Propanal → HCID 22871225, compound

HRID 52262Notes

Reaction equation

HRID 52262 reaction equation
[Br:1][C:2]1[C:11]2[O:10][CH2:9][C@H:8]([NH:12][CH:13]([CH3:15])[CH3:14])[CH2:7][C:6]=2[C:5]([O:16][CH3:17])=[CH:4][CH:3]=1.[CH:18](=O)[CH2:19][CH3:20].C([BH3-])#N.[Na+].C(Cl)(Cl)Cl>CO>[Br:1][C:2]1[C:11]2[O:10][CH2:9][C@H:8]([N:12]([CH:13]([CH3:14])[CH3:15])[CH2:18][CH2:19][CH3:20])[CH2:7][C:6]=2[C:5]([O:16][CH3:17])=[CH:4][CH:3]=1

Participants

6

Reactant 4

HCID 527PropanalHCID 6212ChloroformHCID 5003444Sodium cyanoborohydrideHCID 54029305(R)-8-Bromo-3-(N-isopropylamino)-5-methoxy-3,4-dihydro-2H-1-benzopyran

Product 1

HCID 22871225HCID 22871225, compoundYield 97%

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Procedure

(R)-8-Bromo-3-(N-isopropylamino)-5-methoxy-3,4-dihydro-2H-1-benzopyran (3.8 g, 11.3 mmol) was dissolved in anhydrous methanol (80 mL) and to this was propanal (8.1 mL, 0.113 mol) added. The reaction was cooled (ice-bath) then sodium cyanoborohydride (1.3 g, 20.3 mmol) was added, the pH was adjusted to 5, and the reaction was allowed to stir at room temperature overnight. The solvent was removed in vacuo, the remains were twice with diethyl ether. The combined ether portions were treated with brine, dried (Na2SO4) filtered, and taken into a 1M solution of Na2CO3 and then extracted the solvent removed in vacuo to give the crude residue. Chromatography on silica (eluent: 7% ethyl acetate/hexane) gave 3.75 g (97% yield) of the title compound as a clear oil [α]21D =-82.5° (C=0.1 CHCl3). GC-MS (70 eV) M=343 (29%). The hydrochloride salt was made by dissolving the base in diethyl ether and dropping an excess of an ethereal HCl solution. The salt was recrystallized from ethanol/diethyl ether to give a white solid. Mp: 177°-9° C.

Workup

  1. additionadded
  2. temperatureThe reaction was cooled (ice-bath)
  3. customThe solvent was removed in vacuo
  4. additionThe combined ether portions were treated with brine
  5. dry with materialdried (Na2SO4)
  6. filtrationfiltered
  7. extractionextracted the solvent
  8. customremoved in vacuo
  9. customto give the crude residue

Sources & evidence

ORD record
ord-7ac780d85e40479eb86ba48410316804
Source dataset
uspto-grants-1997_04
Patent number
US05616610

Reaction notes

Loading…