bluuebunny/crossref_metadata_2025 huggingface dataset:
Preparation and Characterization of Copper(II) and Nickel(II) Complexes with N-Benzyliminodiacetamide Derivatives
Authors: Smrečki Neven , Stilinović Vladimir , Merkaš Maja , Lučić Andrea , Kukovec Boris-Marko , Popović Zora
Published: November 2018

The reactions of substituted N-benzyliminodiacetamides (o-CH3Bnimda, m-CH3Bnimda, p-CH3Bnimda, o-ClBnimda, m-ClBnimda, p-ClBnimda, p-FBnimda, and p-BrBnimda; o-CH3Bn = ortho-methylbenzyl, m-CH3Bn = meta-methylbenzyl, p-CH3Bn = para-methylbenzyl, o-ClBn = ortho-chlorobenzyl, m-ClBn = meta-chlorobenzyl, p-ClBn = para-chlorobenzyl, p-FBn = para-fluorobenzyl, and p-BrBn = para-bromobenzyl) with copper(ii) and nickel(ii) nitrate in aqueous solutions were investigated. Sixteen new complexes [Cu(o-CH3Bnimda)2](NO3)2⋅0.5H2O (1), [Cu(m-CH3Bnimda)2](NO3)2 (2), [Cu(p-CH3Bnimda)2](NO3)2⋅2H2O (3), [Cu(o-ClBnimda)2](NO3)2⋅H2O (4), [Cu(m-ClBnimda)2](NO3)2 (5), [Cu(p-ClBnimda)2](NO3)2⋅2H2O (6), [Cu(p-FBnimda)2](NO3)2⋅2H2O (7), [Cu(p-BrBnimda)2](NO3)2⋅2H2O (8), [Ni(o-CH3Bnimda)2](NO3)2⋅H2O (9), [Ni(m-CH3Bnimda)2](NO3)2⋅2H2O (10), [Ni(p-CH3Bnimda)2](NO3)2⋅H2O (11), [Ni(o-ClBnimda)2](NO3)2 (12), [Ni(m-ClBnimda)2](NO3)2⋅2DMF (13) (DMF = N,N-dimethylformamide), [Ni(p-ClBnimda)2](NO3)2⋅2H2O (14), [Ni(p-FBnimda)2](NO3)2⋅H2O (15), and [Ni(p-BrBnimda)2](NO3)2⋅2H2O (16) were prepared and characterized by infrared spectroscopy and thermal analysis (thermogravimetric and differential thermal analyses). The molecular and crystal structures of three complexes (2, 5, and 13) were determined by X-ray crystal structure analysis. The octahedral coordination environments around the copper(ii) and nickel(ii) ions in complexes 2, 5, and 13 consist of two O,N,O'-tridentate iminodiacetamide ligands. The complexes are trans-isomers with fac-configuration of the chelators.
Polarities of hydrocarbons and non-neighbour resonance integrals
Authors: Brown RD , Burden FR , Mohay GM
Published: November 2018

A study is made of the
polarities predicted for alternant hydrocarbons by the VESCF procedure with
non-neighbour resonance integrals included. Four categories of unsymmetrical
hydrocarbons emerge: purely cyclic six-membered ring compounds (μ ≤
0.1 D), systems containing conjugated chains (μ = 0.1 D), quinodimethanes (μ = 0.3 D), systems containing
four-membered rings (μ = 0.6 D or more). The theoretical values are close
to experiment in the few cases where the latter is available but the need for
further precise experimental studies is emphasized. For comparison, analogous
calculations on non-alternant hydrocarbons are presented. The results suggest
that alternants containing four-membered rings are as polar as typical
non-alternants and that on polarity grounds there is no clear-cut separation
into two categories of hydrocarbon. The discrepancy between
theory and experiment for azulene and possible discrepancies for one or
two other non-alternants 1s discussed. It seems possible that the neglect of
possible σ-bond polarities should be questioned and that recent
theoretical techniques embracing all valence electrons might be needed for full
understanding of hydrocarbon polarities.
The solution dipole moments and the atomic polarizations of chloro-, bromo-, and iodo-benzenes
Authors: Huang HH , Sullivan VR
Published: November 2018

Dielectric constant and
density measurements of solutions of chloro-, bromo-, and iodo-benzene
together with those of p-dichloro-, p-dibromo- and p-diiodo-benzene in
carbon tetrachloride at 25� are given. Distortion and atomic polarization
values for the polar solutes are estimated by a method proposed by B�ttcher; the values are compared with other estimates of PD
and PA. To obtain quantitative information of atomic polarizations,
using B�ttcher's method, greater precision than is
usual in solution dielectric constant measurements would be required.
Benzene-induced solvent shifts of proton resonances in the N.M.R. spectra of α-diketones
Authors: Bowie JH , Gream GE , Laffer MH
Published: November 2018

Solvent shifts [ΔC6H6
= δCCk4 ? δCCl4 p.p.m.] are recorded for a
number of acyclic and cyclic α-diketones. Benzene produces upfield shifts
of methyl and methylene resonances in the spectra of saturated acyclic and
cyclic α-diketones. The shift of the α-methylene resonance of acyclic
a-diketones may be related to the length (and bulk) of the side-chain. The
formation of a 1 : 1 complex is proposed, and variable temperature studies (in
toluene-ds) have allowed calculation of thermodynamic parameters for
an acyclic and a cyclic compound. The dependence of solvent shifts on the
position of methyl and hydrogen substituents of aromatic α-diketones has
been demonstrated.
Coordination derivatives and reactions of dichloropentafluorophenylindium
Authors: Deacon GB , Parrott JC
Published: November 2018

The complexes C6F5InCl2,L
[L = N,N,N?,N?-tetramethylethylenediamine (tmed), 2,2?-bipyridyl (bpy),
1,10-phenanthroline (phen), 2,2?:6?,2?- terpyridyl (tpy) or (Ph2PCH2)2]
have been prepared by reaction of C6F5InCl2,diox
(diox = 1,4-dioxan) with the appropriate ligands, and
are considered to contain five-coordinate indium on the basis of indium- chlorine
stretching frequencies. Monomeric structures are likely for all complexes
except C6F5InCl2,tmed, which is dimeric with
bridging tmed. Atmospheric moisture converts C6F5InCl2,L
(L = phen or tpy) into
monohydrates, in which water is not coordinated. Reaction of C6F5InCl2,diox
with pyridine, triphenylphosphine and dimethyl sulphoxide causes quantitative
rearrangement into the corresponding indium trichloride and tris-pentafluorophenylindium complexes. The derivatives (C6F5)nIn(ox)3-n(n = 1 or 2; ox =
quinolin-8-olate) have been prepared by cleavage of (C6F5)3In,diox
with quinolin-8-ol, and C6F5In(ox)2 has also
been obtained from C6F5InCl2,diox and thallous
quinolin-8-olate.
Aromatic amides. VIII. Z,E Isomer ratios and stereochemistry about aryl-nitrogen bonds in N-aryl amides and thioamides
Authors: Bate DL , Rae ID
Published: November 2018

