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US4847412A Expired / Lapsed US ⏱️ 0.0 years remaining

Process for racemizing an optically active N-benzylidene amino-acid amide

Assignee: DSM IP Assets BV
•
Filing: 1986-04-10
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Granted: 1989-07-11
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Expires: 2006-04-10
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Abstract

Abstract The invention relates to a process for racemizing an optically active N-benzylidene amino-acid amide, characterized in that a solution of the N-benzylidene amino-acid amide is mixed in a water-miscible organic solvent with at least 0.05 mole strong base per liter solution. The invention further relates to a process for preparing an L-amino acid by enzymatic separation of the corresponding DL-amino-acid amide with an enzyme preparation from Pseudomonas putida, in which process also unconverted D-amino-acid amide is left behind in solution, characterized in that benzaldehyde is added to the solution, during which addition a precipitate of D-N-benzylidene amino-acid amide is being formed, this precipitate is subsequently, after being separated off, dissolved in an acetone-water mixture, 0.08-0.15 mole KOH/liter solution is subsequently added, the resulting solution is stirred for 1-20 hours at 20 DEG -60 DEG C., sulphuric acid is then added until the pH of the solution is 5 and the resulting sulphuric acid salt of the DL-amino-acid amide is finally, after isolation at pH 8-10, converted into the DL-amino-acid amide and this DL-amino-acid amide is used again.

Inventors

  • 👤 Wilhelmus H. J. Boesten
  • 👤 Hans E. Schoemaker
  • 👤 Bernardus H. N. Dassen

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-08 21:41
CPC Classifications
C; C12; C12P; C12P13/00; C12P13/04; C12P13/08; C12P41/00; C12P41/006; C12P41/007

Claims Analysis

Total Claims: 13
Claim 1
Independent Claim 34 words
Process for racemizing an optically active N-benzylidene amino-acid amide, wherein a solution of the N-benzylidene amino-acid amide in a water-miscible organic solvent is mixed with at least 0.05 mole strong base per liter solution.
Claim 2
Dependent Claim 34 words
Process for racemizing an optically active N-benzylidene amino-acid amide, wherein a solution of the N-benzylidene amino-acid amide in a water-miscible organic solvent is mixed with at least 0.05 mole strong base per liter solution.
Claim 3
Dependent Claim 63 words
Process for preparing a DL-amino-acid amide from an optically active amino-acid amide, wherein an optically active amino-acid amide is converted into the corresponding N-benzylidene amino-acid amide, a solution of the N-benzylidene amino-acid amide in a water-miscible organic solvent is subsequently mixed with at least 0.05 mole strong base per liter solution and the resulting DL-N-benzylidene amino-acid amide is converted into the DL-amino-acid amide.
Claim 4
Dependent Claim 63 words
Process for preparing a DL-amino-acid amide from an optically active amino-acid amide, wherein an optically active amino-acid amide is converted into the corresponding N-benzylidene amino-acid amide, a solution of the N-benzylidene amino-acid amide in a water-miscible organic solvent is subsequently mixed with at least 0.05 mole strong base per liter solution and the resulting DL-N-benzylidene amino-acid amide is converted into the DL-amino-acid amide.
Claim 5
Dependent Claim 49 words
Process according to claim 2, wherein the DL-N-benzylidene amino-acid amide is converted into the DL-amino-acid amide by bringing the solution containing DL-N-benzylidene amino-acid amide with acid to pH 3-7 and by subsequently converting the formed DL-amino-acid amide salt in an aqueous medium at pH 8-10 into the DL-amino-acid amide.
Claim 6
Dependent Claim 19 words
Process according to claim 1, wherein the racemization is carried out with 0.08-1.0 mole strong base per liter solution.
Claim 7
Dependent Claim 36 words
Process according to claim 1, wherein the strong base used is NaOH, KOH, LiOH, Ca(OH) 2 or tetraalkylammonium hydroxide, in which each of the alkyl groups contains 1-4 C atoms independently of any of the others.
Claim 8
Dependent Claim 23 words
Process according to claim 5, wherein tetraalkylammonium hydroxide is used in the form of a basic ion exchanger with free OH -- groups.
Claim 9
Dependent Claim 15 words
Process according to claim 1, wherein the organic solvent applied is acetone, methanol or ethanol.
Claim 10
Dependent Claim 15 words
Process according to claim 3, wherein the acid used is hydrochloric acid or sulfuric acid.
Claim 11
Dependent Claim 23 words
Process according to claim 3, wherein the acid is used in an amount equivalent to the total amount of base (Schiff base+strong base).
Claim 12
Dependent Claim 18 words
Process according to claim 3, wherein the DL-amino-acid amide is obtained from the corresponding salt while using KOH.
Claim 13
Dependent Claim 21 words
Process according to claim 1, wherein after addition of strong base the solution is stirred for 10 minutes to 24 hours.

References Cited (Backward Citations)

US440792A Cited
US4172846A Cited
US4275217A Cited
US4401820A Cited
US4713470A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1992-07-10 1993-01-09 1993-07-11 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1996-07-10 1997-01-09 1997-07-11 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2000-07-10 2001-01-09 2001-07-11 $7700.00 Window Closed / Lapsed

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