Oligo carbamate

Some other 3-thienyl ether derivatives have been prepared. Poly[3-oligo(oxyethylene)-4-methyltiophene] showed an absorption peak at 550 nm (95JCS(CC)2293). On the other hand, poly[3-(N-succinimido(tetra-ethoxy)oxy)-4-methylthiophene] was prepared and it is able to react with amines to give the corresponding carbamate with a 15-crown-5 attached substructure. This polymer showed absorption at 429 nm and fluorescence at 543 nm (04T11169). 

In peptide synthesis the use of a suitable protection for the N-terminal amino group is required not only to prevent the formation of a complex mixture of oligo- and cyclo-peptides, but an additional demand on the functionality applied for this purpose is that it should prevent possible racemization of the activated amino acid. Racemization usually takes place via an intermediate oxazolone (7) that forms readily from A -acyl-protected amino acids (Scheme 2). This side reaction can be mostly suppressed by using a carbamate as an N-terminal-protecting group. Therefore, nearly all blocking functions currently applied in this field are of the urethane type. 

Sutherland and coworkers used ethyl carboxylate protecting groups when they reacted an oligo(ethyleneoxy)bis(carbamate) with a ditosylate or dihalide... 

In -this paper, we will shortly discuss our approach to prepare hydroxy-terminated MDl/BDO-based urethane oligomers and their 4-diphenylmethane carbamates, 18 and describe in more detail the synthesis of monodisperse hydroxy-terminated oligo(oxy-tetramethylenes), their use for the investigation of the prepolymer formation, and the synthesis of linear PU-elastomers with narrow (monodisperse) soft and/or hard segment length distribution by using the hydroxy-terminated segment precursors. The chemical structures of the model systems studied in this... 

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