Methyl 2-(4-benzyl-1-(5-chloro-2-nitrophenyl)piperazin-2-yl)acetate → 3-benzyl-10-chloro-1,2,3,4,4a,5-hexahydropyrazino[1,2-a][1,5]benzodiazepin-6(7H)-one

HRID 80504Notes

Reaction equation

[CH2:1]([N:8]1[CH2:13][CH2:12][N:11]([C:14]2[CH:19]=[C:18]([Cl:20])[CH:17]=[CH:16][C:15]=2[N+:21]([O-])=O)[CH:10]([CH2:24][C:25](OC)=[O:26])[CH2:9]1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1>[Fe].C(O)(=O)C>[CH2:1]([N:8]1[CH2:13][CH2:12][N:11]2[C:14]3[CH:19]=[C:18]([Cl:20])[CH:17]=[CH:16][C:15]=3[NH:21][C:25](=[O:26])[CH2:24][CH:10]2[CH2:9]1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1

Participants

Conditions

Temperature: 85 °C

Procedure

A round bottom flask was charged with methyl 2-(4-benzyl-1-(5-chloro-2-nitrophenyl)piperazin-2-yl)acetate (Example 24A, 19.4 g, 48.0 mmol) and iron (8.05 g, 144 mmol) followed by acetic acid (70 mL). The solution was heated at 85° C. for 2 hours. The solution was concentrated onto silica gel, and eluted through a silica column (0-10% methanol/dichloromethane). The product was then concentrated and redissolved in dichloromethane. Addition of sodium hydroxide (1M) caused the title compound to precipitate. 1H NMR (300 MHz, DMSO-d6) δ ppm 9.56 (s, 1H), 7.22-7.40 (m, 5H) 7.00-7.09 (m, 2H), 6.88-6.96 (m, 1H), 3.54 (s, 2H), 3.07-3.21 (m, 1H), 2.94-3.05 (m, 1H), 2.71-2.87 (m, 2H), 2.52-2.61 (m, 1H), 2.04-2.27 (m, J=10.71 Hz, 2H), 1.84-1.95 (m, 2H); MS (ESI) m/z 341.9 (M+H)+.

Workup

concentrationThe solution was concentrated onto silica gel
washeluted through a silica column (0-10% methanol/dichloromethane)
concentrationThe product was then concentrated
dissolutionredissolved in dichloromethane
additionAddition of sodium hydroxide (1M)
customto precipitate

Sources & evidence

ORD record: ord-c76fbcfa42e84015bc68b02977b393cc
Source dataset: uspto-grants-2014_09
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08846663B2

Reaction notes

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