For 4?-substituted 2?,6?-diethylacetanilides,
the Z/E isomer ratio depends on the nature of the 4?- substituent, the Z isomer
being relatively favoured by electron-withdrawing substituents. The acyla- tion shifts of the ortho
aromatic protons for 4?-substituted thiopivalanilides
are greatest when the substituent is electron- withdrawing. These relationships
complement the previously observed changes in isomer ratios of thioamides and
acylation shifts of amides. It is proposed that the Z isomer is more nearly
planar when the 4?- substituent is electron-withdrawing. As the substituent
becomes more electron-releasing, the amide group is able to twist more out of
the ring plane and the Z isomer is destabilized, relative to the E isomer, by
n-π electron repulsions.
Electrophilic substitution with chlorothioformamidinium salts. Synthesis and reactions of some Pyrrolyl- and Indolyl-thioformamidinium salts
Authors: Harris RLN
Published: November 2018

Reaction of pyrroles and indoles with chlorothioformamidinium
salts in benzene gives pyrrolyl- and indolyl-thioformamidinium salts in fair to good yield.1
These compounds are reactive and versatile intermediates and can be converted
into the corresponding esters and amides and their thio
derivatives and to a variety of pyrrolyl- and indolyl-substituted heterocycles.
The condensation of some phenols with malic acid, maleic acid and maleic anhydride
Authors: Molyneux RJ , Jurd L
Published: November 2018

Optimum yields of coumarins are obtained by Pechmann
condensation of polyphenols with malic acid in the
presence of sulphuric acid at 100- 120� in the absence of water. Under these
conditions the Ponndorf reaction with maleic acid
does not occur.��� Pechmann
condensation of pyrogallol with malic acid gives substantial quantities of the
novel dicoumarin (2), while the condensation of
resorcinol with maleic anhydride in the presence of zinc chloride yields the
benzoyl dihydrocoumarin (5a).
Terpenoid constituents of Indian Glochidion species: Glochidion accuminatum and Glochidion thomsoni. Partial synthesis of glochidone
Authors: Talapatra B , Dutta S , Maiti BC , Pradhan DK , Talapatra SK
Published: November 2018

Glochidone (1),
glochidonol(2) and β-sitosterol were isolated from Glochidion accuminatum
while G. thomsoni furnished glochidone (1), lup-
20(29)-ene-1β,3β-diol (3) and β-sitosterol. A partial synthesis of
glochidone has been achieved in 25% yield by the 2,3-dichloro-5,6- dicyanobenzoquinone
dehydrogenation of lupenone.
Studies of Some Tetraazacyclopentadecadiene Complexes of Nickel(II). The Crystal and Molecular-Structure of (1RS,8SR)-(5,7,7,13,15,15-Hexamethyl-1,4,8,12-Tetraazacyclopentadeca-4,1 2-Diene)Nickel(II) Perchlorate Hydrate
Authors: Curtis NF , Gainsford GJ
Published: November 2018

The crystal and molecular structure has been determined by X-ray diffractometry for the singlet ground state nickel(II) compound of a fifteen- membered tetraaza macrocyclic ligand , formed by reaction of a mixture of tris ( ethanediamine )nickel(II) and tris (propane-1,3- diamine )nickel(II) perchlorates with acetone. The compound, (1RS,8SR)- 5,7,7,13,15,15-hexamethyl-1,4,8,12-tetraazacyclopentadeca-4,12- diene )nickel(II) perchlorate hydrate, [Ni( hmpd )](ClO4)2.H2O, is monoclinic, space group P21/C, a 1158.76(14), b 1319.53(22), c 1630.35(21) pm, β 96.209(10)°, R 0.046, Rw 0.062 for 2798 reflections. The nickel(II) ion is in tetrahedrally distorted square-planar coordination [mean Ni-N distances 188.9 pm ( imine ), 191.9 pm (amine), displacements of nitrogens c. �20 pm from mean coordination plane]. Triplet ground state compounds [Ni( hmpd )( acac )]ClO4 and [{Ni( hmpd )}2C2O4](ClO4)2, with the macrocycle in folded coordination, were prepared and converted into an isomeric form of [Ni( hmpd )](ClO4)2. The 3,5,7,7,13,15,15-heptamethyl homologue of [Ni( hmpd )]2+ was prepared by reaction of tris (propane-1,2-diamine)- and tris (propane-1,3-diamine)- nickel(II) perchlorates with acetone. The electronic (d-d), 1H N.M.R. and 13C N.M.R . spectra of compounds of these macrocyclic cations, and of (5,5,7,13,15,15-hexamethyl-1,4,8,12-tetraazacyclopentadeca-7,12-diene) nickel(II) are reported.
Excess Molar Volumes of Binary Mixtures of Ethyl Acetate and Propyl Acetate With Normal Alkanols
Authors: Ortega J , Pena JA , Pazandrade MI
Published: November 2018

This article reports measurements of VE/m at 298.15 K for binary mixtures of n- alkanols CnH2n+1OH (from n = 2 to n = 10) with ethyl and propyl acetates. All the excess volumes are positive over the entire concentration range, with VE/m increasing with the length of the alkanol chain. Suitable equations have been fitted to the data for each mixture. The results are compared with data previously published.
The Chemistry of 5-Oxodihydroisoxazoles. II. Photolysis and Pyrolysis of 2-(Isoquinolin-1-yl)-3-methyl-5-oxo-2,5-dihydroisoxazole-4-carboxylate
Authors: Singh Y , Prager RH
Published: November 2018

Photolysis of ethyl 2-( isoquinolin-1-yl )-3-methyl-5-oxo-2,5-dihydroisoxazole-4-carbolate occurs by two pathways. The major pathway involves the loss of CO2 to form an imino carbene which may cyclize to form the expected (6) or rearranged (8) imidazo[2,1-a] isoquinolines or react with nucleophiles and recyclize to form the 4-oxopyrimido[2,1-a]isoquinolines. The minor pathway involves electrocyclic ring opening of the isoxazolone and ring closure with or without loss of CO. Pyrolysis leads predominantly to an imino carbene which reacts intramolecularly to give (6) or undergoes insertion into CH bonds.
Psammopemmins (A-C), Novel Brominated 4-Hydroxyindole Alkaloids From an Antarctic Sponge, Psammopemma sp.
Authors: Butler MS , Capon RJ , Lu CC
Published: November 2018

Two specimens of a marine sponge Psammopemma sp. collected from Prydz Bay, Antarctica, have been found to contain three new brominated 4-hydroxyindole alkaloids: psammopemmin A (4), -B (5) and -C (6). These novel secondary metabolites, which also incorporate a unique 2-bromopyrimidine moiety, have been assigned structures on the basis of detailed spectroscopic analysis and derivatization.
Nitrones and Oxaziridines. XLIV. Synthesis of Indol-3- and -2-ylmethyl-Substituted 1-Pyrroline 1-Oxides
Authors: Black DS , Craig DC , Debdas RB , Kumar N
Published: November 2018

