104084-85-7Relevant academic research and scientific papers
Heterodiene and Heteroene Activity of Benzoyl Isothiocyanates towards Electron-Rich Alkynes. Synthesis and Crystal Structure of Regioisomeric 1,3-Oxazine-thiones.
Kniezo, Ladislav,Kristian, Pavol,Dondoni, Alessandro,Pedrini, Paola,Andreetti, Giovanni Dario,Ugozzoli, Franco
, p. 537 - 578 (2007/10/02)
The reactions of benzoyl isothiocyanate (2a-c) with 1-diethylaminopropyne (1) lead to mixtures of regioisomeric 1,3-oxazinethiones (4) - (6) in variable ratios depending on the substituent ( H, p-NO2, p-OMe ) in the phenyl ring of (2) and the solvent polarity.Benzoyl isocyanate (3) and (1) give exclusively the 1,3-oxazine-4-one (7).The 1,3-oxazinethiones (4) - (6) are interpreted to arise from three concurrent processes, a (4+2) and a (2+2)-cycloaddition as well as a 1,2-addition, which involve the alkyne triple bond and different sites of the isothiocyanate.From benzoyl isothiocyanate (2a) and ethoxyacetylene, the only product isolated is the formal (4+2)-cycloadduct 1,3-oxazine-2-thione derivative (16a).The structures of three selected oxazinethiones were established by X-ray crystallography.
