Isopropanol → HCID 54419660, compound

Using a procedure suggested by S. Terao, et al., Synthesis, 467 (1979), a mixture of 521 mg (3.66 mmoles) of 2-methyl-2-[4-methylpentyl]oxirane (produced in accordance with Example XV) and 1.73 g (8.47 mmoles of aluminum isopropoxide in 10 mL of toluene was heated at reflux for 3.75 hours. [Note: On a larger scale, the isopropyl alcohol formed during the reaction can be continuously removed by fractional distillation, thereby enabling one to use considerably less aluminum isopropoxide to effect this isomerization.] After cooling to room temperature, the reaction mixture was treated with 15 mL of 2M aqueous hydrochloric acid to decompose the aluminum complex. The mixture was subsequently diluted with 25 mL of ether and 30 mL of 10% aqueous sodium chloride. After separating the layers, the organic layer was washed in successive order with 10% aqueous sodium chloride (1×25 mL) and saturated brine (1×25 mL), and then was dried over anhydrous sodium sulfate and filtered. Removal of the volatile organic solvents by evaporation at reduced pressure afforded, after evaporative distillation, 482 mg (93% yield) of the named allylic alcohols: boiling point 58°-71° C. (bath temperature, 0.20 mm). Proton NMR analysis indicated that the product was a 2:1 mixture of 6-methyl-2-methylene-1-heptanol and 2,6-dimethyl-2-hepten-1-ol respectively, accompanied by approximately 10% of what appeared to be a saturated C-9 alcohol (2,6-dimethyl-1-heptanol). 2,6-Dimethyl-2-hepten-1-ol was characterized by two singlets at δ4.09 (CH2OH, E stereoisomer), and 3.94 (CH2OH, Z stereoisomer), and two triplets at δ5.37 and 5.24 (vinyl H, Z and E stereoisomers). The corresponding signals for 6-methyl-2-methylene-1-heptanol appeared as singlets at δ4.02 (CH2OH), 4.97 (one vinyl H), and 4.81 (the second vinyl H).

1. customTerao, et al., Synthesis, 467 (1979)
2. temperaturewas heated
3. temperatureat reflux for 3.75 hours
4. customcan be continuously removed by fractional distillation
5. additionthe reaction mixture was treated with 15 mL of 2M aqueous hydrochloric acid
6. additionThe mixture was subsequently diluted with 25 mL of ether and 30 mL of 10% aqueous sodium chloride
7. customAfter separating the layers
8. washthe organic layer was washed in successive order with 10% aqueous sodium chloride (1×25 mL) and saturated brine (1×25 mL)
9. dry with materialwas dried over anhydrous sodium sulfate
10. filtrationfiltered
11. customRemoval of the volatile organic solvents
12. customby evaporation at reduced pressure
13. customafforded
14. distillationafter evaporative distillation, 482 mg (93% yield) of the named allylic alcohols
15. additiona 2:1 mixture of 6-methyl-2-methylene-1-heptanol and 2,6-dimethyl-2-hepten-1-ol respectively

ORD record

ord-556e971aea144ca8bfb983e5600f2cbe

Source dataset

uspto-grants-1993_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05231232