@article{oai:nagasaki-u.repo.nii.ac.jp:00016736,
 author = {Hagimori, Masayori and Matsui, Sayaka and Mizuyama, Naoko and Yokota, Kenichirou and Nagaoka, Junko and Tominaga, Yoshinori},
 issue = {33},
 journal = {European Journal of Organic Chemistry},
 month = {Nov},
 note = {In the synthesis of 4H-quinolizine derivatives involving the use of a sulfonyl ketene dithioacetal, we found a novel reaction in which the remaining methylsulfanyl group was replaced with a proton after the ring-closure reaction in the quinolizine skeleton under mild conditions, without the use of any metallic reagent. The reaction of 3,3-bis(methylsulfanyl)-2-phenylsulfonylacrylonitriles (1a,b) with 2-pyridylacetonitrile (2a) in the presence of potassium carbonate as a base in DMSO afforded 4-imino-2-methylsulfanyl-3-phenylsulfonyl-4H-quinolizine-1-carbonitriles (3a,b). The methylsulfanyl group at the 2-position of 3a,b was readily removed under methanol reflux conditions to afford 4-imino-3-phenylsulfonyl-4H-quinolizine-1-carbonitriles (4a,b) in good yields. Alkyl 3-phenylsulfonyl-4H-quinolizine-1-carboxylates (4c-f) were directly synthesized from sulfonyl ketene dithioacetal (1a,b) with alkyl 2-pyridylacetates (2b,c) and involved desulfanylation by simple hydrolysis. In addition, the fluorescent properties of these compounds were investigated., European Journal of Organic Chemistry, 2009(33), pp.5847-5853; 2009},
 pages = {5847--5853},
 title = {Novel Synthesis of 4H-Quinolizine Derivatives Using Sulfonyl Ketene Dithioacetals},
 volume = {2009},
 year = {2009}
}