L-Proline 1,1-dimethylethyl ester → (S)-tert-Butyl-1-(2-(7-nitro-2H-benzo[b][1,4]thiazin-4(3H)-yl)-2-oxoethyl)pyrrolidine-2-carboxylate

HRID 1917183Notes

Reaction equation

HRID 1917183 reaction equation
Cl[CH2:2][C:3]([N:5]1[CH2:10][CH2:9][S:8][C:7]2[CH:11]=[C:12]([N+:15]([O-:17])=[O:16])[CH:13]=[CH:14][C:6]1=2)=[O:4].[NH:18]1[CH2:22][CH2:21][CH2:20][C@H:19]1[C:23]([O:25][C:26]([CH3:29])([CH3:28])[CH3:27])=[O:24]>C1COCC1.CCOC(C)=O.C(=O)(O)[O-].[Na+]>[C:26]([O:25][C:23]([C@@H:19]1[CH2:20][CH2:21][CH2:22][N:18]1[CH2:2][C:3]([N:5]1[CH2:10][CH2:9][S:8][C:7]2[CH:11]=[C:12]([N+:15]([O-:17])=[O:16])[CH:13]=[CH:14][C:6]1=2)=[O:4])=[O:24])([CH3:29])([CH3:27])[CH3:28]

Participants

6

Reactant 2

HCID 6453108L-Proline 1,1-dimethylethyl esterHCID 591440782-Chloro-1-(7-nitro-2H-benzo[b][1,4]thiazin-4(3H)-yl)ethanone

Product 1

HCID 59144152(S)-tert-Butyl-1-(2-(7-nitro-2H-benzo[b][1,4]thiazin-4(3H)-yl)-2-oxoethyl)pyrrolidine-2-carboxylate

Reagents, catalysts & solvents 3

HCID 8028TetrahydrofuranSolventHCID 8857Ethyl AcetateSolventHCID 516892Sodium BicarbonateSolvent2×

Conditions

Temperature
55 °C

Procedure

A solution of 2-chloro-1-(7-nitro-2H-benzo[b][1,4]thiazin-4(3H)-yl)ethanone (1.0 g, 3.67 mmol) in THF (20 mL) was treated with (S)-tert-butyl pyrrolidine-2-carboxylate (0.942 g, 5.50 mmol), followed by saturated sodium bicarbonate (4 mL). The mixture was heated at 55° C. for 3 hours then stirred at room temperature overnight (17 hours). The mixture was diluted with EtOAc (50 mL) and saturated sodium bicarbonate (10 mL) then stirred for 20 minutes. The contents were poured into a separatory funnel, and the organic layer was separated, dried (Na2SO4), filtered, and concentrated to give a dark yellow residue. This residue was subjected to silica gel chromatography using the Biotage purification system (column: Silicycle 40 g; 20:80 EtOAc:hexanes gradient to 60:40 EtOAc:hexanes over 8 column volumes; flow rate: 35 mL/min; collection wavelength: 254 nm). A yellow residue was obtained (1.47 g, 98%). 1H-NMR (CDCl3) δ 8.09 (d, J=2.4 Hz, 1H), 7.91 (dd, J=2.4, 8.7 Hz, 1H), 7.75 (d, J=9.0 Hz, 1H), 4.10 (brs, 2H), 3.74 (brd, J=13.2 Hz, 1H), 3.40 (brd, J=13.5 Hz, 1H), 3.37-3.21 (m, 3H), 3.12-3.04 (m, 1H), 2.61 (brdd, J=8.1, 16.2 Hz, 1H), 2.21-2.07 (m, 1H), 1.95-1.77 (m, 3H), 1.43 (s, 9H); ESI-MS (m/z, %): 408 (MH+, 50), 352 (100).

Workup

  1. stirringthen stirred for 20 minutes
  2. additionThe contents were poured into a separatory funnel
  3. customthe organic layer was separated
  4. dry with materialdried (Na2SO4)
  5. filtrationfiltered
  6. concentrationconcentrated
  7. customto give a dark yellow residue
  8. customthe Biotage purification system (column: Silicycle 40 g; 20:80 EtOAc:hexanes gradient to 60:40 EtOAc:hexanes over 8 column volumes; flow rate: 35 mL/min; collection wavelength: 254 nm)
  9. customA yellow residue was obtained (1.47 g, 98%)

Sources & evidence

ORD record
ord-f6aa52c2bb5d41ce86a679a54188d004
Source dataset
uspto-grants-2013_12
Patent number
US08618286B2

Reaction notes

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