3-(2'-Nitroethy1) indole (3) and more importantly 1,3-dimethyl-2-(2'-nitroethyl) indole (10) have served as precursors for the construction of several 1-pyrroline 1-oxides (6), (15) and (17) and the related 1-pyrrolines (7), (16) and (18) via the γ-nitro ketones (4): (12) and (14). Attempts to oxidize these structures to achieve highly conjugated systems were unsuccessful. X-Ray crystallographic data are presented for the 1-pyrroline 1-oxides (15) and (17).
The X-Ray Crystal-Structure of (+/-)-Pandamarine, the Major Alkaloid of Pandanus-Amaryllifolius
Authors: Byrne LT , Guevara BQ , Patalinghug WC , Recio BV , Ualat CR , White AH
Published: November 2018

The structure (2) of ( �)-pandamarine , the major alkaloid isolated from the leaves of Pandanus amaryllifolius Roxb., has been determined by an X-ray diffraction study. Diffractometer data at 295 K were refined by least-squares techniques to a residual of 0.049
2244 'observed' reflections). Crystals of (2) are triclinic, P1, a 13.077(2), b 9.857(5), c 7.214(2) �, α 106.91(3), β 96.22(2), γ 100.01(2)0, Z 2.
The Expression of Distinctive Secondary Metabolites by Different Eucalyptus spp
Authors: Carman RM
Published: November 2018

A survey of the essential oils of various Eucalyptus species shows that there are sufficient compounds present to support the expectation that differences between species will be expressed or accompanied at the secondary metabolite level by different chemicals, rather than by a different mix of similar chemicals.
Characterization of a Crystalline Residue From a Swimming Pool: Disodium Copper(II) Tetrakis(isocyanurate) Hexahydrate
Authors: Hart RD , Skelton BW , White AH
Published: November 2018

Coupled with chemical analysis, a single-crystal X-ray structure determination of lilac deposit from a swimming pool, shows the deposit to be the title compound Na2Cu(C3H2N3O3)4.6H2O. Crystals are triclinic, P1, a 10.459(1), b 10.434(3), c 6.762(4) � , α: 71.73(4), β 83.67(4), γ 62.82(2), Z 1 formula unit; 1265 'observed' diffractometer reflections were refined to R 0.052. The copper atoms are located on crystallographic inversion centres, four-coordinated by a pair of water molecules [Cu-O, 1.937(6) � ] and a pair of ligand nitrogen atoms [Cu-N, 1.941(9) � ]. Interactions from ligand oxygen atoms to sodium ions link the structure into a polymeric array.
Synthesis of 3-Methyl-4-oxo-3,4-dihydroquinazoline-5-sulfonamide and a Herbicidal Sulfonylurea Derivative
Authors: Bell S , Bonadio A , Watson KG
Published: November 2018

Starting with 6-chloroquinazolin-4(3H)-one (5), a convenient synthesis of 3-methyl-4-oxo-3,4-dihydroquinazoline-5-sulfonamide (11) has been achieved. The sulfonamide (11) was used to prepare a highly herbicidal sulfonylurea derivative (13).
Intramolecular Homolytic Displacement. XXIII. Selectivity in the Induced Decomposition of Ethyl t-Butylperoxymethylpropenoate by Radicals Formed From Methyl Propanoate and Derivatives
Authors: Degueilcastaing M , Navarro C , Ramon F , Maillard B
Published: November 2018

Thermal decomposition of t-butyl peracetate in a solution of ethyl t- butylperoxymethylpropenoate in methyl propanoate led to the products of substitution of the three different hydrogens in the molecule of the methyl ester by the 2,3-epoxy-2-ethoxycarbonylpropyl group. An SHi reaction on the peroxide function, following the addition to the double bond, is responsible for the formation of these epoxides . Such a result is due to the low regioselectivity of the hydrogen abstraction from methyl propanoate by t- butoxyl radicals, and no improvement could be obtained by changing the relative ratios of the reactants, in converse to previous results described for similar reactions. Thus, selective creation of alkyl radicals was developed through the generation of tributylstannyl radicals as mediator radicals, by reaction of t- butoxyl radicals on tributyltin hydride or hexabutylditin ; the mediator radicals abstract an iodine atom from the alkyl iodide. Application of this methodology to the three iodo derivatives of methyl propanoate permitted us to obtain selectively each of the three epoxides.
Tandem Radical Cyclizations: a One-Step Synthesis of Stereoisomeric Tricyclo[6.3.0.02,6]undecanes From Acyclic Precursors
Authors: Curran DP , Sun SN
Published: November 2018

Radical cyclization of (1E,5Z)-1-iodoundeca-1,5,10-triene with triphenyltin hydride provides one acyclic, one monocyclic, two bicyclic and four tricyclic products. At low concentration (0.002 M), the title tricycloundecane products resulting from triple cyclization predominate, but the stereoselectivity is low. Cyclization of (1E,5Z)-1-iodo-8,8-bis( phenylsulfonyl )undeca-1,5,10-triene followed by reductive desulfonylation provides a similar ratio of products to the parent. The results show that this class of triple cyclization occurs well, but the level of stereoselectivity must be raised for it to become synthetically useful.
Cyclization Reactions of Tethered Radicals Derived From 4-O-Substituted α-D-erythro-Octa-2,6-dienopyranosides: Stereoselective Access to Carbocycles and Branched-Chain Sugars
Authors: Lopez JC , Gomez AM , Fraserreid B
Published: November 2018

The chemo- and stereo- selectivities in the cyclization of tethered radicals, derived from α-D-erythro-octa-2,6-dienopyranosides, in which there is competition between 5-exo and 6-exo ring closures, have been examined. Use of silicon tethers resulted in a preferred 6-exo-trig addition. However, tethered mixed iodo acetals have shown an unprecedented relation between the stereogenic centre in the acetal and the preferred addition pathway. In addition, changes in the oxidation state at the termini of the olefins have a profound effect upon site selectivity, thus leading to 3-deoxy 3-C-substituted carbohydrates, off-template branched-chain sugars, or functionalized cyclopentanes.
Preparation and Biological Activity of Heteroaryl-Substituted Bile Steroids
Authors: Brown CL , Harding MM , Krippner GY , Rainone S , Webster LK
Published: November 2018

