H-Cit-PABA synthesis

6synthesis methods

Product Name:H-Cit-PABA
CAS Number:1037794-22-1
Molecular formula:C13H20N4O3
Molecular Weight:280.32

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Yield:1037794-22-1 94%

Reaction Conditions:

with piperidine in N,N-dimethyl-formamide at 20; for 0.5 h;

Steps:

13.2 Step 2 : Preparation of (S)- 1 -( 1 -(4-(hydroxymethyl)phenyl amino)- 1 -oxo-5 - ureidopentan-2-ylcarbamoyl)cyclobutanecarboxylic acid 10b

To a stirred solution of lOe (4.2 g, 8.3 mmol) in dry DMF (20 ml) was added piperidine (1.65 mL, 17 mmol, 2 eq) dropwise at r.t. The mixture was stirred at r.t. for 30 min, and solid precipitate formed. Dry DCM (50 mL) was added, and the mixture became transparent immediately. The mixture was stirred at r.t. for another 30 min, and LCMS showed lOe was consumed. It was concentrated to dryness under reduced pressure (make sure no piperidine remained), and the residue was partitioned between EtOAc and H₂0 (50 mL / 20 mL). Aqueous phase was washed with EtOAc (50 mL x 2) and concentrated to give (S)-2-amino-N-(4-(hydroxymethyl)phenyl)-5-ureidopentanamide lOd as an oily residual (2.2 g, 94%) (contained small amount of DMF).

References:

WO2016/90038,2016,A1 Location in patent:Page/Page column 124-125