Polyamino alcohols

This approach has been elegantly demonstrated by Biemann and co-workers [174]. They have adapted one of their earlier methods of modifying peptides [193] by esterification, N-terminal acetylation and then reduction with LiAlH4 (or LiAlD4) to give the polyamino-alcohol. These steps are preceded by chemical or enzymatic hydrolysis of the protein to di, tri- and tetrapeptides and concluded by O-silylation of the alcohol and side chain acid or hydroxyl function (see Scheme 1.1). 

The reconstructed total ionization chromatogram of the trimethylsily-lated polyamino alcohols, prepared by the outlined procedure, from the acid hydrolysis of the C-terminal cyanogen bromide fragment of actin is shown in Figure 1.14 [51]. The identification of the peaks was achieved by... 

Figure 1.15. Oligopeptides identified by GC-MS-computer as their O TMS polyamino alcohol derivatives from acid hydrolysate of C terminal cyanogen bromide fragment of actin. The reassembled eicosapeptide is shown (A) (reproduced from [51])...

Fig. 3.27. Gas chromatogram of a mixture of O-trimethylsilylated trifluoro-dideuteroethyl polyamino alcohol derivatives from a limited acid hydrolysis of 1.0 fimol of the amino terminal peptides from the carboxypeptidase inhibitor of potatoes. Reproduced from [S14] with permission of Academic Press.

Discussion of various strategies in the peptide structural work through the gas-phase methods is beyond the scope of this chapter. Sensitivity and accuracy of identification are the most important assets of such techniques. An example of the peptide GC is shown in Fig. 3.27, where a profile of O-trimethylsilylated trifluoro-dideuteroethyl polyamino alcohols is eluted at relatively high column temperature [511] the sample was obtained from the carboxypeptidase inhibitor of potatoes. 

The first approach in the synthesis of a bifunctional DOTA-derivative is to start with a tetrapeptide. This precursor may be obtained by a peptide route. The treatment with borane to convert the peptide to a linear polyamino alcohol, followed by tosylation and cyclization leads to the macrocycle (O Fig. 45.9). The modification for the coupling of the final BFC to a biomolecule is introduced already at the begiiming with the choice of the first amino acid. The final alkylation of the amines of the macrocycle leads to a BFC with four acetic acid groups for the complexation of the radiometal (Moi and Meares 1988). 

In this HAM protocol, ammonia was generated by the hydrolysis of urea in an acidic medium. Final cleavage of the oxazolidinone units produces the desired polyamino alcohols, which can be utilized as ligands in metal-catalyzed asymmetric transfer hydrogenations. 

The lower members of the homologous series of 1. Alcohols 2. Aldehydes 3. Ketones 4. Acids 5. Esters 6. Phenols 7. Anhydrides 8. Amines 9. Nitriles 10. Polyhydroxy phenols 1. Polybasic acids and hydro-oxy acids. 2. Glycols, poly-hydric alcohols, polyhydroxy aldehydes and ketones (sugars) 3. Some amides, ammo acids, di-and polyamino compounds, amino alcohols 4. Sulphonic acids 5. Sulphinic acids 6. Salts 1. Acids 2. Phenols 3. Imides 4. Some primary and secondary nitro compounds oximes 5. Mercaptans and thiophenols 6. Sulphonic acids, sulphinic acids, sulphuric acids, and sul-phonamides 7. Some diketones and (3-keto esters 1. Primary amines 2. Secondary aliphatic and aryl-alkyl amines 3. Aliphatic and some aryl-alkyl tertiary amines 4. Hydrazines 1. Unsaturated hydrocarbons 2. Some poly-alkylated aromatic hydrocarbons 3. Alcohols 4. Aldehydes 5. Ketones 6. Esters 7. Anhydrides 8. Ethers and acetals 9. Lactones 10. Acyl halides 1. Saturated aliphatic hydrocarbons Cyclic paraffin hydrocarbons 3. Aromatic hydrocarbons 4. Halogen derivatives of 1, 2 and 3 5. Diaryl ethers 1. Nitro compounds (tertiary) 2. Amides and derivatives of aldehydes and ketones 3. Nitriles 4. Negatively substituted amines 5. Nitroso, azo, hy-drazo, and other intermediate reduction products of nitro com-pounds 6. Sulphones, sul-phonamides of secondary amines, sulphides, sulphates and other Sulphur compounds... 

Polyhydroxy- phenols. amino acids, di- and polyamino compounds, amino alcohols. Sulphonic acids. Sulphinic acids. Salts. sulphinic acids, aminosulphonic acids and sulphonamides. Some diketones and /3-keto esters. Ethers and acetals. Lactones. Acyl halides. Diaryl ethers. intermediate reduction products of nitro compounds. Sulphones, sulphonamides of secondary amines, sulphides, sulphates and other sulphur compounds. 

This chapter considers the results received from enantioselective electrochemical reactions mainly from hydrogenations on metal (Pt, Ni), graphite, and Hg cathodes modified with chiral compounds (polyamino acids, alkaloids, and amino alcohols). Enantioselectivities of hydrogenation reactions were not effective, ee values did not exceed 50%, except in the cases of dehydrohalogenation and oxidation, from which optical yields reached above 90%. 

Amino-alcohols Polyamino-compounds Sulphonic acids Salts of amines or urea Salts of alkali metals Ammonium salts of organic acids... 

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