Org. Synth. 1928, 8, 66
DOI: 10.15227/orgsyn.008.0066
ETHYL p-AMINOBENZOATE
[Benzocaine]
Submitted by Roger Adams and F. L. Cohen.
Checked by Henry Gilman and S. A. Harris.
1. Procedure
A solution of
19.5 g. (0.1 mole) of ethyl p-nitrobenzoate (Note 1) in
150 cc. of 95 per cent alcohol is placed in the reaction bottle of the catalytic reduction apparatus
(p. 61), and
0.2 g. of platinum oxide catalyst
(p. 463) is added. The mixture is shaken with
hydrogen until three molecular equivalents have been absorbed. The time required is about seven minutes. The
platinum is filtered off and the alcohol removed from the filtrate by distillation. The
ethyl p-aminobenzoate, recrystallized from about
40 cc. of ether, melts at
89–90°. The yield is
15–16.5 g. (
91–100 per cent of the theoretical amount).
2. Notes
1.
The
ethyl p-nitrobenzoate should be freed from acid and recrystallized from alcohol until it melts at
57°.
3. Discussion
Ethyl p-aminobenzoate can be prepared by the esterification of
p-aminobenzoic acid,
1 and by the reduction of
ethyl p-nitrobenzoate with
ammonium sulfide,
2 electrolytically,
3 and with
tin and alcoholic hydrochloric acid.
4 Although the reducing agent used commercially is generally
iron and water in the presence of a little acid, the catalytic reduction procedure described is by far the most convenient for the laboratory. The catalytic reduction of
ethyl p-nitrobenzoate has been described in the literature.
5
This preparation is referenced from:
Appendix
Chemical Abstracts Nomenclature (Collective Index Number);
(Registry Number)
Benzocaine
alcohol (64-17-5)
hydrochloric acid (7647-01-0)
ether (60-29-7)
hydrogen (1333-74-0)
iron (7439-89-6)
tin (7440-31-5)
platinum oxide
platinum (7440-06-4)
aminobenzoic acid (118-92-3)
ammonium sulfide
Ethyl p-aminobenzoate (94-09-7)
ethyl p-nitrobenzoate (99-77-4)
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