Dehydroabietylamine → 99306-87-3

Participants

Reaction Steps

dl-5-Benzyloxymethyl-cyclopent-2-enyl-4-hydroxy-1-acetic acid (88.5 g.) in ether (1500 ml.) was slowly treated with dehydroabietylamine (92.4 g.) in ether (500 ml.). The precipitated salt (140 g., [α]DMeOH = + 19°) was collected by filtration and was crystallised from benzene (20 ml./g.) to afford a salt (54 g.), [α]D = + 13° (methanol). Two subsequent crystallisations from benzene (50 ml./g; 2 hours at room temperature) gave the dehydroabiethylamine salt of l-5α-benzyloxymethyl-4β-hydroxycyclopent-2-enyl-1β-acetic acid (42 g.), [α]DMeOH = + 10°. A suspension of this salt in ether-water (2:1) was treated with 1.2 equivalents of 5% potassium hydroxide and extracted with ether. The aqueous layer was then treated with 8N sulphuric acid to pH 1.5, saturated with ammonium sulphate and extracted with chloroform to yield the pure l-5α -benzyloxymethyl-4β-hydroxy-cyclopent-2-enyl-1β-acetic acid, which showed [α]D = -26.5°; [α]365° = -78° (CHCl3) and [α]D = -5.4°. [α]365° = -13° (MeOH). The mother liquors from the first benzene crystallisation were diluted with ether to obtain a benzene-ether ratio of 5:4 and stored for 3 hours at 5°. The precipitated salt (48 g., [α]DMeOH = + 27°) was collected by filtration and recrystallised from benzene-ether (1 g. salt, benzene 20 ml., ether 40 ml.) to yield 44 g. of the dehydroabietylamine salt of d-5β-benzyloxymethyl-4α-hydroxy-cyclopent-2-enyl-1α-acetic acid, [α]DMeOH = + 28.8°. In a similar way, the 5α-p-methoxybenzyloxymethyl-4β-hydroxy-cyclopent-2-enyl-1β-acetic acid was obtained from the dl-acid.

Provenance & Evidence