Preparation Of Cis Research Articles

Preparation and Odour of Cis- and Trans-2-Methyltetrahydrofuran-3-Thiol Acetates

The preparation of cis- and trans-2-methyltetrahydrofuran-3-thiol acetates from ( E)-3-penten-1-ol is reported. The mesylate of ( E)-3-penten-1-ol was converted into trans- or cis-2-methyl-3-hydroxytetrahydrofuran by oxidation with H2O2 and HCOOH or with KMnO4. cis- or trans-2-Methyltetrahydrofuran-3-thiol acetate was prepared by mesylation and an SN2 nucleophilic substitution with AcSH from trans- or cis-2-methyl-3-hydroxytetrahydrofuran respectively. The configuration of the products was confirmed by their synthesis. Olfactory evaluation of cis- and trans-2-methyltetrahydrofuran-3-thiol acetates indicated some differences both in odour feature and intensity.

Copper Indium Diselenide thin films using a hybrid method of chemical bath deposition and thermal evaporation

ABSTRACTCopper indium diselenide (CIS) based solar cells are one among the promising thin film solar cells. Most of the processes reported for the preparation of CIS directly or indirectly involve Se vapor or H2Se gases which are extremely toxic to health and environment. In this work, we report the preparation of CIS thin films by stacked layers of Glass/In/Se/Cu2Se and Glass/In/Se/Cu2Se/Se. For this, first indium (In) thin film was thermally evaporated on glass substrate on which selenium (Se) and copper selenide (Cu2Se) thin films were deposited sequentially by chemical bath deposition. Selenium thin films were grown from an aqueous solution containing Na2SeSO3 and CH3COOH at room temperature, triple deposition for 7, 7 and 10 min from consecutive baths. Copper selenide thin films were deposited at 35 °C for 1 hour from an aqueous bath containing CuSO4, Na2SeSO3 and NH4OH. Analysis of the X-ray diffraction patterns of the thin films formed at 400 °C from the precursor layer containing extra selenium layer showed the presence of chalcopyrite CuInSe2, without any secondary phase. Morphology of all the samples was analyzed using Scanning Electron Microscopy. Optical band gap was evaluated from the UV-Visible absorption spectra of these films and the values were 1.1 eV and 1 eV respectively for CIS thin films formed at 400 °C from the selenium deficient and selenium rich precursor layers. Electrical characterizations were done using photocurrent measurements. Thus preparation of a CuInSe2 absorber material by a non-toxic selenization process may open up a low cost technique for the fabrication of CIS based solar cells.

ChemInform Abstract: Preparation of cis- and trans-Cycloalkane-Condensed Pyrimidinediones by Azetidinone Ring Transformation.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform Abstract: Synthesis of Highly Hindered 1,2-Diaryl Diketones and of cis- and trans-1,2-Diacetoxy-1,2-bis(aryl)ethenes.

Highly hindered 1,2-diaryl diketones can be synthesized in good yields by the reaction of 1-aryllithium with CO in THF solution at atmospheric pressure; preparation of cis- and trans-1,2-diacetoxy-1,2-bis(Mes)ethene can be also afforded by a similar procedure and further quenching with Ac2O.

Synthesis, spectroscopy and antiproliferative activity of cis- and trans-platinum(II) complexes with diethyl (pyridin-4-ylmethyl)phosphate. X-ray crystal structure of trans-Pt(II) complex

Preparations of cis- and trans-platinum(II) complexes of diethyl (pyridin-4-ylmethyl)phosphate (4-pmOpe) have been described. These complexes were identified and characterized by far-IR, 1H NMR, 13C NMR, 31P NMR and 195Pt NMR and microanalyses. The crystal and molecular structure of trans-platinum(II) complex i.e., trans-[PtCl 2(4-pmOpe) 2] was determined by the X-ray diffraction. Novel complexes were assayed for their potential antiproliferative effect against HT 29 (colorectal adenocarcinoma) and A 549 (non-small cell lung cancer) cell lines as well as normal human peripheral blood lymphocytes. The results obtained indicate that novel analogues of cis-diamminedichloroplatinum(II) cause inhibition of cells growth which suggest that they could be chemotherapeutic drugs in the future.

