1762
MAHMOODI, SALEHPOUR
1
2-Methylbenzoic acid (IIa). A mixture of 4 ml
1685 m. H NMR spectrum, , ppm: 3.7 s (3H), 4.3 s
(2H), 7.2 m (7H), 8.1 d (1H).
(30 mmol) of o-xylene, 8 ml of concentrated nitric
acid, and 16 ml of water was heated for 55 h at 145
155 C. The progress of the reaction was monitored
by TLC. The mixture was cooled to 0 C, and the
precipitate was filtered off, washed with 20 ml of
water, and dissolved in 10 ml of 10% aqueous NaOH
on cooling. Unreacted o-xylene was removed by
extraction with diethyl ether (3 10 ml). The aqueous
phase was treated with 0.1 g of charcoal, and the
mixture was heated on a steam bath and filtered
through a Buchner funnel. The filtrate was neutralized
with 2.3 ml of concentrated hydrochloric acid under
vigorous stirring, and the precipitate was filtered off,
washed with ice water, and dissolved in 3.5 ml of
ethanol. The solution was treated with charcoal,
heated on a steam bath, ans filtered while hot. The
filtrate was diluted with 4.8 ml of water at 55 60 C.
The mixture was cooled, and the precipitate was fil-
tered off and washed with 2.5 ml of cold 50% ethanol.
Yield 2.2 g (55%), mp 100 101 C [17]. IR spectrum,
2-(1-Naphthylmethyl)benzoic acid (IIe). Reaction
time 20 h. Yield 60%, mp 137 139 C. IR spectrum,
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1
cm : 3200 s, 1690 w, 1080 m. H NMR spectrum,
, ppm: 4.8 s (2H), 6.8 8.2 m (11H).
2-(4-Methoxybenzoyl)benzoic acid (IIId). A solu-
tion of 13.34 g (10 mmol) of powdered anhydrous
aluminum chloride in 30 ml of nitrobenzene was
added dropwise over a period of 40 min to a solution
of 4.4 ml (40 mmol) of anisole and 7.4 g (50 mmol)
of phthalic anhydride in 120 ml of nitrobenzene while
stirring at room temperature. The mixture was stirred
for 5.5 h at room temperature, poured into a mixture
of 600 ml of 20% hydrochloric acid and 400 g of ice,
and treated with ether (3 20 ml + 100 ml). The com-
bined extracts were washed with water (3 30 ml)
and with a saturated solution of NaHCO3 (5 40 +
100 ml). The alkaline extract was washed with diethyl
ether (3 20 ml) and acidified with 10% hydrochloric
acid. The colorless precipitate was filtered off and
dried. Yield 10.8 g (85%), mp 130 132 C. IR spec-
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1
, cm : 3200 s, 1680 m. [17]. H NMR spectrum, ,
ppm: 2.6 s (3H), 7.3 m (3H), 8.1 m (1H), 9.6 s (1H).
Mass spectrum, m/z (Irel, %): 137 (5.9), 136 (60), 118
(100), 91 (95.7), 65 (40.4).
1
1
trum, , cm : 3200 s, 1685 m. H NMR spectrum, ,
ppm: 3.7 s (3H), 6.7 m (2H), 7.6 m (6H), 9.0 s (1H).
Compounds IIIb, IIIc, and IIIe were synthesized
2-(Arylmethyl)benzoic acids IIb IIe (general
procedure) [18]. A mixture of 4.3 g (66 mmol) of zinc
dust, 0.43 g (1.58 mmol) of mercury(II) chloride,
0.2 ml of concentrated hydrochloric acid, and 5.5 ml
of water was stirred at room temperature until it
became homogeneous. Water, 2.7 ml, concentrated
hydrochloric acid, 0.65 ml, toluene, 3.6 ml, and acid
III, 10 mmol, were added, and the mixture was heated
for 20 40 h at the boiling point, 1.8 ml of concen-
trated hydrochloric acid being added every 6 h to
maintain its concentration constant. The mixture was
cooled, and the aqueous phase was separated, diluted
with 7.2 ml of water, and extracted with diethyl ether
(3 15 ml). The extracts were combined with the
organic phase, washed with water, dried over MgSO4,
and evaporated, and the residue was purified by
recrystallization.
in a similar way.
2-Benzoylbenzoic acid (IIIb). Yield 84%,
mp 94 C (monohydrate) [20], mp 128 C [21]. IR
1
1
spectrum, , cm : 3200 s, 1670 m. H NMR spec-
trum, , ppm: 7.9 m. Mass spectrum, m/z (Irel, %):
228 (1.6), 227 (8.2), 226 (53.3), 182 (68.6), 149 (82),
105 (100), 77 (85.5), 51 (38.8).
2-(4-Methylbenzoyl)benzoic acid (IIIc). mp 137
1
138 C [21]. IR spectrum, , cm : 3200 s, 1690 m.
1H NMR spectrum, , ppm: 2.3 s (3H), 7.5 m (8H).
Mass spectrum, m/z (Irel, %): 241 (3.9), 240 (20), 149
(21.2), 119 (100), 91 (32.5), 65 (20).
2-(1-Naphthoyl)benzoic acid (IIId). Methylene
chloride was used as solvent instead of nitrobenzene.
1
mp 173 C [22]. IR spectrum, , cm : 3200 s, 1680 w,
1650 w. 1H NMR spectrum, , ppm: 7.2 8.2 m (10H),
9.1 m (1H).
2-Benzylbenzoic acid (IIb). Reaction time 30 h.
This study was supported in part by the Research
Committee of the Guilan University.
Yield 70%, mp 110 112 C [17]. IR spectrum,
cm : 3200 s, 1695 m. H NMR spectrum, , ppm:
4.4 s (2H), 7.2 m (8H), 7.9 d (1H).
,
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REFERENCES
2-(4-Methylbenzyl)benzoic acid (IIc). Reaction
1
time 40 h. mp 111 112 C [19]. IR spectrum, , cm :
1. Cassady, J.M. and Suffness, M., Anticancer Agents
Based on Natural Product Models, Cassady, J.M.
and Douros, J.D., Eds., New York: Academic, 1980,
vol. 5, p. 201; Dictionary of Natural Products,
London: Chapman and Hall, 1994, vol. 2, pp. 1609,
1
3200 s, 1670 m. H NMR spectrum, , ppm: 2.4 s
(3H), 4.8 s (2H), 7.4 m (7H), 8.3 d (1H).
2-(4-Methoxybenzyl)benzoic acid (IId). Reaction
1
time 40 h. Yield 70%. IR spectrum, , cm : 3200 s,
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 39 No. 12 2003