Synthesis and reactions of 2-(alkylthio)-4,4-dimenthyl-1,3-thiazole-5(4H)-thiones

Six 2-(alkylthio)-substituted 4,4-dimethyl-1,3-thiazole-5(4H)-thiones were synthesized according to a new method. The reactions of these compounds with allyl- and benzyllithium reagents, 1,3-dipoles, and dimethyl acetylenedicarboxylate proceeded in a similar manner to 2-alkyl-substituted analogues, while methyllithium reacted in a different way yielding trithio-orthoester derivatives.     

Behavior and characteristics of biogenic amines, ornithine and lysine derivatized with the o-phthalaldehyde-ethanethiol-fluorenylmethyl chloroformate reagent

The stability and characteristics of the ornithine (Orn), lysine (Lys), putrescine (Put), cadaverine (Cad), 1,7-diaminoheptane (Diah), spermidine (Spd) and spermine (Spm) derivatives obtained with the o-phthalaldehyde (OPA)-ethanethiol (ET)-fluorenylmethyl chloroformate (FMOC) reagent has been investigated. The stoichiometry of the introduced, two-step derivatization process has been followed by photodiode array (DAD) and fluorescence (FL) detections, simultaneously, while the composition of derivatives was confirmed by on-line HPLC-electrospray ionization (ESI) MS measurements. Depending on the composition of the OPA reagents, in addition to the secondary amino group-containing Spd and Spm, under common aqueous conditions also Orn and Lys do react with FMOC resulting in derivatives of various compositions. Applying the OPA-ET reagent of increasing methanol (Met) content (38-80%, v/v) the formation of the FMOC group containing Orn and Lys derivatives could be considerably decreased. Optimum elution condition (18 min, including equilibration) was developed for the simultaneous quantitation of Orn, Lys, Put, Cad, Diah, Spd and Spm, in the presence of the rest of protein amino acids. The practical utility of the method was demonstrated by the analysis of mouse tissues. Average reproducibility of quantitations, characterized with the relative standard deviation percentages of fluorescence intensities and UV responses, in order of listing, proved to be 2.1% and 2.1%, respectively.     

Near infrared reflectance spectroscopy for the fast identification of PVC-based films

Near infrared (NIR) reflectance spectroscopy was used to develop a non-destructive and rapid qualitative method for the analysis of plastic films used by the pharmaceutical industry for blistering. Three types of films were investigated: 250 microm PVC [poly(vinyl chloride)] films, 250 microm PVC films coated with 40 g m(-2) of PVDC [poly(vinylidene dichloride)] and 250 microm PVC films coated with 5 g m(-2) of TE (Thermoelast) and 90 g m(-2) of PVDC. Three analyses were carried out using different pre-treatment options and a PLS (partial least squares) algorithm. Each analysis was aimed at identifying one type of film and rejecting all types of false sample (different thickness, colour or layer). True and false samples from four plastics manufacturers were included in the calibration sets in order to obtain robust methods that were suitable regardless of the supplier. Specificity was demonstrated by testing validation sets against the methods. The tests showed 0% of type I (false negative identification) and 1% of type II errors (false positive identification) for the PVC method, 13 and 3%, respectively, for the PVC-PVDC method and no error for the PVC-TE-PVDC method. Type II errors, mostly due to the slight sensitivity of the methods to film thickness, are easily corrected by simple thickness measurements. This study demonstrates that NIR spectroscopy is an excellent tool for the identification of PVC-based films. The three methods can be used by the pharmaceutical industry or plastics manufacturers for the quality control of films used in blister packaging.     

The photoionization detector : Theory, performance and application as a low-level monitor of oil vapour

The photoionization detector (PID) is being developed for the detection of low centrations of oil in the carbon dioxide coolant of gas-cooled reactors. In this paper the theoretical response of the PID is derived and compared with its practical response and with that of the flame ionization detector (FID). The PID response is shown to depend primarily upon ionization potential and molar concentration unlike FID response which depends upon carbon number. The dependence of PID response upon the carrier gas used is discussed and the citerion of detection using the PID to measure oil vapour in carbon dioxide was found to be 2ppb.     

Nucleophilic additions of lithiated allylphenylsulfone to nitrones: experimental and theoretical investigations

The nucleophilic addition of lithiated allylphenylsulfone to nitrones at −80 °C proceeds exclusively α to the phenylsulfonyl group affording anti adducts in high yield. At 0 °C isoxazolidines are obtained with complete all-trans selectivity. The formation of these compounds involves isomerization of the allylsulphonyl moiety to give a transient vinylsulfone that then undergoes a subsequent intramolecular Michael addition. The addition to several nitrones has been studied and theoretical calculations have been refined to accurately explain the selectivity of the allylation reaction.     

Bioluminescent reporter bacteria detect contaminants in soil samples

Applied Biochemistry and Biotechnology - Reporter strains of bacteria were tested using soil samples from several sites near a leaking fuel oil storage facility. The reporter bacteria utilized the...     

Synthesis and spectral properties of 2,3-dihydro-4-(para-substituted-phenyl)-7-[(o-, m-, and p-substituted)phenoxy]-1H-1,5-benzodi-azepine-2-thiones

A series of twelve new 2,3-dihydro-4-(para-substituted-phenyl)-7-[(o-, m-, and p-substituted)phenoxy]-1H-1,5-benzodiazepine-2-thiones, which have potentially useful pharmacological properties, has been synthesized by condensing the 3,3-dimercapto-1-(para-substituted phenyl)-2-propen-1-one with 3,4-diaminophenyl-R-phenyl ethers. The structure of all products was corroborated by ir, ¹H-nmr, ¹³C-nmr and ms.     

Hydroxamic acid polymers. II. Design of a polymeric chelating agent for iron

The iron chelating ability of hydroxamic acid polymers was studied as a function of the atomic chain spacing separating neighboring hydroxamic acid units. Two polymers were prepared, one having the hydroxamic acid group separated by 11 atoms and the other by three atoms. The iron binding of these polymers was compared with the model compound desferrioxamine B (DFO) and with a previously prepared polymer having a nine-atom spacing. Mole ratio plots indicated the following order of stability: DFO ≈ 11 atom > 9 atom > 3 atom. These results are in accordance with the picture derived from molecular models which shows that with a spacing of 11 atoms, three neighboring hydroxamic acids can fit the octahedral arrangement of the iron (III) complex without appreciable strain. Some strain is introduced when the spacing becomes only nine atoms, and with three atoms, complex formation between three neighboring groups becomes virtually impossible.     

The reaction of 1,2-dilithiotetrafluorobenzene with group V halides

Although the arsenic containing analogue of triptycene, 5,10-$\text{o}$-benzenoarsanthrene $\text{A}$ (E=As) was isolated some time ago [1] the related derivatives of antimony and bismuth are unknown. We now find that when 1,2-diiodotetrafluorobenzene is treated with methyllithium at -78/dg, to afford the little studied dilithiotetrafluorobenzene [2], and the appropriate metal chloride is added to the resulting solution, perfluorinated analogues of $\text{A}$ (E = As, Sb, or Bi) are obtained in good yield. These are stable volatile solids.