Structure, stability, and interconversion barriers of the rotamers of cis-[Pt(II)Cl(2)(quinoline)2] and cis-[Pt(II)Cl(2)(3-bromoquinoline)(quinoline)] from X-ray crystallography, NMR spectroscopy and molecular mechanics evidence.

Reported are the preparations of cis-[PtCl(2)(quinoline)(2)] and cis-[PtCl(2)(3-bromoquinoline)(quinoline)] and an investigation of the stabilities and interconversion of the rotamer forms of these complexes. Both head-to-head (HTH) and head-to-tail (HTT) rotamer forms are found in the crystal structure of cis-[PtCl(2)(quinoline)(2)]. The NOESY NMR spectrum of cis-[PtCl(2)(quinoline)(2)] in dmf-d(7) at 300 K is consistent with conformational exchange brought about by rotation about the Pt-N(quinoline) bonds. H.H nonbonded distances between H atoms of the two different quinoline ligands were determined from NOESY data, and these distances are in accord with those observed in the crystal structure and derived from molecular mechanics models. cis-[PtCl(2)(3-bromoquinoline)(quinoline)] was prepared to alleviate the symmetry-imposed absence of inter-ring H2/H2 and H8/H8 NOESY cross-peaks for cis-[PtCl(2)(quinoline)(2)]. Molecular mechanics calculations on the complexes show the HTT rotamers to be 1-2 kJ mol(-)(1) more stable than the HTH forms, consistent with the (1)H spectra where the intensities of resonances for the two forms are approximately equal. Variable-temperature (1)H NMR spectra of cis-[PtCl(2)(quinoline)(2)] in dmf-d(7) indicate a rotational energy barrier of 82 +/- 4 kJ mol(-)(1). Variable-temperature (1)H NMR spectra indicate that the Br substituent on the quinoline ring does not affect the energy barrier to interconversion between the HTT and HTH forms (79 +/- 5 kJ mol(-)(1)). The steric contribution to the rotation barrier was calculated using molecular mechanics calculations and was found to be approximately 40 kJ mol(-)(1), pointing to a possible need for an electronic component to be included in future models.

From a classic approach in cancer chemotherapy towards differentiation therapy: acyclic and cyclic seven-membered 5-fluorouracil O,N-acetals.

Novel derivatives of 5-fluorouracil (5-FU) possessing a broader spectrum of antitumor activity and fewer toxic side effects than 5-FU have been sought. Herein, we report three different types of 5-FU O,N-acetals: a) a novel class of 5-fluorouracil-containing acyclonucleosides. The antitumor activities of such compounds were assessed against HEp human cells showing that (RS)-1-¿[3-(2-hydroxyethoxy)-1-cyclopentoxy]propyl¿-5-fluorouracil 3c is 4-fold more active than 5-FU. (RS)-1-¿[3-(2-hydroxyethoxy)-1-isopropoxy]propyl¿-5-fluorouracil 3b has important potential advantages over 5-FU because of its lower toxicity and its ability to induce myogenic differentiation in rhabdomyosarcoma cells. Our results suggest that this drug may be useful for differentiation therapy in this type of tumor; b) within the cyclic prodrugs of 5-FU, a series of new ring-expanded isosteres (1,4-oxaheteroepanes) of Ftorafur were synthesized. The level of diastereoselectivity in the preparation of cis and trans 1-(3-chloromethyl)-1,4-dioxepan-5-yl)-5-fluorouracil, although modest, suggests a potentially general approach for controlling the stereochemistry of this unexplored class of reactions involving the preparation of 5-FU seven-membered O,N-acetals; c) new 5-FU acyclic analogs containing two 5-FU moieties at both ends of the molecules with a linker having two amide bonds have been designed and synthesized. These bis(5-FU-O,N-acetals) show interesting antineoplastic activities against the HT-29 cell line.

Synthesis of Highly Hindered 1,2-Diaryl Diketones and of cis- and trans-1,2-Diacetoxy-1,2-bis(aryl)ethenes

Highly hindered 1,2-diaryl diketones can be synthesized in good yields by the reaction of 1-aryllithium with CO in THF solution at atmospheric pressure; preparation of cis- and trans-1,2-diacetoxy-1,2-bis(Mes)ethene can be also afforded by a similar procedure and further quenching with Ac2O.

