DL-methionine sulfoxide

C5H10O2 3-methyl butanoic acid 503-74-2 -37.00 1.1060 1 5747 C5H11N03S DL-methionine sulfoxide 454-41-1 25.00 1.1832 2... 

A soln. of DL-methionine, 3 moles diethyl azodicarboxylate, ethanol, and water stirred 3 hrs. at room temp. DL-methionine sulfoxide. Y 97,5%. - The reaction is dependent on the presence of a proton-donating group. F. e. and limitations s. R. Axen, M. Chaykovsky, and B. Witkop, J. Org. Chem. 52, 4117 (1967). 

Figure 21.9. Oxygen transfer from [ M(02)(a-XWii039))2] to L-methionine, to give DL-methionine sulfoxide.

Catal3Ttic oxidation of L-methionine and DL-methionine sulfoxide has thus been successfully achieved in the presence of excess H2O2, 70-99% yields have been obtained over 20- 8h. For the TMSP [Zr(02)(a-GeWn039)]2 , the reaction scope has been extended to alcohol oxidation in aqueous solutions through a MW-assisted protocol (Table 21.9). ... 

Methionine sulfoxide [454-41-1, 62697-73-8] M 165.2, m >240 (dec). Likely impurities are dl-methionine sulfone and dZ-methionine. Crystd from water by adding EtOH in excess. 

All these enzymes have similar specificity and require the L-cysteine sulfoxide portion of the molecule. S-alkyl cysteines are not substrates 18, 24, 27, 39) neither are sulfoxides of N-substituted L-cysteine, / -di-methyl-L-cysteine, y8-thiopropionic acid 18), D-cysteine 19), and dl-methionine 18, 24, 39), nor do the enzymes act on L-cysteine itself 24, 27, 39), cysteic acid, cysteinesulfinic acid 24, 27), or cycloalliin 24, 39). There may be some action on S-ethylcysteine sulfone (42). 

Shi T, Rabenstein DL. Convenient synthesis of human calcitonin and its methionine sulfoxide derivative. Bioorg. Med. Chem. Lett. 2002 12 2237-2240. 

The alkaline Fe(CN)6 oxidations, described hereafter, were found to be first order in Fe(CN)g ion. The oxidation of DL-methionine (Meth) was fractional order both in Meth and OH ions. The mechanism assumed the formation of an adduct, of Fe(CN)6 and Meth, which decomposed to a radical in the rate-determining step. Further oxidation of the radical in the fast step resulted in the product methionine sulfoxide. The same reaction catalysed by Ru(III) was first order in Ru(III), had a fractional order in OH , and slowed with increasing methionine concentrations. The proposed mechanism suggested the formation of a complex between [Ru(H20)50H] +, the reactive Ru(III) species, and Meth. The product was methionine sulfone nitrile. The outer-sphere Ru(III)-catalysed oxidation of L-proline to glutamic acid was first order in Ru(III), fractional order in OH , and of zero order in proline.The oxidation of serine and threonine was first order in amino acid and zero order in OH . The reactivities of serine and threonine... 

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