The synthesis, and growth inhibition studies against the L1210 mouse leukaemia, �MCF-7 human breast cancer and SKOV-3 ovarian carcinoma cell lines, of derivatives of lithocholic acid and cholic acid in which quinoline-3-carboxylate and acridine-9-carboxylate are substituted at the 3 and/or the 24 position are reported. The 3α,24-diheteroaryl-substituted steroid systems, lithocholic acid, cholic acid, quinoline and acridine-9-carboxylic acid showed no significant biological activity against any of the cell lines. In contrast, when either a single quinoline-3-carboxylate or acridine-9-carboxylate unit is substituted onto position 24 of the steroid derivatives, significant activity against L1210, and weak activity against the MCF-7 and SKOV-3 lines is exhibited. DNA thermal denaturation studies of these compounds showed no detectable binding to calf thymus DNA.
Synthesis and Structural Systematics of Nitrogen Base Adducts of Group 2 Salts. I. Some Adducts of Group 2 Halides With Acetonitrile
Authors: Waters AF , White AH
Published: November 2018

Recrystallization of
anhydrous Group 2 halides from anhydrous acetonitrile has yielded, in a number
of cases, adducts MX2.nMeCN suitable for characterization by room-temperature
single-crystal X-ray

studies, which revealed
novel stereochemical types. Magnesium(II) bromide yields a trisolvate, ionic
with disproportionated ligand arrays, as [Mg(NCMe)6][MgBr4] (1), an unusual
combination of homoleptic cationic and anionic species. Crystals are triclinic,
Pī , a 19.129(1), b l6.870(8), c 8.737(7) Ǻ,α 83.96(3), β 87.93(4), γ 65.24(2)�,
Z=4 f.u .; R was 0.068 for N o
3181 'observed' (I > 3σ(I)) reflections.
Mg-N are 2.12(2)-2.18(2) Ǻ, and Mg-Br are 2.452(7)-2.481(6) Ǻ.
Calcium(II) bromide, by contrast, yields a disolvate ,
an infinite polymer, with the two MeCN ligands trans in a quasi-octahedral coordination sphere,
and the polymer comprising a ... Ca(μ-Br)2Ca(μ-Br)2... linear array.
Crystals of 1:2 CaBr2/MeCN (2) are orthorhombic, Pbam ,
a l4.252(3), b 8.539(2), c 4.2088(6) Ǻ, Z=2 f.u .;
R 0.043 for N
o 352. Ca-N is 2.46(1) Ǻ, and Ca-Br 2.8765(9) Ǻ. CaI2 and SrI2
yield pentasolvates as neutral, molecular species [( MeCN )5MX2] (3) and (4), with the halides trans in a
pentagonal bipyramidal coordination sphere. They are isomorphous . orthorhombic, Pcab ,
a ≈ 18.4, b ≈ 14.6, c ≈ 14.3 Ǻ, Z = 8 f.u .; R were 0.042 and 0.059 for N o
2297 and 1489 respectively. Ca-I are
3.132(2), 3.116(2) Ǻ and Sr -I are 3.265(3),
3.238(3) Ǻ, while Ca-N are (range) 2.518(8)-2.566(8) Ǻ and Sr -N 2.68(2)-2.73(2) Ǻ.
Synthesis and Structural Systematics of Nitrogen Base Adducts of Group 2 Salts. VI. Mixed Oligodentate-Aliphatic-Base/Oxygen Ligand Adducts
Authors: Waters AF , White AH
Published: November 2018

In the course of synthesizing oligodentate aliphatic nitrogen base adducts of Group 2 metal salts, a number of mixed- ligand species have been isolated with oxygen ligands , and characterized by room-temperature single-crystal X-ray studies. BaCl2.4en.H2O ≡[(en)4Ba(OH2)] Cl2 (1) is monoclinic, P 21/c, a 9.456(4), b 14.953(6), c 14.82(1) Ǻ, β 100.78(6)°, Z = 4 f.u ., R 0.043 for No 1862 independent 'observed' (I > 3σ(I)) diffractometer reflections. Ba -N range between 2.900(9) and 2.97(1) Ǻ, and Ba-O is 2.779(8) Ǻ in the nine-coordinate BaN8O environment. CaCl2.2dien.H2O ≡ [( dien )2Ca(OH2) Cl ] Cl (2) is monoclinic, P 21/c, a 10.808(4), b 11.999(4), c 15.71(1) Ǻ, β 123.58(4)°, Z = 4 f.u ., R 0.050 for No 3134; CaBr2.2dien.2H2O ≡ [( dien )2Ca(OH2)2] Br2 (3) is monoclinic, P 21/c, a 18.001(3), b 11.983(6), c 21.562(5) Ǻ, β 124.97(2)°, Z = 8 f.u ., R 0.045 for No 2858; CaBr2.2dien.2MeOH ≡ [( dien )2Ca( HOMe )2] Br2 (4) is orthorhombic, P212121, a 16.620(8), b 12.78(1), c 9.765(4) Ǻ, Z = 4 f.u ., R 0.073 for No 878. In (2)-(4), the cation configurations are similar, being of the form [L2Ca( dien )2], L (L') being the unidentate ligand, with the eight-coordinate calcium environments [L2Ca(N3)2] in a common isomeric configuration, the two ligands L being cis in an array of quasi-2 symmetry. Ca- Cl in (2) is 2.834(1) Ǻ; Ca-N generally range between 2.52(5) and 2.64(1) Ǻ; Ca-O(H2O) is 2.418(2) in (2), 2.434(7)-2.496(7) Ǻ in (3), while Ca-O( MeOH ) in (4) are 2.43(2) and 2.43(2) Ǻ. [Mg(HOMe)6] I2.2tmeda (5) ( tmeda = Me2N(CH2)2NMe2), orthorhombic, Pbca, a 23.423(8), b 15.306(4), c 9.345(1) Ǻ, Z = 4 f.u ., R 0.052 for No 1928, provides a usefully precise description for the centrosymmetric cation, Mg-O being 2.069(4), 2.080(4), 2.096(5) Ǻ, with Mg-O-C 128.4(4) l28.9(4), l29.7(4)°. [( tmeda )SrI2 ( HOMe )3].½tmeda (6), monoclinic, P 21/c, a 7.730(1), b 35.493(9), c 11.081(2) Ǻ, β 126.49(1)°, R 0.042 for No 3161, has a seven-coordinate, quasi-pentagonal bipyramidal SrN2I2O3 array about the metal with trans-iodines.
Crystal and Molecular Structures of M3(μ3-η2-PhC2C≡CPh)(μ-CO)(CO)9 (M = Ru and Os)
Authors: Bruce MI , Skelton BW , White AH , Zaitseva NN
Published: November 2018

