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1.
An equimolecular mixture of [Pd(RNC)2Cl2] (R = Ph, p-Me C6H4) and [Pd(MeCN)2Cl2] reacts in boiling, 1,2-dichloroethane to give the binuclear complexes [Pd(RNC)Cl2]2.These compounds undergo a variety of bridge-splitting reactions with neutral or anionic ligands yielding complexes of the type cis and trans [Pd(RNC)LX2] or [Pd(RNC)X3]− (L = PPh3, pyridine, C6H11NC; X = CL, Br).By reaction of [Pd(PhNC)Cl3]− with MeOH the anionic carbene complex [Pd{C(NHPh)OMe}Cl3]− is obtained.[Pd(PhNC)Cl2]2 reacts with p-toluidine (excess) or o-aminopyridine to give the corresponding mononuclear carbene derivatives.In the case of the mixed derivative [Pd(p-MeC6H4NC)(C6H11NC)Cl2], only the more activated p-tolylisocyanide was found to react with p-toluidine.The complexes have been characterized by elemental analysis, conductivity measurements, i.r. and 1H n.m.r. spectra where possible. 相似文献
2.
Yuchun Jiang Xia Zhu Yu Wang Francis Verpoort Xiaohong Chang 《Inorganica chimica acta》2011,376(1):144-151
μ-Chloro bridged dinuclear cyclometallated Pd(II) complexes [Pd{(4-R)C6H3CHNC6H3-2,6-i-Pr2}(μ-Cl)]2 (R = H, OMe) were prepared by reaction of Na2PdCl4 with benzylideneanilines. Unexpectedly, Na2PdCl4 reacted with Schiff-bases bearing a furyl or a thienyl ring to give N-coordinated non-cyclometallated Pd(II) species [Pd(C4H3XCHNC6H3-2,6-i-Pr2)2Cl2] (X = O, S). Treating [Pd{(4-R)C6H3CHNC6H3-2,6-i-Pr2}(μ-Cl)]2 (R = H, OMe) with an excess of NaN3 or NH4SCN generated μ-N3 bridged or μ-SCN bridged cyclometallated Pd(II) complexes [Pd{(4-R)C6H3CHNC6H3-2,6-i-Pr2}(μ-Y)]2 (R = H, OMe; Y = N3, NCS). The complexes were characterized by FTIR, NMR spectroscopy, elemental analysis and X-ray crystallography. 相似文献
3.
Reactions of H[AuCl4] with N-substituted 2-pyridine thiocarboxamide ligands 2-(C5H4N)C(S)NHR (R = p-C6H4Me, CH2Ph, Me, p-C6H4OMe) gave cycloaurated derivatives {(C5H4N)C(S)NR}AuCl2, with the ligand bonded as the thiol tautomer through the deprotonated SH group and the pyridine N atom to give a five-membered metallacyclic ring. The X-ray structure determination of the R = CH2Ph derivative shows a square-planar gold(III) complex that dimerises in the solid state by weak Au···S intermolecular interactions. In contrast, in the reaction of H[AuCl4] with 2-(C5H4N)C(S)NHR where R = 2-pyridyl, the ligand was oxidised to give a 1,2,4-thiadiazolo[2,3-a]pyridinium heterocyclic ring that was crystallographically characterised. 相似文献
4.
