Reaction gas chromatography/mass spectrometry. 4—structure elucidation of cyclic sulphides by gas chromatography/mass spectrometry with the use of on‐line hydrodesulphurization

Abstract

A method for structure determination of cyclic sulphides within mixtures is described. It involves the use of a vapour phase hydrodesulphhtion micro-reactor (Raney nickel) located between the chromatographic column and the mass spectrometer (hydrogen and deuterium are used as carrier and reagent gases). A comparative examination of the mass spectra of the cydic sulphides, as well as of the hydrocarbons and their deuterio analogues (deuterium atoms are bonded to carbon atoms which had been attached to sulphnr) derived from the sulphides under the catalytic conditions employed, permits unambiguous determination of the size of the heterocycle and the position of the substituents.

Mass spectrometry of 1,2,5-oxadiazole N-oxide derivatives: use of deuterated analogues in fragmentation pattern studies

“…16,17 Initially, we tried to prepare di-deuterium analogue, at the benzylic position, of derivative 6. The synthesis of the di-deuterium chloride 3 was attempted by trying to exchange the "acidic" benzylic-protons using a biphasic system NaOD-D 2 O/ CDCl 3 at different temperatures (room temperature to reflux for 24 h) (as shown in Scheme 1).…”

“…A mixture of 1-d 1 (300 mg, 1.6 mmol) and SOCl 2 (0.19 mL) was stirred at room temperature for 24 h. The reaction mixture was treated with ice, sodium bicarbonate saturated solution (until basic pH), and extracted three times with EtOAc (20 mL). Then of the work-up process the residue was purified by chromatography (Al 2 O 3 , petroleum ether:EtOAc (0 to 5%)) to yield 300 mg (89%), colorless oil; IR ν max /cm (17). A mixture of N-nitrosopiperazine tetradeuterated 16 (190 mg, 1.4 mmol) in MeOH (5 mL) was stirred at room temperature, Raney nickel (170 mg) was then added, and the air in the flask was replaced by hydrogen.…”

Derivatization in Mass Spectrometry—5. Specific Derivatization of Monofunctional Compounds

“…The extension of this methodology is the insertion of a vaporphase hydrodesulfurization microreactor (Pd / Al 2 O 3 or Raney nickel; carrier gas-hydrogen) into the GC/MS system. 161,162 This approach enables operation with submicrogram amounts of sample and provides rapid analysis. The microreactor may be located before or after chromatographic column.…”

Reaction gas chromatography/mass spectrometry. Part IX: Post‐column hydrodesulfurization in capillary GC/MS as an aid in structure elucidation of cyclic sulfides within mixtures

“…We reported recently [2] that the use of post-column hydrodesulfurization in GClMS can assist effectively in structural studies of monocyclic sulfides in mixtures. Alkylsubstituted thiolanes and thianes were used, and with supported Raney nickel as catalyst and hydrogen or deuterium as carrier and reagent gas, mass spectra of the corresponding alkane or its dideuterio analog could be registered for each effluent.…”

“…Since the position of the deuterium label could be readily deduced from the mass spectrum, a more reliable determination of the size of the heterocycle and the position of the substituents could be made. As the packed column was used in [2], we decided now to extend the method by applying the capillary column, which affords efficient separation of both structural and geometrical isomers. The potential of the method is demonstrated by the analysis of the synthetic mixture containing the isomeric methyl-substituted thiabicyclononanes.…”