Sodium Dithionite → Methyl 4-amino-3-(methylamino)benzoate

HRID 2064259Notes

Reaction equation

HRID 2064259 reaction equation
S(S([O-])=O)([O-])=O.[Na+].[Na+].[CH3:9][O:10][C:11]([C:13]1[CH:18]=[CH:17][C:16]([N+:19]([O-])=O)=[C:15]([NH:22][CH3:23])[CH:14]=1)=[O:12].C(=O)(O)[O-].[Na+]>O1CCCC1.C(O)C>[NH2:19][C:16]1[CH:17]=[CH:18][C:13]([C:11]([O:10][CH3:9])=[O:12])=[CH:14][C:15]=1[NH:22][CH3:23]

Participants

6

Reactant 3

HCID 24489Sodium DithioniteHCID 516892Sodium BicarbonateHCID 15892779Methyl 3-(methylamino)-4-nitrobenzoate

Product 1

HCID 57835341Methyl 4-amino-3-(methylamino)benzoateYield 68.5%

Reagents, catalysts & solvents 2

HCID 702EthanolSolventHCID 8028TetrahydrofuranSolvent

Procedure

Add an aqueous solution of sodium hydrosulfite (17.4 g, 100 mmol in 80 mL of water) to methyl-3-(methylamino)-4-nitrobenzene carboxylate (855 mg, 4.75 mmol) in tetrahydrofuran (70 mL) and ethanol (30 mL) at 0° C. The orange solution turned to an orange suspension upon addition. Stir the mixture at room temperature for 2 hours. The orange suspension turned to a yellow suspension over this time. Add saturated sodium bicarbonate (100 mL) then the yellow suspension turned colorless. Extract the mixture with ethyl acetate (2×100 mL). Wash the combined organics with brine (30 mL). Dry over magnesium sulfate, filter, concentrate, and dry under high vacuum to yield methyl 4-amino-3-(methylamino)benzoate (586 mg, 68%) as a yellow oil. The resulting oil began to crystallize upon standing after 10 minutes. 1H NMR (400 MHz, CDCl3) δ ppm 2.89 (s, 3H), 3.37-3.81 (m, 2H), 3.85 (s, 3H), 6.67 (d, J=8.01 Hz, 1H), 7.33 (d, J=1.37 Hz, 1H), 7.44 (dd, J=8.11, 1.66 Hz, 1H).

Workup

  1. additionThe orange solution turned to an orange suspension upon addition
  2. extractionExtract the mixture with ethyl acetate (2×100 mL)
  3. washWash the combined organics with brine (30 mL)
  4. dry with materialDry over magnesium sulfate
  5. filtrationfilter
  6. concentrationconcentrate
  7. customdry under high vacuum

Sources & evidence

ORD record
ord-74f514692dd24f818da9ef6037bb6f58
Source dataset
uspto-grants-2012_10
Patent number
US08288405B2

Reaction notes

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