Syntheses, Crystal Structures, and Antitumor Activities of Two 2-Trifluoromethyl-5,6,7,8-tetrahydrobenzo[4,5]-thieno[2,3-d]pyrimidin-4-amine Derivatives

Two novel 2-trifluoromethyl-5,6,7,8-tetrahydrobenzo[4,5]thieno[2,3-d]pyrimidin-4-amine derivatives were synthesized by nucleophilic substitution of two appropriate amines with 4-chloro-2-(trifluoromethyl)-5,6,7,8-tetrahydrobenzothieno[2,3-d]pyrimidine, which started from 2-amino-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carbonitrile, trifluoroacetic acid(TFA) and phosphorous oxychloride by one-pot procedure. Their structures were determined by single-crystal X-ray diffraction. Compound 1, N-(furan-2-ylmethyl)-2-trifluoromethyl-5,6,7,8-tetrahydrobenzothieno[2,3-d]pyrimidin-4-amine, crystallizes in the monoclinic system, space group C2/c with a = 26.352(3), b = 7.5991(8), c = 17.1423(18) A, β = 114.667(2)°, V = 3119.5(6) A3 and Z = 8. Compound 2, N-(3-silatranylpropyl)-2-trifluoromethyl-5,6,7,8-tetrahydrobenzothieno[2,3-d]pyrimidin-4-amine, crystallizes in the monoclinic system, space group P21/n with a = 13.4394(13), b = 8.9446(9), c = 18.9657(18) A, β = 101.9640(10)°, V = 2230.3(4) A3 and Z = 4. The preliminary bioassay indicated that compound 2 exhibits more potent antitumor activity against BCG-823 than 5-fluorouracil(5-FU).

Facile Synthesis of Bis-Trifluoromethyl 1,8-Dioxo-Octahydroxanthene Derivatives

Xanthene and Xanthenediones are structural components of several bioactive and semi-synthetic molecules. This work described an expeditious synthesis of novel and hitherto unreported bis-trifluoromethyl xanthene dione derivatives. The reaction of two equivalents of 5-trifluoromethyl cyclohexane-1,3- dione with substituted aromatic aldehydes in the presence of ethanol containing 1 - 2 drops of HCl was facile under microwave irradiation. Short reaction time (25 min), good to excellent yields (80% - 95%), good atom economy, and simple workup are the major advantages of the above procedure. Moreover, the fluorinated products represent synthetically useful stable intermediates that could find applications in pharmaceutical, agricultural and material industries.

Asymmetric Bioreduction of 3,5-Bis（trifluoromethyl） Acetophenone to Its Corresponding Alcohol by Candida troplcalis

(S)-3,5-bistrifluoromethylphenyl ethanol is a key chiral intermediate for the synthesis of NK-1 receptor antagonists. Enantioselective synthesis of (S)-3,5-bistrifluoromethylphenyl ethanol was successfully performed in high enantiomeric excess (e.e.) through asymmetric reduction of 3,5-bis(trifluoromethyl) acetophenone catalyzed by Candida tropicalis 104 cells. The influence of some key reaction parameters such as substrate concentration, co-substrate and its concentration, biomass and reaction time was examined, respectively. The results showed that these factors obviously influence the yield, but the optical purity of the prepared product remains intact. The opti-mum conditions for the preparation of (S)-3,5-bistrifluoromethylphenyl ethanol were found to be as follows: sub-strate concentration 50 mmol?L?1; 50 g·L-1 of maltose as co-substrate; wet cell concentration 300 g·L-1; reaction for 30 h. Under above optimal conditions, the maximum yield for (S)-3,5-bistrifluoromethylphenyl ethanol reached 70.3% with 100% of product e.e.

