Vicarious NucleophilicSubstitution of Hydrogen in Nitroarenes with in situ Generated Carbanionsof 1-Methyl-3-chloro-1,3-dihydro-2,1-benzisothiazole 2,2-Dioxides
Abstract:Base-induced transformation of an equimolar mixture of 1-alkyl-1,3-dihydro-2,1-benzisothiazole 2,2-dioxides (benzosultams) and their 3,3-dichloro derivatives furnishes 1-alkyl-3-chloro-1,3-dihydro-2,1-benzisothiazole 2,2-dioxides which react with nitroarenes according to the vicarious nucleophilic substiution of hydrogen (VNS) mechanism giving 3-(nitroaryl)benzosultams.
“…Interesting possibilities of synthesis of condensed quinoline systems are offered by [4+2] cycloaddition reactions of short-lived aza- ortho -xylylenes 325 generated by thermal (>180 °C) extrusion of sulfur dioxide from benzosultams, which are readily accessible via intramolecular, oxidative (Scheme 119), , or vicarious (Scheme 120) 322 substitution of hydrogen in 3-nitro- N -(methane or chloromethanesulfonyl)anilines. Aza- ortho -xylylenes can be trapped with a dienophile, e.g., N -phenylmaleimide (NPMI), to form condensed 1,2,3,4-tetrahydroquinoline derivatives (Scheme 128). ,,, …”
Section: 7 Quinolines and Other Condensed Pyridinesmentioning
confidence: 99%
“…3-Chlorobenzosultams generated in situ via halophilic reaction of an equimolar mixture of benzosultam and 3,3-dichlorobenzosultam 212 in the presence of solid NaOH in DMSO enter VNS substitution in nitroarenes and heteronitroarenes readily to form 3-aryl derivatives (Scheme 59). 213…”
Section: Alkyl Substituents Containing Sulfur In R-positionmentioning
confidence: 99%
“…Aza-ortho-xylylenes can be trapped with a dienophile, e.g., N-phenylmaleimide (NPMI), to form condensed 1,2,3,4-tetrahydroquinoline derivatives (Scheme 128). 213,325,328,329 Intramolecular VNS in N-pentenyl-and N-hexenyl-N-chloromethanesulfon(m-nitro)anilides provides benzosultams that undergo thermal extrusion of SO 2 leading to aza-ortho-xylylenes suitable for intramolecular [4+2] cycloaddition leading to 1,2,3,4-tetrahydroquinoline derivatives (Scheme 129). 329 Aza-ortho-xylylenes generated from 3-alkylbenzosultams do not enter [4+2] cycloaddition but undergo a [1,5] sigmatropic hydrogen shift leading to 2-vinylaniline derivatives.…”
Section: Quinolines and Other Condensed Pyridinesmentioning
“…Interesting possibilities of synthesis of condensed quinoline systems are offered by [4+2] cycloaddition reactions of short-lived aza- ortho -xylylenes 325 generated by thermal (>180 °C) extrusion of sulfur dioxide from benzosultams, which are readily accessible via intramolecular, oxidative (Scheme 119), , or vicarious (Scheme 120) 322 substitution of hydrogen in 3-nitro- N -(methane or chloromethanesulfonyl)anilines. Aza- ortho -xylylenes can be trapped with a dienophile, e.g., N -phenylmaleimide (NPMI), to form condensed 1,2,3,4-tetrahydroquinoline derivatives (Scheme 128). ,,, …”
Section: 7 Quinolines and Other Condensed Pyridinesmentioning
confidence: 99%
“…3-Chlorobenzosultams generated in situ via halophilic reaction of an equimolar mixture of benzosultam and 3,3-dichlorobenzosultam 212 in the presence of solid NaOH in DMSO enter VNS substitution in nitroarenes and heteronitroarenes readily to form 3-aryl derivatives (Scheme 59). 213…”
Section: Alkyl Substituents Containing Sulfur In R-positionmentioning
confidence: 99%
“…Aza-ortho-xylylenes can be trapped with a dienophile, e.g., N-phenylmaleimide (NPMI), to form condensed 1,2,3,4-tetrahydroquinoline derivatives (Scheme 128). 213,325,328,329 Intramolecular VNS in N-pentenyl-and N-hexenyl-N-chloromethanesulfon(m-nitro)anilides provides benzosultams that undergo thermal extrusion of SO 2 leading to aza-ortho-xylylenes suitable for intramolecular [4+2] cycloaddition leading to 1,2,3,4-tetrahydroquinoline derivatives (Scheme 129). 329 Aza-ortho-xylylenes generated from 3-alkylbenzosultams do not enter [4+2] cycloaddition but undergo a [1,5] sigmatropic hydrogen shift leading to 2-vinylaniline derivatives.…”
Section: Quinolines and Other Condensed Pyridinesmentioning
A new application of Pd-catalysed allylation is reported that enables the synthesis of a range of branched sp -functionalised sulfonamides, a compound class for which few reported methods exist. By reacting benzyl sulfonamides with allylic acetates in the presence of Pd catalysts and base at room temperature, direct allylation was efficiently performed, yielding products that are analogues of structural motifs seen in biologically active small molecules. The reaction was performed under mild conditions and could be applied to nanomolar sigma-receptor binders, thus enabling a late-stage functionalisation and efficient expansion of drug-like chemical space.
The replacement of hydrogen occurs at the para-position of the nitro-group. A mechanism is discussed. -(WOJCIECHOWSKI*, K.; MODRZEJEWSKA, H.; Synthesis 2003, 10, 1503-1505; Inst. Org. Chem., Pol. Acad. Sci., PL-01-224 Warszawa, Pol.; Eng.) -C. Herrmann 44-115
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