(t, 1H, aryl proton), 7.54–7.70 (m, 4H, aryl protons), 7.89–7.94
(m, 2H, aryl protons), 10.52 (s, 1H, CO2H), 13.09 (br s, 1H,
NH); δC(68 MHz; (CD3)2SO; Me4Si) 117.40, 118.46, 122.50,
127.21, 129.03, 129.07, 129.26, 129.79, 131.28, 132.46, 137.95,
(C᎐O acid), 1635 (C᎐O amide). M Found: 254.1. C H NO
requires 255.27.
᎐
᎐
r
15 13
3
2-[(3-Nitrophenyl)aminocarbonyl]benzoic acid (1H). Heating
was required to dissolve 3-nitroaniline in the required volume
of chloroform. Mixing was carried out while the amine solution
was still hot and the solution was allowed to stand for 15 h.
Off-white solid (89%); mp 203–205 ЊC (sinters), 238–241 ЊC
(re-melts) (lit.,4 202 ЊC, decomposes); δH(270 MHz; (CD3)2SO;
Me4Si) 7.60–7.74 (m, 4H, aryl protons), 7.93–8.02 (m, 3H, aryl
protons), 8.77 (t, 1H, aryl protons), 10.85 (s, 1H, CO2H), 13.15
(br s, 1H, NH); δC(68 MHz; (CD3)2SO; Me4Si) 113.09, 117.45,
124.94, 127.29, 129.17, 129.25, 129.60, 131.39, 137.71, 140.02,
147.34, 166.52, 167.33 (13 signals observed); νmax/cmϪ1 3304
140.35, 166.51, 166.95; νmax/cmϪ1 3310 (NH), 1718 (C᎐O acid),
᎐
1660 (C᎐O amide). M Found: 275.69. C H NO Cl requires
᎐
r
14 10
3
275.9.
2-[(4-Chlorophenyl)aminocarbonyl]benzoic acid (1C). White
solid (89%); mp 183–184 ЊC, (decomposes) (lit.,4 184–185 ЊC);
δH(270 MHz; (CD3)2SO; Me4Si) 7.40 (d, 2H, aryl protons),
7.55–7.69 (m, 3H, aryl protons), 7.74 (d, 2H, aryl protons), 7.91
(d, 1H, aryl proton), 10.49 (s, 1H, CO2H), 13.10 (br s, 1H, NH);
δC(68 MHz; (CD3)2SO; Me4Si) 121.06, 126.96, 127.83, 128.61,
129.56, 129.65, 129.93, 131.83, 138.57, 138.72, 167.43, 167.58;
νmax/cmϪ1 3320 (NH), 1725 (C᎐O acid), 1640 (C᎐O amide). M
(NH), 1706 (C᎐O acid), 1672, 1656 (C᎐O amide). M Found:
᎐
᎐
r
287.3. C14H10N2O5 requires 286.24.
᎐
᎐
r
Found: 274.8. C14H10NO3Cl requires 275.69.
2-[(4-Nitrophenyl)aminocarbonyl]benzoic acid (1I). A solu-
tion of phthalic anhydride and a solution of 4-nitroaniline,
prepared as described above, were both raised to bp. After
mixing, the solution was stoppered and allowed to stand at rt
for 50 h. Yellow solid (97%); mp 190 ЊC (sinters, decomposes),
263–264 ЊC (re-melts) (lit.,4,27 192–193 ЊC, decomposes, 186 ЊC);
δH(270 MHz; (CD3)2SO; Me4Si) 7.60–7.74 (m, 3H, aryl pro-
tons), 7.96 (coincident d, 3H, aryl protons), 8.28 (d, 2H, aryl
protons), 11.00 (s, 1H, CO2H), 13.21 (br s, 1H, NH); δC(68
MHz; (CD3)2SO; Me4Si) 118.66, 124.49, 127.31, 129.18, 129.24,
2-[(4-Hydroxyphenyl)aminocarbonyl]benzoic
acid
(1D).