Synthesis, Crystal Structure, and Biological Activity of 4-Chlorobenzaldehyde (2-trifluoromethylTrifluoromethyl-5,6,7,8-tetrahydrobenzo[4 ,5]-thieno[2,3-d]pyrimidin-4-yl)hydrazone Monohydrate

The novel title compound 4-chlorobenzaldehyde (2-trifluoromethyl-5,6,7,8- tetrahydrobenzo[4,5]thieno[2,3-d]pyrimidin-4-yl)hydrazone monohydrate (C18H14ClF3N4SH2O, Mr = 428.86) has been synthesized by a condensation reaction of 4-chlorobenzaldehyde with (2-trifluoromethyl-5,6,7,8-tetrahydrobenzo[4,5]thieno[2,3-d]pyrimidin-4-yl)hydrazine, and its crystal structure was determined by single-crystal X-ray diffraction. The crystal belongs to monoclinic, space group P21/c with a = 7.4252(7), b = 26.344(2), c = 10.3095(9) , = 109.407(2)°, V = 1902.0(3) 3 , Z = 4, Dc = 1.498 g/cm3 , μ = 0.356 mm-1 , F(000) = 880, the final R = 0.0564 and wR = 0.1681 for 2343 observed reflections with I > 2 (I). X-ray diffraction analysis reveals that the title hydrazone molecule is nearly planar except for the cyclohexene and trifluoromethyl moieties. In the crystal packing, the molecules form stacks by a three-dimensional framework, which results from intermolecular N(3)-H(3)···O(1), O(1)-H(1B)···N(2), O(1)- H(1B)···N(4) and O(1)-H(1A)···F(1) hydrogen bonds via water molecules together with π-π stacking interactions. Molecular geometry of the title compound in the ground state optimized by B3LYP functional with 6-311G** basis sets indicates that the calculations are in agreement with the experimental data. The preliminary bioassay suggested that the title compound exhibits relatively good fungicidal activity against Fusarium oxysporium f.sp.vasinfectum and Dothiorella gregaria.

Synthesis, Crystal Structure, and Antitumor Activity of 1-(4-Methoxybenzylidene)-2-(1-phenyl-6-trifluoromethyl-1H-pyrazolo[3,4-d]pyrimidin-4-yl)hydrazine Monohydrate

The novel title compound 1-(4-methoxybenzylidene)-2-(1-phenyl-6-trifluoromethyl-1H-pyrazolo[3,4-d]pyrimidin-4-yl)hydrazine monohydrate(C20H15F3N6O·H2O, Mr = 430.40) has been synthesized by a four-step procedure including the cyclization, chlorination, hydrazinolysis and condensation reaction, and its crystal structure was determined by single-crystal X-ray diffraction. The crystal belongs to orthorhombic, space group Pbca with a = 8.3779(13), b = 17.607(3), c = 26.774(4) , V = 3949.2(11) 3, Z = 8, Dc = 1.448 g/cm3, μ = 0.117 mm–1, F(000) = 1776, the final R = 0.0553 and wR = 0.1516 for 2354 observed reflections with I > 2■(I). X-ray diffraction analysis reveals that the title compound is almost coplanar except for the trifluoromethyl and phenyl moieties. In the crystal packing, the molecules are linked by intermolecular O(1W)–H(1WA)···N(2), O(1W)–H(1WA)···N(4) and N(5)–H(5A)···O(1W) hydrogen bonds via water molecules and stacked through π-π stacking interactions. The preliminary bioassay suggested that the title compound exhibits relatively good antitumor activity against HepG2 and BCG-823.

Syntheses, Crystal Structures, and Biological Activities of Two Enantiomeric 2-Trifluoromethylthieno[2,3-d]pyrimidin-4-amine Derivatives

