2- and 4-Nitrobenzenesulfonamides: Exceptionally versatile means for preparation of secondary amines and protection of amines

Fukuyama, Tohru; Jow, Chung-Kuang; Cheung, Mui

doi:10.1016/0040-4039(95)01316-a

Cited by 971 publications

(618 citation statements)

References 3 publications

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“…The use of a base to deprotonate the hydrochloride salt of the alkoxylamine reagent in the reaction medium may also favour the rearrangement. 23 We found that protecting the secondary amine with the 2-nitrobenzenesulfonamide (Ns) group 24,25 was a very convenient way to avoid the problem of rearrangement of 4a and 4b through intramolecular cyclization. Thus, Oalkyl-N-nosyl hydroxylamines 5a-8a were prepared easily, in good yields, by sulfonylation (NsCl/ pyridine/ CH 2 Cl 2 ) of hydroxylamines 5, 6, 7 26 and 8, respectively, followed by acidic workup and crystallization from acetone/hexane 27 (Scheme 1).…”

Section: Romentioning

confidence: 99%

Efficient one-pot synthesis of 1-alkoxy-2-arylaminoimidazolines from N-alkoxy-N-(2-aminoethyl)-2-nitrobenzenesulfonamides and arylisothiocyanates

Mascaraque

Nieto

Dardonville

2008

Tetrahedron Letters

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Abstract-A new synthetic approach towards 1-alkoxy-2-aminoimidazolines that uses N-alkoxy-N-(2-aminoethyl)-2-nitrobenzenesulfonamides as nucleophile reagents for the reaction with isothiocyanates is reported. Hence, the synthesis of 1-alkoxy-2-aminoimidazolines was performed in high yield with a one pot procedure involving thiourea formation, nosyl group removal and spontaneous cyclization (42-77% overall yield).

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Section: Romentioning

confidence: 99%

Efficient one-pot synthesis of 1-alkoxy-2-arylaminoimidazolines from N-alkoxy-N-(2-aminoethyl)-2-nitrobenzenesulfonamides and arylisothiocyanates

Mascaraque

Nieto

Dardonville

2008

Tetrahedron Letters

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“…entry 1, Table 2). The enantioenriched sulfonylated product (2R)-6a underwent facile deprotection with thioglycolic acid [33] and DBU in MeCN (93%) with no detectable erosion of its enantiopurity. Concomitantly, catalyst (-)-4a was recovered quantitatively as a single enantiomer (see Supporting Information).…”

Section: Methodsmentioning

confidence: 99%

Kinetic Resolution of 2‐Substituted Indolines by N‐Sulfonylation using an Atropisomeric 4‐DMAP‐N‐oxide Organocatalyst

et al. 2017

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Abstract:The first catalytic kinetic resolution by N-sulfonylation is described. 2-Substituted indolines are resolved (s = 2.6-19) using an atropisomeric 4-dimethylaminopyridine-N-oxide (4-DMAP-N-oxide) organocatalyst. Use of 2-isopropyl-4-nitrophenylsulfonyl chloride is critical to the stereodiscrimination and enables facile deprotection of the sulfonamide products with thioglycolic acid. A qualitative model that accounts for the stereodiscrimination is proposed.

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“…Incorporation of the ethylene bridge was done after coupling Fmoc-His(Trt) (where Trt denotes trityl) to the resin-bound Val. The Fmoc protecting group was replaced with the base-and acid-resistant 4-nitrobenzenesulfonyl group [6]. Then the resin was treated with a large excess of 1,2-dibromoethane in the presence of tetramethylguanidine in DMF at 60 °C for 4 h. …”

Section: Solid-phase Organic/peptide Synthesismentioning

confidence: 99%

Exploratory neuropharmacological evaluation of a conformationally constrained thyrotropin-releasing hormone analogue

Teixidó¹,

Prókai-Tátrai²,

Wang³

et al. 2007

Brain Research Bulletin

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A conformationally constrained peptidomimetic derived from the endocrine and neuroactive tripeptide thyrotropin-releasing hormone (pGlu-His-Pro-NH 2 ) was synthesized by convenient solidphase organic chemistry and evaluated as a potential central nervous system agent. While this ethylene-bridged peptide analogue has been reported to lack the hormonal effect of the native peptide, we have shown in animal models that it possesses central nervous system activity characteristic of thyrotropin-releasing hormone. Compared to control, the peptidomimetic showed significant analeptic and antidepressant-like potencies. Moreover, an enhanced selectivity in antidepressant-like effect was measured when compared to that of the native peptide. Immobilized artificial membrane chromatography and in vitro metabolic stability studies also revealed that this constrained peptidomimetic has higher affinity to the blood-brain barrier than the native peptide and is metabolically stable. Consequently, this structure may be used as a template to design centrally selective and metabolically stable thyrotropin-releasing hormone analogues as potential neuropharmaceutical agents.

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2- and 4-Nitrobenzenesulfonamides: Exceptionally versatile means for preparation of secondary amines and protection of amines

Cited by 971 publications

References 3 publications

Efficient one-pot synthesis of 1-alkoxy-2-arylaminoimidazolines from N-alkoxy-N-(2-aminoethyl)-2-nitrobenzenesulfonamides and arylisothiocyanates

Efficient one-pot synthesis of 1-alkoxy-2-arylaminoimidazolines from N-alkoxy-N-(2-aminoethyl)-2-nitrobenzenesulfonamides and arylisothiocyanates

Kinetic Resolution of 2‐Substituted Indolines by N‐Sulfonylation using an Atropisomeric 4‐DMAP‐N‐oxide Organocatalyst

Exploratory neuropharmacological evaluation of a conformationally constrained thyrotropin-releasing hormone analogue

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