06-17-04 01:04
No 513924
It is cited in this paper on rhodium (../rhodium /halide.
Undecanal
A solution of 2.80 g. of potassium hydroxide and 4.55 g. of 2-nitropropane in 75 ml. of 95% ethanol was added dropwise in the course of 45 minutes to a refluxing solution of 11.75 g. of undecyl bromide (all reactants 0.05 M) in 50 ml. of 95% ethanol. Refluxing was continued for an additional 15 minutes. The solution was cooled and decanted from a deposit of sodium bromide; ethanol was removed in vacua, the residue taken up in 75 ml. of ether, washed with water (2x30 ml.) and dried over magnesium sulfate. After removal of ether, undecanal10a was distilled at 64-66°C/0.7mmHg, yield 7.3 g. (85%), n25 1.4500; 2,4-dinitrophenylhydrazone, mp 105-106°C; oxime, mp 71-72°C. A second preparation was started at room temperature and then heated under reflux for two hours, resulting in a similar yield.
This latter experiment illustrates a general procedure for monocarbonyl compounds. In the same manner there was prepared: dodecanal, bp 126-138°C/15mmHg10b;46% yield from dodecyl bromide; semicarbazone, mp 100-101°C10c; 2,4-dinitrophenylhydrazone, mp 102-103°C; 3,4-methylenedioxyphenylacetone, bp 110-111°C/0.8mmHg10d; 90% yield from 1-piperonyl-2-bromoethane (2-bromosafrole)11; semicarbazone, mp 158-159°C10d; 1,2-cyclohexadione, bp 80-81°C/16mmHg11 30% yield from 2-chlorocyclohexanone13 (reaction begun in ice-bath); bis-phenylhydrazone, mp 150-151°C.10f
I am wondering if this procedure could be utilized with chloro or iodosafrole. The one chloro compound they use results in a large drop in yield (30% 1,2-cyclohexadione from 2-chlorocyclohexanone versus 90% MDP2P from bromosafrole!) Would iodo or chlorosafrole react better or worse in this reaction than the bromo compound and would any changes in reaction time, etc. be necessary?
