Hydrochloric Acid → 4-(6-Aminobenzothiazol-2-yl)piperazine-1-carboxylic acid benzyl ester

HRID 1783496Notes

Reaction equation

[CH2:1]([O:8][C:9]([N:11]1[CH2:16][CH2:15][N:14]([C:17]2[S:18][C:19]3[CH:25]=[C:24]([N+:26]([O-])=O)[CH:23]=[CH:22][C:20]=3[N:21]=2)[CH2:13][CH2:12]1)=[O:10])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.Cl[Sn]Cl.Cl.[OH-].[Na+]>CCO.O>[CH2:1]([O:8][C:9]([N:11]1[CH2:16][CH2:15][N:14]([C:17]2[S:18][C:19]3[CH:25]=[C:24]([NH2:26])[CH:23]=[CH:22][C:20]=3[N:21]=2)[CH2:13][CH2:12]1)=[O:10])[C:2]1[CH:3]=[CH:4][CH:5]=[CH:6][CH:7]=1

Participants

Conditions

Temperature: 70 °C

Procedure

A mixture of 4-(6-nitrobenzothiazol-2-yl)piperazine-1-carboxylic acid benzyl ester (1.13 g, 2.84 mmol), SnCl2 (2.56 g, 11.3 mmol), and conc. HCl (0.35 mL, 4.25 mmol) in EtOH was heated at 70° C. overnight, diluted with water, neutralized with 1 N NaOH to pH 10, and extracted with CH2Cl2. The combined extracts were filtered through a pad of silica gel. The filtrate was concentrated in vacuo to provide the title compound (0.80 g, 77%), characterized by NMR and mass spectral analyses.

Workup

extractionextracted with CH2Cl2
filtrationThe combined extracts were filtered through a pad of silica gel
concentrationThe filtrate was concentrated in vacuo

Sources & evidence

ORD record: ord-2785adce26aa4f3cb36dcb4fb2aa1cc0
Source dataset: uspto-grants-2009_03
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07501421B2

Reaction notes

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