[New dyes containing gallocyanine for staining histological sections].

We designed and synthesized a new class of serine protease inhibitors based on the oxazinone core. To this end, we first developed a short and efficient route to synthesize a new 3,4-dihydro[1,4]oxazin-2-one ring. Then we successfully synthesised the corresponding 5-bromo derivatives which have never been reported before, and demonstrated their inhibitory activities on alpha-chymotrypsin.

Oxazines↗

PubMed2002

Mass spectrometric studies of benzoxazine resorcarenes.

Eleven differently substituted 3,4-dihydro-2H-1,3-benzoxazine resorcarenes were studied by electrospray ionisation (ESI) and matrix-assisted laser desorption/ionisation (MALDI) mass spectrometry, using Fourier transform ion cyclotron resonance (FT-ICR) and time-of-flight (TOF) mass spectrometers, respectively. Under ESI conditions it was possible to transfer the intact resorcarenes from solution to the gas phase, yielding [M + H](+) and [M + 2H](+) ions as the main ions observed. Energy increase of the ions induced ready decomposition through successive eliminations of four CH(2)NR groups. Ion-molecule reactions showed that the ionising proton was situated somewhere inside the molecule and could not be reached with neutral reagent gases. In the host-guest complexation experiments, the benzoxazine resorcarenes studied turned out to be poor hosts for alkali metal and ammonium ions. In MALDI experiments, 2,5-dihydroxybenzoic acid proved to be the best matrix for these compounds. However, the intensity of the [M + H](+) ions was low for all compounds, and extensive fragmentation with consecutive elimination of CH(2)NR groups was observed.

Oxazines↗

PubMed1997

Liquid secondary ionization mass spectrometry and collision-induced dissociation study of 2-chloro-N10-substituted phenoxazines.

Positive-ion liquid secondary ionization mass spectrometry in combination with 3-nitrobenzyl alcohol as the liquid matrix was used to investigate the mass spectral features of a set of 21 N10-substituted derivatives of 2-chlorophenoxazine. The N-10 substitution included propyl, butyl and acetyl groups containing various secondary amines (N,N-diethylamine, N,N-diethanolamine, morpholine, piperidine, pyrrolidone or beta-hydroxyethylpiperazine) or a chloro group. These compounds are potent multi-drug resistance modulators. The molecular ions are observed as M+ and [M + H]+ ions. In general, the fragmentation pathways of these molecules are similar and very straightforward. The phenoxazine ring system remains stable under the Cs+ ion beam bombardment conditions, while fragmentations are observed along the length of the alkyl and acetyl side-chains. The fragmentation reactions were corroborated by acquiring product ion and constant neutral loss tandem mass spectrometric scans of the pertinent ions.

Oxazines↗