The molecular structures M3(μ3-η2-PhC2C≡CPh)(μ-CO)(CO)9 (M = Ru and Os) are described: these complexes are similar to several mono-alkyne derivatives, with one C≡C triple bond of the diyne ligand attached in the 2η1,η2-(||) mode to the closed triangular M3 core. The M-M edge parallel to the complexed C≡C triple bond is asymmetrically bridged by a CO ligand; the coordination about each M atom is completed by three terminal CO ligands. Crystals of the isomorphous Os [ Ru ] complexes were triclinic, space group Pī (Ci1, No. 2), a 18.869(9) [18.881(5)], b 9.164(3) [9.188(3)], c 8.548(2) [8.595(6)] Ǻ, α 65.73(2) [66.00(3)], β 78.53(3) [78.43(4)], γ 87.25(3) [87.58(2)]°, Z 2. 7323 [3638] observed data [I > 3σ(I)] were refined to R 0.031 [0.030] and Rw 0.036 [0.032].
The Structure of Subconfluentic Acid, a Depside From the Lichen Lecidella cf. cyanosarca
Authors: Elix JA , Wardlaw JH , David F
Published: November 2018

The structure of the depside subconfluentic acid (4-[2'-hydroxy-4'-methoxy-6'-(2"-oxopentyl)benzoyloxy]-2-methoxy-6-pentylbenzoic acid) has been unambiguously established by synthesis.
Molybdenum Hexacarbonyl Promoted Ring-Opening of Hydroxyimino Isoxazoles: Unexpected Pyrazole Formation
Authors: Andersonmckay J , Savage GP , Simpson GW
Published: November 2018

Fused isoxazoles underwent reductive ring-opening in the presence of molybdenum hexacarbonyl to give the corresponding β-disubstituted compounds. 3,6,6-Trimethyl-6,7-dihydro-1,2-benzisoxazol-4(5H)-one oxime underwent reductive ring-opening in the presence of molybdenum hexacarbonyl to give 3,6,6-trimethyl-6,7-dihydro-1H-indazol-4(5H)-one. A mechanism is proposed.
Phenserine, a Novel Anticholinesterase Related to Physostigmine: Total Synthesis and Biological Properties
Authors: Brossi A , Pei XF , Greig NH
Published: November 2018

Phenserine, the phenylcarbamate analogue of physostigmine , is a drug candidate of potential use for treating Alzheimer's disease. Phenserine inhibits acetylcholinesterase selectively, improves memory dramatically in experimental animals without toxicity, and reduces the production of β-amyloid precursor protein, the source of the Alzheimer's toxin β-amyloid. Phenserine was made from physostigmine in two steps, and it can be prepared in the required optically active form by total synthesis. For this purpose, the oxindole route developed by Julian in his total synthesis of physostigmine was vastly improved. Details of this work performed at the National Institutes of Health and at Institutions sponsored by this agency are presented herein.
Stoechadone: a New Naphthoquinone From Conospermum stoechadis
Authors: Aguinaldo AM , Armstrong JA , Cannon JR , Colegate SM , Comber MF , Marchant NG , Sargent MV
Published: November 2018

Extraction of the dried root bark of the Western Australian plant Conospermum stoechadis Endl . has yielded 3,6,7-trimethoxy-2-methylnaphthalene-1,4-dione, stoechadone (1). The structure was elucidated by spectroscopic methods and was confirmed by a short synthesis from methyl homoveratrate (3).
Imidazo[1,2-b]Pyridazines. XXI. Syntheses of Some 3-Acylaminomethyl-6-(chloro, fluoro, methoxy, methylthio, phenoxy and phenylthio)-2-(phenyl, 4-t-butylphenyl, 4-cyclohexylphenyl, β-naphthyl and styryl)imidazo[1,2-b]pyridazines and Their Interaction With Central and Peripheral-Type Benzodiazepine Receptors
Authors: Barlin GB , Davies LP , Harrison PW , Ireland SJ , Willis AC
Published: November 2018

Some 3-(aliphatic and aromatic) acylaminomethyl derivatives of 6-( chloro, fluoro, methoxy, methylthio, phenoxy and phenylthio )-2-(phenyl, 4-t-butylphenyl, 4-cyclohexylphenyl, β- naphthyl and styryl ) imidazo [1,2-b] pyridazines have been prepared and tested for binding to central benzodiazepine receptors present in rat brain membrane, and to peripheral-type (mitochondrial) benzodiazepine receptors present in rat kidney membrane. Some of these compounds which contained 2-(4-t-butylphenyl, 4-cyclohexylphenyl and styryl ) substituents bound strongly and selectively to peripheral-type benzodiazepine receptors. For example, 2-(4′-t-butylphenyl)-6-chloro-2-(4″-fluorobenzamidomethyl) imidazo [1,2-b] pyridazine in tests for the displacement of [3H]diazepam from both peripheral-type and central benzodiazepine receptors gave IC50 <1.0 nM and 9% displacement at 1000 nM , respectively. Steric effects appeared to be more restrictive in the interaction of these ligands with central benzodiazepine receptors rather than with peripheral-type benzodiazepine receptors; X-ray structure analyses of two typical compounds are reported.
Photochemical Nitration by Tetranitromethane. XXXII. Adduct Formation in the Photochemical Reaction of Phenanthrene and Tetranitromethane
Authors: Butts CP , Eberson L , Fulton KL , Hartshorn MP , Robinson WT
Published: November 2018

Photolysis of the phenanthrene/tetranitromethane charge-transfer complex yields the triad of phenanthrene radical cation, nitrogen dioxide, and trinitromethanide ion. Recombination of this triad in dichloromethane at 20° gives 9-nitrophenanthrene (1), trans-10-trinitromethyl-9,10-dihydrophenanthren-9-yl nitrate (2a), trans-9-nitro-10-trinitromethyl-9,10-dihydrophenanthrene (2b), and trans-10-trinitromethyl-9,10-dihydrophenanthren-9-ol (2c). Adduct formation is partially suppressed when trifluoroacetic acid (0.7 M) is added to the dichloromethane solvent at 20°, the major product identified being 9-nitrophenanthrene (1). At -20° in dichloromethane, or in acetonitrile at 20°, 10'-nitro-9,9',10,10'-tetrahydro-9,9'-biphenanthren-10-yl nitrate (3) is formed, apparently by reaction of nitrogen dioxide with phenanthrene. X-Ray crystal structure determinations are reported for adducts (2a,b).
Novel Uperin Peptides From the Dorsal Glands of the Australian Floodplain Toadlet Uperoleia inundata
Authors: Bradford AM , Raftery MJ , Bowie JH , Tyler MJ , Wallace JC , Adams GW , Severini C
Published: November 2018