4-Aminophenol was recrystallised (with decolourising char-
coal) from aqueous ethanol before use and suspended in chloro-
form (100 cm3) by vigorous magnetic stirring. Pyridine (10 cm3)
was added followed by the phthalic anhydride solution. Stirring
was continued for 1 h. The product was filtered under vacuum
and dried at 80 ЊC. Off-white solid (82%). Material was purified
for analysis by dissolving in saturated KHCO3, filtering to
remove insoluble solids and neutralisation with 6 M HCl. The
precipitate was further purified by recrystallisation from ethyl
acetate–methanol (85 : 15 approx.). White solid; mp 289–290 ЊC
(lit.,27 289 ЊC); δH(270 MHz; (CD3)2SO; Me4Si) 6.72 (d, 2H, aryl
protons), 7.44–7.66 (m, 5H, aryl protons), 7.84 (d, 1H, aryl
proton), 9.20 (br s, 1H, OH), 10.0–15.00 approx. (1H, NH),
10.07 (s, 1H, CO2H); δC(68 MHz; (CD3)2SO; Me4Si) 114.49,
120.79, 127.24, 128.64, 128.86, 129.69, 130.69, 130.93, 138.37,
129.33, 131.51, 137.75, 141.70, 145.08, 166.44, 167.55; νmax
/
cmϪ1 3313 (NH), 1714 (C᎐O acid), 1652 (C᎐O amide). M
᎐
᎐
r
Found: 288.0. C14H10N2O5 requires 286.24.
2-(Phenylaminocarbonyl)benzoic acid (1J). White solid (94%);
mp 167–168 ЊC (decomposes) (lit.,4,27 169 ЊC, decomposes);
δH(270 MHz; (CD3)2SO; Me4Si) 7.06 (t, 1H, aryl proton), 7.32
(t, 2H, aryl protons), 7.51–7.70 (m, 5H, aryl protons), 7.87 (d,
1H, aryl proton), 10.30 (s, 1H, CO2H), 13.00 (br s, 1H, NH);
δC(68 MHz; (CD3)2SO; Me4Si) 119.17, 122.92, 127.33, 128.17,
128.91, 129.10, 129.52, 131.23, 138.43, 139.05, 166.75, 166.83;
νmax/cmϪ1 3333 (NH), 1722 (C᎐O acid), 1653 (C᎐O amide). M
152.70, 165.91, 166.88; νmax/cmϪ1 3287 (NH), 1714 (C᎐O acid),
᎐
1653 (C᎐O amide). M Found 257.2. C14H11NO4 requires
᎐
r
257.25.
2-[(3-Methoxyphenyl)aminocarbonyl]benzoic acid (1E). White
solid (94%); mp 160–161.5 ЊC (lit.,4,9 171, 159–161 ЊC); δH(270
MHz; (CD3)2SO; Me4Si) 3.74 (s, 3H, OCH3), 6.65–6.68 (m, 1H,
aryl proton), 7.19–7.29 (m, 2H, aryl protons), 7.43 (s, 1H, aryl
proton), 7.53–7.67 (m, 3H, aryl protons), 7.89 (d, 1H, aryl
proton), 10.33 (s, 1H, CO2H), 13.03 (br s, 1H, NH); δC(68 MHz;
(CD3)2SO; Me4Si) 54.96, 105.06, 108.36, 111.50, 127.30, 128.94
(2C?), 129.06, 129.49, 131.20, 138.36, 140.20, 158.84, 166.74,
᎐
᎐
r
Found: 246.3. C14H11NO3 requires 241.25.
2-[(4-Sulfonatophenyl)aminocarbonyl]benzoic acid: pyridin-
ium (monohydrate) (1K). Phthalic anhydride (3.70 g) and sul-
fanilic acid (4.33 g) were added to DMF (100 cm3). After the
addition of pyridine (2.0 cm3), the mixture was heated with
stirring to 100 ЊC for 20 min. At this point the majority of the
solid material had dissolved. The mixture was then poured into
acetone (400 cm3) and cooled in an ice bath for 20 min. The
crude product was filtered under vacuum, washed well with
diethyl ether to remove any remaining DMF, and dried at 60 ЊC.
