Application of Odorless Thiols for the Cleavage of 2‐ and 4‐Nitrobenzenesulfonamides
摘要:
Several odorless or faint-smelling thiols were tested to cleave 2- and 4-nitrobenzenesulfonyl groups, which are widely utilized for selective protection and activation of amines. p-Mercaptobenzoic acid (7) was found to be the most useful thiol for cleaving the o- and p-nosyl groups in terms of ease of separation of the product from the workup residue, reaction temperature, and reaction time.
Chemoselective Hydrogenation Reaction of Unsaturated Bonds in the Presence of an o-Nitrobenzenesulfonyl Group
摘要:
Chemoselective hydrogenation of unsaturated compounds bearing an o-nitrobenzenesulfonyl (Ns)-amide moiety, affording the corresponding saturated compounds, was accomplished efficiently without loss of the nitro group by using the Pd/MS3A catalyst and a H-2 balloon. Partial hydrogenation of alkynes bearing an Ns group to corresponding cis alkenes was achieved with the combination of the Pd/BN catalyst and an additive (diethylenetriamine or acetic acid).
2- and 4-Nitrobenzenesulfonamides: Exceptionally versatile means for preparation of secondary amines and protection of amines
作者:Tohru Fukuyama、Chung-Kuang Jow、Mui Cheung
DOI:10.1016/0040-4039(95)01316-a
日期:1995.9
4-Nitrobenzenesulfonamides, readily prepared from primary amines, undergo smooth alkylation by Mitsunobu reaction or by conventional methods to give N-alkylated sulfonamides in near quantitative yields. These sulfonamides could be deprotected readily via Meisenheimer complexes upon treatment with thiolates in DMF at room temperature, giving secondaryamines in high yields.