The dorsal glandular extract of the floodplain toadlet Uperoleia inundata contains more than 50 peptides: we report the amino acid sequences and bioactivity data of 13 of these. The peptides have been sequenced by using a combination of mass spectrometry and automated Edman sequencing. Ten of the peptides have been synthesized in order to confirm their structures, and to enable bioassays to be carried out. Ten peptides are host- defence agents, including ( i ) a powerful new neuropeptide of the tachykinin family which we name uperin 1.1 [ pGlu Ala Asp Pro Asn Ala Phe Tyr Gly Leu Met (NH2)], and (ii) nine antibiotic peptides including five uperins 2 [e.g. uperin 2.1, Gly Ile Val Asp Phe Ala Lys Lys Val Val Gly Gly Ile Arg Asn Ala Leu Gly Ile (OH)], three uperins 3 [e.g. uperin 3.1, Gly Val Leu Asp Ala Phe Arg Lys Ile Ala Thr Val Val Lys Asn Val Val (NH2)] and uperin 4.1 [ Gly Val Gly Ser Phe Ile His Lys Val Val Ser Ala Ile Lys Asn Val Ala (NH2)]. The function of the three other characterized peptides in the amphibian integument is not known, viz. ( i ) uperin 5.1 [ Phe Gln Phe Val Asn Pro Ser Asp Ile Val Phe Gly Ser (OH)] and (ii) the two uperins 6 [e.g. uperin 6.1, Gly Leu Ala Gly Ala Ile Ser Ser Ala Leu Asp Lys Leu Lys Gln Ser Gln Leu Ile Lys Asn Tyr Ala Lys Lys Leu Gly Tyr
Pro Arg (OH)].
Structural Characterization of Two Crystalline Forms of Bis[2-(1,5-dimethyltrazol-3-yl)-1,10-phenanthroline]-iron(II) Perchlorate—a Spin Crossover System
Authors: Sugiyarto KH , Craig DC , Goodwin HA
Published: November 2018

At room temperature bis [2-(1,5-dimethyltriazol-3-yl)-1,10-phenanthroline]iron(II) perchlorate has magnetic and Mossbauer spectral properties which indicate that it contains both singlet and quintet state iron(II) in a ratio of approximately 1:2. Two polymorphs were identified in a small batch of crystals grown from acetone/ethanol for crystal structure determination. In polymorph 1 the average iron-nitrogen distance (1.97 Ǻ) is close to the value usually obtained for purely singlet state iron(II) in an [FeN6]2+ system, whereas that for polymorph 2 (2.09 Ǻ) is consistent with the 1:2 ratio of singlet-to-quintet state species. The Mossbauer spectrum of the crystallographic sample is virtually identical to that of the bulk sample. There are small differences in the coordination sphere which could account for the different extent of stabilization of the singlet state in the two polymorphs. The crystal packing differs markedly for the two polymorphs but reveals no obvious rationalization for the spin-state differences. Bis [2-(1,5-dimethyltriazol-3-yl)-1,10-phenanthroline]iron(II) perchlorate , two-thirds water (polymorph 1): monoclinic, space group P 21/c, a 10.766(3), b 25.806(3), c 12.491(4) Ǻ, β 91.17(1)°, Z 4. Bis [2-(1,5-dimethyltriazol-3-yl)-1,10-phenanthroline]iron(II) perchlorate monohydrate (polymorph 2): orthorhombic, space group Pbca, a 16.687(4), b 12.272(2), c 34.305(8) Ǻ, Z 8.
Preparation and Characterization of the Dicarbon Cluster Complex Ru5(μ5-C2)(μ5-SMe)2(μ-PBu2)2(CO)11
Authors: Adams CJ , Bruce MI
Published: November 2018

The preparation of the bis -tertiary phosphine C2(Pbu2)2 ( dpba ) is described. Pyrolysis of the ruthenium carbonyl derivative {Ru3(CO)11}2(μ- dbpa ) gives Ru5(μ5-C2PBu2)(μ-PBu2)(CO)13[in 41% overall yield from Ru3(CO)12)] which in turn reacts with Me2S2 to give Ru5(μ5-C2)(μ5-SMe)2(μ-PBu2)2(CO)11(19%).
Studies in Thiohydantoin Chemistry. I. Some Aspects of the Schlack-Kumpf Reaction
Authors: Duggan BM , Laslett RL , Wilshire JFK
Published: November 2018

An investigation has been carried out into the Schlack-Kumpf reaction, i.e., the reaction of amino acids with a mixture of acetic anhydride, acetic acid and sodium thiocyanate (occasionally ammonium thiocyanate was used). Particular emphasis was placed on the reactions with amino acids containing sensitive or functional side chains, i.e., serine, threonine , arginine , proline , lysine, histidine , cysteine , and aspartic and glutamic acids. The reaction of serine, and of certain of its O- and N-substituted derivatives, takes an unusual course to give an acetylated thiohydantoin derivative of cysteine. Correspondingly, threonine gives an acetylated thiohydantoin derivative of β- methylcysteine. Similar reactions occurred with the 3-phenylthiohydantoin derivatives of serine and of threonine to give acetylated thiohydantoin derivatives of cysteine and of β-methylcysteine respectively.
Chemical Modification of Alkoxide Precursors for Lead Zirconate Titanate Formation
Authors: Tursiloadi S , Imai H , Hirashima H
Published: November 2018

Lead zirconate titanate (PZT) gel monolith was prepared by partially hydrolysing metal alkoxide solutions which were modified with acetylacetone ( acacH ). Lead diisopropoxide zirconium tetrabutoxide and titanium tetraisopropoxide were used as starting materials. After aging of the translucent monolithic gel at room temperature for several days or drying at 90°C for 18 h, the most significant feature in the infrared spectrum is the presence of bands at about 1550 cm-1 which can be assigned to the v(C-O) and v(C-C) vibrations of the acetylacetonate group coordinated to the metal cations of titanium and zirconium. Diffraction peaks of PbO were found after heating at 300°C for 2 h. After heating at 450°C for 2 h, diffraction peaks of pyrochlore Pb2Ti2O6 and perovskite PZT phases were observed. The diffraction peaks of PbO and the pyrochlore phase disappeared after heating at 600°C, and the tetragonal perovskite phase was stable up to 1000°C. Diffraction peaks of the perovskite phase were also found after heating at 430°C for 24 h.
The Synthesis of Bisguanidinoalkanes and Guanidinoalkanes, N- or N'-Substituted With Pyrimidines, as Analogues of Chlorhexidine
Authors: Elmes BC , Holan G , Wernert GT , Winkler DA
Published: November 2018

A series of N,N???- alkanediylbis [N?-(5-halopyrimidin-2-yl)guanidine] salts has
been synthesized along with N,N???-(trans-cyclohexane-1,4-diyl) bis [N'-(5-chloropyrimidin-2-yl)guanidine], N,N???-(cis-cyclohexane-1,4-diyl) bis [N?-(5-chloropyrimidin-2-yl)guanidine] dihydrochloride and N-(cis-4-amino-cyclohexan-1-yl)-N'-(5-chloropyrimidin-2-yl)guanidine
dihydrochloride . Furthermore, a series of
N-(alkan-1-yl)-N?-(5-chloropyrimidin-2yl)guanidine hydrochlorides and
N-(6-aminohexan-1-yl)-N?-(5-chloropyrimidin-2-yl)guanidine dihydrochloride
were synthesized. This series of compounds was prepared by displacement
reactions of 2-methylsulfonylpyrimidines with bisguanidinoalkanes
or by condensation of 5-chloro-2-cyanoaminopyrimidine
(5-chloropyrimidin-2-ylcyanamide) with alkylamines .
Attempted Synthesis of a Highly Strained Bicyclic Alkyne: Reaction of 8-Chloro-6,9-Dihydro-5,9-Methano-5h-Benzocycloheptene With Potassium T-Butoxide and an Anomalous Substitution Reaction at a Vinyl System
Authors: Tumer F , Taskesenligil Y , Dastan A , Balci M
Published: November 2018

