rates of solvolysis of 6-OTf in both 70percent EtOH-30percent H2O and 25percent AcOH-75percent HCOOH.Furthemore, the solvolysis rate constants of 6-OTf in all solvents examined correlate with those of 2-adamantyl triflate.These data support a kΔ mechanism for 6-OTf and are discussed in terms of the decreased importance of electrostatic solvation of the forming carbocation from 6-OTf than from pinacolyl brosylate.
- Roberts, Donald D.,Hall, Edward W.
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p. 2573 - 2579
(2007/10/02)
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- Studies on Organic Fluorine Compounds. XLIV. The Diels-Alder Reaction of Trifluoromethylated Cyclopropenyl Ketone and Its Imine
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The thermolysis of 1,5,6,7-tetrakis(trifluoromethyl)-2,3,4-triazabicyclohepta-2,6-diene (3) without a solvent gave 1--2,2,2-trifluoroethylimine (2).The flash vacuum pyrolysis of 3 gave 1,2,3-tris(trifluoromethyl)cyclopropene (6). 1,2,3,4-Tetrakis(trifluoromethyl)pyrrole (5) was produced in both reactions. 1,2,3-Tris(trifluoromethyl)cyclopropen-3-yl trifluoromethyl ketone (1) and 2 were found to react as good dienophiles and gave products obtained through the transition states where the electron-deficient part of the dienophiles attracted the electron-rich part of the diene components, a hetero atom or the diene moiety. Keywords ----- trifluoromethyl; cyclopropenyl; ketone; imine; Diels-Alder reaction; butadiene; cyclopentadiene; furan; pyrrole; bromination
- Kobayashi, Yoshiro,Yoshida, Tsutomu,Nakajima, Masaharu,Ando, Akira,Hanzawa, Yuji
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p. 3608 - 3616
(2007/10/02)
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- 2,4-Diazabicyclononane Skeletons from cis-Benzene Trioxide
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By treating cis-benzene trioxide (1) with guanidine in buffered tert-butyl alcohol solution the 1:1-adducts DL-(1α,2β,4β,5α,6α,10α)-8-imino-3-oxa-7,9-diazatricyclo2,4>decane-5,10-diol (13a) and DL-(1α,2α,3β,5β,6α,7α)-9-imino-4-oxa-8,10-diazatricyclo3,5>decane-2,6-diol (12a) resulting from 1,3(1,2)-bridging in 1 are obtained in 88-91percent (9-12percent) yields.Trifluoroacetamidine (acetamidine) is also selectively 1,3-added to 1.From 13a via generally regiospecific hydrolysis (26a), thiolysis (30a, d), ammonolysis (34a), hydrazinolysis (34d), and HCl-/HBr-addition (39a, c) access to highly functionalised 2,4-diazabicyclononane derivatives is opened.During the "ring-chain tautomerism" observed for 26a and 34d (28a, 36d) the adamantoid orthocarbonic acid intermediates (27a, 35d) cannot be identified directly.The spectroscopic structure elucidations (not always unequivocal because i.a. of conformational flexibility of the skeletons) are confirmed by X-ray structural analysis for 29f, 36e, 38, and 43.
- Fritsche-Lang, Wolfram,Wilharm, Peter,Haedicke, Erich,Fritz, Hans,Prinzbach, Horst
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p. 2044 - 2078
(2007/10/02)
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- Glycosyl Imidates, 12. - Direct Synthesis of O-α- and O-β-Glycosyl Imidates
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1-O-Unsubstituted aldoses afford with halogen-activated nitriles under base catalysis directly O-α- and O-β-glycosyl imidates which can be isolated as stable compounds.Investigations with 2,3,4,6-tetra-O-benzyl- and -acetylglucose (1a, b), trichloroacetonitrile and trifluoroacetonitrile and NaH and K2CO3, respectively, as base have demonstrated, that the β-glucopyranosyl-1-oxido oxygen atom is more nucleophilic (rapid formation of 3a-β, 3b-β, 4a-β, and 4b-β) than the α-glycopyranosyl-1-oxido oxygen atom.Because of the reversibility of these reactions, however,due to the anomeric effect finally the thermodynamically more stable α-imidates 3a-α, 3b-α, 4a-α, and 4b-α are formed exclusively.Therefore O-α- and O-β-glycosyl imidate formation can be conducted highly diastereoselectively. - From trichloroacetonitrile and other 1-O-unsubstituted carbohydrates the imidates 7-α - 13-β were obtained as stable compounds. - Less activated nitriles (chloroacetonitrile, dichloroacetonitrile) have proven not or not so successful in the direct O-glycosyl imidate formation. - N-Aryl ketenimines yielded cleanly base-catalyzed direct O-glycosyl imidate formation.However, because of the irreversibility of this reaction under the reaction conditions only kinetic product formation was observed (leading to the β-imidates 14a-β - 14d-β and 15d-β.Similarly 1-O-unprotected mannose gave only the β-product 16d-β.
- Schmidt, Richard R.,Michel, Josef,Roos, Michael
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p. 1343 - 1357
(2007/10/02)
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- An Azidopiperideine -> Dihydrodiazepine Ring Expansion of the Fluorocarbon Class: Synthesis of Perfluoro-(1,4-dimethyl-2,3-diazacyclohepta-1,3-diene) via Thermolysis of Perfluoro-(6-azido-2,6-dimethyl-1-azacyclohexene)
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Flow pyrolysis of perfluoro-(6-azido-2,6-dimethyl-1-azacyclohexene) at ca. 380 deg C and 1 mmHg yields perfluoro-(1,4-dimethyl-2,3-diazacyclohepta-1,3-diene) (mainly) plus its isomers perfluoro-(1,5-dimethyl-6,7-diazabicyclohept-6-ene) and perfluoro-(2,4-dimethyl-1,3-diazacyclohepta-1,3-diene); the molecular geometry of the first of these products has been determined by gas-phase electron diffraction methods.
- Abed-Rabboh, Mohammad,Banks, Ronald E.,Beagley, Brian
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p. 1117 - 1118
(2007/10/02)
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- On the Chemistry of (Trifluoromethyl)sulfinylamine, CF3NSO, and Related Compounds
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CF3NSF2 (1) reacts with PCl5 to yield CF3NSCl2 (2) which is converted to the title compound 4 with Ag2O as is well known. 4 can also be obtained from CF3NCl2 (3) and SOCl2, and it reacts with XeF2 to form CF3NSOF2 (5) and with HCl to yield CF3NH2 (6).All reactions were also carried out with the corresponding C2F5 compounds (1a - 6a).The hydrochloride of 6a decomposes via (C2F5)2NH * HCl (11) yielding CF3CF2 - N = CFCF3 (13) in contrast to 6a, which forms CF3CN (14).CF3 - NSN - CF3 (8) can be obtained directly from 4 or from 2 and 3 or 2 and 6, respectively.CF3 - NSN - C2F5 (9) and C2F5 - NSN - C2F5 (10) are formed in the reaction of 2a with 6. 1 reacts with BBr3 to form (trifluoromethyl)imidosulfur dibromide (7).
- Leidinger, Walter,Sundermeyer, Wolfgang
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p. 2892 - 2897
(2007/10/02)
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