Alkynyl Pd(II) azido complexes of the type [Pd(N3)(CCR)L2] (1-3) were obtained by reactions of aqueous NaN3 with [Pd(Cl)(CCR)L2] (R = Ph or C(O)OMe). Treating compounds 1-3 with organic isocyanides (R-NC) afforded novel complexes, trans-[Pd(CCPh)(NCNR)(PMe3)2] (R = 2,6-Me2C6H3 (4) or 2,6-Et2C6H3 (5)) and trans-[Pd(CCR)(CN4-t-Bu)L2] (6: L = PMe3, R = Ph; 7: L = PEt3, R = C(O)OMe; 8: L = PMe3, R = C(O)OMe), which contain either a carbodiimido or a C-coordinated tetrazolato group. Reactions of compounds 1 and 2 with R-NCS (R = 2,6-Me2C6H3 or CH2CH3) and 1,4-phenylene diisothiocyanate (C6H4(NCS)2) smoothly proceeded to give tetrazole-thiolato complexes, trans-[Pd(CCPh)(SCN4-R)L2] (L = PMe3, R = Et (9) or 2,6-Me2C6H3 (10); L = PEt3, R = 2,6-Me2C6H3 (11)), and a phenylene-bridged dinuclear Pd(II) tetrazole-thiolato complex, [(PEt3)2(CCPh)Pd(SCN4-(μ-C6H4)-SCN4)Pd(CCPh)(PEt3)2] (12), respectively. Complexes 9-12 contain the Pd-S bond that is formed by the dipolar cycloaddition of the organic isothiocyanate to the Pd-azido bond. In contrast, the corresponding reactions of compounds 1and 2 with C6F5CN and Me3SiCN (organic nitriles, R-CN) gave an N-coordinated Pd(II)-tetrazolato compound {trans-[Pd(CCPh)(N4C-C6F5)(PMe3)2] (13)} and a mixture of Pd(II)-cyano complexes {trans-[Pd(CCPh)(CN)(PEt3)2] (14) and [Pd(CN)2(PEt3)2] (15)}, respectively. Bis(phosphine) bis(cyano) complexes of Pd and Ni, [M(CN)2L2] (L = PEt3, PMe3; L2 = DEPE), could be obtained independently by the reactions of [M(N3)2L2] with excess Me3SiCN in organic solvents. 相似文献
5.
Iwona Winiecka Paweł Jaworski Aleksander Paweł Mazurek Dorota Marszałek Anna Goldnik Daniel Sokulski 《Journal of peptide science》2016,22(2):106-115
In search for new drugs lowering arterial blood pressure, which could be applied in anti‐hypertensive therapy, research concerning agents blocking of renin‐angiotensin‐aldosteron system has been conducted. Despite many years of research conducted at many research centers around the world, aliskiren is the only one renin inhibitor, which is used up to now. Four novel potential renin inhibitors, having structure based on the peptide fragment 8–13 of human angiotensinogen, a natural substrate for renin, were designed and synthesized. All these inhibitors contain unnatural moieties that are derivatives of N‐methylleucyl‐β‐hydroxy‐γ‐amino acids at the P2‐P1' position: 4‐[N‐(N‐methylleucyl)‐amino]‐3‐hydroxy‐7‐(3‐nitroguanidino)‐heptanoic acid (AHGHA), 4‐[N‐(N‐methylleucyl)‐amino]‐3‐hydroxy‐5‐phenyl‐pentanoic acid (AHPPA) or 4‐[N‐(N‐methylleucyl)‐amino]‐8‐benzyloxycarbonylamino‐3‐hydroxyoctanoic acid (AAHOA). The previously listed synthetic β‐hydroxy‐γ‐amino acids constitute pseudodipeptidic units that correspond to the P1‐P1' position of the inhibitor molecule. An unnatural amino acid, 4‐methoxyphenylalanin (Phe(4‐OMe)), was introduced at the P3 position of the obtained compounds. Three of these compounds contain isoamylamide of 6‐aminohexanoic acid (ε‐Ahx‐Iaa) at the P2'‐P3' position. The proposed modifications of the selected human angiotensinogen fragment are intended to increase bioactivity, bioavailability, and stability of the inhibitor molecule in body fluids and tissues. The inhibitor Boc‐Phe(4‐OMe)‐MeLeu‐AHGHA‐OEt was obtained in the form of an ethyl ester. The hydrophobicity coefficient, expressed as log P varied between 3.95 and 8.17. In vitro renin inhibitory activity of all obtained compounds was contained within the range 10?6‐10?9 M. The compound Boc‐Phe(4‐OMe)‐MeLeu‐AHPPA‐Ahx‐Iaa proved to be the most active (IC50 = 1.05 × 10?9 M). The compounds Boc‐Phe(4‐OMe)‐MeLeu‐AHGHA‐Ahx‐Iaa and Boc‐Phe(4‐OMe)‐MeLeu‐AHPPA‐Ahx‐Iaa are resistant to chymotrypsin. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd. 相似文献
6.
