(R)-1,4-di-Boc-piperazine-2-carboxylic acid Methyl ester synthesis
- Product Name:(R)-1,4-di-Boc-piperazine-2-carboxylic acid Methyl ester
- CAS Number:637027-24-8
- Molecular formula:C16H28N2O6
- Molecular Weight:344.4
173774-48-6
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74-88-4
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637027-24-8
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Yield:637027-24-8 100%
Reaction Conditions:
Stage #1: (R)-piperazine-1,2,4-tricarboxylic acid 1,4-di-tert-butyl esterwith potassium carbonate in N,N-dimethyl-formamide at 20 - 25; for 0.5 h;
Stage #2: methyl iodide in N,N-dimethyl-formamide at 15 - 25; for 16 h;
Steps:
1.3 Preparation of Piperazine-1,2,4-(R)-tricarboxylic acid, 1,4-di-tert-butyl-2-methyl ester (3)
Part 3 Preparation of Piperazine-1,2,4-(R)-tricarboxylic acid, 1,4-di-tert-butyl-2-methyl ester (3) Potassium carbonate (4.0 kg; 29 mol) is added to a solution of piperazine-1,2,4-(R)-tricarboxylic acid, 1,4-di-tert-butyl ester (2, 3.0 kg) in DMF (22.0 L) at ambient temperature. The resulting mixture is stirred at 20-25° C. for about 30 minutes. The reaction mixture is then cooled to 15-20° C. Methyl iodide (1.0 L; 16 mol) is added, and stirred at 20-25° C. for at least 16 hours. The reaction progress is monitored by TLC (sampling every 1 to 2 hours) and GC-MS. After the reaction is complete, MTBE (17.0 L) is charged and solids are removed by filtration. The filtrate is transferred back to the reactor and cooled to 15-20° C. Water (11.0 L) is added while maintaining the temperature below 15° C. The pH is adjusted to 4-5 by adding 6 N HCl (100.0 mL). The phases are allowed to settle, and the aqueous phase is extracted twice with MTBE (22.0 L each). The MTBE extracts are combined, and washed sequentially with water (22.0 L) and brine (22.0 L). The MTBE phase is dried over MgSO4, filtered, and concentrated to a residue at about 35° C. under vacuum to remove the MTBE. The solid residue is dried at ambient temperature under vacuum until a constant weight is obtained to afford piperazine-1,2,4-(R)-tricarboxylic acid, 1,4-di-tert-butyl-2-methyl ester (3, 2.5 kg; 100%) as an off-white solid.
References:
US2011/3812,2011,A1 Location in patent:Page/Page column 21
279227-92-8
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24424-99-5
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637027-24-8
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$116.00/100mg
24424-99-5
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252990-05-9
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637027-24-8
36 suppliers
$116.00/100mg