1738-80-3

Upstream product

• 56-45-1 L-serin 
• 104-15-4 toluene-4-sulfonic acid 
• 100-51-6 benzyl alcohol 

Downstream Products

• 59524-02-6 N-tert-butoxycarbonyl-L-serine benzyl ester 
• 77313-45-2 Boc-Ser-Ser-OBzl 
• 135575-89-2 N-benzyloxycarbonyl-L-phenylalanyl-L-serine benzyl ester 
• 96409-01-7 ester bezylique de la N-(chloro-2-ethyl)-N-nitrosocarbamyl-L-serine 
• 153989-59-4 N-9-fluorenylmethyloxycarbonyl-L-alanyl-L-serine benzyl ester 
• 70874-12-3 Boc-Ala-Ser-OBzl 
• 138478-05-4 2-benzyloxycarbonyl-2-palmitoylaminoethanol 
• 123765-20-8 benzyl (2S)-2-amino-3-[tert-butyl(dimethyl)silyl]oxypropanoate 
• 312933-68-9 N-(2,3,4,6-Tetra-O-acetyl-β-D-galactopyranosyloxycarbonyl)-L-leucyl-L-serine benzyl ester 
• 55788-21-1 H-Ser-Ser-OBzl 
• 77313-46-3 Boc-Thr-Ser-Ser-OBzl 
• 1311414-55-7 Boc-Trp-Trp-Ser-OBzl 
• 1185198-42-8 N-[2-chloro-9-(tetrahydropyran-2-yl)-9H-purin-6-yl]-N-cyclopropylglycyl-L-serine benzyl ester 
• 96854-28-3 (R)-<2-(Benzyloxycarbonyl)-2-<(methoxycarbonyl)amino>ethyl>triphenylphosphonium Iodide 

Relevant academic research and scientific papers

One-step preparation of enantiopure l- or d-amino acid benzyl esters avoiding the use of banned solvents

The enantiomers of amino acid benzyl esters are very important synthetic intermediates. Many of them are currently prepared by treatment with benzyl alcohol and p-toluenesulfonic acid in refluxing benzene or carbon tetrachloride, to azeotropically remove water, and then precipitated as tosylate salt by adding diethyl ether. Here, we report a very efficient preparation of eight l- or d-amino acid benzyl esters (Ala, Phe, Tyr, Phg, Val, Leu, Lys, Ser), in which these highly hazardous solvents are dismissed using cyclohexane as a water azeotroping solvent and ethyl acetate to precipitate the tosylate salt. With some work-up modifications and lower yield, the procedure can be applied also to methionine. Chiral HPLC analysis shows that all the benzyl esters, including the highly racemizable ones such as those of phenylglycine, tyrosine and methionine, are formed enantiomerically pure under these new reaction conditions thus validating the solvents replacement. Contrariwise, toluene cannot be used in place of benzene or carbon tetrachloride because leading to partially or totally racemized amino acid benzyl esters depending on the polar effect of the amino acid α-side chain as expressed by Taft’s substituent constant (σ*).

Biosynthesis of Hyalodendrin and Didethiobis(methylthio)hyalodendrin, Sulphur-containing 2,5-Dioxopiperazines of the 3S,6S Series

cyclo-(L-Phe-L-Ser) 8, a known biosynthetic precursor of the (3R,6R)-epidithiodioxopiperazine gliotoxin 4, was efficiently incorporated (42percent), in Hyalodendron sp. (FSC-601) cultures, into the 3S,6S metabolite didethiobis(methylthio)hyalodendrin (DBH) 7 without significant change in the 3H:14C ratio.None of the three diasteromers of cyclo-(L-Phe-L-Ser) was incorporated into DBH to any significant extent.The 13C label from cyclo-(L-Phe-L-Ser) was located, in the expected site, in DBH by 13C NMR spectroscopy.Gliotoxin derived in Gliocladium virens from the doubly labelled precursor 8 was degraded to locate, in similar manner, the 14C label.The N-methyl derivative 16 of cyclo-(L-Phe-L-Ser) was not incorporated detectably into either gliotoxin or DBH.Radioactivity from the doubly labelled, linear dipeptides 17 and 18, possible precursors for the cyclodipeptide 8, was incorporated with moderate efficiency into gliotoxin.However, the 3H:14C ratios for the dipeptides and the derived gliotoxin differd substantially, indicating that the peptides had undergone cleavage in the fungus before incorporation.