S. K. Moiseev I. A. Cherepanov P. V. Petrovskii M. G. Ezernitskaya H. Butenschn M. Strotmann V. N. Kalinin 《Inorganica chimica acta》1998,280(1-2)
Structures of the complexes (η3-C3H5)Pd(μ-η6:1-CH2PhCr(CO)3 and (η3-C3H5)Pd[μ-η6:1-CH(Ph)Ph]Cr(CO)3 in solution were evaluated by NMR (1H and 13C) and IR spectroscopy. The dynamic behaviour of the complexes was investigated. Quick rotation (on the NMR time scale) of the tricarbonylchromium groups around the axis passing through the centre of the η6-coordinated phenyl ring and the chromium atom takes place at room temperature and becomes slow on cooling. The η3-allylic ligand was proved to undergo no dynamic changes in solution. Unlike the solid state, the semi-bridging carbonyl groups between chromium and palladium atoms are absent or very weak in solution. Cross-coupling reactions of the complexes with organohalides are described. 相似文献
7.
Gregorio Sánchez Joaquín García Luis García Gregorio López 《Inorganica chimica acta》2010,363(6):1084-12865
The reaction between Pd(dba)2 and phosphino-amide ligands yielded the unexpected Pd(II) homoleptic complexes [Pd(o-Ph2PC6H4CO-NR)2] [R = iPr (1), Ph (2), 4-MeC6H4 (3), 4-FC6H4 (4)], in which an κ2-P,N coordination mode for diphenylphosphine-benzamidate ligands is observed. In order to induce amide protonation in the ligands and subsequent κ2-P,O coordination, compounds (1-4) were treated with HClO4(aq) to give cationic complexes [Pd(o-Ph2PC6H4CO-NHR)2][ClO4]2 (5-8). These complexes and the analogous with iminophosphine ligands [Pd(o-Ph2PC6H4CHN-R)2] [ClO4]2 [R = iPr (9), Ph (10)] can be alternatively obtained when [PdCl2(PhCN)2] is treated with AgClO4 in the presence of the corresponding ligand. The reaction of Pd(dba)2 with iminophosphines has also been explored, yielding in this case the Pd(0) derivatives [Pd(o-Ph2PC6H4CHN-R)2] [R = iPr (11), Ph (12)]. X-ray structures of (3), (4), (5), (8) and (9) have been established, allowing an interesting comparative structural discussion. 相似文献
8.
Gianfranco Bellachioma Barbara Binotti Giuseppe Cardaci Carla Carfagna Alceo Macchioni Stefano Sabatini Cristiano Zuccaccia 《Inorganica chimica acta》2002,330(1):44-51
Complexes [M(η1,η2-C8H12OMe)((2,6-(R)2---C6H3)N=C(R′)---C(R′)=N((2,6-(R)2---C6H3))]PF6 (where M=Pd, R=H and R′2=Me2 (1), M=Pd, R=Me and R′2=Me2 (2), M=Pd, R=Et and R′2=Me2 (3), M=Pd, R=iPr and R′2=Me2 (4), M=Pd, R=iPr and R′2=An (5), M=Pt, R=iPr and R′2=An (6)) were synthesized by the reaction of [M(η1,η2-C8H12OMe)Cl]2 with the appropriate α-diimine ligand in the presence of NH4PF6. Their ion pair structure in solution was investigated by detecting dipolar interactions between protons belonging to the cation and fluorine nuclei of the anion (interionic contacts) in the 19F, 1H-HOESY NMR spectra. In complexes 1–4, the anion in solution is located close to the peripheral protons of the α-diimine ligand and it interacts with the R′ protons and with the R protons that point toward the R′ groups. The steric protection of apical position exerted by the R substituents is clearly illustrated by the absence of interionic contacts between any protons of the cycloctenylmethoxy-moiety and the anion for R≥Me in 1–4. In complexes 5 and 6 the interactions between the anion and the peripheral N,N protons also predominate but other anion–cation orientations are significantly present and, consequently, the interionic structure is less specific. 相似文献
9.