ChemInform Abstract: Novel Preparation of cis,cis‐Trisubstituted Cyclopropane Nucleosides.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Synthesis of Highly Hindered 1,2-Diaryl Diketones and of cis- and trans-1,2-Diacetoxy-1,2-bis(aryl)ethenes

Highly hindered 1,2-diaryl diketones can be synthesized in good yields by the reaction of 1-aryllithium with CO in THF solution at atmospheric pressure; preparation of cis- and trans-1,2-diacetoxy-1,2-bis(Mes)ethene can be also afforded by a similar procedure and further quenching with Ac2O.

Preparation of cis- and trans-[OsCl2(Me2SO)4], and X-Ray Crystal Structures of the All-S-Bound Isomers

Efficient syntheses of the cis and trans isomers of [OsCl2(Me2SO)4] are reported. While a structural study of thetrans isomer confirms the spectroscopically assigned all-S-bound Me2SO configuration, a crystallographic determination of the cis isomer reveals a previously unheralded all-S-bound Me2SO geometry, in contrast to the spectroscopically inferred configuration predominant in solution which has one O-bound ligand. Fortrans-[OsCl2(Me2SO)4], crystals are tetragonal, space group I 4/m, with a 9·092(2), c 11·212(3) Å, Z 2, 566 unique reflections (34 parameters), converging at R 0·026 and Rw 0·032. For cis-[OsCl2(Me2SO)4], crystals are triclinic, space group P-1, with a 8·193(2), b 8·941(3), c 13·837(3) Å, α 79·77(2), β 79·91(2), γ 65·03(2)°, Z 2, 4152 unique reflections (173 parameters), converging at R 0·021 and Rw 0·018.

Preparation of cis-[MoI 4(Ph 2PCH 2CH 2PPh 2)] − and structure of (THF) 3Na(μ-I) 3MoI(Ph 2PCH 2CH 2PPh 2) with a new coordination environment around sodium

The complex cis-[MoI 4(dppe)] − is obtained in good yields from trans-[MoI 4(THF) 2] − and dppe (dppe = 1,2-bis(diphenylphosphino)ethane) or directly from the interaction of MoI 3(THF) 3, I − and dppe and has been isolated as the PPh 4 and Na(THF) 3 salts. The sodium salt has been characterized crystallographically; monoclinic P2 1/n, a = 12.790(2), b = 16.512(7), c = 23.117(4) A ̊ , β = 103.65(1)°, V = 4744(1) A ̊ 3, D calc = 1.84 g cm −3, Z = 4, R = 0.039 for 4485 independent observed reflections ( F o 2 ⩾ 3 σ( F o 2). The structure features an octahedral coordination aroung both Na and Mo atoms in an overall face-sharing bioctahedral structure with the two metals being bridged by three iodide ligands. This is an unprecedented case of a structure containing an O 3I 3 coordination for Na ions and iodide ligands bridging sodium with a transition metal. The 1H NMR properties of the complex are also examined in comparison to those of the MoI 3(dppe)(THF) precursor.

A Convenient Preparation of 1-Mercapto-3-azidocyclo-butane from 1,1-Cyclobutanedicarboxylic Acid

Abstract A convenient method for the preparation of cis- and trans-1-mercapto-3-azidocyclobutane from 1,1-cyclobutanedicarboxylic acid is described. The long range “W” coupling pathway was used to distinguish the cis isomer from the trans isomer.

Chemistry of 4-fluoroglutamic acid. Part 2. Separation of the diastereomers on a large scale. Preparation of cis- and trans-4-fluoro-5-pyrrolidone-2-carboxylic acids (4-fluoropyroglutamic acids)

Separation of the 4-fluoroglutamic acid diastereomers has been achieved by crystallizationof the hydrochlorides of their dialkyl esters 1b and 2d. Subsequent hydrolysis affordedthe diastereomers 1a and 2a in 100% steric purity. Conversion of the acids into the 5-methyl esters followed by treatment with ammonia gives rise to the trans and cis isomersof 4-fluoro-5-pyrrolidone-2-carboxylic acid, 3 and 4. NMR data are given.

