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Synthesis of 5-Phenyliodonium Tosylates from 6-Aminouracils and Their Reactivity

초록/요약

Halogenations and aminations at the C-5 position of 6-aminouracil have been attempted with hypervalent iodine intermediates. (6-Amino-uracil-5-yl)-phenyl-iodonium tosylate was synthesized by using 6-aminouracils and [hydroxy(tosyloxy)iodo]benzene (Koser’s reagent). Halogenation at the C-5 position of 6-aminouracil phenyliodonium salts was achieved by hydrogen halide or tetrabutylammonium halide in DMF. Inhibitiors of thymidine phosphorylase, 4k (6A5CU) and 4l (6A5BU), were synthesized by HX and TBAX under mild conditions. Halogenations can be performed at the C-5 position of 6-amido-uracil phenyliodonium salts by acylation at 6-amino position and subsequent addition of hydrogen halide. Nucleophilic substitution at the C-5 position of 6-aminouracil phenyliodonium tosylates was investigated with various nucleophiles such as amines, nitriles and azides. As a result, 6-amino-5-cyano-uracil was prepared with 6-aminouracil and tetrabutylammonium cyanide. Also, amination at the C-5 position of 6-aminouracils was facilitated by secondary amines and (6-amino-uracil-5-yl)-phenyl-iodonium tosylate in DMF. With a view to application of this chemistry, new heterobicyclic compounds containing hexahydro-pteridine moiety have been synthesized. Also, O-tosylation at the C-5 position of 6-aminouracil was achieved by heating (6-amino-uracil-5-yl)-phenyl-iodonium tosylate in acetonitrile at 80 oC.

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초록/요약

6-Amino-uracil의 5번 위치에 halogenations과 aminations을 hypervalent iodine의 중간체를 거쳐 시도하였다. 6-Amino-uracil과 [hydroxy(tosyloxy)iodo]benzene (Koser’s reagent)를 이용하여 안정한 (6-amino-uracil-5-yl)-phenyl-iodonium tosylate를 쉽게 합성하였다. 형성된 iodonium tosylate 염으로부터 Bu4N+X-/DMF와 HX/DMF 조건에서 6-amino-uracil의 5번 위치에 할로겐기를 도입하였다. 이 반응을 이용하여 thymidine phosphorylase의 저해제로 알려진 6A5BU와 6A5CU를 합성하였다. Halogenations의 응용으로 (6-amino-uracil-5-yl)-phenyl-iodonium tosylates에서 6-amino 위치에 acylation 통하여 6-amido-uracil을 합성한 후 HX을 사용하여 uracil의 5번 위치에 halogenation을 할 수 있었다. (6-Amino-uracil-5-yl)-phenyl-iodonium tosylates에 amine, -CN, -N3등을 도입하고자 시도 해 보았다. 그 결과 tetrabutylammonium cyanide을 이용하여 cyano기를 도입시켰으며 이차 amines의 경우에는 (6-amino-uracil-5-yl)-phenyl-iodonium tosylates와 반응시켜 uracil의 5번 위치에 secondary amino를 도입시켰다. 이 amination의 반응을 이용하여 새로운 bicyclic 구조인 hexahydro-pteridine-2,4,6-trione구조를 포함하는 화합물을 합성하였다. 또한 (6-amino-uracil-5-yl)-phenyl-iodonium tosylates를 acetonitrile 용매 하에 가열하여 6-amino-uracil의 5번 위치에 tosyloxy기를 도입할 수 있었다.

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