Two enantiomeric 2-trifluoromethyl-6,7-dihydro-5H-cyclopenta[4,5]thieno[2,3-d]pyrimidin-4-amine derivatives were synthesized by nucleophilic substitution of two chiral amines with 4-chloro-2-trifluoromethyl-6,7-dihydro-5H-cyclopenta[4,5]thieno[2,3-d]pyrimidine,which started from 2-amino-5,6-dihydro-4H-cyclopenta[b]thiophene-3-carbonitrile,trifluoroacetic acid(TFA) and phosphoryl trichloride via one-pot procedure.Their structures were determined by single-crystal X-ray diffraction.Enantiomer(R)-3,(R)-N-(1-phenylethyl)-2-trifluoromethyl-6,7-dihydro-5H-cyclopenta[4,5]thieno[2,3-d]pyrimidin-4-amine crystallizes in the tetragonal system,space group P4_3 with a = 8.6847(6),b = 8.6847(6),c = 22.419(2) A,V= 1690.9(3) A^3,Z = 4,D_c =1.428 g/cm^3,μ = 0.228 mm^(-1),F(000) = 752,the final R = 0.0463 and wR = 0.1257 for 3442 observed reflections with I > 2σ(I).Enantiomer(S)-3,(S)-N-(1-phenylethyl)-2-trifluoromethyl-6,7-dihydro-5H-cyclopenta[4,5]thieno[2,3-d]pyrimidin-4-amine crystallizes in the tetragonal system,space group P4_1 with a = 8.688,b = 8.688,c = 22.421 A,V = 1692.4 A^3,Z = 4,D_c = 1.426 g/cm^3,μ = 0.227mm^(-1),F(000) = 752,the final R = 0.0682 and wR = 0.1806 for 3182 observed reflections with I >2σ(I).The preliminary bioassay indicated that the R-enantiomer exhibits higher antitumor activity against MCF-7 than gefitinib.

SYNTHESIS AND CHARACTERIZATION OF ORGANO-SOLUBLE FLUORINATED POLYIMIDES FROM 4,4'-BIS(3-AMINO-5-TRIFLUOROMETHYLPHENOXY)-BIPHENYL AND VARIOUS AROMATIC DIANHYDRIDES

An aromatic diamine monomer, 4,4'-bis(3-amino-5-trifluoromethyl phenoxy)-biphenyl (TFBPDA), was synthesized via the nucleophilic displacement reaction of 3,5-dinitrobenzotrifluoride and 4,4'-biphenol. The monomer was reacted with various aromatic dianhydrides via the high temperature polycondensation procedure to provide a series of polyimides. The polyimides, PI-1 to PI-4, show good solubility not only in aprotic solvents, such as N-methyl-2-pyrrolidinone and N,N-dimethylacetamide, but also in many common solvents, such as m-cresol, chloroform and cyclopentanone. PI-4, derived from 4,4'-(hexafluoroisopropylidene)diphthalic anhydride and TFBPDA, was even soluble in toluene. Moreover, PI films exhibit good thermal stability, outstanding transparency in the visible light region and acceptable mechanical and electrical properties. The excellent combined properties of the polyimides make them as a good candidate for fabricating microelectronics.

Trifluoromethylation of Carbonyl Compounds with Sodium Trifluoroacetate

In the presence of copper (I) halide as catalyst, a variety of carbonyl compounds could be trifluoromethylated with sodium trifluoroacetate to give the corresponding alcohols in moderate to high yields.

Synthesis, crystal structure, and fluorescence of two dimeric europium(III) complexes with 2-(trifluoromethyl)benzoate

Two complexes [Eu2(2-TFMBA)6(2,2’-bipy)2]·2H2O (1) and Eu2(2-TFMBA)6(1,10-phen)2 (2) (2-TFMBA=2-(Trifluoromethyl) benzoate; 2,2’-bipy=2,2’-bipyridine; 1,10-phen=1,10-phenanthroline) were synthesized by solvent method and determined by X-ray diffrac-tion analysis. Complex 1 crystallizes in monoclinic system with space group P21/c, whereas complex 2 crystallizes in triclinic system with space group Pī. Both are binuclear molecules with an inversion center. In complex 1, two center Eu3+ ions are linked together by four 2-TFMBA ligands in bidentate-bridging mode. Each Eu3+ ion is eight-coordinated with six O atoms from five 2-TFMBA ligands and two N atoms from one 2,2’-bipy molecule. In complex 2, two center Eu3+ ions are linked together by four 2-TFMBA ligands in two modes, namely, bidentate-bridging and tridentate-bridging. Each Eu3+ ion is nine-coordinated with seven O atoms from five 2-TFMBA ligands and two N atoms from one 1,10-phen molecule. The two complexes both exhibited strong red fluorescence under ultraviolet light, and the 5D0→7Fj (j=0–4) transition emissions of Eu3+ ion were observed in their emission spectra.

