30571-10-9Relevant academic research and scientific papers
STABLE SELENOXANTHENIUM YLIDES : SYNTHESIS AND NEW REDUCTIVE CYCLIZATION OF SELENOXANTHEN-10-IO(ALKOXALYL ALKOXYCARBONYL)METHANIDES AND THEIR RELATED COMPOUNDS
Kataoka, Tadashi,Tomimatsu, Kiminori,Shimizu, Hiroshi,Hori, Mikio
, p. 75 - 78 (1983)
Stereoisomers of 9-substituted selenoxanthen-10-io(alkoxalyl alkoxycarbonyl)methanides were prepared from the corresponding selenoxides and activated acetylenes.In the reaction of 9-phenylselenoxanthene 10-oxide(1c) with methyl propiolate afforded an unexpected product, methyl 9-phenylselenoxanthen-9-ylpropiolate(5) together with ylide(2e).The selenonium ylides underwent new reductive cyclization with sodium borohydride to afford new cyclic selenonium ylides.
REACTIVITIES OF HETEROAROMATIC CATIONS CONTAINING A GROUP VIB ELEMENT IN NUCLEOPHILIC REACTIONS. REACTIONS OF 9-PHENYL-XANTHYLIUM, -THIOXANTHYLLIUM, AND -SELENOXANTHYLIUM SALTS WITH AMINES, SODIUM PHENOLATE, AND SODIUM BENZENETHIOLATE
Hori, Mikio,Kataoka, Tadashi,Shimizu, Hiroshi,Hsu, Chen Fu,Hasegawa, Yukio,Eyama, Noriko
, p. 2271 - 2276 (2007/10/02)
Reactions of 9-phenylchalcogenoxanthyllium salts (1a-c) with some nucleophiles have been examined in order to find the differences in reactivity in nucleophilic reactions.The chalcogenoxanthylium salts (1a-c) react with aniline in ether to give 9-anilino-9-phenylchalcogenoxanthenes (7a-c).However, in acetonitrile the xanthylium salt (1a) affords N,4-bis(9-phenylxanthen-9-yl)aniline (9a) together with the anilinoxanthene (7a) (at room temperature) or 9-(p-aminophenyl)-9-phenylxanthene (8a) (at reflux) and the sulphur (1b) and the selenium derivative (1c) affords only the anilino derivatives (7b,c), respectively.In the reactions with sodium phenolate, the thioxanthylium salt (1b) gave 9-phenoxy-9-phenylthioxanthene (13b), whereas the oxygen (1a) and the selenium congener (1c) gave O,4-bis(9-phenylchalcogenoxanthen-9-yl)phenols (15a,c) together with the 9-phenoxy derivatives (13a,c), respectively.The results show that the thioxanthylium salt (1b) gave the products formed on attack by the heteroatom of the ambident nucleophiles and the ratio of the carbon attack increased in the order (1a) > (1c) > (1b).This difference would be attributable to the properties of carbocations at the 9-position in the heteroaromatic cations (1a-c).
Synthesis, Stereochemistry and Reactions of Selenoxanthen-10-io(alkoxalyl alkoxycarbonyl)methanides and Related Compounds
Kataoka, Tadashi,Tomimatsu, Kiminori,Shimizu, Hiroshi,Hori, Mikio
, p. 2666 - 2675 (2007/10/02)
Selenoxanthen 10-oxides (5a-d) reacted with methyl propiolate, dimethyl and diethyl acetylenedicarboxylates to afford selenoxanthen-10-iometanides (6a-i).The 9-isopropyl derivative gave only trans-ylides and the 9-phenyl congener formed cis- and trans-ylides.The stereochemistry is discussed on the basis of the nuclear magnetic resonance spectral data.Reduction of the selenoxanthenium ylides with sodium borohydride afforded the ylide lactones (16a-c) and the ylide alcohols (17a-f).The Product ratio depended on the solvent used.Keywords - selenium ylide; selenoxide; selenoxanthene; methyl propiolate; dimethyl acetylenedicarboxylate; stereoisomer; stereochemistry; sodium borohydride reduction; lactonization
CHEMISTRY OF CIS- AND TRANS-9-PHENYLSELENOXANTHENE-N-ARYLSULFONYLSELENILIMINES
Tomimatsu, Kiminori,Kataoka, Tadashi,Shimizu, Hiroshi,Hori, Mikio
, p. 97 - 110 (2007/10/02)
cis- and trans-9-Phenylselenoxanthene-N-(arylsulfonyl)selenilimines were synthesized and isolated.Their stereochemistry was ascertained from the NMR spectra.Cis isomers reacted with chloramine-T or -B by an SN2 type substitution to form trans i
