Family and Garcia-Garibay
26.9, 44.3, 52.7, 124.7, 128.9, 129.0, 135.8, 146.4, 212.6. HATR-
IR (cm-1): 3430, 2948, 2859, 2741, 2537, 2457, 1681, 1623, 1605,
1583, 1534, 1455, 1379.
Experimental Section
Solution and solid-state photolysis experiments were conducted
for each salt. For solution experiments, each salt (5 mg) was
dissolved in 5 mL of deoxygenated 50% methanol/50% water. For
the solid state, the salts were sandwiched between two pyrex slides
and placed in the photolysis chamber approximately 6 cm away
from the lamp. After 1 h of exposure to the output of a medium
pressure Hg Hannovia lamp, the reaction mixtures were acidified
with 1 M HCl and the organic photoproducts and starting material
extracted with ethyl acetate. The resulting mixture was dissolved
in dry methanol and treated with an excess of 1.0 M Trimethylsilyl-
diazomethane in ether to produce the methyl esters, which were
(R)-1-(Naphthalene-1-yl)ethanaminium 4,4′-(2,4-Bis(carboxy-
phenyl)-2,4-dimethyl-3-pentanone) (S4, (R)-Dinapthyethyl Salt).
Mp 204 °C, 228 °C 1H NMR (500 MHz, CD3OD) δ 1.23 (12H, s),
1.68 (6H, d, J ) 6.5 Hz), 5.27 (2H, q, J ) 6.5 Hz, 7 Hz), 7.23
(4H, d, J ) 8.5 Hz), 7.58 (10H, dt), 7.88 (2H, m), 7.93 (2H, d, J
) 8.5 Hz), 8.11 (4H, d, J ) 8.5 Hz). 13C NMR (125 MHz, CD3OD)
δ 19.4, 20.6, 26.8, 26.9, 45.9, 52.6, 52.7, 121.7, 121.8, 124.7, 124.8,
125.0, 125.3, 125.6, 126.4, 128.4, 128.5, 128.6, 128.9, 129.0, 130.0,
133.9, 135.6, 136.5, 146.4, 173.4, 212.6. HATR-IR (cm-1): 2971,
2927, 2168, 1684, 1607, 1582, 1515, 1467, 1383, 794.
1
then analyzed by GC and H NMR for conversion. The methyl
ester analogue of bis-benzoic acid A was also photolyzed as a
control.
4-(Dimethylamino)pyridinium 4,4′-(2,4-Bis(carboxyphenyl)-
1
2,4-dimethyl-3-pentanone) (S5, DMAP Salt). Mp 297 °C. H
NMR (500 MHz, (CD3)2SO) δ 1.20 (12H, s), 2.910 (12H, s), 6.55
(4H, dd, J ) 6.5 Hz), 7.24 (4H, d, J ) 8.5 Hz), 7.81 (4H, d, J )
8 Hz), 8.06 (4H, d, J ) 6.5 Hz). 13C NMR (125 MHz, CD3OD)
26.8, 26.9, 38.3, 52.8, 106.6, 124.9, 125.3, 128.5, 129.0, 129.1,
134.1, 141.2, 147.1, 156.8, 172.2, 212.5. HATR-IR (cm-1) 2923,
2517 (broad), 1684, 1646, 1604, 1560, 1460, 1385, 1212.
2,4-Di-p-carboxyphenyl-2,4-dimethyl-3-pentanone Methyl Es-
ter (M). Mp 179 °C. 1H NMR (500 MHz, CDCl3) δ 1.30 (12H, s),
3.92 (6H, s), 7.24 (4H, d), 7.92 (4H, d, J ) 8 Hz). 13C NMR (125
MHz, CDCl3) δ 27.6, 52.0, 53.3, 125.7, 128.4, 129.6, 149.2, 166.7,
211.9 HATR-IR (cm-1) 2924, 1719, 1681, 1609, 1441, 1271. HR-
EIMS m/z calcd for C23H26O5Na [M + Na] 405.1672, found
405.1686.
Synthesis of 2,4-Di-p-carboxyphenyl-2,4-dimethyl-3-penta-
none A. Periodic acid (360 mg, 1.6 mmol, 5.2 mmol) was dissolved
in acetonitrile (50 mL) by vigorous stirring.27 Then CrO3 (12 mg,
0.119 mmol, 50 mol%) was dissolved into solution. 2,4-Di-p-tolyl-
2,4-dimethyl-1,3-pentanone (prepared from a known literature
synthesis)13 (90 mg, 0.306 mmol, 1 equiv) was then added, and
the reaction mixture was allowed to stir for 2 h. The solvent was
removed in vacuo, and the reaction residue was then washed with
water. The product was extracted with ethyl acetate, and the organic
layer was washed with brine and dried with MgSO4. The product
was obtained in quantitative yield as a white powder after
evaporation of the solvent. Mp 305 °C. 1H NMR (500 MHz, MeOD)
δ 1.36 (12H, s), 7.33 (4H, d, J ) 8.5 Hz), 7.94 (4H, d, J ) 8.5 Hz)
(acid protons were not observed in this solvent). 13C NMR (125
MHz, MeOD) δ 26.8, 125.4, 125.6, 128.9, 129.3, 149.1, 168.2,
212.0. HATR-IR (cm-1) 2975.92 (broad), 1680.74, 1608.42. HR-
EIMS m/z calcd for C21H22O5Na [M + Na] 377.1359, found
377.1352.
