Terpenoids—LVII Synthesis of some germacrane derivatives

Both liquid and solid hexahydrocostunolides obtained by the pressure hydrogenation of costunolide (V) and solid dihydrocostunolide (VI) respectively, give the same optically active hexahydrogermacol (IIIa), when subjected to controlled reduction with LiAlH₄, followed by Huang-Minlon reduction. The alcohol (IIIa) on oxidation with chromic oxide gives optically active hexahydrogermacrone (IIa). Dehydration of IIIa with KHSO₄ followed by catalytic hydrogenation gives the optically inactive saturated hydrocarbon, germacrane (IV). Since the total synthesis of solid dihydrocostunolide (VI) has already been achieved the preparation of IIIa, IIa and IV from VI constitutes a total synthesis of the above three compounds.     

Distorted pentacoordinate copper(II) complexes containing a tridentate ligand

Summary Copper(II) complexes with a tridentate chelating ligand within the general 2N, X (X = O or S) donor class, containing abis(benzimidazolyl) donor set, were prepared and characterized. X-band e.p.r. spectra of the complexes indicateg >g and the largeg and lowA have been interpreted in terms of a distorted basal plane. Superimposed on theg component are five SHF lines withA _N = 16±2G, supporting the interaction of two nitrogen atoms with the copper nucleus. Thus, the basal plane of the complex comprises 2N atoms, with the ligand hetero atom being axially coordinated.     

Lanthanon (III) Derivatives of Monofunctional Bidentate Schiff Bases

The 1:1, 1:2 and 1:3 interactions of lanthanon (III) isopropoxide with monofunctional bidentate Schiff bases as salicylidene-o-toluidine (SOTH) and salicylidene-p-p-toluidine (SPTH) have been investigated. The resulting products Ln(OPr¹)₂(SB), Ln(OPr¹)(SB)₂ and Ln(SB)₃ (where Ln=Pr, Nd and Sm and SB^1? is the anion of the corresponding Schiff base) have been isolated in almost quantitative yields. The infrared spectra of these compounds have been recorded and plausible structures suggested.     

Doubly charged ion mass spectra: 1-Aliphatic nitriles

The doubly charged ion mass spectra for 12 aliphatic nitriles (1–9 carbon atoms) have been obtained using an Hitachi RMU-7L double focusing mass spectrometer. These spectra show some characteristic features such as extensive loss of hydrogen and the grouping of ions in the spectra into n-1 groups where n is the number of carbon atoms in the molecule (n<6). There are no indications of HCN or CN loss in the doubly charged ion spectra of the monosubstituted nitriles. SCF calculations of the energy and structure of doubly charged ions in the propionitrile spectra have been carried out.     

Effect of interaction of thenoyltrifluoroacetone with neutral oxo-donors in the synergistic extraction of tervalent actinides

The interaction of HTTA with TBP, DOSO, DBBP and TOPO in xylene has been studied by a spectrophotometric method. The complex species formed is HTTA. S (where S is a neutral donor) and the equilibrium constants for the formation of the species follow the order TOPO > DBBP > DOSO > TBP. After application of a correction for the HTTA-S interaction, the free HTTA and S concentrations in the organic phase were calculated. Plots of log D vs. log [HTTA] for the tervalent actinides Am, Cm, Bk and Cf gave straight lines with a slope of 3 only after application of the interaction correction, otherwise curves with slopes varying from 3 to 2 were found. The equilibrium constants of the organic phase synergistic reactions of the tervalent actinides are found to be approximately 10% higher after application of the HTTA-S interaction correction.     

Adsorption behaviour of metal ions on hydroximate resins

Some new chelating ion-exchange resins containing a hydroxamic acid moiety attached to a divinylbenzene styrene (DVBS) copolymer, i.e. glycine hydroximate in DVBS (GH-DVBS). anthranilic acid hydroximate in DVBS (AAHDVBS), malonic acid dihydroximate in DVBS (MAH-DVBS) and iminodiacetic acid dihydroximate in DVBS (IDAAH-DVBS). have been synthesized and their various physicochemical characteristics studied. The degree of retention of metal ions by the resins at equilibrium has been determined in terms of the molar distribution coefficient (k(d)). In general, the resins having a dihydroximate moiety are found to be more efficient compared to monohydroximate resins. However, it is of interest to note that the monohydroximate derivative of amino acid (GH-DVBS) showed better metal retention capability than the dihydroximate of carboxylic acid (MAH-DVBS). The selectivity of the resins for transition and highly charged metal ions is quite high compared to that for alkaline earth metals. All the synthesized resins can be utilized for the separation of a mixture of metal ions because the differences in the distribution coefficient values are large enough to permit good separations on columns. However, the GH-DVBS resin was tried for the separation of copper cobalt and copper nickel mixtures at pH 5.5 using the column mode of operation.     

Role of Cyanex-272 as an extractant for uranium in the determination of rare earths by ICP-AES

A chemical separation procedure has been developed for the extraction of uranium from some of the crucially important rare earths using a novel extractant viz. Cyanex-272 (2,4,4-trimethyl pentyl phosphinic acid). The near total extraction of uranium and quantitative separation of rare earth elements has been validated using inductively coupled argon plasma - atomic emission spectrometry (ICP-AES). The recovery of some of the representative elements has been confirmed by radioactive tracer studies. The back extraction of uranium from the organic phase was carried out using a solution of 0.5M Na₂CO₃ which resulted in a near total recovery of uranium into the organic phase. These studies have enabled determination of sub ppm amounts of the analyte elements with a precision of 5% RSD utilizing prior chemical separation of rare earths from 1 g uranium samples in just three extractions with Cyanex-272.     

Trends in the energies of cation and anion states of alkan-1-ols

We report results of a systematic investigation of the energies of positive-ion and negative-ion states in alkan-1-ol molecules CnH_2n+1 OH (n = 1–5) in low-energy electron impact experiments using a beam of nearly mono-energetic electrons. The measurements have been conducted in a crossed electron-beam/molecular-beam apparatus wherein positive ions are detected using a quadrupole mass spectrometer whereas unstable negative ions are observed as resonance structures in the electron transmission function. Theoretical calculations of anion and cation energies have been carried out using the semi-empirical HAM/3 technique.     

Tail-end purification of americium from plutonium loading effluents using a mixture of octyl (phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide and tri-N-butyl phosphate

The tail-end purification of Am from Pu loading effluents in 7.5M HNO₃ containing 160 mg l^–1 Am and 1.2 mg l^–1 Pu has been carried out. With 0.2M CMPO+1.2M TBP in dodecane as the extractant and stripping by 0.04M HNO₃+0.05M NaNO₂, the Pu level is brought down to 31.2 g l^–1. When the acidity was reduced to 4.2M HNO₃, one contact with 20% TLA/dodecane and subsequent extraction by a mixture of CMPO and TBP and stripping with 0.04M HNO₃+0.05M NaNO₂ gave Am samples without any detectable amounts of Pu. The recovery of Am was 90% by the first procedure and 98% by the second one.