Diethyl squarate → 6-chloro-3-(2-ethoxy-3,4-dioxocyclobut-1-enylamino)-2-hydroxy-N,N-dimethylbenzamide

HRID 1528216Notes

Reaction equation

HRID 1528216 reaction equation
[Cl:1][C:2]1[C:7]([C:8]([N:10]([CH3:12])[CH3:11])=[O:9])=[C:6]([OH:13])[C:5]([N+:14]([O-])=O)=[CH:4][CH:3]=1.[H][H].[CH2:19]([O:21][C:22]1[C:23](=O)[C:24](=[O:29])[C:25]=1[O:26]CC)[CH3:20]>CO.O.[Pt]=O>[Cl:1][C:2]1[C:7]([C:8]([N:10]([CH3:12])[CH3:11])=[O:9])=[C:6]([OH:13])[C:5]([NH:14][C:23]2[C:24](=[O:29])[C:25](=[O:26])[C:22]=2[O:21][CH2:19][CH3:20])=[CH:4][CH:3]=1

Participants

6

Reactant 3

HCID 123228Diethyl squarateHCID 895256866-chloro-2-hydroxy-N,N-dimethyl-3-nitrobenzamideHCID 178418361HCID 178418361, compound

Product 1

HCID 895255256-chloro-3-(2-ethoxy-3,4-dioxocyclobut-1-enylamino)-2-hydroxy-N,N-dimethylbenzamideYield 54%

Reagents, catalysts & solvents 2

HCID 86587499Platinum oxide monohydrateCatalystHCID 887MethanolSolvent2×

Procedure

A solution of 5.96 g (24.4 mmol, 1 eq) of 6-chloro-2-hydroxy-N,N-dimethyl-3-nitrobenzamide in 100 ml of methanol in the presence of 0.58 g of platinum oxide hydrate was stirred at hydrogen atmospheric pressure for 3 hours. The reaction medium was filtered through celite and the filtrate was concentrated. The solution obtained was added dropwise to 8.0 g (48.8 mmol, 2 eq) of 3,4-diethoxy-3-cyclobutene-1,2-dione in solution in 50 ml of methanol. The reaction medium was stirred at ambient temperature for 18 hours. The solvent was evaporated off and the residue was chromatographed on silica gel (300 g prepacked column, eluent heptane/acetone, from 50 to 100% of acetone). 4.42 g of 6-chloro-3-(2-ethoxy-3,4-dioxocyclobut-1-enylamino)-2-hydroxy-N,N-dimethylbenzamide were obtained in the form of a beige solid. Yield=54%.

Workup

  1. filtrationThe reaction medium was filtered through celite
  2. concentrationthe filtrate was concentrated
  3. customThe solution obtained
  4. customThe solvent was evaporated off
  5. customthe residue was chromatographed on silica gel (300 g prepacked column, eluent heptane/acetone, from 50 to 100% of acetone)

Sources & evidence

ORD record
ord-7a1f7fc792c94dcb873db9830d797f41
Source dataset
uspto-grants-2015_07
Patent number
US09090596B2

Reaction notes

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