White solid (8.1 g, 81%). Material was purified for analysis by
recrystallisation from water (about 5 cm3 gϪ1) and was isolated
as a monohydrate; mp 168–169 ЊC (decomposes); δH(270 MHz;
(CD3)2SO; Me4Si) 6.0–13.00 approx. (2H, NH; 2H, H2O), 7.55–
7.69 (m, 7H, aryl protons), 7.89 (d, 1H, aryl proton), 8.10 (t,
2H, aryl protons), 8.63 (t, 1H, aryl proton), 8.96 (d, 2H, aryl
protons), 10.46 (s, 1H, CO2H); δC(68 MHz; (CD3)2SO; Me4Si)
118.08, 125.61, 126.81, 127.32, 129.00, 129.07, 129.41,
131.28, 138.21, 139.29, 141.58, 142.26, 145.82, 166.73, 166.80;
νmax/cmϪ1 3551, 3451 (NH), 1708 (C᎐O acid), 1670 (C᎐O
166.78 (14 signals observed); νmax/cmϪ1 3335 (NH), 1725 (C᎐O
᎐
acid), 1640 (C᎐O amide). M Found 271.0. C H NO requires
᎐
r
15 13
4
271.27.
2-[(4-Methoxyphenyl)aminocarbonyl]benzoic acid (1F). The
4-methoxyaniline was recrystallised (with decolourising char-
coal) before use. White solid (94%); mp 156–158 ЊC (lit.,4,27 156–
157, 138 ЊC); δH(270 MHz; (CD3)2SO; Me4Si) 1.0–6.5 approx.
(1H, NH), 3.75 (s, 3H, OCH3), 6.92 (d, 2H, aryl protons), 7.55–
7.67 (m, 5H, aryl protons), 7.87 (d, 1H, aryl proton), 10.32 (s,
1H, CO2H); δC(68 MHz; (CD3)2SO; Me4Si) 55.22, 113.46,
120.78, 127.39, 128.88, 129.10, 129.74, 131.19, 132.35, 138.51,
154.81, 166.36, 167.02; νmax/cmϪ1 3285 (NH), 1708,1694 (C᎐O
᎐
acid), 1659 (C᎐O amide). M Found 272.6. C H NO requires
᎐
r
15 13
4
᎐
᎐
271.27.
amide). Found: C, 54.46; H, 4.31; N, 6.59. C19H18N2O7S (mono-
hydrate) requires C, 54.54; H, 4.34; N, 6.70%. Mr Found: 401.7.
C19H16N2O6S (anhydrous solid) requires 400.41.
2-[(4-Methylphenyl)aminocarbonyl]benzoic acid (1G). White
solid (86%); mp 153–154 ЊC (sinters), 193–195 ЊC (re-melts)
(lit.,4,27 160–161, 155 ЊC); δH(270 MHz; (CD3)2SO; Me4Si) 2.26
(s, 3H, CH3), 7.13 (d, 2H, aryl protons), 7.50–7.67 (m, 5H, aryl
protons), 7.87 (d, 1H, aryl proton), 10.25 (s, 1H, CO2H) 11.0–
15.0 approx. (1H, NH); δC(68 MHz; (CD3)2SO; Me4Si) 20.68,
119.14, 127.31, 128.50, 128.83, 129.02, 129.56, 131.14, 131.73,
136.56, 138.41, 166.48, 166.86; νmax/cmϪ1 3315 (NH), 1725
Substituted phthalimides
The substituted phthalimides were prepared by the following
general method, unless specified otherwise.
The appropriate substituted phthalanilic acid (1A–1K, 1.0 g)
was added to glacial acetic acid (10 cm3) and heated in a water
J. Chem. Soc., Perkin Trans. 2, 2001, 512–521
519