Synthesis and Herbicidal Activity of 5-Heterocycloxy-3-substituted-1-(3-trifluoromethyl)phenyl-1H-pyrazole

The authors synthesized a series of novel 5-heterocycloxy-3-substituted-1-(3-trifluoromethyl)phenyl-1H- pyrazole derivatives. Herbicidal activities of the two intermediate compounds and thirteen target compounds were evaluated via Brassica napus and Echinochloa crusgalli(L.) Beauv tests. Bioassay results show that some of the compounds exhibit better inhibiting activities against Brassica napus and some of the compounds exhibit bleaching activities against Echinochloa crusgalli(L.) Beauv at 100 μg/mL.

Synthesis and Crystal Structure of N-[(3aR,4R,4aR,5aS,6S,6aS)-1,3-Dioxooctahydro-4,6-ethenocyclopropa[f]isoindol-2(1H)-yl]-3-(trifluoromethyl)phenylmethanimine

The crystal structure of the title compound(C19H15F3N2O2,Mr = 360.33) was determined by single-crystal X-ray diffraction.The crystal belongs to triclinic,space group P1,with a = 6.5604(7),b = 13.9614(16),c = 18.1790(18) ,α = 102.749(7),β = 97.542(6),γ = 94.355(4)°,V = 1600.5(3) 3,Z = 4,Dc = 1.495 g/cm3,λ(MoKα) = 0.71070,F(000) = 744,μ(MoKα) = 0.122 mm-1,R = 0.0434 and wR = 0.1051.A total of 7590 unique reflections were collected,of which 5429 with |F|2 ≥ 2σ|F|2 were observed.The two cyclohexene rings in the molecule adopt boat-boat conformations with the deviations of ring atoms C(9) and C10 from the C(5)/C(6)/C(7)/C(8) plane(Ⅰ) by 1.1204(0.0023) and 1.1132(0.0023) ,respectively,whereas from the C(2)/C(3)/C(5)/C(8) plane(Ⅱ) by 1.1627(0.0022) and 1.1818(0.0021) ,respectively.In the cyclopropane and lactam rings,atoms C(11) and N(1) point towards the double bond of C(9)-C(10) and the dihedral angle between the ring plane(Ⅲ) containing C(1),C(2),C(3) and C(4) and plane(IV) consisting of C(6),C(7) and C(11) is 55.76(0.07)°.The dihedral angles between planes Ⅳ and Ⅰ and Ⅱ and Ⅲare 63.58(0.07)° and 58.10(0.06)°,respectively.The dihedral angle between the benzene ring C(13)～ C(18) and plane Ⅳ is 42.41(0.06)°.

Trifluoromethyl enable high-performance single-emitter white organic light-emitting devices based on quinazoline acceptor

Single-emitter white organic light-emitting diode(WOLED) based on small organic molecule exhibits great potential in simplifying fabrication process of WOLEDs. However, the design and synthesis of molecule for highly efficient single-emitter WOLED still remains a challenge. Herein, two asymmetric donor-acceptor-acceptor'(D-A-A') type molecule(PTZ-PQ-F and PTZ-PQ-CF3) are developed by employing trifluoromethyl(CF_(3)) or fluorine atom as secondary acceptor, which can exhibit white lighting with dual emission bands consisting of blue traditional fluorescence from quasi-axial(ax) conformer and orange thermally activated delayed fluorescence(TADF) from quasi-equatorial(eq) conformer. The introduction of CF_(3) into PTZ-PQ-CF3 greatly enhanced the photoluminescence quantum yield(PLQY) by suppressing the nonradiative deactivation. Owing to electron-inductive-effect of CF3, the “eq” conformer of PTZ-PQCF3 exhibits a much smaller ΔESTof 0.01 e V to realize more efficient reverse intersystem crossing(RISC)process, and then enhance the exciton utilization(nearly 100%) of the whole dual emission system. Consequently, single-emitter WOLEDs based on PTZ-PQ-CF3 show nearly standard white emission with EQE of 13.0% and CIE of(0.35, 0.36) in m CP host and show warm white emission with high EQE of 25.5%and CIE of(0.40, 0.47) in 35 Dcz PPy host, which are the best performance among reported single-emitter WOLEDs.

