ChemicalBook CAS DataBase List ALPHA-METHYL-L-P-TYROSINE

ALPHA-METHYL-L-P-TYROSINE synthesis

9synthesis methods

Product Name:ALPHA-METHYL-L-P-TYROSINE
CAS Number:672-87-7
Molecular formula:C10H13NO3
Molecular Weight:195.22

Benzenepropanamide, α-amino-4-methoxy-α-methyl-, (αS)-

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672-87-7
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Yield:672-87-7 84%

Reaction Conditions:

with water;hydrogen bromide at 120; for 5 h;Product distribution / selectivity;

Steps:

6

Example 6Metyrosine 1 To a 100 mL flask with a reflux condenser was charged amide 4 (5.50 g of a mixture containing 4 (3.37 g, 16.1 mmol) and phenylacetamide (2.13 g)) and 48% HBr (30 mL). The solution was heated for 5 h at 120° C. and was cooled to room temperature. H₂O (60 mL) was added and the solution was washed with EtOAc (3×35 mL). The aqueous phase was concentrated in vacuo to provide a beige paste. The paste was dissolved in H₂O (15 mL) and the resulting mixture was heated to 65° C. Activated carbon (300 mg, Type NORIT SX) was added and the mixture was stirred for 15 min, was filtered and the filter pad was washed with water (2×4 mL). The combined filtrates were heated to 55° C. and the pH was adjusted to 5-6 using 32% aq. NH₃. The mixture was cooled to 0° C., was stirred for 15 min and was filtered. The collected solids were washed with cold water (2×5 mL) and were dried in vacuo to provide (-)-α-methyl-L-tyrosine (or metyrosine) 1 (2.65 g, 84%) as a white solid. HPLC (Zorbax C18, NaH₂PO₄10 mM pH=3/MeCN (100:0) 10 min, (100:0) to (0:100) 15 min, 0:100 5 min) t_R=10.1 min. Chiral HPLC (Nucleosil Chiral-1, CuSO₄10 mM/MeCN 10:1) t_R=16.9 min. m.p.=320-321° C. [α]₅₄₆=+201° (c=0.5 Copper complex solution) (lit.²+185-190° Copper complex solution preparation: Solution A (anhydrous NaOAc dissolved in H₂O (150 mL) in 250 mL volumetric flask, glacial acetic acid (50 mL) added and diluted to volume with H₂O) mixed with Solution B (cupric sulfate (62.5 g) diluted to volume with H₂O in a 200 mL volumetric flask) in a 1 L volumetric flask and was diluted to volume with H₂O. Metyrosine solution (5 mg/mL) was prepared in this solution.To obtain an NMR spectrum (taking into account the low solubility of the product), a small sample (10 mg) was transformed into its HCl salt. The sample was dissolved in 2 M HCl and the solution was evaporated to dryness. ¹H NMR (D₂O, 400 MHz) 1.49 (s, 3H); 2.90 (d, J=14.5 Hz, 1H); 3.16 (d, J=14.5 Hz, 1H); 6.75 (d, J=8.2 Hz, 2H), 7.01 ((d, J=8.2 Hz, 2H). ¹³C NMR (D₂O, 100.6 MHz) 21.6; 41.6; 61.0; 116.0, 125.0; 131.7; 155.5; 173.8.