The present invention relates to nucleosides of formula I wherein R
1
, R
2
and R
3
are as defined herein that modulateTh1 and Th2 immune activity, methods of using compounds according to formula I, alone or in combination therapy, for treatment of a bacterial or a viral infection, a parasite infestation, a cancer or tumor or an autoimmune disease and compositions containing prodrugs of the nucleoside of formula Ia.
1
A facile one step synthesis of a wide variety of N-protected (Boc, Z, Fmoc) α-amino aldehydes under mild conditions is described. Pure N-protected (Boc, Z, Fmoc) α-amino aldehydes were obtained in high yields by reduction of N-protected (Z, Boc, Fmoc)-N-carboxyanhydrides (UNCAs) with equivalent amounts of lithium tris(tertbutoxy)aluminium hydride [LiAlH(O-t-Bu)3] or lithium tris[(3-ethyl-3-pentyl)oxy]aluminium
Rapid, one-pot synthesis of urethane-protected tripeptides
作者:Yun-Fei Zhu、William D. Fuller
DOI:10.1016/0040-4039(94)02391-n
日期:1995.2
Urethane-protected tripeptides are synthesized in solution, without isolation or purification of intermediates, using urethane-protected N-carboxyanhydrides as coupling reagents and hydrogenation for removal of N-protection.
N-protected α-alkyl-γ-amino-β-keto-esters were synthesized from the corresponding N-urethane protected N-carboxyanhydride (UNCAs) by reaction with lithium enolates in fairly good yields. These compounds are candidates for mimicking the transition state analogue in enzyme inhibitors. They constitute, however, interesting and diverse building blocks for using in combinatorial chemistry.