Org. Synth. 1977, 57, 72
DOI: 10.15227/orgsyn.057.0072
4-NITROBENZYL FLUORIDE
[Benzene, 1-(fluoromethyl)-4-nitro-]
Submitted by W. J. Middleton
1 and E. M. Bingham.
Checked by Eugene R. Kennedy, Ronald F. Sieloff, and Carl R. Johnson.
1. Procedure
Caution! Protective gloves should be worn when handling diethylaminosulfur trifluoride because this material can cause severe HF burns.
A
dry, 1-l., three-necked, round-bottomed flask is fitted with a
500-ml. dropping funnel,
thermometer, a
magnetic stirrer, and a
reflux condenser protected from the atmosphere with a
drying tube. The apparatus is flushed with dry
nitrogen, and
150 ml. of dry dichloromethane and
21 ml. (0.16 mole) of diethylaminosulfur trifluoride [
Org. Synth., Coll. Vol. 6, 440 (1988)] are added to the flask. The contents of the flask are cooled to 10°, and a solution of
23.0 g. (0.150 mole) of 4-nitrobenzyl alcohol (Note 1) in
450 ml. of dichloromethane is added dropwise at a fast rate (45 minutes). The reaction mixture is allowed to come to room temperature and poured into a
beaker containing 300 g. of ice, decomposing any unreacted
diethylaminosulfur trifluoride. The organic layer is separated, and the water layer is extracted twice with
45-ml. portions of dichloromethane. The organic layer and extracts are combined, washed with 150 ml. of water, and dried over anhydrous
magnesium sulfate. Evaporation to dryness under reduced pressure gives
20.9–22.1 g. (
90–95%) of crude product. Recrystallization from
500 ml. of pentane yields
15.5 g. (
67%) of
4-nitrobenzyl fluoride as colorless needle-shaped crystals, m.p.
36–37° (Note 2).
2. Notes
1.
4-Nitrobenzyl alcohol is available from Eastman Organic Chemicals or Aldrich Chemical Company, Inc.2.
An additional quantity of product of lesser purity can be obtained as a second crop by evaporation of the
pentane.
3. Discussion
This procedure is an example of a broadly applicable, simple method for replacing the hydroxyl group of functionally substituted and unsubstituted primary, secondary, and tertiary alcohols with
fluorine.
Diethylaminosulfur trifluoride,
2 the fluorinating reagent used in this procedure, is less likely to cause rearrangements or dehydration than other reagents sometimes used for this purpose (SF
4, HF, HF·pyridine, SeF
4·pyridine, and (C
2H
5)
2NCF
2CHClF).
3 Furthermore,
diethylaminosulfur trifluoride is a liquid that can be measured easily and used in standard glass equipment at moderate temperatures and atmospheric pressure.
Some alcohols that have been converted into the corresponding fluorides by reactions with
diethylaminosulfur trifluoride include
1-octanol,
2-methyl-2-butanol,
2-butanol,
cycloöctanol,
ethylene glycol,
crotyl alcohol,
2-phenylethanol,
2-bromoethanol,
ethyl lactate, and
ethyl α-hydroxynaphthaleneacetate.
34-Nitrobenzyl fluoride has also been prepared in
40–60% yield by the reaction of
4-nitrobenzyl bromide with
mercuric fluoride4 and in mixture with the
ortho and
meta isomers by the nitration of
benzyl fluoride.
5
This preparation is referenced from:
Appendix
Chemical Abstracts Nomenclature (Collective Index Number);
(Registry Number)
nitrogen (7727-37-9)
2-BROMOETHANOL (540-51-2)
ethylene glycol (107-21-1)
Pentane (109-66-0)
dichloromethane (75-09-2)
2-phenylethanol (60-12-8)
ethyl lactate (687-47-8)
magnesium sulfate (7487-88-9)
1-Octanol (111-87-5)
2-Methyl-2-butanol (75-85-4)
Fluorine (7782-41-4)
mercuric fluoride (7783-39-3)
Crotyl alcohol
2-Butanol (78-92-2)
Diethylaminosulfur trifluoride (38078-09-0)
4-NITROBENZYL FLUORIDE,
Benzene, 1-(fluoromethyl)-4-nitro- (500-11-8)
4-nitrobenzyl alcohol (619-73-8)
ethyl α-hydroxynaphthaleneacetate
4-nitrobenzyl bromide (100-11-8)
benzyl fluoride (350-50-5)
cyclooctanol
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