Treatment of alkene (9) with N- bromosuccinimide
gave a mixture of monobromides [(10) and (11)] which
were hydrolysed to the corresponding exo alcohol (13). Oxidation of (13) and subsequent hydrogenation
of unsaturated ketone (14) afforded the ketone (15). Ketone (15) was treated
with PCl5, followed by potassium t- butoxide to give chloro alkene (8b). Reaction of
(8b) with potassium t- butoxide resulted in the
formation of unexpected allyl ether (18) whose formation mechanism has already
been discussed.
Preparation and Characterization of Some Cobalt(III) Complexes of 2-Aminomethylbenzimidazole
Authors: Gable RW , Hartshorn RM , Mcfadyen WD , Nunno L
Published: November 2018

The coordination chemistry of 2-aminomethylbenzimidazole (ambi) has been studied with cobalt(III), and the cationic complexes fac-[Co(ambi),3]3+, asym-[Co(en) (ambi)2]3+ and [Co(en)2(ambi)]3+ have been prepared. The last cation, in the form of the chloride salt [Co(en)2(ambi)] Cl3.H2O, has been structurally characterized: monoclinic, space group P 21/c, a 7.6692(14), b 14.954(2), c 15.941(3) Ǻ, β 92.64(2)°, Z 4.
Potential Antimalarials. XXII. Some 2,4-Diamino-5-(3- and 4-trifluoromethylphenyl and 3,4-methylenedioxyphenyl)pyrimidines
Authors: Barlin GB , Kotecka B , Rieckmann KH
Published: November 2018

A series of 10 pyrimethamine analogues containing 3'- and 4'-trifluoromethyl and 3',4'-methylenedioxy groups has been prepared and tested for in vitro antimalarial activity against the FC-27 and K-1isolates of Plasmodium falciparum. Several of these compounds were almost as active as pyrimethamine against the drug-sensitive FC-27 isolate, and like pyrimethamine , they were much less active against the drug-resistant K-1 isolate. The 4'-trifluoromethyl compunds, however, showed much smaller differences.
Patellins 1-6 and Trunkamide A: Novel Cyclic Hexa-, Hepta- and Octa-peptides From Colonial Ascidians, Lissoclinum sp.
Authors: Carroll AR , Coll JC , Bourne DJ , Macleod JK , Zabriskie TM , Ireland CM , Bowden BF
Published: November 2018

Patellins 1-5 have been isolated from the colonial ascidian Lissoclinum patella from Viti Levu , Fiji. Patellins 1 and 2 are cyclic hexapeptides, while patellins 3-5 are cyclic octapeptides. Two of these peptides ( patellins 3 and 5), a new cyclic octapeptide ( patellin G), a new cyclic heptapeptide ( trunkamide A), and the known metabolite lissoclinolide have also been isolated from a Lissoclinum sp. collected on the Great Barrier Reef, Australia. All structures were determined by high-field n.m.r. and mass spectroscopic methods, and by h.p.l.c . Analysis of the constituent amino acids after hydrolysis of the peptides and derivatization according to Marfey's procedure.
17O N.M.R. Line Broadening and T1, T2 Measurements on CrO42- and HCrO4-
Authors: Brasch NE , Buckingham DA , Clark CR , Rowan AE
Published: November 2018

The increase in the line width of the 17O signal of CrO42- (ΔvCrO42- = 11�2 Hz) on adding acid is attributed to a much broader HCrO4- signal
ΔvHCrO4). This broadening is shown to have acid-independent (Δv0 = 67�5 Hz) and acid-dependent [Δv1 = (1.0�0.1) × 108 Hz M-1] contributions. Direct T1 and T2 measurements give T1 ≈ 70 ms, T2 ≈ 40 ms for CrO42- with the difference being attributed to spin coupling (T2' = 90 ms). For HCrO4- T1 = 8�3 ms, and the acid- catalysed Δv1 contribution is attributed to rapid exchange of H,+ in H2CrO4 (k ≈ 1×109 s-1) showing that spin exchange effects are important for this ion.
The Potential Dependence of the Rate Constant for Charge Transfer at the Semiconductor-Redox Electrolyte Interface
Authors: Matthews D , Stanley A
Published: November 2018

The kinetics of charge transfer at the semiconductor- redox electrolyte interface is described in terms of the Gurney- Gerischer -Marcus (GGM) model by using nuclear configuration potential energy diagrams, electronic configuration potential energy diagrams, density of state distributions and rate constant distributions. The model of identical parabolas for the nuclear configuration diagrams is used; this leads to Gaussian oxidant and reductant distribution functions, g(E), where E is the vertical transition (Franck-Condon) energy. The rate constant distribution, k(E), is obtained from the overlap between occupied and unoccupied state distribution functions of the semiconductor and redox electrolyte. Integration of k(E) gives the rate constant which is calculated as a function of the Helmholtz potential, VH, for various values of the reorganization energy, Ereorg. Three types of semiconductor are considered: intrinsic, doped and highly doped. For intrinsic semiconductors the charge transfer rate constant is relatively small and involves both the conduction and valence bands. For symmetric charge transfer (zero energy change, E0.0, for the reaction) both oxidation and reduction occur between the redox electrolyte and both bands of the semiconductor. For unsymmetrical reactions, charge transfer tends to involve only one of the bands; for net reduction, the valence band is involved, whereas for net oxidation the conduction band is involved. For doped semiconductors the rate constant is larger and only one band is involved; for n-type it is the conduction band, and for p-type it is the valence band. For highly doped semiconductors with the Fermi level in either the conduction or valence bands. the rate constant is even larger and only one band is involved. Changes in Helmholtz potential affect k(E) in a similar way to that for metals. However, unlike for metals, the calculated Tafel plots for highly doped n-type semiconductors are shown to exhibit a Marcus inversion region. This is a consequence of the energy gap between conduction and valence bands of the semiconductor. For doped semiconductors, changes in the Helmholtz potential also produce a maximum in the Tafel plot and because of the relatively low currents involved this maximum should be experimentally observable. For intrinsic semiconductors, variation of Helmholtz potential without inclusion of band bending in the semiconductor produces unexpectedly low Tafel slopes which are related to the ratio of the band gap to the reorganization energy, so that the larger the ratio the smaller the Tafel slope. This unexpected result, which amounts to an assumption of band edge unpinning, is shown to accurately account for the experimentally observed Tafel slopes for reduction at n-WSe2 of the dimethylferrocenium ion in acetonitrile.
7,9-Dihydroxy-1,8-cineole and 2α,7-Dihydroxy-1,8-cineole: Two New Possum Urinary Metabolites
Authors: Carman RM , Garner AC
Published: November 2018

