Hydrochloric Acid → 4-(3,4-Dihydro-2H-1-benzopyran-2-yl)aniline

HRID 1462953Notes

Reaction equation

HRID 1462953 reaction equation
C([NH:4][C:5]1[CH:10]=[CH:9][C:8]([CH:11]=[CH:12][C:13]([C:15]2[CH:20]=[CH:19][CH:18]=[CH:17][C:16]=2[OH:21])=O)=[CH:7][CH:6]=1)(=O)C.Cl.Cl.NC1C=CC(C2CC(=O)C3C(=CC=CC=3)O2)=CC=1>[Zn].C(O)(=O)C>[NH2:4][C:5]1[CH:10]=[CH:9][C:8]([CH:11]2[CH2:12][CH2:13][C:15]3[C:16](=[CH:17][CH:18]=[CH:19][CH:20]=3)[O:21]2)=[CH:7][CH:6]=1

Participants

6

Reactant 3

HCID 313Hydrochloric AcidHCID 20452423HCID 20452423, compoundHCID 54341076HCID 54341076, compound

Product 1

HCID 204524314-(3,4-Dihydro-2H-1-benzopyran-2-yl)aniline

Reagents, catalysts & solvents 2

HCID 23994ZincCatalystHCID 176Acetic AcidSolvent

Procedure

4-Acetylamino-2'-hydroxychalcone (7.20 g.), was boiled under reflux with acetic acid (100 ml) and concentrated hydrochloric acid (25 ml.) for 7 hrs. The clear solution of 4'-aminoflavanone hydrochloride was treated under a nitrogen atmosphere with amalgamated zinc (from zinc powder (40 g.) and mercuric chloride (0.8 g.)) and stirred at room temperature for 4 hrs. The residual zinc was filtered off and washed with acetic acid. The combined washings and filtrate were neutralised to bicarbonate solution, and the oily product extracted into dichloromethane. The solution was chromatographed on neutral alumina, eluting with dichloromethane and the first fraction evaporated giving the solid 4'-aminoflavan, which was recrystallised from boiling 60°-80° C. petroleum ether, cooling to -10° C., yielding 180 mg., m.p. 85°-87° C.

Workup

  1. filtrationThe residual zinc was filtered off
  2. washwashed with acetic acid
  3. extractionthe oily product extracted into dichloromethane
  4. customThe solution was chromatographed on neutral alumina
  5. washeluting with dichloromethane
  6. customthe first fraction evaporated

Sources & evidence

ORD record
ord-018ecac057d14dc08fd64921c08331a1
Source dataset
uspto-grants-1984_07
Patent number
US04461907

Reaction notes

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