74250-10-5Relevant academic research and scientific papers
Organic Photochemistry, XXXVI. - Dihydro-2H-thiopyran S-Oxides, Synthons for α,β-Unsaturated Aldehydes
Praefcke, Klaus,Weichsel, Christian
, p. 333 - 343 (2007/10/02)
Irradiation of dihydro-2H-thiopyran S-oxides 1a-g in benzene leads via desulfuration to the α,β-unsaturated aldehydes 2 and 3 mostly as mixtures of their E/Z-isomers.The assignment of their configurations is based on 1 H- and 13 C-NMR data which are discussed in detail.This type of photoreaction represents a new four-carbon homologation method for the carbonyl compounds from which the dihydro-2H-thiopyrans 1 are synthesized.It is shown by deuterium labelling of the S-oxide 1c that the photoreaction 1-> 2+3 involves an intramolecular hydrogen transfer.
Organosulfur Compounds, L. - 2H-Thiopyrans and Dihydro-2H-thiopyrans, Synthons for Thiophenes
Praefcke, Klaus,Weichsel, Christian
, p. 1604 - 1619 (2007/10/02)
2H-Thiopyran derivatives yield thiophenes on pyrolysis at 240-260 deg C.The influence of substitution in positions 3 to 6 of the 2H-thiopyrans on these new thermal rearrangement and fragmentation reactions is dealt with, and some proposed mechanisms are discussed in detail.A novel three-step synthesis of thiophenes from carbonyl compounds via the corresponding thiones, their -cycloaddition with 1,3-dienes with formation of dihydro-2H-thiopyrans and subsequent thermal conversion is described.In this reaction sequence, whose scope and limitations are outlined, t he thiocarbonyl compound contributes the sulfur and the 1,3-diene the carbon skeleton of the desired thiophenes.