Visible-light-enabled multicomponent synthesis of trifluoromethylated 3-indolequinoxalin-2(1H)-ones without external photocatalysis

A novel and sustainable visible-light-enabled multicomponent reaction involving quinoxalin-2(1H)-ones,indoles,and CF3SO2Na that does not require an external photocatalyst is described.This photoinduced reaction employs air as the sole oxidant,thereby providing a green and highly step-efficient approach to a series of biologically important trifluoromethylated 3-indolequinoxalin-2(1H)-ones.

Iodomethane as an organocatalyst for the aerobic ortho-selective trifluoromethylation of pyridines

Iodomethane is usually used as an electrophilic methylation reagent.Herein,we report its use as a C1 organocatalyst for the aerobic ortho-selective trifluoromethylation of pyridines in the absence of a transition metal.Trifluoroacetic acid(TFA)was employed as an inexpensive,readily available trifluoromethyl source.The reaction efficiently produced a variety of trifluoromethylation products,with good functional group compatibility.Pyridine-containing drug molecules could also be selectively trifluoromethylated for late-stage functionalizations.Mechanistic studies showed that iodomethane selectively reacted with the pyridine starting material,rather than the pyridine product,to generate the corresponding N-methylpyridinium iodide.The decarboxylation of trifluoroacetic acid produced a trifluoromethyl anion,which added to the methylpyridinium iodide,and the subsequent aerobic rearomatization led to the generation of the ortho-trifluoromethylated product.

Regioselective electrochemical radical cascade cyclization of internal alkynes to selenated and trifluoromethylated dihydropyran

Dihydropyran(DHP)compounds are not only found in natural products and bioactive molecules,but also serve as important precursors in organic synthesis.Nonetheless,traditional methods for the construction of such compounds are usually limited to disubstituted DHPs.To address this synthetic challenge,reported here is an efficient electrochemical strategy toward the selenated and trifluoromethylated DHP compounds.The reaction proceeded smoothly under mild electrolysis conditions.The broad substrate scope(>50 examples)and scalable synthesis demonstrated the complexity-building potential of the strategy.Initial mechanistic studies reveal that cyclization may involve a radical process.This protocol may promote the further development of diversified synthesis of multi-substituted dihydropyran.

Copper-catalyzed asymmetric 1,3-dipolar cycloaddition of azomethine ylides withβ-trifluoromethyl-substituted alkenyl heteroarenes

Copper-catalyzed asymmetric 1,3-dipolar cycloaddition of azomethine ylides andβ-trifluoromethyl-substituted alkenyl heteroarenes was developed for the first time.A wide range of enantioenriched pyrrolidines containing both heteroarenes and trifluoromethyl group with multiple stereogenic centers could be readily accessible by this method with good to high yields and excellent levels of both stereo-and regioselectivity(up to 99%yield,>20:1 rr,>20:1 dr,and up to 95%ee).Notably,substratecontrolled umpolung-type dipolar cycloaddition was also disclosed in this protocol to achieve regiodivergent synthesis withα-aryl substituted aldimine esters as the dipole precursors.Systematic DFT studies were conducted to explore the origin of the stereo-and regioselectivity of this 1,3-dipolar cycloaddition,and suggest that copper(Ⅱ)salt utilized in this catalytic system could be reduced in-situ to the active copper(Ⅰ)species and might be responsible for the observed high stereo-and regioselectivity.

