Convergent procedure for the synthesis of trifluoromethyl-containing N-(pyridinyl-triazolyl)pyrimidin-2-amines

This study describes a simple and efficient procedure to synthesize a novel series of fourteen 4-substituted N-(5-pyridinyl-1H-1,2,4-triazol-3-yl)-6-(trifluoromethyl)pyrimidin-2-amines, where the 4-substituents are H, CH₃, C₆H₅, 4-FC₆H₄, 4-CH₃C₆H₄, 4-CH₃OC₆H₄ and 2-Furyl; from the cyclocondensation reaction of N-[5-(pyridinyl)-1H-1,2,4-triazol-3-yl]guanidines with 4-alkoxy-4-alkyl(aryl/heteroaryl)-1,1,1-trifluoroalk-3-en-2-ones. The reactions were carried out in ethanol under reflux for 18 h and led to 40-68% yields. N-(Pyridyl-triazolyl)guanidine precursors were further obtained from reactions of cyanoguanidine with nicotinic or isonicotinic acid hydrazides and the halogenated enones from trifluoroacetylation of enolethers or acetals.     

Preparation of N,N,N′-tris(trimethylsilyl)amidines; a convenient route to unsubstituted amidines

The tris(trimethylsilyl)amidines RC(NSiMe₃)N(SiMe₃)₂ (R  C₆H₅, p-CH₃C₆-H₄, p-ClC₆H₄, p-MeOC₆H₄, p-Me₂NC₆H₄, p-CF₃C₆H₄, p-C₆H₅C₆H₄ and CF₃) are prepared by the reaction of the respective nitriles with (Me₃Si)₂NLi·OEt₂ in ether to give intermediates RC(NLi)N(SiMe₃)₂. Heating these intermediates with ClSiMe₃ in toluene affords the products, which are isolated by vacuum distillation, in high yield. With 1,4-dicyanobenzene, two equivalents of reagents affords the per(trimethylsilyl)-1,4-diamidine. Hydrolysis of the intermediates with 6N ethanolic HCl affords the unsubstituted amidine hydrochlorides RC(NH)NH₂·HCl (R  C₆-H₅, p-MeOCh₆H₄, p-ClC₆H₄, p-O₂NC₆H₄) in high yield.     

ortho-, meta- and para-nitrophenylgold(I) complexes

Treatment of [BzPh₃P][AuCl₂] with [Hg(x-C₆H₄NO₂)₂] (x = o, m, or p) gives anionic gold(I) complexes of the type [BzPh₃P][Au(R)Cl](R = o-, m- or p-C₆H₄NO₂, Bz = C₆H₅CH₂). The chloro ligand in [Au(o-C₆H₄NO₂)Cl]^? can be replaced by bromo or iodo ligands by use of NaBr or NaI. The anions [Au(R)Cl]^? react with neutral monodentate ligands, L, to give neutral mononuclear complexes [Au(R)L] (R = o-C₆H₄NO₂, L = PPh₃, AsPh₃; R = m-C₆H₄NO₂, L = PPh₃) and with 1,2-bis(diphenylphosphino)ethane (dpe) to give [Au₂(R)₂(dpe)] (R = o-C₆H₄NO₂). The corresponding [Au(p-C₆H₄NO₂)Cl]^? reacts with PPh₃ or AsPh₃ to give mixtures containing [AuClL]. The anionic ortho-nitrophenylgold(I) complex is much more stable than its meta- or para-nitrophenyl isomers. These are thought to be the first reports of nitrophenylgold(I) complexes.     

The first synthesis of dihydro-3H-pyrido[2,3-b][1,4]diazepinols and a new alternative approach for diazepinone analogues

The first synthesis of a series of 2-aryl(heteroaryl)-4-trifluoromethyl-4,5-dihydro-3H-pyrido[2,3-b][1,4]diazepin-4-ols, where aryl = C₆H₅, 4-FC₆H₄, 4-ClC₆H₄, 4-BrC₆H₄, 4-CH₃C₆H₄, 4-OCH₃C₆H₄, 4,4′-biphenyl, 1-naphthyl and heteroaryl = 2-thienyl, 2-furyl obtained from the direct cyclocondensation reaction of 4-methoxy-1,1,1-trifluoroalk-3-en-2-ones with 2,3-diaminopyridine in 54-71% yield, is reported. Another alternative and efficient route for the synthesis of a series of 2-aryl(heteroaryl)-3H-pyrido[2,3-b][1,4]diazepin-4(5H)-ones from the reaction 4-methoxy-1,1,1-trichloroalk-3-en-2-ones with 2,3-diaminopyridine, in 54-70% yield, is also reported.     

