1-Phenyl-1-propanone → 1H-Inden-1-one, 2-methyl-

Temperature

80 °C

A mixture of propiophenone (30 g, 223.6 mmol) hexamethylenetetramine (HMTA) (43.8 g, 313 mmol) and acetic anhydride (41 g, 402 mmol) was heated at 80° C. for 4 hours under a nitrogen atmosphere. The reaction mixture was cooled to 30° C. and quenched into a stirred mixture of methylene chloride (200 ml) and sodium hydroxide (200 of 2N solution). The organic layer was separated and washed with aqueous HCl (100 ml of 1N solution). The methylene chloride solution containing the product, 2-methyl-1-phenyl-prop-2-en-1-one was azeotropically dried by distilling CH2Cl2 to approximately 50 ml volume and was directly used in the next step without any further operation. The CH2Cl2 solution was added to concentrated H2SO4 (130 ml) at such a rate that the reaction temperature was maintained between 50°-60° C. The CH2Cl2 was removed by distillation and nitrogen sweep as soon as it was added. The reaction mixture was stirred at 50°-60° C. for one hour, cooled to 20° C. and quenched into a stirred mixture of methylene chloride (200 ml) and water (200 g). After separating the aqueous layer, the organic layer was concentrated in the rotary evaporator to produce 121 g (82%) of 2-methyl-inden-1-one (Example 1, Table 1).

1. temperatureThe reaction mixture was cooled to 30° C.
2. customquenched into a stirred mixture of methylene chloride (200 ml) and sodium hydroxide (200 of 2N solution)
3. customThe organic layer was separated
4. washwashed with aqueous HCl (100 ml of 1N solution)
5. additionThe methylene chloride solution containing the product, 2-methyl-1-phenyl-prop-2-en-1-one
6. customwas azeotropically dried
7. distillationby distilling CH2Cl2 to approximately 50 ml volume
8. additionThe CH2Cl2 solution was added to concentrated H2SO4 (130 ml) at such a rate that the reaction temperature
9. temperaturewas maintained between 50°-60° C
10. customThe CH2Cl2 was removed by distillation and nitrogen sweep as soon as it
11. additionwas added
12. temperaturecooled to 20° C.
13. customquenched into a stirred mixture of methylene chloride (200 ml) and water (200 g)
14. customAfter separating the aqueous layer
15. concentrationthe organic layer was concentrated in the rotary evaporator

ORD record

ord-09dd512f386245b991c6bb109bb65a9f

Source dataset

uspto-grants-1996_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05489712