Complex (S,S)-[Pd{C6H4(CH2CHNH2CO2CH2CH3)}(μ-Br)]2 (3) was prepared following the method by Vicente and Saura-Llamas (Organometallics 26:2768–2776, 2007), by the reaction of l-ethylphenylalanate and Pd(OAc)2 in 1:1 molar ratio under acetonitrile heating conditions and subsequently treating with NaBr. In addition, the cleavage of
halogeno-bridge of the complex 3 via nucleophilic attack of some neutral ligands such as triphenylphosphine, pyridine, 2,4,6-trimethylpyridine and piperidine
were investigated and the corresponding complexes (S)-[Pd{C6H4(CH2CHNH2CO2CH2CH3)(Y)(Br)}] (4a–f) were obtained in moderate yields. The six-member orthopalladated complexes were characterized by 1H-NMR, 31P-NMR, FT-IR and elemental analysis techniques. 相似文献
10.
Normen Szesni 《Inorganica chimica acta》2004,357(6):1789-1798
Photolysis of the allenylidene pentacarbonyl chromium complexes [(CO)5CrCCC(R1)R2] (R1=NMe2, NPh2; R2=NMe2, OMe, Ph) in THF in the presence of equimolar amounts of XR3 (XR3=various phosphanes, P(OMe)3, AsPh3, SbPh3) affords cis-allenylidene tetracarbonyl XR3 complexes, cis-[(CO)4(XR3)CrCCC(R1)R2]. When in the photolysis of [(CO)5CrCCC(NMe2)Ph], the phosphanes PR3 (R=C6H4F-p, C6H4Cl-p, OMe) are used in excess (three equivalents) two carbonyl ligands are displaced and the mer-tricarbonyl complexes mer-[(CO)3(PR3)2CrCCC(NMe2)Ph] are formed both PR3 ligands being mutually trans. The structure of the new complexes is established by IR, NMR, and UV-Vis spectroscopy, that of cis-[(CO)4(PPh3)CrCCC(NMe2)Ph] additionally by an X-ray structural analysis. As indicated by the spectroscopic data of the compounds, these complexes are best described as hybrids of allenylidene and zwitterionic alkynyl complexes with delocalization of the electron pair at nitrogen bonded to the Cγ atom of the allenylidene ligand towards the metal center. The relative contribution of the allenylidene and zwitterionic alkynyl resonance forms is influenced by XR3. Increasing the donor properties of XR3 favors the allenylidene resonance form. 相似文献
11.
Graeme Hogarth Ebony-Jewel C.-R.C.R. Rainford-Brent Idris Richards 《Inorganica chimica acta》2009,362(4):1361-6826
The bis(2-methoxyethyl)dithiocarbamate complexes [M{S2CN(CH2CH2OMe)2}2] (M = Ni, Cu, Zn, Pd) are readily prepared and the three lighter complexes have been crystallographically characterised. Disproportionation of [Cu{S2CN(CH2CH2OMe)2}2] upon addition of Cu(ClO4)2 · 6H2O affords the copper(III) complex [Cu{S2CN(CH2CH2OMe)2}2][ClO4] which has also been crystallographically characterised. Unlike other copper(III) dithiocarbamate salts, there are no intermolecular cation-cation or cation-anion interactions. 相似文献
12.