Reactions of methyltris(triarylphosphine)cobalt : II. Rearrangement of triarylphosphine and oxidative additions of aryl halides

Solutions of [(C₆H₅)₃P]₃CoCH₃ (I) in C₆H₅Cl yield biphenyl, triphenylphosphine, methyldiphenylphosphine and diphenylphosphine. In 4-ClC₆H₄CH₃, 4-methylbiphenyl and 4,4′-bitolyl form as well. Solutions of I in C₆H₆, C₆D₆, C₆H₅CH₃, C₆H₅Br yield only triphenylphosphine and biphenyl, while in 4-FC₆H₄I 4,4′-difluorobiphenyl is formed but no biphenyl. The cobalt compound is recovered as (Ph₃P)_nCoX or as CoX₂ (XCl, Br, I, n = 3 or 2) from reactions with arylhalides. The results are rationalized in terms of the very strong tendency for I to undergo oxidative addition reactions.     

Antimony—sulphur bonded compounds : IV. Further studies on the thermal decomposition of tetra-organoantimony mercaptides

The thermolytic decomposition of Ph₄SbSAr in organic solvents are reported. Solvent-derived products from decompositions in CCl₄ and cyclohexane confirm the free radical nature of the reactions.Thermal decompositions of Ph₃ (p-MeC₆H₄)SbSC₆H₄OMe-p, or Ph(p-MeC₆H₄)₃SbSC₆H₄X(Xp-MeO or H) provide mixed triarylstibines,[Ph₃_nSb(C₆H₄Me-p)_n (n0, 1, 2 and 3), disulphide (XC₆H₄SSC₆H₄X), monosulphides (PhSC₆H₄X and p-MeC₆H₄SC₆H₄X), arenes, (PhH and PhMe) and biaryls (Ph₂,PhC₆H₄Me-p and p-MeC₆H₄C₆H₄Me-p).     

The solid state structure of arene-mercury(II) complexes from magic-angle spinning carbon-13 NMR and the solution carbon-13 NMR of some complexes of mercury(II) with arenes having bulky aliphatic substituents

The cross-polarization magic angle spinning ¹³C NMR spectra of Hg(SbF₆)₂ - 2 Arene (Arene = C₆HMe₅, 1,2,4,5-C₆H₂Me₄, 1,2,3,4-C₆H₂Me₄, or C₆H₆) have been measured. The spectra of the complexes of C₆HMe₅ and 1,2,4,5-C₆H₂Me₄ are consistent with static η¹-bonding of the mercury to the arene at an unsubstituted carbon atom, while the spectra of the 1,2,3,4-C₆H₂Me₄ and C₆H₆ complexes show the arene to have time-averaged C_s or C₂, and C₆ symmetry respectively, at the temperature of measurement (300 K).The reduced temperature ¹³C NMR spectra of Hg(Arene)_n²⁺ (n = 1 or 2; Arene = 1,3,5-C₆H₃R₃ (R = Me, i-Pr, or t-Bu)) in SO₂ solution are also reported and affirm that in these intramolecularly mobile species the mercury bonds in an η¹-manner, with unsubstituted aryl carbon atoms being the strongly preferred point of mercury attachment. This site preference is further demonstrated by the solution ¹³C NMR spectra of Hg(Arene)_n²⁺ (Arene = 1,2,3,4-C₆H₂-Me₄, n = 1 or 2; Arene = 1,4-C₆H₄R₂, R = Me or t-Bu, n = 1). The spectra of the 1,4-C₆H₄R₂ complexes and Hg(p-C₆H₄-t-BuMe)²⁺ provide clear evidence for steric influence of the binding site.Like Hg(C₆Me₆)₂²⁺, but unlike most of the complexes of substituted benzenes which have been studied, Hg(1,3,5-C₆H₃-i-Pr₃)₂²⁺ exchanges only slowly with excess free ligand.     

