(S)-N-ALPHA-T-BUTYLOXYCARBONYL-PYROGLUTAMIC ACID T-BUTYL ESTER

To a 1-neck 1 L round bottom flask was charged 40 g (216 mmol) (S)-5-oxo- pyrrolidine-2-carboxylic acid fer/-butyl ester followed by 350 mL MeCN. The reaction was cooled to 5 N-Methylimidazole (0.031 g, 0.378 mmol) and Boc anhydride (0.907 g, 4.16 mmol) were added to a mixture of tert-butyl pyroglutamate 4 (0.700 g, 3.78 mmol) in tert-BuOH (15 mL) at 30 °C. The synthesis of the vinylproline derivative 6a was conducted proceeding from L-pyroglutamic acid (1a) in six steps (scheme 3). As an alternative, the synthesis of 6a was developed in five stages proceeding from L-proline (16a) with the aid of an electrochemical oxidation of 17a as the key step (step p). As a further suitable intermediate, compound 6b was synthesized by Cu-catalyzed substitution of the methoxy group in 4a (scheme 3).The (S)-tert-butyl 5-oxopyrrolidine-2-carboxylate (21.65 g, 116.9 mmol) was dissolved in acetonitrile (300 mL) with 4-dimethylaminopyridine (1.29 g, 10.6 mmol) and the mixture was cooled to 0 A solution of 20.0 g of lactam 206 (108 mmol) in 200 ml of anhydrous acetonitrile was added with 25.6 ml of BocStep A22a. A solution of tert-butyl (S)-5-oxopyrrolidine-2-carboxylate (5.0 g, 27.0 mmol) in acetonitrile (100 mL) was treated with (Boc)A stirred mixture of pyroglutamic acid 5 (5.0g, 38.7mmol), Boc anhydride (16.9g, 77.4mmol), and DMAP (0.2g, 1.6mmol) in tert-BuOH (20mL) was refluxed for 12h under nitrogen atmosphere. Upon cooling at room temperature, solvent was removed under vacuum, and the residue was purified by flash chromatography (SiO

Molecular Weight:285.34
XLogP3:1.9
Hydrogen Bond Acceptor Count:5
Rotatable Bond Count:5
Exact Mass:285.15762283
Monoisotopic Mass:285.15762283
Topological Polar Surface Area:72.9
Heavy Atom Count:20
Complexity:416
Defined Atom Stereocenter Count:1
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes