Reaction chromatography phenyl groups

The reaction of iV-benzyloxycarbonyl L-proline acid chlorides 134 with imine 135 in the presence of triethylamine, at room temperature, gave the corresponding spiro-(3-lactams 136, 137 as a 1 1 mixture of diastereoisomers, which were separated by column chromatography. The Staudinger reaction proceeds with complete stereoselectivity with a cis relative disposition of the pyrrolidine nitrogen and the phenyl group, but no asymmetric induction was observed. However, very... 

Insulin was reacted with performic acid to cleave the disulfide bridges. Two polypeptides were isolated from this reaction, polypeptide A with 21 amino acids and polypeptide B with 30 amino acids. Polypeptide B was reacted with Sanger s reagent and then partially hydrolyzed. This produced a very complex mixture containing individual amino acids, dipeptides, tripeptides, and so on. All of the peptides that had the dinitro-phenyl group on their N-terminal amino acid were then isolated from this mixture. (This was relatively easy to accomplish because these labeled peptides have very different solubility properties from the unlabeled polypeptides in acidic solution.) The labeled peptides were separated by chromatography, and each component was hydrolyzed. The following results were obtained ... 

Solid-phase matrices used for hydrophobic interaction chromatography are composed of hydrophilic structures such as agarose, dextran, and hydrophilic polymers. Hydrophobic sites such as methyl, butyl, octyl, dodecyl, and phenyl groups are chemically attached by means of activation reactions. 

The number of products can be reduced by using a phthalonitrile bearing bulky groups, e.g., phenyl groups (no BBBB compound is obtained), in the 3,6-positions [93,105]. The statistical condensation is carried out by reaction of equimolar amounts of 3,4,5,6-tetraphen-ylphthalonitrile and 4,5-dipentoxyphthalonitriIe with nickel acetate in n-pentanol in the presence of catalytic amounts of DBU at 140°C for 24 h. The reaction products are shown in Fig. 15.9. All reaction products can be isolated by column chromatography [93]. 

---