Formation of the fused system 5H,7H-pyrido[2,3-b:6,5-b′]diindole from 3-arylidene-2-ethoxyindolenines and hydrazine hydrate

Three 12-aryl-5H,7H-pyrido[2,3-b:6,5-b??]diindoles (Ar = Ph, 4-BrC₆H₄, and 4-MeOC₆H₄) were obtained from appropriate 3-arylidene-2-ethoxyindolenines and hydrazine hydrate.     

Trifluoromethyl-containing pyrazolinyl (p-tolyl) sulfones: The synthesis and structure of promising antimicrobial agents

The regiospecific synthesis of a novel series of nine 4-phenyl- and 3-alkyl(aryl)-5-hydroxy-5-trifluoromethyl-4,5-dihydro-1H-1-tosylpyrazoles (pyrazolinyl p-tolyl sulfones), as well as their antimicrobial activity against yeast, such as fungi, bacteria, and alga are reported. The 1-p-tosyl-2-pyrazolines were obtained from the cyclocondensation reaction of 3-phenyl- and 4-alkyl(aryl)-1,1,1-trifluoro-4-alkoxy-3-alken-2-ones, [where alkyl = H, Me and aryl are -C₆H₅, 4-CH₃C₆H₄, 4-OCH₃C₆H₄, 4-FC₆H₄, 4-ClC₆H₄, 4-BrC₆H₄,] with p-tosylhydrazine in a yield of 58-92% when toluene was employed as solvent. The best activity was obtained when the structure possessed a 4-fluorophenyl substituent linked at the carbon-3 of the pyrazoline ring. Subsequently, the dehydration reaction of 3-(4-fluorophenyl) substituted 2-pyrazoline with thionyl chloride/pyridine in benzene as solvent furnished the corresponding 1H-pyrazole in only a moderate yield (49%).     

Synthesis of organoantimony(V) and μ-oxy-bis(triarylantimony) selenocyanates using a phase-transfer catalyst

Several new, pentacoordinated, triorganoantimony bis-selenocyanates [R₃Sb(SeCN)₂ (R = Me, Ph, p-CH₃C₆H₄, p-ClC₆H₄, p-F-C₆H₄ or C₆F₅)], tetraorganostibonium selenocyanates [R₃R′Sb(SeCN) (R = R′ = Ph; R = Ph, and R′ = CH₂CHCH₂)] and μ-oxy-bis(triarylantimony) bis-selenocyanates {[Ar₃SbOSbAr₃](SeCN)₂ (Ar = Ph, p-CH₃C₆H₄, p-ClC₆H₄ or p-FC₆H₄)} have been synthesized from potassium selenocyanate and the corresponding organoantimony halide (chloride and/or bromide) in the presence of the phase-transfer catalyst 18-crown-6, and characterized. Spectroscopic evidence suggested an iso structure (Sb—NCSe). The compounds were also obtained in the absence of 18-crown-6 but in lower yields. Some of these compounds were found to exhibit a significant biological activity.     

Carbamoyl and alkoxycarbonyl complexes of palladium(II) and platinum(II)

Carbamoyl and alkoxycarbonyl complexes of palladium(II) and platinum(II) of the type M(pnp)(CONHR)Cl (pnp = 2,6-bis(diphenylphosphinomethyl)pyridine; M Pd, R  C₆H₅, p-CH₃C₆H₄, p-CH₃OC₆H₄, C₆H₁₁, t-Bu; M  Pt, R  C₆H₅), Pd(pnp)[CON(Pr)₂]Cl (Pr = propyl), M(pnp)(COOR)Cl (M  Pd, R  C₆H₅, CH₃; M  Pt, R  CH₃), Pd(pnp)(COOCH₃)₂ result from reaction of M(pnp)Cl₂ with carbon monoxide and amines or alkoxides at room temperature and atmospheric pressure.The carbamoyl complexes react with bases to give urethane or diphenylurea depending upon the experimental conditions.     

