Browsing by Author "Chen, Hsia-Yuan"

Now showing 1 - 2 of 2

Scaffold-directed traceless synthesis of tetrahydro-beta-carbolinehydantoins
(2007-07-01)
Chen, Chih-Hau
;
Chang, Chia-Mao
;
Chen, Hsia-Yuan
;
Lai, Jin-Ji
;
Sun, Chung-Ming
Pharmacologically interesting tetrahydro-beta-carbolinehydantoins have been prepared through four-step traceless synthesis by a combinatorial approach. Two-arm PEG 1 (MW approximate to 4000) was used as a soluble polymer support and reacted with Fmoc-protected L-tryptophane 2 to form bis-ester 3. The resulting polymer-supported amino ester 3 was deprotected, and amino ester 4 underwent Pictet-Spengler reaction with varoius ketones to form tricyclic indoles 5. The nucleophilic piperidine in the tricyclic indole reacted with isocyanate to generate the urea intermediates and simultaneously intramolecular cyclization to release the target compounds 7 from the support in good yields.
Synthesis of structurally diverse benzimidazolyl benzimidazolones by application of soluble polymer support
(2008-06-30)
Chen, Hsia-Yuan
;
Kulkarni, Manohar V.
;
Chen, Chih-Hau
;
Sun, Chung-Ming
;
應用化學系
Chemical stability and reactivity of a bifunctional polymer conjugate containing an ortho-amino arylamide linkage have been successfully exploited to achieve a parallel synthesis of methoxycarbonylated head-tail bis-benzimidazoles. Regioselective alkylation of the two nitrogens in the benzimidazolone moiety has been carried out by ipso-fluoro displacement, and N-alkylation to generate two diversities. Cleavage of the polymer support has resulted in two libraries of di- and tri-substituted benzimidazolyl benzimidazolones in high purity and high yield. All reaction steps have been monitored by (1)H NMR on the support directly. (c) 2008 Elsevier Ltd. All rights reserved.