Organic compounds -- part of the class 532-570 series – Organic compounds – Carboxylic acid esters
Reexamination Certificate
2008-03-04
2008-03-04
Witherspoon, Sikarl A. (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Carboxylic acid esters
C560S179000, C560S184000, C562S579000, C562S586000
Reexamination Certificate
active
10496591
ABSTRACT:
A method for obtaining a 5-bromolevulinic acid methyl ester or a 5-chlorolevulinic acid methyl ester from either a bromination mixture or a chlorination mixture, containing either a 5-bromo-levulinic acid methyl ester or a 5-chlorolevulinic acid methyl ester, respectively, produced by either brominating or chlorinating levulinic acid or a levulinic acid methyl ester, and further including the steps of dissolving the bromination or chlorination mixture in an organic solvent or solvent mixture and cooling the solution, preferably to −20° C.–−40° C., with the 5-bromolevulinic acid methyl ester or 5-chlorolaevulinic acid methyl ester being crystallized out of the solution. The 5-bromolevulinic acid methyl ester or 5-chlorolevulinic acid is then isolated by draining off the solution with the remaining bromination mixture or chlorination mixture, as appropriate.
REFERENCES:
patent: 3275504 (1966-09-01), Herschler
patent: 5907058 (1999-05-01), Moens
MacDonald, S.F., Methyl 5-Bromovevulinate. Canadian Journal of Chemistry, 1974, vol. 52, p. 3257-3258.
Ha et al. Selective Bromination of Ketones. A Convenient Synthesis of 5-Aminolevulinic Acid. Synthetic Communications, 1994, vol. 24 (18), p. 2557-2562□□.
Schindler Edwin D.
Witherspoon Sikarl A.
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