6-Octenal, 3,7-dimethyl-, (3R)- → (3r)-3,7-Dimethyloctanal

A 3 L indented flask equipped with a mechanical stirrer and a H2 inlet was charged with 205.7 g (1.333 mol) of (R)-citronellal in 7.4L of ethyl acetate. The flask was flushed with 0.1 cu. ft. of H2 and 0.50 g (2.0 mmol) of platinum oxide were added. The reaction was stirred under a slight over-pressure of H2 at ambient temperature for 124 hours. During this time, due to relatively rapid deactivation of the catalyst, an additional 3.50 g (143 mmol.) of platinum oxide had to be added in 5 portions (0.5 g at 3.5 hours, 0.5 g at 22.5 hours, 1.0 g at 96.5 hours and 0.5 g at 121 hours). The course of the hydrogenation was monitored by GC analysis. After 124 hours, GC indicated the hydrogenation to be almost complete with 1.4% of starting material remaining. A total of 1.133 cu. ft. of hydrogen (theoretically 1.166 cu. ft.) had been consumed. The catalyst was removed by filtration through a pad of Celite (diatomaceous earth). The clear filtrate was combined with the filtrate from a previously run, analogous reduction of 10.0 g (64.8 mmol) of (R)-citronellal and concentrated on the rotovapor. Vacuum distillation of the obtained pale yellow liquid through a 30 cm Goodloe column afforded the (R)-3,7-dimethyloctanal in following fractions:

1. customequipped with a mechanical stirrer and a H2 inlet
2. additionwere added
3. additionto be added in 5 portions (0.5 g at 3.5 hours, 0.5 g at 22.5 hours, 1.0 g at 96.5 hours and 0.5 g at 121 hours)
4. waitAfter 124 hours
5. customA total of 1.133 cu. ft. of hydrogen (theoretically 1.166 cu. ft.) had been consumed
6. customThe catalyst was removed by filtration through a pad of Celite (diatomaceous earth)
7. distillationVacuum distillation of the obtained pale yellow liquid through a 30 cm Goodloe column

ORD record

ord-cca7e37764d147e2a3682494d3cc2e18

Source dataset

uspto-grants-1989_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04879395