Carnitinamide chloride, an immediate synthetic precursor of carnitine, was chlorinated at the amide nitrogen. The resultant carnitinechloramide chloride, when treated with a base, revealed that the first-formed isolable and characterisable carnitinechloramide inner salt undergoes solid state conversion into 5-trimethylammoniomethyl-2-oxazolidinone chloride via Hoffmann rearrangement and intramolecular cyclization of the β-hydroxyisocyanate. The trimethylaminomethyl substituent at C-5 of the 2-oxazolidinone was converted into a dimethylaminomethyl group by microwave-assisted demethylation in DMF and then into a methylaminomethyl group by decomposition of the α-chloroethyl carbamate obtained by treatment with α-chloroethyl chloroformate. This sequence of reactions was then applied to both (S)- and (R)-carnitinamide chloride without any racemization to yield both enantiomers of 5-aminomethyl-2-oxazolidinones that are mono-, di- and tri-methylated at the exocyclic nitrogen.
From carnitinamide to 5-aminomethyl-2-oxazolidinones / C. Bolchi, M. Pallavicini, M. Binda, L. Fumagalli, E. Valoti. - In: TETRAHEDRON-ASYMMETRY. - ISSN 0957-4166. - 23:3-4(2012), pp. 217-220. [10.1016/j.tetasy.2012.02.006]
From carnitinamide to 5-aminomethyl-2-oxazolidinones
C. Bolchi;M. Pallavicini;M. Binda;L. Fumagalli;E. Valoti
2012
Abstract
Carnitinamide chloride, an immediate synthetic precursor of carnitine, was chlorinated at the amide nitrogen. The resultant carnitinechloramide chloride, when treated with a base, revealed that the first-formed isolable and characterisable carnitinechloramide inner salt undergoes solid state conversion into 5-trimethylammoniomethyl-2-oxazolidinone chloride via Hoffmann rearrangement and intramolecular cyclization of the β-hydroxyisocyanate. The trimethylaminomethyl substituent at C-5 of the 2-oxazolidinone was converted into a dimethylaminomethyl group by microwave-assisted demethylation in DMF and then into a methylaminomethyl group by decomposition of the α-chloroethyl carbamate obtained by treatment with α-chloroethyl chloroformate. This sequence of reactions was then applied to both (S)- and (R)-carnitinamide chloride without any racemization to yield both enantiomers of 5-aminomethyl-2-oxazolidinones that are mono-, di- and tri-methylated at the exocyclic nitrogen.Pubblicazioni consigliate
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