Debasish Ghorai 《Inorganica chimica acta》2011,372(1):412-416
Treatment of 2,6-bis[(dimethylamino)methyl]-4-methylphenol (1) with [Pd(PhCN)2Cl2] in a 1:1 molar ratio gives the mononuclear Pd(II) complex [PdCl2(OC6H2(CH2NMe2)-2-Me-4-(CH2NHMe2)-6)] (2) containing one ligand with an ammonium hydrogen atom, which forms a bifurcated hydrogen bonding to the phenoxy oxygen and the chlorine atoms, as shown by the single crystal X-ray diffraction study. The reaction between the lithium salt of 1 and [Pd(COD)Cl2] gives the mononuclear Pd(II) complex [Pd(OC6H2(CH2NMe2)2-2,6-Me-4)2] (3). The X-ray structure of 3 showed the presence of two ligands coordinated to one palladium metal center in a trans fashion with two dangling dimethylamine groups. The yield of the complex 3 was improved by carrying out the reaction between [Pd(OAc)2] and 1 in acetone. The solid state structures of the complexes 2 and 3 were confirmed by 1H, 13C, HETCOR NMR, IR and elemental analysis methods. The 1H NMR spectra of 2 and 3 showed two different chemical shifts corresponding to the coordinated and uncoordinated amine groups of the ligand. No decoalescence of signals for the chelate ring puckering process was observed in variable-temperature NMR spectra. 相似文献
13.
《Inorganica chimica acta》2006,359(5):1650-1658
A series of nickel(II) and palladium(II) complexes containing one or two pentafluorophenyl ligands and the phosphino-amides o-Ph2PC6H4CONHR [R = iPr (a), Ph (b)] displaying different coordination modes have been synthesised. The chelating ability of these ligands and the influence of both coligands and the metal centre in their potential hemilabile behaviour have been explored. The crystal structure of (b) has been determined and reveals N–H⋯O intermolecular hydrogen bonding. Bis-pentafluorophenyl derivatives [M(C6F5)2(o-Ph2PC6H4CO-NHR)] [M = Ni; R = iPr (1a); R = Ph (1b); M = Pd; R = iPr (2a); R = Ph (2b)] in which (a) and (b) act as rigid P, O-chelating ligands were readily prepared from the labile precursors cis-[M(C6F5)2(PhCN)2]. X-ray structures of (1a), (1b) and (2a) have been established, allowing an interesting comparative structural discussion. Dinuclear [{Pd(C6F5)(tht)(μ-Cl)}2] reacted with (a) and (b) yielding the monopentafluorophenyl complexes [Pd(C6F5)Cl{PPh2(C6H4–CONH–R)}] (R = iPr (3a), Ph (3b)) that showed a P, O-chelating behaviour of the ligands, confirmed by the crystal structure determination of (3a). New cationic palladium(II) complexes in which (a) and (b) behave as P-monodentate ligands have been synthesised by reacting them with [{Pd(C6F5)(tht)(μ-Cl)}2], stoichiometric Ag(O3SCF3) and external chelating reagents such as cod [Pd(C6F5)(cod){PPh2(C6H4-CONH-R)}](O3SCF3)(R = iPr (4a), Ph (4b)) and 2,2′-bipy [Pd(C6F5)(bipy){PPh2(C6H4-CONH-R)}](O3SCF3) (R = iPr (5a), Ph (5b)). When chloride abstraction in [{Pd(C6F5)(tht)(μ-Cl)}2] is promoted by means of a dithioanionic salt as dimethyl dithiophospate in the presence of (a) or (b), the corresponding neutral complexes [Pd(C6F5){S(S)P(OMe)2}{PPh2(C6H4-CONH-R)}] (R = iPr (6a), Ph (6b)) were obtained. 相似文献
14.
The Suzuki-Miyaura reaction of various aryl halides using [Pd{C6H2(CH2CH2NH2)-(OMe)2,3,4} (μ-Br)]2 have been investigated. This orthopalladated complex is an efficient, stable and non-sensitive to air and moisture catalyst for the hetrocoupling reaction in DMF as the reaction solvent at 130 °C. The combination of dimeric complex as homogenous catalyst and microwave irradiation can be very useful and efficient methods in organic synthesis, so the application of microwave irradiation have been investigated using homogenous dimeric complex [Pd{C6H2(CH2CH2NH2)-(OMe)2,3,4} (μ-Br)]2. Application of dimeric complex as catalyst caused to produce the desired coupling products and the using of microwave irradiation improving the yields of the reactions and shortening the reaction times. 相似文献
15.
