Methanol → Methyl p-aminosalicylate

HRID 1018789Notes

Reaction equation

HRID 1018789 reaction equation
[NH2:1][C:2]1[CH:3]=[C:4]([OH:11])[C:5](=[CH:9][CH:10]=1)[C:6]([OH:8])=[O:7].S(=O)(=O)(O)O.[OH-].[NH4+].[CH3:19]O>>[NH2:1][C:2]1[CH:3]=[C:4]([OH:11])[C:5](=[CH:9][CH:10]=1)[C:6]([O:8][CH3:19])=[O:7]

Participants

5

Reactant 4

HCID 887MethanolHCID 1118Sulfuric AcidHCID 46494-Aminosalicylic AcidHCID 14923Ammonium Hydroxide

Product 1

HCID 77787Methyl p-aminosalicylateYield 60%

Conditions

Temperature
70 °C

Procedure

To a suspension of 9.18 g (0.06 mole) 4-aminosalicylic acid (7) (Aldrich A7,960-4) in 40 mL of dry methanol was added 8 mL of concentrated sulfuric acid slowly. The mixture was heated under reflux at 70 ° C. for 1.5 hours and then it was cooled in an ice-water bath. Enough concentrated ammonium hydroxide solution was added to adjust the pH to 9 and the precipitate was filtered, rinsed with water and dried to give 6.01 g (60%) of 9 as a solid, mp 118-120° (ref. 120-121°). Infrared (IR) and NMR analysis gave the following results: IR (potassium bromide): 3473 and 3379 (NH2), 1643 (C=O),1284, cm−1. 1H nmr (90 MHz, CDCI3):δ 10.96 (1H, s, OH), 7.6 (1H; d, 3JH5-H6=9 Hz; H-6), 6.20-6.08 (2H, cm, H-3 and H-5), 4.2 (2H; br s; NH2), 3.87 (3H, s, CH3).

Workup

  1. temperatureThe mixture was heated
  2. temperatureit was cooled in an ice-water bath
  3. filtrationthe precipitate was filtered
  4. washrinsed with water
  5. customdried

Sources & evidence

ORD record
ord-9d452e41e3624098bb4cc725ffb86993
Source dataset
uspto-grants-2002_11
Patent number
US06482982B1

Reaction notes

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