Acetate-hydrochloric acid → 8-Bromochroman-4-carboxylic acid

HRID 2173254Notes

Reaction equation

HRID 2173254 reaction equation
[Br:1][C:2]1[CH:3]=[CH:4][CH:5]=[C:6]2[C:11]=1[O:10][CH2:9][CH2:8]C2([Si](C)(C)C)C#N.Cl[Sn]Cl.O.Cl.[CH3:23][C:24]([OH:26])=[O:25]>>[Br:1][C:2]1[CH:3]=[CH:4][CH:5]=[C:6]2[C:11]=1[O:10][CH2:9][CH2:8][CH:23]2[C:24]([OH:26])=[O:25]

Participants

4

Reactant 3

HCID 22641269Acetate-hydrochloric acidHCID 43835034Tin dichloride dihydrateHCID 675171838-bromo-4-(trimethylsilyl)-3,4-dihydro-2H-chromene-4-carbonitrile

Product 1

HCID 675164228-Bromochroman-4-carboxylic acid

Procedure

A solution of 8-bromo-4-(trimethylsilyl)-3,4-dihydro-2H-chromene-4-carbonitrile (9.6 g, 29.45 mmol) in a mixture of conc. HCl/HOAc (50 mL/40 mL) was added SnCl2.H2O (26.57 g, 117.8 mmol) and the miture was refluxed for 48 hours. The reaction solution was concentrated and the residue was partitioned between water and EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4 and concentrated to afford 8-bromo-3,4-dihydro-2H-chromene-4-carboxylic acid. 1H-NMR (300 MHz, CDCl3) δ ppm 7.15˜7.46 (m, 2H), 6.75˜6.92 (m, 1H), 4.24˜4.4 (m, 2H), 3.78˜3.84 (m, 1H), 2.1˜2.39 (m, 2H).

Workup

  1. temperaturethe miture was refluxed for 48 hours
  2. concentrationThe reaction solution was concentrated
  3. customthe residue was partitioned between water and EtOAc
  4. washThe combined organic layers were washed with brine
  5. dry with materialdried over anhydrous Na2SO4
  6. concentrationconcentrated

Sources & evidence

ORD record
ord-73d42fb568b84e00b3ed30b2a992a51b
Source dataset
uspto-grants-2015_06
Patent number
US09056859B2

Reaction notes

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