Gelson Manzoni de Oliveira Manfredo Hörner Aline Machado Jorge H.S.K. Monteiro 《Inorganica chimica acta》2011,366(1):203-859
Deprotonated 3-(4-nitrophenyl)-1-phenyltriazene N-oxide reacts with YCl3·6H2O and LnCl3·6H2O (Ln = Eu, Ho, Yb) to give the monoclinic chelate complexes [Y{O2N(C6H4)NNN(O)Ph}4](Et3NH)·H2O (1) (Ph = C6H5; Et = C2H5) and [LnIII{O2N(C6H4)NNN(O)Ph}4](Et3NH)·H2O·{CH3OH∗} {LnIII = Eu (2), Ho (3), Yb∗ (4), in which the metal centers present a square antiprismatic configuration. As already observed for hydrated ammonium complexes of triazene-oxides ligands with (C6H4)−NO2 groups, multiple, effective O···H and N···H interactions hold the species in supramolecular 3D assemblies. The optical and the luminescent properties of the triazene-oxide europium complex 2 are also presented and fully discussed. 相似文献
16.
Tantalaalkylidene compounds, CHRTaCl3L2 (R=tBu or CMe2Ph, L=THF or 1/2dimethoxyethane) mixed with the cyclopalladated dimer [Pd(2-C6H4CH2NMe2)(μ-Cl)]2, 1, afford good yields of heterodimetallic complexes [Pd(2-C6H4CH2NMe2)(μ-Cl)(μ-CHR=TaCl3L], 3a, 3b, in which the TaC unit is η2-interacting with the palladium atom, while a chloride ligand is bridging the tantalum and the palladium atoms. These compounds are fairly stable in air in the solid state and also in solution at RT. The interaction of the TaC unit with Pd in these bimetallic compounds is weak as shown by the ready formation of [Pd(2-C6H4CH2NMe2)PyCl] and CHRTaCl3Py2 upon treatement with pyridine. Compounds analogous to 3a, b can also be obtained with 12 electrons tantalum complexes. Thus treating the same cyclopalladated dimer 1 with CHRTa(OAr)3 (OAr=2,6-diisopropylphenyloxy) led to a much more stable though electron deficient species: [Pd(2-C6H4CH2NMe2)(μ-Cl)(μ-CHtBu=Ta(OAr)3], 3c. Substitution in 3a of one chloride ion by an alkyl group occurred at the tantalum metal via reaction with ZnR2 (R=CH2CMe2Ph) leading to [Pd(2-C6H4CH2NMe2)(μ-Cl)(μ-CHtBu=TaCl3(CH2CMe2Ph)], 4 for which there is no free rotation around the new TaC bond and in which one of the methylene protons is strongly interacting with the palladium centre. This compound is believed to mimic an intermediate to the formation of tantalacarbyne derivative, which was obtained earlier via reaction of the uncomplexed tantalacarbene compound with dialkylzinc compounds. 相似文献
17.
《Inorganica chimica acta》2006,359(11):3677-3692
The reactions of palladium(II) dimers [Pd2Br2(L1)2] and [Pd2Br2(L2)2] (where L1− is [Ph2PCHC(Ph)N(2,6-iPr2C6H3)]− and L2− is [Ph2PCHC(Ph)N(2,6-Me2C6H3)]−) with AgBF4 in a mixture of CH2Cl2 and MeOH give palladium(I) dimers [Pd2(HL1)2][BF4]2 and [Pd2(HL2)2][BF4]2, respectively. These exhibit unusual coordination geometries of the metal centre. Density functional theory (DFT) calculations showed that a phenyl ring of the bridging phosphine is involved in bonding via a delocalised metal-phosphine–phenyl interaction. The remarkable kinetic stability of these palladium(I) species may explain the early termination steps in the CO/ethylene copolymerisation reaction catalysed by Pd(II)–amidophosphines or enolisable Pd(II)–iminophosphines. 相似文献
18.