Generation of(E)-β-trifluoromethyl vinylsulfonohydrazides under photocatalysis and their anti-bacteria activity

Trifluoromethylation/sulfonylation of alkynes from trifluoromethyl thianthrenium triflate and sulfur dioxide under extremely mild reaction conditions provides a facile access to trifluoromethyl-substituted vinyl sulfonohydrazides in moderate to good yields.This multicomponent reaction of trifluoromethyl thianthrenium triflate,alkynes,sulfur dioxide and hydrazines proceeds efficiently under visible light irradiation in the presence of photocatalyst at room temperature with broad substrate scope and excellent functional group compatibility.This reaction is highly stereoselective,and only(E)-isomers are obtained.Additionally,these trifluoromethyl-substituted vinyl sulfonohydrazides are further evaluated for anti-bacteria activity.In vitro activities of these compounds against Staphylococcus aureus(G+)and Escherichia coli(G-)are examined.

Difluorocarbene-derived rapid late-stage trifluoromethylation of 5-iodotriazoles for the synthesis of^(18)F-labeled radiotracers

Difluorocarbene has emerged as a valuable intermediate to synthesize fluorides.However,difluorocarbene-derived synthesis of^(19)F/^(18)F-trifluoromethyl triazoles has not been explored.Herein,we reported the Cu(I)-promoted difluorocarbene-derived^(19)F/^(18)F-trifluoromethylation of iodotriazoles using KF/K^(18)F as the fluorine source.This approach rapidly generated a wide range of 5-trifluoromethyl-1,2,3-triazoles in good yields showing high functional group compatibility.The reaction was effective for late-stage functionalization of bioactive molecules and^(18)F-trifluoromethylation of iodotriazoles.This work provides a practical synthetic methodology for the development of triazole drugs and^(18)F-radiotracers for positron emission tomography.

Nickel-catalyzed umpolung C-S radical reductive cross coupling of S-(trifluoromethyl)arylsulfonothioates with alkyl halides

A new cooperative nickel reductive catalysis and N,N-dimethylformamide-mediated strategy for umpolung C–S radical reductive cross coupling of S-(trifluoromethyl)arylsulfonothioates with alkyl halides to produce alkyl aryl thioethers is described. This reaction features excellent selectivity, wide functionality tolerance, broad substrate scope, and facile late-stage modification of biologically relevant molecules.Mechanistic studies recognize initial generation of an amidyl radical anion via thermoinduced reduction of DMF with Sn, followed by umpolung reduction and single electron transfer of the nucleophilic sulfonyl moiety to form a sulphydryl radical and engage the Ni^(0)/Ni^(Ⅰ)/Ni^(Ⅲ)/Ni^(I) catalytic cycle.

General and Modular Access to Enantioenriched α-Trifluoromethyl Ketones via Nickel-Catalyzed Reductive Trifluoroalkylation

The development of new catalytic enantioselective access to stereogenic CF_(3)-containingmolecules is of great interest for expediting the discovery of lead compounds that remain challenging.Specifically,enantioselective synthesis of valuable ketones featuring stereogenicα-CF_(3) has rarely been reported.We devise a general and modular approach to facilely access enantioenrichedα-CF_(3) ketones via nickel-catalyzed reductive cross-coupling of readily available acid chlorides and racemicα-CF_(3) alkyl bromides in an enantioconvergent fashion under mild conditions.This protocol features neighboring directing group-free,high chemoselectivity,excellent functional group tolerance,facile scale-up,and notable amenability to straightforward downstream elaboration toward pharmaceutically useful enantioenrichedβ-trifluoromethylated secondary and tertiary alcohols,thus constituting a reliable,direct,practical,and efficient synthetic alternative to furnish enantiopureα-CF_(3) carbonyls.Interestingly,an appropriate choice of the phosphine ligand as coligand plays an important role in high efficiency and asymmetric induction.Mechanistic studies suggest a radical chain pathway.