N-tosyl-L-phenylalanine

N-tosyl-L-phenylalanine ethyl ester (Formula 2.18) is a suitable substrate for the proteinase chymotrypsin which hydrolyzes ester bonds. When the ethoxy group is replaced by a chloro-methyl group, an inhibitor whose structure is similar to the substrate is formed (Na-tosyl-L-phenylalanine chloromethylketone, TPCK). 

The similarity with the ORD s obtained by mixing the appropriate models of each unit model molecule of this copolymer N-tosyl L-phenylalanine (X) and N-tosyl tetrahydro-1, 2, 3, 4 isoquinolinoic-3 acid (XI) (Figure 11) has shown that for this irregular polymer the influence of the conformational equilibrium is only of secondary importance when compared with that of the chemical modification [30]. 

Calix[4]arene is a very popular building block for the design of molecules with well-defined mutual positions of substituents. The attachment of amidic residues to this molecule resulted in receptors 35 [65] and 36 [66]. Upon the H NMR titration of 35 by tetrabutylammonium salts of amino acids in acetone-d6y moderate chiral recognition was observed N-Ac-L-Ala K=4,900 M-1, AT-Ac-D-Ala K=5,700 M"1, AT-Ac-L-Phe iC=7,900 M-1, AT-Ac-D-Phe K= 10,500 M"1. The receptors 36a-c formed stable complexes with AT-tosyl-L-phenylalaninate in deuteriochloroform (36a K= 1,626 M"1, 36b 1C=4,836 M"1, 36c K=6y924 M-1). Unfortunately, the measurement using AT-tosyl-D-phenylalaninate has not been reported. 

Various routes exist for the synthesis of the acid chlorides of amino acid derivatives. The following procedure for a-N-tosyl phenylalanyl chloride originated by Popenoe and Du Vignaud (1954) has been repeated by Schoellman and Shaw (1963) and also used by Visser et al. (1971) for the synthesis of N-tosyl-L-alanyl chloride. Phosphorus pentachloride (3.90 g) was added to 5.4 g of tosyl-L-phenylalanine suspended in 75 ml of anhydrous ether at 0°C. The mixture was shaken for 10 min at 0°C, then for 10 min at room temperature and finally stored at 0°C for 1 hr. The crystalline product was filtered off, washed on the funnel quickly with a little ether and then with ice-water... 

N-[N-(benzyloxycarbonyl)-L-aspart-l-oyl-(L-leucyl-L-threonyl-N -tosyl-L-lysine p-nitrobenzyl ester)-4-oyl]-N-[N-(benzyloxycarbonyl)-L-aspart-l-oyl-(L-leucyl-L-threonyl-N -tosyl-L-lysyl-L-aspartic p-nitrobenzyl dlester)-4-oyl]-N-[N-(benzyloxycarbonyl)-L-aspart- l-oyl-(L-phenylalanine methyl ester)-4-oyl]-... 

The starting diazoacetamide is prepared by N-arylation of /-phenylalanine methyl ester (DMP, 5.5 M 4-fluoronitrobenzene, 110°C, lOh, 30%), acetoa-cetylation (2,2,6-triraethyl-4/7-l,3-dioxin-4-one, toluene, 110 °C, 4h, 71%) and diazo group transfer (tosyl azide, triethylamine, acetonitrile, 20 °C, 1.5 h, 90%). 

In an attempt to clarify the relationship between gramicidin S and its bacterial action, Harris and Work (258,259,260) synthesized a series of noncyclic peptides structurally similar to those of the naturally occurring peptides. These peptides are as follows D-phenylalanyl-L-proline methyl ester, L-phenylalanyl-L-proline ethyl ester L-leucyl-n-phenylalanine methyl ester L-leucyl-D-phenylalanyl-L-proline methyl ester L-leueyl-L-phenylalanyl-L-proline ethyl ester L-ornithyl-L-Ieucyl-n-phenylalanyl-L-proline methyl ester a-(L-valyl)-DL-ornithyl-L-leucyl-D-phenylalanyl-L-proline methyl ester o -(L-valyl)-L-ornithyl-L-leucyl-D-phenylalanyl-L-proline a-(L(valyl)-DL-ornithyl-L-leucyl-L-phenylalanyl-L-proline ethyl ester a-(tosyl-L-valyl) -L-ornithyl-L-leucyl-n-phenylalanyl-L-proline methyl ester a-(tosyl-L-valyl)-L-ornithyl-L-leucyl-D-phenylalanyl-L-proline amide. 

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