Qian Sun 《Steroids》2010,75(12):936-943
A novel and practical procedure was developed for the preparation of D-ring unsaturated 17-alkynyl steroids by Pd(PPh3)4/AgOAc-catalyzed coupling of steroidal 17-triflates and alkynes. Firstly treatment of the steroid-17-ones with PhN(Tf)2 and KHMDS in dried THF at −78 °C for 2 h gives the corresponding steroidal 17-triflates products in high yields (97-98%), following the coupling of steroidal 17-triflates and various 1-alkynes by Pd(PPh3)4/AgOAc-catalyzed in the presence of DIPEA for 24 h to yield the desired D-ring unsaturated 17-alkynyl steroids (86-97%). Moreover, it was found that the coupling reaction catalyzed by Pd[(C6H5)3P]4/AgOAc system is selective for aryl triflates or vinyl triflates. By optimizing the reaction conditions, the sole C17-coupling products from steroidal bistriflates were obtained in satisfactory yields. Since D-ring unsaturated 17-alkynyl steroids with conjugated double and triplet bond can be subsequently converted into pentacyclic steroids and 17-oxosteroid derivatives at the side chain of D-ring, this general method provides a highly efficient route to these biologically important compounds. 相似文献
19.
Lawrence W.‐Y. Wong Elena V. Vashchenko Ying Zhao Herman H.‐Y. Sung Valerii V. Vashchenko Vadim Mikhailenko Alexander I. Krivoshey Ian D. Williams 《Chirality》2019,31(11):979-991
Resolution of rac‐3,3,3‐trifluorolactic acid by diastereomeric salt formation was reinvestigated. The use of (S)‐1‐phenylethylamine gives coprecipitation of two diastereomeric phases, 1 (S)‐[NH3CH(CH3)Ph](S)‐[CF3CH(OH)COO] and 2 (S)‐[NH3CH(CH3)Ph](R)‐[CF3CH(OH)COO]·H2O. Pure phase 1 may be obtained using molecular sieves as desiccants. Resolution by (S,S)‐2‐amino‐1‐phenylpropan‐1,3‐diol gives monoclinic (S,S)‐[NH3CH(CH2OH)CHOHPh] (R)‐[CF3CH(OH)‐COO] 3 with minor (S)‐3,3,3‐trifluorolactate contamination, which is precluded in the recrystallized orthorhombic form 4 . A new resolution using inexpensive phenylglycinol gives pure phase 5 (S)‐[NH3CH(CH2OH)Ph] (S)‐[CF3CH(OH)COO] in 76% yield, 94% ee in a single step, in preference to its (S)‐(R) diastereomer 6 . Overall efficient resolution for both enantiomers of the trifluorolactic acid (each ca. 70% yield, 99% ee) may be achieved by various two‐step “tandem” crystallizations, involving direct addition of either water or a second base to the filtrate from the initial reaction. 相似文献
20.
Aditya S. Gundugola Kusum Lata Chandra Elisabeth M. Perchellet Andrew M. Waters Jean-Pierre H. Perchellet Sundeep Rayat 《Bioorganic & medicinal chemistry letters》2010,20(13):3920-3924
A series of 1,4-diaryl tetrazol-5-ones were synthesized by copper mediated N-arylation of 1-phenyl-1H-tetrazol-5(4H)-one with aryl boronic acids, o-R1C6H4B(OH)2 where R1 = H, OMe, Cl, CF3, Br, CCH. The 1,4-diaryl tetrazol-5-ones substituted with OMe, Cl, CF3, Br underwent thionation with Lawesson’s reagent to yield the corresponding 5-thio derivatives. The 1-(2-bromophenyl)-4-phenyl-1H-tetrazole-5(4H)-thione so obtained was subjected to lithiation/protonation and Sonogashira coupling to produce 1,4-diphenyl-1H-tetrazole-5(4H)-thione and 1-(2-ethynylphenyl)-4-phenyl tetrazole-5-thione, respectively. The title compounds were found to be stable to strong Lewis acid conditions. Three of these novel compounds were found to inhibit L1210 leukemia cell proliferation and SK-BR-3 breast cancer cell growth over several days in culture in vitro. Shorter tetrazole derivative treatments also reduced the expression of the Ki-67 marker of cell proliferation in SK-BR-3 cells and the rate of DNA synthesis in L1210 cells. 相似文献