Total synthesis of (+) monomorine I from chiral cyclic β-enamino ester

We describe the total synthesis of (+) Monormorine I 1 and the preparation of cis 2,5 disubstituted functionalized pyrrolidines via cyclic β-enamino esters 4, starting from (S)-pyroglutamic acid.

ChemInform Abstract: Highly Stereoselective Radical Cyclization: Copper‐ or Ruthenium‐Catalyzed Preparation of cis‐ and trans‐β,γ‐Dialkyl γ‐Lactams from Acyclic N‐Allyltrichloroacetamide Derivatives.

AbstractCopper(I)‐catalyzed cyclization of the acetamides (I) yields the lactams (II) or (III) via 1,2‐asymmetric induction.

Selective Preparation of Cis 3,5-Dibromo-4-oxo-2,2,6,6-tetramethylpiperidin-1-hydroxy and Conversion to Nitroxide by Peroxide Copper Catalysed

Abstract Selective preparation of cis-3,5-dibromo-4-oxo-2,2,6,6-tetramethylpiperidin-1-hydroxy (6) and in-situ oxidation of alcohols to ketones and aldehydes by oxoammonium bromide in acetic acid as solvent (5) are described.

ChemInform Abstract: Synthesis and Characterization of (Pt(COD)Cl(NO3)) and (Pt(COD)(NO3)2) and the Use of (Pt(COD)Clx(NO3)2‐x) in the Preparation of cis(Pt(PPh3)2Clx(NO3)2‐x) (x = 0, 1, 2) and (Pt(PPh3)3L)(NO3) (L: Cl, NO3).

AbstractDichlorocyclooctadiene‐Pt(II) (I) is a versatile starting material for the synthesis of Pt(II) compounds.

Synthesis and spectroscopic studies of substituted molybdenum carbonyls ofN, N?-ethylenebis(1,2-dimethylpyrazole-3-carboxaldeneimine) and monodentate tertiary phosphines

Improved preparations ofcis-[LMo(CO)4],cis-[L2Mo(CO)2], and [LMo(CO)3P] where L=N, N′-ethylenebis(1, 2-dimethylpyrazole-3-carboxaldeneimine) and P=P(p-MeOC6H4)3, P(p-MeC6H4)3, P(p-ClC6H4)3 or P(o-MeC6H4)3 are reported. The compounds were characterized by elemental analysis and i.r., electronic and31P n.m.r. spectra. The ν(CO) values for the nonphosphine complexes indicate Mo(4d)−L(π*) back-bonding. Furthermore, L exists in two different configurations in the [{LMo(CO)4}2] and the monomeric derivatives. Electronic spectral data are discussed in terms of the effect of the π-acceptor tendency of the Mo(4d)−L(π*) back bonding.31P n.m.r. and i.r. data of the phosphine-containing compounds indicate that the more electron-withdrawing substituents on the phosphines gave larger31P coordination chemical shifts and larger CO frequencies.

Synthesis and characterization of [Pt(COD)Cl(NO 3)] and [Pt(COD)(NO 3) 2] and the use of [Pt(COD)Cl x(NO 3) 2− x] in the preparation of cis[Pt(PPh 3) 2Cl x(NO 3) 2− x] ( x=0, 1, 2) and [Pt(PPh 3) 3L](NO 3) (L=Cl, NO 3)

[Pt(COD)Cl 2] (COD=1,5-cyclooctadiene) is a versatile starting material for the synthesis of Pt(II) compounds. The preparations of the new compounds [Pt(COD)Cl(NO 3)], [Pt(COD)(NO 3) 2] and [Pt(PPh 3) 3(NO 3)](NO 3) and also of the known compounds cis[Pt(PPh 3) 2Cl 2], cis [Pt(PPh 3) 2Cl(NO 3)], cis[Pt(PPh 3) 2(NO 3) 2] and [Pt(PPh 3) 3Cl](NO 3)are reported. The compounds are characterized by elemental analysis, 31P{ 1H} NMR spectroscopy and IR spectroscopy.