Tosyl alanine

Acidification of diazoketones The conversion of the diazoketone into a chloroketone is usually routine. Schoellman and Shaw (1963), in their synthesis of the chloromethyl ketone derived from phenylalanine, prepared an ethereal solution of the corresponding diazoketone and then treated it with dry HCl for 2 hr. The chloroketone could then be isolated following the removal of solvent. Visser et al. (1971) added concentrated HCl to an ethyl acetate solution of the diazoketone derivative of N-tosyl alanine until the evolution of nitrogen ceased. Removal of solvent, followed by crystallization from chloroform-heptane yielded an analytically pure product. A carbonyl absorption in the region of 1720 cm is diagnostic of haloketones. 

The lower rim C-linked AT-tosyl peptidocalix[4]arenes [78] of type 60 bearing l- or D-amino acid residues were prepared and studied for their anion recognition ability. The H NMR titrations proved that in all cases only the 1 1 complexes are formed in CDC13 with high complexation constants (e.g. 60,d,l-Ala, n=4, R=Pr K60 (HSO )=3,850 M"1, K60 (AT-tosyl-L-alaninate)=6,900 M-1). 

The postulated inversion of configuration during displacement of the tosyl group is unexceptionable. Other individuals [93] have prepared both forms of [2-2H]propionic acid from alanine (shown for D-Ala, 77, to (+ )-76). 

S 2 displacement of the corresponding tosylate intermediate with F anion was used by Mertens [2] and Chen [3] to prepared F-Alanine, (11), and F-tyrosine, (111), derivatives, respectively. 

C11H14CIN03S N-tosyl L-alanine chtoromethyl ketone 31982-00-0 379.20 32.410 1,2 22138 C11H1402 3-tert-butyl-2-hydroxybenzaldehyde 24623-65-2 480.16 41.981 2... 

Inhib. abbrev. DTT = dithioghreitol E64D = epoxysuccinyl-L-leucyl-amido-3-methyl-butane ethyl ester EDTA = ethylene-diamine-tetra-acetic acid EGTA = ethylen-glycol-tetra-acetic acid LHVS = morpholinurea-leucine-homophenyl-alanine-vinylsulfone-phenyl NEM = N-ethyl-maleimide PAI = plasminogen activator inhib. PMSF = phenil-methyl-sulfonil fluoride SBTl = soybean trypsin inhib. TIMP = tissue inhib. of metalloproteinases TPCK = tosyl-L-phenyl-alanyl-chloro-methane Al.so termed stephins. 

As a result of this search, a number of new compounds with interesting properties have been developed. These include bretylium tosylate (2), guanethidine (14), methyldopa [3-(3,4-dihydroxyphenyl)alanine] (18), and pargyline (11). All these compounds produce a more selective inhibition of the sympathetic nervous system, although each differs somewhat one from the other, in both primary mode of action and clinical effects. Of these compounds, guanethidine has received the most extensive therapeutic trial and clinical acceptance. 

The chiral oxime ethers can be synthesized from the oxime and chiral halides or tosylates. The chiral halides and tosylates were obtained from ( —)-ris-myrtanol, (S)-proline. (S)-valine, (S)-leucine, or (S)-alanine. 

More curiously, N-tosylated phenylalanine derivatives [10] and phenyllactic acid [11] can also be converted into 2-phenylnaphthalene in moderate yields whereas 3,4-dimethoxyphenyllactic acid treated with boron tribromide gives Kagan s ether in almost the same yield as 3,4-dimethoxyphenylethanal does [11]. In these cases, the decomposition of aryllactic acid or alanine derivatives may give arylethanal with the formation of water and carbon monoxide, Fig. (4). 

It is interesting to know that the stereoselectivity of the adduct using Corey s catalyst is opposite to that normally observed for oxaza-borolidines generated from A-tosyl derivative of (S)-valine or hexahydrophenyl alanine. 

We devised a method to perform the selective tosylation of the C-2 hydroxyl group in )3-cyclodextrin, and used it to attach the pyridoxamine to this secondary side of the cyclodextrin. Again we saw some preference for transamination of the aromatic ketoac-ids, but by less than we had observed with the pyridoxamine attached to C-6. The tryptophan synthesis was only 25 times as fast as that for alanine, while the phenylalanine formation was 18 times as fast as alanine in competitive reactions. Modest enantioselec-tivities were observed as well with this C-2 linked pyridoxamine, and they differed in detail from those produced with the C-6 isomer that we had reported earlier. 

However, the following suggested method can be used a reference curve can be obtained by measuring the pKo values of N-tosyl L-a-alanine, chosen as a model for PLL, in various acetone-water mixtures. The pK values of PLL in these mixtures can... 

A soln. of carbobenzoxy-L-prolyl-L-phenylalanine, p-nitrobenzyl tosylate, and triethylamine refluxed 1 hr. in dry acetone carbobenzoxy-L-prolyl-L-phenyl-alanine p-nitrobenzyl ester. Y 86%.—No racemization occurs. F. e. s. D. Theo-doropoulos and J. Tsangaris, J. Org. Chem. 29, 2272 (1964). 

Peptides. A soln. of N-(tosyl-DL-alanyl)-2-pyrrolidone and 2 moles methyl dl-alaninate in tetrahydrofuran warmed overnight at 60° in a sealed tube -> methyl tosyl-DL-alanyl-DL-alaninate. Y 89%. F. e. s. H. Tani, N. Oguni, and T. Araki, Bull. Ghem. Soc. Japan 37, 1245 (1964). 

Alanine tosylate-18-crown-6 complex Lyophilize alanine (1 Eq) from 5 mL of water containing p-toluenesulfonic acid monohydrate (1.1 Eq). The alanine-tosylate salt is added to a chloroform solution of 18-crown-6 (1 Eq) and the mixture stirred until homogeneous. Evaporation of chloroform and crystallization of the residue from methanol-ethyl acetate (see Note 6) yields the solid alanine-crown ether complex with a melting point of 123-125°C. 

The tosyl-phenylalanine moiety mimics a substrate like N-tosyl-phenyl-alanine methyl ester and the chloroketone function (see Section 2.3) acts as an electrophile where the chloride ion is displaced by His-57 at the active site of the enzyme. Similarly, a chloromethylketone analogue of lysine inhibits trypsin. 

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