- Design and synthesis of N-nonpolar nucleobase dipeptides: Application of the Ugi reaction for the preparation of dipeptides havingfluoroarylalkyl groups appended to the nitrogen atom
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A single-step one-pot synthesis based on the Ugi four-component condensation of previously unknown dipeptides, 2,3,4 and 5, having afluoroaromatic group appended to the nitrogen atom, is described. The series of dipeptides produced here can be viewed as nonpolar nucleobase dipeptides since the difluorotoluene nucleoside 1 is a well known nonpolar analogue of natural thymidine. A mixture of N-protected amino acids 7, fluorophenethylamines 6, isocyanides 8, and acetone or paraformaldehyde are stirred in methanol in the presence of 3 A molecular sieves to furnish the N-fluoroarylethyl-Aib- or -Gly-containing dipeptides 2 or 3, in moderate yields. The dipeptides 2d and 3b, having a cyclohex-1-enamide moiety, are deprotected readily with 3 M HCl in THF to a3ord the free dipeptides in high yields. The N-fluoroarylmethyl-Aib- or -Gly-containingβ-alanyl dipeptides 4 or 5, designed based on the structure of 2′,5′-linked isoDNA, are also synthesized in a similar fashion to the preparation of 2, in moderate to good yields as both protected and free dipeptides.
- Das, Biplab Kumar,Shibata, Norio,Takeuchi, Yoshio
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p. 197 - 206
(2007/10/03)
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- Application of the Ugi four-component condensation reaction for the synthesis of α,α- and α,β-dipeptides substituted with fluoroarylalkyl pendent groups
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The application of the Ugi four-component condensation reaction for the synthesis of α,α- and α,β-dipeptides substituted with fluoroarylalkyl pendent groups was reported. The Ugi reaction using readily available fluorophenethyl amines was examined in the analysis. The method was applicable to the peptides containing a variety of amino acids attached to a diverse series of fluoroarylalkyl groups.
- Shibata, Norio,Das, Biplab Kumar,Takeuchi, Yoshio
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p. 4234 - 4236
(2007/10/03)
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- Syntheses of 1-[(2-hydroxyethoxy)methyl]- and 1-[(1,3-Dihydroxy-2-propoxy)methyl]- derivatives of 5-substituted-2,4-Difluorobenzene: Unnatural acyclo thymidine mimics for evaluation as anticancer and antiviral agents
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A group of 1-[(2-hydroxyethoxy)methyl]- (12) and 1-[(1,3-dihydrdxy-2-propoxy)methyl]- (13) derivatives of 2,4-difluorobenzene possessing a variety of C-5 substituents (R = Me, H, I, NO2) were designed with the expectation that they may serve as
- Wang, Zhi-Xian,Duan, Weili,Wiebe, Leonard I.,De Clercq, Erik,Balzarini, Jan,Knaus, Edward E.
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p. 1397 - 1411
(2007/10/03)
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