Synthetic heparinoids labelled with 125I and 35S

The labelling of a water-soluble synthetic polyelectrolyte, having anticoagulant activity, has been studied. The polyelectrolyte is derived from cis-1,4-polyisoprene and contains N-sulfate and carboxylate groups. [125I]-Iodination of the polyelectrolyte, using the Chloramine-T method and an electrolytic method, resulted in a [125I]-labelled polyelectrolyte from which release of the label occurred. Resulfation of a partially desulfated polyelectrolyte with a [35S]-sulfur trioxide trimethylamine complex resulted in a [35S]-labelled polyelectrolyte which showed no release of the label

Comparison of surface iodination methods by electron microscopic autoradiography applied in vitro to different life-stages of Dipetalonema vitae (Filarioidea)

Different stages of Dipetalonema viteae (males, females, microfilariae, and 3rd-stage larvae) have been iodinated in vitro under physiological conditions by chloroglycoluril, lactoperoxidase or chloramine T. The concentrations of the catalysts were correlated with the viability of the worms. Localization of the label with the different iodination methods had been visualized by electron microscopical autoradiography. Chloroglycoluril-mediated iodination is predominantly localized on the filarial cuticle. Lactoperoxidase-catalysed iodination is less specific and chloramine T catalyses iodination in a gradient decreasing from the cuticle to inner structures. It is necessary to visualize the labelling by electron microscopical autoradiography prior to biochemical and immunological experiments to avoid the extraction of structures iodinated by leakage of the catalyst into sub-cuticular region

Understanding N-nitrosodimethylamine Formation in Water: Chloramine Chemistry, Kinetics, and A Proposed Reaction Pathway

The formation of N-nitrosodimethylamine (NDMA) in drinking water systems is a concern because of its potential carcinogenicity and occurrence at toxicologically relevant levels. The postulated mechanism for NDMA formation involves a substitution between dichloramine and amine-based precursors to form an unsymmetrical dimethylhydrazine (UDMH), which is then oxidized by ground-state molecular oxygen to form NDMA. However, this latter reaction is spin forbidden, thus likely occurs at a slow rate. It is hypothesized that the reaction between monochloramine and hydroxylamine (a nitrification product) may form an intermediate, which is involved in the NDMA formation pathway. This intermediate may also be generated from dichloramine decay, in the absence of hydroxylamine. In this study, a series of batch kinetic experiments were conducted to investigate the decomposition of chloramine species at pH 8.0 to 10.0 and the concomitant formation of NDMA. Chloramine species were quantified using UV/Vis spectroscopy (Direct UV) and colorimetric methods (Hach) and compared to simulations from the unified chloramine model. NDMA was quantified using GC-MS following liquid-liquid extraction. The model captured the decay of monochloramine and dichloramine adequately, with the exception of monochloramine at pH 10.0, possibly due to an interference from a previously reported unidentified chloramine decomposition compound (UC1). NDMA formation was pH dependent with the maximum yields at pH 9.0 and the fastest kinetics at pH 10.0. A second unidentified compound (UC2), with a mass spectrum identified as UDMH, was detected only at pH 9.0 and 10.0 in batch reactors with DMA and dichloramine. Importantly, NDMA formation appeared to be insensitive to the presence or absence of UC2, suggesting UC2 was not involved in NDMA formation. Hydroxylamine accelerates the decomposition of monochloramine. The reaction between DMA and hydroxylamine formed a third unidentified compound (UC3), preliminarily identified as acetoxime, which was not observed in the presence of monochloramine. Upon addition of hydroxylamine, NDMA yields decreased by more than half in batch reactors with DMA and monochloramine. On balance, the findings suggest the existence of a NDMA formation pathway that may not involve UDMH, and points to the need for studies with scavengers and donors of short-lived species from chloramine decay

Analysis of iodinated quorum sensing peptides by LC-UV/ESI ion trap mass spectrometry

Five different quorum sensing peptides (QSP) were iodinated using different iodination techniques. These iodinated peptides were analyzed using a C-18 reversed phase HPLC system, applying a linear gradient of water and acetonitrile containing 0.1% (m/v) formic acid as mobile phase. Electrospray ionization (ESI) ion trap mass spectrometry was used for the identification of the modified peptides, while semi-quantification was performed using total ion current (TIC) spectra. Non-iodinated peptides and mono- and di-iodinated peptides (NIP, MIP and DIP respectively) were well separated and eluted in that order. Depending on the used iodination method, iodination yields varied from low (2%) to high (57%)

Studies in the reactions of N, N-Dimethyl chloramine and a variety of tri coordinate phospohorus compounds

In this work the reactions "between various phosphorus (III) species and dimethyl chloramine have been studied. In all cases the phosphorous (III) species were oxidised to phosphorus (v), in most cases by ohloramination, that is by the addition of the dimethylamino group to the phosphorus producing a phosphonium cation with chloride as the anion. Me(_2)NCl + PX(_3) → Me(_2)NPX(_3)(^+)Cl(^-) This reaction occurred in the cases of Me(_2)NPCl(_2), (Me(_2)N)(_2)PCl, (C(_6)H(_5)O)(_5)P, Me(_2)N(C(_6)H(_5))PCl, (C(_6)H(_5))(_2)PCl and C(_6)H(_5)PCl(_2) although in the latter two cases the salt was too unstable to be isolated as the chloride but the systems could be stabalised as the tetrachloroborate or hexachloroantirnonatesalts. It is likely that dimethyichloramine chloraminated trimsthyl phosphite to give a similar species, but this decomposed quickly giving chlororethane and Me(_2)NP0(0Me)(_2). In the case of (Me(_2)N)(_2)P chlorination occurred giving (Me(_2)N)(_3)PCl(_2) and (Me(_2)N)(_2). Phosphorus trichloride seemed to be an intermediate case, as, in the presence of excess phosphorus trichloride the following reaction occurred:- 4PCl(_3) + 3Me(_2)NCl → Me(_2)NPCl(_4) + Me(_2)NPCl(_3)PCl(_6) + Me(_2)NPCl(_2

One-Pot Synthesis of 5,6-Dihydro-4H-1,2-Oxazines by Cyclization of Ketoximes with Derivatives of Allylbenzene

A new series of 5,6-dihydro-4H-1,2-oxazines were synthesized via hetero Diels-Alder reaction of  α-nitrosolefins with derivatives of allylbenzene. α-Nitrosoolefins were generated from ketoximes by the action of chloramine-T and triethylamine

Kinetics and mechanism of hallogenative oligomerization of mesityl oxide by Chloramin-T. Evidence for a novel pathway in aqueous sulphuric acid

The kinetics of the reaction between mesityl oxide and chloramine-T (CAT) in aqueous sulphuric acid in the presence of KHSO4 has been studied. The results indicate a radical chain mechanism to be operative which is quite novel in CAT kinetics