Hydrochloric Acid → Cinnamoylbenzene

HRID 742085Notes

Reaction equation

HRID 742085 reaction equation
O[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][C:3]=1[C:8](=[O:10])[CH3:9].C(=O)/C=[CH:13]/[C:14]1[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=1.[OH-].[Na+].Cl>O.CO>[C:14]1([CH:13]=[CH:9][C:8]([C:3]2[CH:4]=[CH:5][CH:6]=[CH:7][CH:2]=2)=[O:10])[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=1

Participants

7

Reactant 4

HCID 313Hydrochloric AcidHCID 83752'-HydroxyacetophenoneHCID 14798Sodium HydroxideHCID 637511Cinnamaldehyde

Product 1

HCID 7189Cinnamoylbenzene

Reagents, catalysts & solvents 2

HCID 887MethanolSolventHCID 962WaterSolvent

Procedure

A solution of 5.00 g (36.7 mmol) of 2'-hydroxyacetophenone, 4.85 g (36.7 mmol) of trans-cinnamaldehyde, 11.10 g NaOH (in 20 mL of water) and 250 mL MeOH was stirred for 23 hours before the solution was poured into 1000 mL water. The resulting mixture was neutralized with dilute HCl and the yellow precipitate was collected by filtration. Recrystallization from MeOH gave a pure intermediate chalcone product. Further oxidation of the above chalcone was carried out with excess H2O2 (30%) in basic (NaOH aq.) MeOH solution for 12 hours. This solution was poured into water, and neutralized with dilute HCl. The resulting light yellow precipitate was collected by filtration and the pure desired product was obtained by recrystallization from MeOH with 7% overall yield. MP: 189°-191° C. Quantum yield (relative to 3-hydroxyflavone in CH2Cl2) 0.04. Extinction coefficient εmax (M-1 cm-1) 26,000. λmax (abs)=374 nm and λmax (em)=600 nm.

Workup

  1. filtrationthe yellow precipitate was collected by filtration
  2. customRecrystallization from MeOH

Sources & evidence

ORD record
ord-6f20d9d0c5a1493e82e3064bc02629a9
Source dataset
uspto-grants-1996_09
Patent number
US05552551

Reaction notes

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