Author Topic: piperonal --> isosafrole / 92%  (Read 1880 times)

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piperonal --> isosafrole / 92%
« on: February 17, 2002, 04:41:00 PM »
3,4-(Methylenedioxy)-beta-methylstyrene = isosafrole

"Three-component synthesis of (E)-,-unsaturated amides of the piperine family"
Rainer Schobert* , Sven Siegfried and Gary J. Gordon
J. Chem. Soc., Perkin Trans. 1, 2001, (19), 2393 - 2397

Results and discussion

... Olefination with ethylidenetriphenylphosphorane produced
cis-trans-isomeric mixtures of 3,4-(methylenedioxy)--methylstyrene ...


To a well stirred suspension of ethyltriphenylphosphonium bromide
(7.5 g, 20.2 mmol) in dry THF (100 mL),
a solution of n-butyllithium (12.6 mL of a 1.6 M solution in hexane,
20.2 mmol) was added dropwise over a period of 30 min at 0 °C.
The mixture was warmed to room temperature and stirred for 60 min.
A solution of piperonal 3a (3.0 g, 20.0 mmol) in THF (25 mL) was then
slowly added and the resulting mixture left stirring for a further 6 h.
Water (100 mL) was added, the organic layer was separated, the aqueous phase
extracted twice with diethyl ether and the combined organic phases were
finally dried over MgSO4. After filtration and evaporation of the solvents
the residue was eluted from silica gel with CH2Cl2 to remove phosphine oxide
and the residue was purified by distillation, bp 121 °C/15 Torr
(lit.[17] bp 123 °C/11.5 Torr), 3.0 g (18.5 mmol, 92%) as a colourless oil,
mixture of Z- and E-isomers (Z-E = 1:10)

[17] R. Hoering and G. Baum, Chem. Ber., 1909, 42, 3080

the pdf is on the way to rhodium ...

"Whatever there is to learn has to be learned the hard way."
Castaneda's teacher Don Juan Matus


  • Guest
Re: piperonal --> isosafrole / 92%
« Reply #1 on: February 17, 2002, 05:20:00 PM »
Interesting in theory, but pretty useless in practise.

Maybe someone should have told these authors that safrole is a naturally occuring compound, so they could have avoided doing a Wittig...

I'm not fat just horizontally disproportionate.


  • Guest
Re: piperonal --> isosafrole / 92%
« Reply #2 on: February 17, 2002, 10:15:00 PM »
I want all syntheses to interesting compound archived on my page, both easy and obscure. This synthesis is also featured in Vogel 5th ed.


  • Guest
Re: piperonal --> isosafrole / 92%
« Reply #3 on: February 18, 2002, 02:40:00 AM »

I have ton's (>20) of interesting PDF's regarding Amphetamine, Phenethylamine, Tryptamine, Precursors, Etc.

I emailed a bunch to you a few months ago, but I don't think that you ever got them. Please Msg me to arrange an exchange.