Oxidative alkylamination of azinones as a direct route to aminoazinones: study of some condensed diazinones

Oxidative alkylamination of azinones is a promising method for the preparation of a great variety of alkylaminoazinones. Treatment of 6,8-dimethyl-2-R-pyrimido[4,5-c]pyridazin-3,5,7(2H,6H,8H)-triones 7, 1,3-dimethyl-5-R-pteridin-2,4,6(1H,3H,6H)-triones 8 and 1,3,6-trimethylpyrimido[4,5-d]pyrimidin-2,4,7(1H,3H,6H)-trione 9 with alkylamine/AgPy₂MnO₄ or alkylamine/KMnO₄ has been shown to produce their 4-, 7- and 5-alkylamino derivatives, respectively, in good yields. While 1-methylquinoxalin-2(1H)-one 10 is smoothly alkylaminated under the above conditions giving 3-alkylamino derivatives, quinoxaline itself does not take part in this reaction. Factors influencing oxidative alkylamination of azinones and a regioselectivity of the process are discussed.     

Reactions of (η5-C5H5)2Tir compounds with organic cyanides

The syntheses and properties of the titanium(III) complexes Cp₂Tir · R′CN (R = C₆H₅, o-, m-, p-CH₃C₆H₄, CH₂C₆H₅, C₆F₅, Cl; R′ = CH₃, t-C₄H₉, C₆H₅, o-CH₃C₆H₄, 2,6-(CH₃)₂C₆H₃) are described. In the complexes the nitrogen atom of the cyanide ligands is coordinated to the metal. The thermal stabilities of the complexes depend markedly on R and R′; on heating they undergo a novel reaction in which two cyanide ligands are coupled by formation of a CC bond, while the metal is oxidized to titanium(IV).     

Synthesis of molecular chains: phenylene thioether and sulfoxide oligomers

The application of a general synthetic approach to prepare molecular chains is reported. It is based on a step-by-step method each consisting first in a Pd-catalyzed reaction between ArI and HXAr′Br (Ar=aryl, Ar′=arylene) to give ArXAr′Br followed by a Cu-catalyzed replacement of Br by I to give ArXAr′I that can be reacted with HXAr′Br in the following step. The application of this method is here illustrated to prepare phenylene sulfide oligomers (X=S). Starting from RC₆H₄I-4 (R=H, MeO, NO₂, NH₂) and HSC₆H₄Br-x (x=2, 4) it is possible to grow chains in one direction to give X(C₆H₄S-m)_nC₆H₄R-4 (n=1, X=Br, m=4, R=H, MeO, NO₂, NH₂, SMe and m=2, R=H, MeO, NO₂; n=1, X=I, m=2 or 4, R=H, MeO, NO₂; n=2, X=Br, m=2 or 4, R=H, MeO, NO₂; n=2, X=I, m=4, R=MeO, NO₂; n=3, X=Br, m=4, R=MeO, NO₂; n=3, X=I, m=4, R=NO₂ and n=4, X=Br or I, m=4, R=NO₂). From HSC₆H₄Br-x and IC₆H₄I-4 the chains can grow in two directions to give X(C₆H₄S-4)_nC₆H₄X-4 (n=2 or 4, X=Br or I), 2-XC₆H₄(SC₆H₄-4)_nSC₆H₄X-2 (n=3 or 5, X=Br). Using diiodomesitylene the dithioethers C₆HMe₃-2,4,6-(SC₆H₄X-4)₂-1,3 (X=Br, I) have been prepared. The series of sulfoxides X(C₆H₄S(O)-4)_nC₆H₄R-4 (X=Br, n=1, R=MeO, n=3, R=NO₂, n=4, R=Br; X=R=I, n=2) has been obtained from the corresponding thioethers and PhICl₂.     