Photoproducts.
DC Benzoic Acid, 4,41-(1,1,2,2-tetramethyl-1,2-ethanediyl)-
bis-, Dimethyl Ester.28 Mp 195 °C. 1H NMR (500 MHz, CDCl3)
δ 1.34 (12H, s), 3.91 (6H, s), 7.08 (4H, d, J ) 8 Hz), 7.83 (4H, d,
J ) 8 Hz). 13C NMR (125 MHz, C6D6) δ 25.7, 43.6, 51.1, 124.5,
128.5, 129.5, 133.2, 166.4. HR-EIMS m/z calcd for C22H26O4Na
[M + Na] 377.1723, found 377.1732.
Salts.
St Benzoic Acid, 4-(1-Methylethenyl)-, Methyl Ester.29 1H
NMR (500 MHz, C6D6) δ 1.96 (3H, s), 3.49 (6H, s), 4.95 (1H, s),
5.26 (1H, s), 6.87 (2H, d, J ) 8 Hz), 6.97 (4H, d, J ) 8 Hz). 13C
NMR (125 MHz, C6D6) δ 23.2, 51.1, 114.1, 128.5, 129.8, 133.4,
140.1, 151.4, 166.4.
Tetradecan-1-aminium 4,4′-(2,4-Bis(carboxyphenyl)-2,4-di-
methyl-3-pentanone) (S1, Tetradecyl Salt). Mp 185 °C. 1H NMR
(500 MHz, CD3OD) δ 1.23 (12H, s), 1.27 (48H, broad s), 1.60
(6H, s), 2.84 (8H, t, J ) 7.5 Hz), 7.23 (4H, d, J ) 8.5 Hz), 7.87
(4H, d, J ) 8.5 Hz). 13C NMR (125 MHz, CD3OD) δ 12.88, 22.19,
25.94, 26.84, 27.23, 28.70, 28.93, 28.97, 29.11, 29.21, 29.25, 31.53,
39.26, 52.7, 124.73, 129.01, 135.74, 146.50, 173.56, 212.52. HATR-
IR (cm-1): 2920, 2850, 2168, 1685, 1627, 1607, 1582, 1509, 1468,
1384.
iPB Ethyl, 1-[4-(Methoxycarbonyl)phenyl]-1-methyl.30 1H
NMR (500 MHz, C6D6) δ 1.12 (6H, d) 2.52-2.58 (1H, m), 3.50
(3H, s), 7.62 (2H, d, J ) 7 Hz), 8.12 (2H, d, J ) 7 Hz). 13C NMR
(125 MHz, C6D6) δ 24.6, 33.9, 51.1, 125.4, 126.3, 153.7, 166.4.
Diisopropylammonium 4,4′(2,4-Bis(carboxyphenyl)-2,4-di-
methyl-3-pentanone) (S2, DIPA Salt). Mp 275-290 °C. 1H NMR
(500 MHz, CD3OD) δ 1.30 (12H, s), 1.34 (24H, d, J ) 6.5 Hz),
3.51 (4H, m), 7.29 (4H, d, J ) 8.5 Hz), 7.93 (4H, d, J ) 8.5 Hz).
13C NMR (125 MHz, CD3OD) δ 17.8, 26.8, 26.9, 52.8, 125.1, 129.2,
147.6, 171.3, 212.4. HATR-IR (cm-1): 3379, 2977, 2869, 2747,
2513, 1683, 1607, 1587, 1542, 1501, 1463, 1380, 1234.
Piperidinium 4,4,′-(2,4-Bis(carboxyphenyl)-2,4-dimethyl-3-
Acknowledgment. This work was supported by NSF grants
CHE0551938 and DMR0605688.
Supporting Information Available: Spectroscopic data for
all salts and experimental procedures for the photochemical
experiments. This material is available free of charge via the
1
pentanone) (S3, Piperidinium Salt). Mp 220-240 °C. H NMR
JO802761T
(500 MHz, CD3OD) δ 1.29 (12H, s), 1.67 (4H, broad), 1.74 (8H,
broad s), 3.06 (8H, broad s), 7.23 (4H, d, J ) 8.3 Hz), 7.86 (4H,
d, J ) 8.3 Hz). 13C NMR (125 MHz, CD3OD) δ 21.8, 22.6, 26.8,
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2480 J. Org. Chem. Vol. 74, No. 6, 2009