Organic Syntheses, Coll. Vol. 6, p.371 (1988); Vol. 51, p.103 (1971).
has been identified as a carcinogen; OSHA has issued emergency standards on its use. All procedures involving benzene
should be carried out in a well-ventilated hood
, and glove protection is required.
A 500 ml., Parr hydrogenation bottle
is flushed with nitrogen
, and 20.0 g. of 5% rhodium-on-alumina (Note 1)
is weighed directly into the hydrogenation bottle. The catalyst is wet by cautiously adding 25 ml. of 95% ethanol
, and a solution of 40.0 g. (0.278 mole) of 1-naphthol (Note 2)
in 125 ml. of 95% ethanol
is added to the bottle, along with 3 ml. of acetic acid
. The mixture is shaken in a Parr apparatus (Note 3)
at an initial pressure of 55–60 p.s.i. of hydrogen
. The theoretical hydrogen
absorption is reached in about 12 hours (Note 4)
. The catalyst is removed by suction filtration and washed twice with 50-ml. portions of ethanol (Note 5)
. The combined ethanol
solutions are concentrated with a rotary evaporator
, yielding a viscous residue (39–41 g.
), which is dissolved in 150 ml. of benzene
. The solution is washed with 75 ml. of 10% sodium hydroxide
solution, then with 75 ml. of water, dried over magnesium sulfate
for at least 3 hours, and concentrated with a rotary evaporator, giving 39–41 g.
) of a mixture3
consisting of the geometrical isomers of 1-decalol
may be isolated as a crystalline solid from the mixture by the addition of 15–20 ml. of heptane
, followed by cooling. The product is isolated by filtration and recrystallized from a minimum amount of n-heptane
, yielding 13–14 g.
) of cis,cis-1-decalol
, m.p.4 92–93°
The catalyst is available from Engelhard Industries.
A purified grade of 1-naphthol should be used. Material available from Eastman Organic Chemicals, Aldrich Chemical Company, Inc., and Matheson, Coleman and Bell
is satisfactory. Experiments with technical grade 1-naphthol
have indicated that this material requires purification by sublimation in order to give satisfactory results.
It has been found that the rhodium
catalyst is not nearly as sensitive to poisoning as platinum
catalyst. The metal inlet tube to the reaction bottle was merely rinsed with acetone
, followed by ethanol
, and the rubber stopper
was soaked in 30–40% sodium hydroxide
A variety of experiments have shown that for bicyclic aromatic nuclei the weight ratio of reactant to catalyst should be 2:1, whereas for monocyclic aromatic nuclei, the reactant to catalyst ratio should be 3:1. For the latter systems, hydrogen
absorption is usually complete within 6–8 hours (see Discussion section).
The catalyst may be reused after washing thoroughly with ethanol
and drying at 125° for 12–15 hours. The activity, however, is somewhat decreased. Care should be exercised to never leave the catalyst exposed to air in the presence of a flammable solvent.
has been reduced to 1-decalol
,4 Raney nickel
and Raney copper
The reactions catalyzed by nickel
required elevated temperatures and pressure. The present procedure allows the preparation of substantial quantities of 1-decalol
under much more convenient conditions and shorter reaction times. Previous methods4,5,6
require costly catalysts or high-pressure equipment and frequently result in a high degree of hydrogenolysis. The submitters have found that the present method is applicable to a wide variety of aromatic nuclei, some of which are listed in Table I.
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