Zur synthese von siloxanen: I. Die hydrolyse von chlorsiloxanen

The kinetics of hydrolysis reactions of some chlorodisiloxanes and of the chloropentasiloxanes (Me₃) SiO)₂Si(Me)OSiAr(Cl)OSiMeAr′ (with Ar = Ph and Ar′ = p-ClC₆H₄, C₆H₅ or p-MeC₆H₄; or Ar′ = Ph and Ar = p-ClC₆H₄, C₆H₅ or p-MeC₆H₄ in dioxane were studied by ¹H NMR spectroscopy.Because of their high hydrolysis rate the chlorodisiloxanes can be reacted only with equimolar amounts of H₂O. The formal second order rate constants and also the ? value evaluated can be used only in a tentative way.From hydrolysis reactions of the chloropentasiloxanes with an excess of H₂O and different amounts of HCl or HClO₄ the following results were obtained: hydrolysis is catalysed by HCl and HClO₄. The reaction is of first order with respect to chlorosiloxane. With respect to HCl at a tenfold excess of H₂O the order is in the range 0.5–0.7. Our results indicate, that there is a “non-catalysed” hydrolysis besides the acid catalysed reaction, ?-Values for the variation of Ar (0.7) and Ar′ (0.3) can be derived from the rate constants of the acid catalysed reactions of chloropentasiloxanes with a tenfold amount of water. The results are interpreted in mechanistic terms.     

Mass spectrometry of π-complexes of transition metals : XVII. Ionm̄olecule reaction products in mass spectra of mixtures of π-cyclopentadienyl- and π-arenemetal carbonyls with aromatic and heterocyclic compounds

Ion—molecule reactions occur in the ionization chamber of a mass spectrometer during the combined vaporization of arenechromium tricarbonyls (ArCr(CO)₃, Ar = C₆H₆, C₆H₅Cl, C₆H₅N(CH₃)₂, C₄H₄S, C₄H₄Se) and cyclopentadienylmetal carbonyls (C₅H₄RM(CO)_n, M and R = Mn, H;Mn, Cl; Mn, Br; Mn, COCH₃; Re, H; V, H) with various aromatic and heterocyclic compounds (L). In all cases secondary ions of sandwich type [ArCrL]⁺ or [C₅H₄RML]⁺ containing a new metalligand bond are formed.     

The thiolate anion as a nucleophile Part III. Reactions with various fluorobenzenes

The reactions of the fluorobenzenes, C₆F₅H, o-C₆H₂F₄, m-C₆H₂F₄, p-C₆H₂F₄, 1,3,5-C₆F₃H₃, 1,2,4-C₆F₃H₃, o-C₆F₂H₄, m-C₆F₂H₄, p-C₆F₂H₄ and C₆F₅H with thiolate anion nucleophiles RS^? (primarily MeS^?), have been studied in ethylene glycol/pyridine mixtures as a solvent. Multiple replacement of fluorine atoms was observed in the more highly fluorinated compounds, but in all cases two aromatic fluorine atoms were not replaced. Difluorobenzene and fluorobenzene did not react. The product orientations have been deduced from their NMR spectra. The mass spectra of the isomeric products C₆F₂H₃(SMe), C₆F₃H₂(SMe) and C₆F₂H₂(SMe)₂ have been examined.     

Synthesis, crystal structures and in vitro antitumor activities of some arylantimony derivatives of analogues of demethylcantharimide

A series of novel arylantimony derivatives of analogues of demethylcantharimide with the formulae Ar_nSbL_(5−n) and Ar_nSbL^′_(5−n)(LH=N-hydroxy-demethyldehydrogencantharimide, L^′H=N-hydroxy-demethylcantharimide, n=3, 4; ArC₆H₅, 4-CH₃C₆H₄, 3-CH₃C₆H₄, 2-CH₃C₆H₄, 4-ClC₆H₄, 4-FC₆H₄) were synthesized and characterized by elemental analysis, IR, ¹H NMR and mass spectroscopy. The crystal structures of (C₆H₅)₄SbL, (4-CH₃C₆H₄)₃SbL₂ and (3-CH₃C₆H₄)₃SbL^′₂ were determined by X-ray diffraction. The in vitro antitumor activities of all compounds against six cancer cells are reported.     

