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General synthesis of 2,1-benzisoxazoles (anthranils) from nitroarenes and benzylic C-H acids in aprotic media promoted by combination of strong bases and silylating agents.

Wiȩcław M, Bobin M, Kwast A, Bujok R, Wróbel Z, Wojciechowski K - Mol. Divers. (2015)

Bottom Line: Carbanions of phenylacetonitriles, benzyl sulfones, and dialkyl benzylphosphonates add nitroarenes at the ortho-position to the nitro group to form [Formula: see text]-adducts that, upon treatment with trialkylchlorosilane and additional base (t-BuOK or DBU), transform into 3-aryl-2,1-benzisoxazoles in moderate-to-good yields.

View Article: PubMed Central - PubMed

Affiliation: Institute of Organic Chemistry, Polish Academy of Sciences, Ul. Kasprzaka 44/52, PO Box 58, 01-224, Warszawa, Poland.

ABSTRACT
Carbanions of phenylacetonitriles, benzyl sulfones, and dialkyl benzylphosphonates add nitroarenes at the ortho-position to the nitro group to form [Formula: see text]-adducts that, upon treatment with trialkylchlorosilane and additional base (t-BuOK or DBU), transform into 3-aryl-2,1-benzisoxazoles in moderate-to-good yields.

No MeSH data available.


Common methods for the synthesis of 2,1-benzisoxazoles
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Sch2: Common methods for the synthesis of 2,1-benzisoxazoles

Mentions: Numerous methods for the synthesis of 2,1-benzisoxazoles have been developed starting from ortho-substituted benzene derivatives containing substituents suitable for cyclization to form a fused isoxazole ring (Scheme 2). The most frequently used are compounds containing such pairs of groups as carbonyl and azido (a) [17–20], nitro and carbonyl (b) [21–24], and alkyl and nitro (c) [25–27]. Dehydration of ortho-nitrobenzyl derivatives substituted with electron-withdrawing groups at their methylene unit (d) provides anthranils [28–31]. Another approach (e), introduced by Davis and Pizzini in 1960 [32], consists of a condensation of nitroarenes and arylacetonitriles, in which the new carbon atom of the isoxazole ring originates from the methylene group of the latter reagent [1, 8, 10, 32, 33].


General synthesis of 2,1-benzisoxazoles (anthranils) from nitroarenes and benzylic C-H acids in aprotic media promoted by combination of strong bases and silylating agents.

Wiȩcław M, Bobin M, Kwast A, Bujok R, Wróbel Z, Wojciechowski K - Mol. Divers. (2015)

Common methods for the synthesis of 2,1-benzisoxazoles
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4591207&req=5

Sch2: Common methods for the synthesis of 2,1-benzisoxazoles
Mentions: Numerous methods for the synthesis of 2,1-benzisoxazoles have been developed starting from ortho-substituted benzene derivatives containing substituents suitable for cyclization to form a fused isoxazole ring (Scheme 2). The most frequently used are compounds containing such pairs of groups as carbonyl and azido (a) [17–20], nitro and carbonyl (b) [21–24], and alkyl and nitro (c) [25–27]. Dehydration of ortho-nitrobenzyl derivatives substituted with electron-withdrawing groups at their methylene unit (d) provides anthranils [28–31]. Another approach (e), introduced by Davis and Pizzini in 1960 [32], consists of a condensation of nitroarenes and arylacetonitriles, in which the new carbon atom of the isoxazole ring originates from the methylene group of the latter reagent [1, 8, 10, 32, 33].

Bottom Line: Carbanions of phenylacetonitriles, benzyl sulfones, and dialkyl benzylphosphonates add nitroarenes at the ortho-position to the nitro group to form [Formula: see text]-adducts that, upon treatment with trialkylchlorosilane and additional base (t-BuOK or DBU), transform into 3-aryl-2,1-benzisoxazoles in moderate-to-good yields.

View Article: PubMed Central - PubMed

Affiliation: Institute of Organic Chemistry, Polish Academy of Sciences, Ul. Kasprzaka 44/52, PO Box 58, 01-224, Warszawa, Poland.

ABSTRACT
Carbanions of phenylacetonitriles, benzyl sulfones, and dialkyl benzylphosphonates add nitroarenes at the ortho-position to the nitro group to form [Formula: see text]-adducts that, upon treatment with trialkylchlorosilane and additional base (t-BuOK or DBU), transform into 3-aryl-2,1-benzisoxazoles in moderate-to-good yields.

No MeSH data available.