Chemical syntheses for 7,9-dihydroxy-1,8-cineole (8a) and 2α,7-dihydroxy-1,8-cineole (9a) arereported. These products are identical with the urinary metabolites isolated from brushtail possums fed 1,8-cineole (1) and 2α-hydroxy-1,8-cineole (4) respectively.
Mirabilins (A-F): New Alkaloids From a Southern Australian Marine Sponge, Arenochalina mirabilis
Authors: Barrow RA , Murray LM , Lim TK , Capon RJ
Published: November 2018

An Australian marine sponge Arenochalina mirabilis (Lendenfeld 1887) collected from the Great Australian Bight has been found to contain six tricyclic alkaloids, mirabilins A-F (5)-(10), isolated and identified as their N-acetyl derivatives (11)-(16). Structures for the mirabilins were secured by detailed spectroscopic analysis.
Properties of Olean-12-ene-3α,16β,22α,28-tetrol and Some Derivatives
Authors: Hambley TW , Hambley TW , Lewis KG , Lewis KG , Tucker DJ , Tucker DJ , Turner P , Turner P
Published: November 2018

Reaction of olean-12-ene-3β,16β,22α,28-tetrol ( chichipegenin ) (1) with methyl orthoformate gives the 16β,22α,28-orthoformate (2). Acetylation of the ortho ester followed by hydrolysis gives the tetrol 3β-monoacetate (5). It is shown that intramolecular hydrogen bonding occurs in the tetrol (1) and the 3β-monoacetate (5) in non-polar solvents. X-Ray crystallographic data on the tetrol and its tetraacetate (4) are reported. The tetrol,C30H50O4, M 474.72, crystallized in the orthorhombic space group P 212121 with a 12.363(6), b 31.888(3), c 6.962(3) Ǻ, V 2745(1) Ǻ3, Dc(Z = 4) 1.149 g cm-3, N = N(unique) 2394, No 1878 [I > 1.5σ(I)], Nvar 500; R 0.038, Rw 0.040. The tetraacetate , C38H58O8, M 642.87, crystallized in the monoclinic space group P 21, with a 10.603(2), b 16.569(1), c 10.814(1) Ǻ, β 98.72(1)°, V 1877.9(4) Ǻ3, Dc(Z = 2) 1.137g cm-3 N 3090, Rmerge 4.67% for N(unique) 2917, No 2663 [I > 2.5σ(I)], Nvar 414; R 0.053, Rw 0.050.
Synthesis of Unsaturated Analogues of Glutamic Acid: Amination of Trianions From Unsaturated Dicarboxylic Acids With Chloramine
Authors: Allan RD , Duke RK , Hambley TW , Johnston GAR , Mewett KN , Quickert N , Tran HW
Published: November 2018

Trianions can be formed from dicarboxylic acids which contain a β,γ -double bond, and amination with chloramine yields β,γ-unsaturated α-amino acids. This methodology provides a convenient synthesis of amino acids that are inaccessible by other routes. (Z)-3-Phenylthiopent-2-enedioic acid and all four stable unsaturated analogues of the conformationally restricted glutamate analogue 1-aminocyclopentane-1,3-dicarboxylic acid have been synthesized to demonstrate the applicability of the method. The structure of one of the amino acid products, (�)-cis-1-aminocyclopent-4-ene-1,3-dicarboxylic acid (7), has been determined; it crystallizes in the space group P21/c, a 9.245(24), b 8.455(2), c 9.311(3) Ǻ, β 95.00(2)°, and the structure was refined to R 0.035 for 980 F.
Preparation and Partial Characterization of Two New Hexavalent Uranium Metal Uranates
Authors: Sterns M , Withers RL , Midgeley P , Vincent R
Published: November 2018

The preparation, chemical characterization and structural investigation by X-ray and electron diffraction of two uranates (VI), namely Sr5U3O14 and of Pb11U5O26, are reported. The strontium compound, the unit cell of which is metrically tetragonal with a = 11.248(5), c = 11.086(5) Ǻ, Z = 4, was shown by electron diffraction to be orthorhombic, space group Pbca with a = b. Crystals of Sr5U3O14 are invariably submicroscopically twinned and, because of the identity of a and b, mimic tetragonal symmetry. The lead uranate , Pb11U5O26, was shown to be a long-period superstructure with unit cell dimensions a = 44.54, b = 15.586, c = 8.241 Ǻ, Z = 8.
Inclusion of 4,4'-Bipyridine (γbpy) in Its Copper(II) Aqua Perchlorato Complex. Crystal Structure of [Cu( γbpy )(H2O)2(ClO4)2]n.( γbpy )n
Authors: Chen XM , Tong ML , Luo YJ , Chen ZN
Published: November 2018

An example of a 4,4'-bipyridine ( γbpy ) clathrate in its copper(II) complex has been established. The compound, [Cu( γbpy )(H2O)2(ClO4)2]n.( γbpy )n, crystallizes in the monoclinic space group C2/c with a 16.651(3), b 11.089(2), c 14.360(3) Ǻ, β 116.45(3)°, V 2373.9(8)Ǻ3. The crystal structure comprises γbpy -bridged linear polymeric [Cu( γbpy )(H2O)2(ClO4)2]n chains, where the copper atom, located on a crystallographic twofold axis, is coordinated in an elongated octahedral environment by two nitrogen atoms of the bridging γbpy ligands (Cu-N 1.998(4)Ǻ) and two water molecules (Cu-O 1.968(3)Ǻ) at the equatorial positions, and two perchlorate oxygen atoms at the axial positions (Cu-O 2.414(4)Ǻ). The chains are interconnected by hydrogen bonds between the aqua ligands and the uncoordinated perchlorate oxygen atoms to form two-dimensional layers with cavities each enclosing a γbpy molecule. Hydrogen bonding between the aqua ligands and the nitrogen atoms of the solvate γbpy molecules further extends the structure into a three-dimensional network in the solid.
The Synthesis and Some Manipulations of Dialkyl 6-Aryl (or Alkyl)-2-oxotetrahydro-2H-pyran-3,5-dicarboxylates
Authors: Lawrence RM , Perlmutter P
Published: November 2018

A new, one-pot annulation process, involving conjugate addition of the sodium salts of dimethyl (or dibenzyl ) malonate to alkyl 2-(1- hydroxyalkyl ) propenoates, produces a mixture of dialkyl 6-aryl(or alkyl)-2-oxotetrahydro-2H-pyran-3,5-dicarboxylates. Alkylations of the cis-isomers were found to be highly stereoselective . The ntroduction of unsaturation into these molecules is also described.