Mercaptophenylacetic acid

Mercaptophenylacetic acid, acetic anhydride, and sodium nitrite yielded the first example (169, R = Ph) of a meso-ionic 1,3,2-oxathiazol-5-one this compound has a dipole moment of 4.5 D. An X-ray crystallographic investigation of the 4-phenyl-l,3,2-oxathiazol-5-one (169, R = Ph) has been reported. This compound is incorrectly described as a thiosydnone. The bond distances support the structure with tetracovalent sulfur, and on this evidence alone the compound 169, R = Ph, could be judged not to be meso-ionic because it can, on the basis of the X-ray evidence, be more satisfactorily represented by a covalent formulation. 

Recently, cLac (cyclic peptide-mimicking lactadherin) was synthesized using NCL and studied for phosphatidylserine (PS) recognition [64, 65]. The linear precursors for the synthesis of cLac derivatives were prepared following standard protocols for automated Fmoc-peptide synthesis and the cyclic peptides (cLac variants) were obtained in the presence of 4-mercaptophenylacetic acid and isolated via HPLC in yields of 60-70% (Fig. 9). All the synthesized cLac variants were labeled with the thiol-reactive fluorescein-5-maleimide in DMF containing 2% N-methylmorpholine (NMM) by taking advantage of the free cysteine side chain [65]. 

An ice-cold ethereal soln. of a-mercaptophenylacetic acid, ethyl nitrite, and a catalytic amount of coned. H2SO4 treated with 2 moles dicyclohexylcarbodiimide -> 4-phenyl-l,3,2-oxathiazolium 5-oxide. Y 87-90%. F. e. s. H. Gotthardt, Tetrah. Let. 1971, 1277 B. 105, 188 (1972). 

Mercapto-2-phenylacetic acid. a-Mercaptophenylacetic acid. Thiomandelic acid... 

Mercapto-A -phenylacetamide, in M-00016 2-Mercapto-2-phenylacetic acid, see M-00019 a-Mercaptophenylacetic acid, see M-00019... 

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