Hydrogen Bromide → 1-(1,2,3,4-Tetrahydro-4,4-dimethyl-1-naphthalenyl)-1-propanone

HRID 1979512Notes

Reaction equation

HRID 1979512 reaction equation
P(=O)(O)(O)O.C([C:8]([C:18]1[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=1)([CH2:13][CH:14]=[C:15]([CH3:17])[CH3:16])[C:9](=[O:12])[CH2:10][CH3:11])#N.Br>C(O)(=O)C>[CH3:17][C:15]1([CH3:16])[C:19]2[C:18](=[CH:23][CH:22]=[CH:21][CH:20]=2)[CH:8]([C:9](=[O:12])[CH2:10][CH3:11])[CH2:13][CH2:14]1

Participants

5

Reactant 3

HCID 260Hydrogen Bromide2×HCID 1004Phosphoric AcidHCID 20439314HCID 20439314, compound

Product 1

HCID 1664451-(1,2,3,4-Tetrahydro-4,4-dimethyl-1-naphthalenyl)-1-propanoneYield 24%

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent2×

Conditions

Temperature
105 °C

Procedure

In a 3-liter flask provided with a thermometer and stirrer 200 g of phosphorus pentoxide are added while cooling to 500 g of 85% phosphoric acid and subsequently 150 g of 4-cyano-7-methyl-4-phenyl-oct-6-en-3-one are added at ca. 50° C. The mixture is stirred at 105° C. until starting material is no longer present (gas chromatography/thin-layer). 1000 g of 48% hydrobromic acid and 500 g of glacial acetic acid are then added. After 12 hours, a further 200 g of 48% hydrobromic acid and 100 g of glacial acetic acid are added and the temperature is raised to 110° C. After a total reaction time of 30 hours, the mixture is cooled, ice is added and the mixture is extracted with ether, washed neutral with water, with 10% sodium hydroxide and again with water, dried over sodium sulphate and evaporated. Vacuum distillation gives 32 g of 1,1-dimethyl-4-propionyl-tetralin of boiling point 75° C./0.05 mmHg; nD20 =1.5263; yield 24%. Odour: see (3).

Workup

  1. additionare added
  2. additionare added at ca. 50° C
  3. temperaturethe temperature is raised to 110° C
  4. temperatureAfter a total reaction time of 30 hours, the mixture is cooled
  5. additionice is added
  6. extractionthe mixture is extracted with ether
  7. washwashed neutral with water, with 10% sodium hydroxide and again with water
  8. dry with materialdried over sodium sulphate
  9. customevaporated
  10. distillationVacuum distillation

Sources & evidence

ORD record
ord-af7bdc69fc9c44fd9049e65d8bfd7f6c
Source dataset
uspto-grants-1984_11
Patent number
US04481133

Reaction notes

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