Molecular and polymeric uranyl and thorium hybrid materials featuring methyl substituted pyrazole dicarboxylates and heterocyclic 1,3-diketones

A series of seven novel f-element bearing hybrid materials have been prepared from either methyl substituted 3,4 and 4,5-pyrazoledicarboxylic acids, or heterocyclic 1,3- diketonate ligands using hydrothermal conditions. Compounds 1, [UO₂(C₆H₄N₂O₄)₂(H₂O)], and 3, [Th(C₆H₄N₂O₄)₄(H₂O)₅]·H₂O feature 1-Methyl-1H-pyrazole-3,4-dicarboxylate ligands (SVI-COOH 3,4), whereas 2, [UO₂(C₆H₄N₂O₄)₂(H₂O)], and 4, [Th(C₆H₅N₂O₄)(OH)(H₂O)₆]₂·2(C₆H₅N₂O₄)·3H₂O feature 1-Methyl-1H-pyrazole-4,5-dicarboxylate moieties (SVI-COOH 4,5). Compounds 5, [UO₂(C₁₃H₁₅N₄O₂)₂(H₂O)]·2H₂O and 6, [UO₂(C₁₁H₁₁N₄O₂)₂(H₂O)]·4.5H₂O feature 1,3-bis(4-N¹-methyl-pyrazolyl)propane-1,3-dione and 1,3-bis(4-N¹,3-dimethyl-pyrazolyl)propane-1,3-dione respectively, whereas the heterometallic 7, [UO₂(C₁₁H₁₁N₄O₂)₂(CuCl₂)(H₂O)]·2H₂O is formed by using 6 as a metalloligand starting material. Single crystal X-ray diffraction indicates that all coordination to either [UO₂]²⁺ or Th(IV) metal centers is through O-donation as anticipated. Room temperature, solid-state luminescence studies indicate characteristic uranyl emissive behavior for 1 and 2, whereas those for 5 and 6 are weak and poorly resolved.     

Studies of lambert's reaction: The formation of [Mn2(CO)8(μ-AsR2)2] complexes from tertiary arsines and [Mn2(CO)10] at high temperatures

Although very bulky ligands e.g.(o-MeC₆H₄)₃E or (μ-C₁₀H₇)₃E (E = P or As) are inert, the normal photochemical or thermal reaction of tertiary phosphines or arsines, L, with [Mn₂(CO)₁₀] is CO substitution with the formation of [Mn₂(CO)₈(L)₂] derivatives (I). At elevated temperatures some triarylarsines, R₃As, undergo Lambert's reaction with ligand fragmentation to give [Mn₂(CO)₈(μ-AsR₂)₂] complexes (II) (R = Ph, p-MeOC₆H₄, p-FC₆H₄, or p-CIC₆H₄) even though, in the absence of [Mn₂(CO)₁₀] R₃As are stable under the same conditions. Exceptional behaviour is exhibited by (p-Me₂NC₆H₄)_3- As which forms a product of type I; by some HN(C₆H₄)₂AsR which give a product of type II as a result of loss of the non-aryl groups R = PhCH₂, cyclo-C₆H₁₁, or MeO; and by Ph(α-C₁₀H₇₂P which is the only phosphine to form a product of type II, albeit in trace amounts only. The thermal decomposition of a n-butanol solution of [Mn₂(CO)₈(AsPh₃)₂] in a sealed tube gives C₆H₆ and [Mn₂(CO)₈(α-AsPh₂)₂], whilst in an open system in the presence of various tertiary phosphines, L, [Mn(H)(CO)₃(L)₂] are obtained. It is suggested that Lambert's reaction is a thermal fragmentation of [Mn(CO)₄(AsR₃]^* radicals, the first to be recognised. They lose the radical R^* which abstracts hydrogen from the solvent. The resulting [Mn(CO)₄(AsR₂)] moiety dimerises to [Mn₂(CO)_8-(α-AsR₂)₂]. the reaction is facilitated by the stability of the departing radical (e.g. PhCH₂ or MeO) and, as the crowding about As is relieved, by its size (e.g. Ph, cyclo-C₆H₁₁, o-MeC₆H₄, or α-C₁₀H₇). In general, phosphine-substituted radicals [Mn(CO)₄(PR)₃]^* do not undergo this decomposition, probably because the PC bonds are much stronger than AsC.