2845-62-7Relevant articles and documents
Spiro-fysed 2-alkoxy-2-amino-Δ3-1,3,4-oxadiazolines. Synthesis and thermolysis to corresponding aminooxycarbenes
Couture, Philippe,Warkentin, John
, p. 1264 - 1280 (2007/10/03)
Δ3-1,3,4-Oxadiazolines spiro-fused at C2 to C2 to oxazolidines (12) or to C2 of tetrahydro-1,3-oxazines (13) were synthesized. The oxadiazolines undergo thermolysis in benzene at 90°C with first-order rate constants of (1.6-50) × 10-5 s-1. The dependence of these rate constants on the nature of the substituents present on the oxadiazoline ring is consistent with a mechanism involving a carbonyl ylide intermediate. Substituents on N of the oxazolidine or tetrahydro-1,3-oxazine moieties play a major role in determining the fragmentation pathways. Oxadiazolines with N-carbonyl groups (12c-j, 13d,e) afford essentially quantitative yields of the corresponding aminooxycarbenes, while other fragmentation reactions compete with carbene generation in the case of oxadiazolines with N-methyl (12b, 13c) or N-sulfonyl (12k) groups.
Unconventional Regiospecific Syntheses of Aromatic Carbonamides and Thiocarbonamides by Means of Tin-Mediated Friedel-Crafts Reactions
Arnswald, Martin,Neumann, Wilhelm P.
, p. 7022 - 7028 (2007/10/02)
Friedel-Crafts reactions of stannylarenes 1 with tosyl isocyanate (TsNCO, 2) give N-tosylcarbonamides 3 via ipso substitution of the stannyl group.Thus, unconventionally substituted aromatic carbonamides can be obtained.The combination of the reaction of 1 and 2 with that of 1 and chlorosulfonyl isocyanate (14) allows one-pot syntheses of N-(arylsulfonyl)-substituted aromatic carbonamides with optional substitution patterns on both aromatic rings.The known ipso-specific substitutions of stannylarenes with 14 are extended to bi- and tricyclic arenes as well as to thiophenes 6 and 22.One stannyl group can serve as a leaving group for two aromatic systems, as shown with diaryldialkyltins 29.Also, stannylalkanes such as 27 react with 14 to afford alkylsulfonyl isocyanates and products of further reactions, such as 28.From the reactions of 1 with ethoxycarbonyl isocyanate (32), ortho- and meta-substituted aromatic thiocarbonamides 33 which are potential precursors for further syntheses, are accessible.The scope, limitations, and mechanism of these electrophilic substitutions are outlined.
Eine neue Palladium-katalysierte Carbonylierung von aromatischen N-Chlorsulfonamidaten zu Arylsulfonylisocyanaten
Besenyei, Gabor,Nemeth, Sandor,Simandi, Laszlo J.
, p. 1168 - 1169 (2007/10/02)
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