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Synthesis and Ionophoric Properties of Crown Ether Capped with a Convergent Hydroxamic Acid Function
| Content Provider | Semantic Scholar |
|---|---|
| Author | Kim, Duck Hee Kim, Mi Yee Kang, Byung Ha Chang, S. |
| Abstract | The structures and functions of classical crown ethers have been continually evolved to meet the specific requirements for the recognition of more demanding target systems. 1 One of the most frequently employed approaches is the introduction of extra binding sites into the basic framework of crown ethers as are well-exemplified systems of the lariat crown ethers. 2 Among these, lariat crown ethers having pH-responsive functions in their arm, such as carboxylic acid and hydroxamic acid derivatives, are particularly attractive for the ionophoric applications. 3 In particular, hydroxamic acid functions are employed frequently in many natural and synthetic ionophore systems and exhibited very unique binding behaviors toward some transition metal ions. Meanwhile, in many of the designed supramolecular systems, obtaining a specific convergent orientation of particular ligating functions toward active site is highly desirable for selective and strong binding of targeted guests. For these purpose, U-shaped structural motif of Kemp’s triacid is known to be very useful and resulted in the developments of many sophisticated supramolecular systems. 8-10 In this paper, we report the synthesis of a novel crown ether having a convergent hydroxamic acid function by utilizing the structural motif of Kemp’s triacid and its selective ionophoric behavior toward some of heavy and transition metal ions in competitive transport experiments. The hydroxamic acid derivative 3 was prepared from the Kemp’s triacid-capped 15-crown-5 ether 1 as shown in Scheme 1. Kemp’s triacid-capped derivative 1 was prepared by the reaction of 2-aminomethyl-15-crown-5 ether 11 with Kemp’s triacid following the reported procedure. 12 The acid derivative was converted into its acyl chloride by the treatment with oxalyl chloride, which was subsequently reacted with O-benzylhydroxylamine (CH 2Cl2/NEt3) to yield benzyl derivative 2 (60%). Deprotection of benzyl derivative by hydrogenation under Pd/C condition 13 afforded the desired hydroxamic acid derivative 3 in moderate yield (85%). 14 |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://ocean.kisti.re.kr/downfile/volume/chemical/JCGMCS/2002/v23n1/JCGMCS_2002_v23n1_160.pdf |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | BENZALKONIUM CHLORIDE 1 g in 59 g TOPICAL GEL [Berry Scented Hand Sanitizer] Behavior Binding Sites Bis(Chloromethyl) Ether Carboxylic Acids Crown Ethers Crown group Ethers for general anesthesia Experiment Hydrogenation Hydroxamic Acids Ionophores Ions Motif Palladium Requirement Synthetic intelligence Thioctic Acid Transition Elements ethyl ether oxalyl chloride |
| Content Type | Text |
| Resource Type | Article |
