A new high-performance liquid chromatographic/electrospray ionization tandem mass spectrometric method for the simultaneous determination of cyclophosphamide, methotrexate and 5-fluorouracil as markers of surface contamination for occupational exposure monitoring

A new high-performance liquid chromatographic/electrospray ionization tandem mass spectrometric (HPLC/ESI-MS/MS) method was developed for the simultaneous quantification of 5-fluorouracil (5FU), methotrexate (MTX) and cyclophosphamide (CP) in environmental samples. These compounds, commonly used in the treatment of cancer, are recognized as genotoxic. In order to estimate the occupational exposure of hospital personnel handling these drugs, wipe samples were taken from the working surfaces and directly analyzed (with trophosphamide as internal standard) using a reversed-phase capillary column and MS/MS detection. This is the first HPLC/MS/MS method for the simultaneous determination of 5FU, MTX and CP. The present method offers high sensitivity, with detection limits of 1.1 microg l(-1) for MTX and CP and 33.3 microg l(-1) for 5FU, avoiding any sample preconcentration procedure. Rapidity, specificity, high accuracy (mean values between 92.4 and 99.9%) and precision (mean RSD values between 3.4 and 12.1%) make the method suitable for the routine determination of these three antineoplastic drugs.     

C.I. Calculations on the lower transitions in the terphenyl and quaterphenyl di-valent ions

Energies and transition dipole moments for the lower electronic transitions in the terphenyl and quaterphenyl di-valent ions have been calculated starting from the Pople SCF MO's for the ground state ions. The configuration interaction included about one-hundred singly and doubly excited configurations. The results of the calculations for the lower allowed electronic transitions are in very satisfactory agreement with the experimental spectra.     

"Exact" surface free energies of iron surfaces using a modified embedded atom method potential and lambda integration

Previously a new universal lambda-integration path and associated methodology was developed for the calculation of "exact" surface and interfacial free energies of solids. Such a method is in principle applicable to any intermolecular potential function, including those based on ab initio methods, but in previous work the method was only tested using a relatively simple embedded atom method iron potential. In this present work we apply the new methodology to the more sophisticated and more accurate modified embedded atom method (MEAM) iron potential, where application of other free- energy methods would be extremely difficult due to the complex many-body nature of the potential. We demonstrate that the new technique simplifies the process of obtaining "exact" surface free energies by calculating the complete set of these properties for the low index surface faces of bcc and fcc solid iron structures. By combining these data with further calculations of liquid surface tensions we obtain the first complete set of exact surface free energies for the solid and liquid phases of a realistic MEAM model system. We compare these predictions to various experimental and theoretical results.     

The relative permittivity of 1,2-ethanediol+2-methoxyethanol+water ternary mixtures

The relative permittivities for the ternary 1,2-ethanediol (component 1) + 2-methoxyethanol (2) + water (3) solvent system have been measured for 66 mixtures covering the whole mole fraction composition 0X₁/X₂/X₃ 1 range at –10, –5 and 0 °C. The experimental data were used to test some empirical relations stating the dependence of = (X₁, X₂, X₃). A comparison between the calculated and experimental data show that these equations can be usefully employed to predict values in correspondence of the experimental data gaps.     

Studies towards the total synthesis of contignasterol

The (17R,20S,22S,24S) C₂₀-C₂₉ segment of contignasterol has been stereoselectively prepared in 8 steps and 40% overall yield from (S)-carvone. Synthetic studies towards contignasterol's C/D ring functionalization/isomerization are also reported.     

New N6‐substituted 8‐alkyl‐2‐phenylmethylsulfanyl‐adenines. II

Title compounds bearing substituents on C(2), C(6) and C(8) were prepared from a newly synthesized pyrimidine derivative 11. The new pyrimidine 11 was generated from compound 2 through two different synthetic schemes. In one pathway, compound 2 was nitrosated, reduced and alkylated to produce com pounds 9 , 10 and 11 respectively (Scheme). In an alternate route using compound 2 as the starting material, a coupling reaction using the diazonium salt derived from p‐methylaniline afforded the azo derivative 7 , which was subsequently alkylated and reductively cleaved to form compounds 8 and 11 respectively (See Scheme). Compound 11 was annulated to the corresponding hypoxanthine derivatives 12–14 ; compounds 12 and 13 were chlorinated with phosphorus oxychloride, then reacted with amines to yield compound 17 and 20 respectively. Compounds 21 , 22 and 23 were obtained by oxidation of the corresponding sulfide as depicted in Scheme. Alkylation of the thiol function of 1 gave a mixture of 3 and 4. Compound 3 was chlo rinated to 5. Nitration of 5 resulted in electrophilic aromatic substitution of the aryl ring and concomitant oxidation of the sulfide to the sulfoxide, producing 6.     

2,4‐Diamino‐5‐(1‐naphthyl)‐3,5‐diaza‐1‐azoniaspiro[5.5]undeca‐1,3‐diene chloride

The title salt, C₁₈H₂₂N₅⁺·Cl^?, is a member of a new series of lipophilic 4,6‐di­amino spiro‐s‐triazines which are potent in­hib­itors of di­hydro­folate reductase. The protonated triazine ring deviates from planarity, whereas the cyclo­hexane ring adopts a chair conformation. A rather unusual hydrogen‐bonding scheme exists in the crystal. There is a centrosymmetric arrangement involving two amino groups and two triazine ring N atoms, with graph‐set R(8) and an N?N distance of 3.098 (3) Å, flanked by two additional R(8) systems, involving two amino groups, a triazine ring N atom and a Cl^? anion, with N?Cl distances in the range 3.179 (2)–3.278 (2) Å. Furthermore, the Cl^? anion, the protonated triazine ring N atom and an amino group form a hydrogen‐bonding system with graph‐set R(6).     

Spectroscopic Investigation on the Acrolein Hydration

The progress with time of the UV and ¹H NMR spectra of an aqueous solution of acrolein shows that, contrary to assumptions of previous authors, hydracrylaldehyde is not the only reaction product: in addition to it and its hydrated form, spontaneous oxidation products are present.