134672-72-3Relevant articles and documents
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
Das, Biplab Kumar,Shibata, Norio,Takeuchi, Yoshio
, p. 197 - 206 (2007/10/03)
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.
Novel nitrogen-containing titanocenes, and the use thereof
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, (2008/06/13)
Titanocenes of the formula I STR1 in which R1 are cyclopentadienyl? groups and R2 and R3 are aromatic radicals which are substituted in both ortho-positions by fluorine and, in addition, are substituted by a pyrrylalkyl group, amidoalkyl group or imidoalkyl group, are suitable as photoinitiators for the photopolymerization of ethylenically unsaturated compounds.