Pincock and Young
1093
than 10% of the base peak. Intensities are reported as a per-
cent of the base peak.
(14), 89 (10), 77 (21), 63 (16), 51 (15). HR-MS calcd. for
C10H10O: 146.0731; found: 146.0741.
5-Methoxy-2-methyl-1-indenol 3b
Indenone synthesis
mp 77–78 °C. 1H NMR (CDCl3) δ: 7.32 (d, 1H, J =
7.9 Hz), 6.68 (d, 1H, J = 2.3 Hz), 6.61 (dd, 1H, J1 = 7.9,
J2 = 2.3 Hz), 6.27 (s, 1H), 4.78 (broad s, 1H), 3.79 (s, 3H),
2.05 (broad s, 3H), 1.64 (broad s, 1H). 13C NMR (CDCl3) δ:
160.3, 149.9, 144.74, 137.3, 126.6, 123.9, 109.1, 106.9,
78.2, 55.4, 13.9. GC–MS: 176 (70), 175 (27), 174 (13), 162
(11), 161 (100), 160 (22), 159 (11), 146 (19), 145 (30), 133
(19), 132 (10), 131 (20), 118 (13), 116 (12), 115 (35), 105
(11), 103 (24), 102 (11), 91 (12), 89 (13), 79 (12), 78 (10),
77 (34), 75 (10), 63 (20), 51 (13). HR-MS calcd. for
C11H12O2: 176.0837; found: 176.0835.
2-Methyl-1-indenone 4a and 5-methoxy-2-methyl-1-
indenone 4b
These indenones were prepared using the procedure of
Floyd and Allen (), outlined in Scheme 2.
6-Methoxy-2-methyl-1-indenone 4c
The precursor to this indenone, 6-methoxy-2-methyl-1-
indanone 5 (X = 6-CH3O), was prepared using the procedure
of Sam and Plampin (), outlined in Scheme 2. To a solution
of 13.9 g (79 mmol) of 5 (X = 6-CH3O) in 170 mL of CCl4
was added 14.4 g (90 mmol) of bromine in 70 mL of CCl4.
After the addition was complete, the mixture was stirred at
room temperature for 2 h. The solvent and excess bromine
were removed under reduced pressure and 20.5 g (79 mmol,
6-Methoxy-2-methyl-1-indenol 3c
1
mp 103–105 °C. H NMR (CDCl3) δ: 7.08 (d, 1H, J =
2.4 Hz), 7.01 (d, 1H, J = 8.0 Hz), 6.74 (dd, 1H, J1 = 8.0,
J2 = 2.4 Hz), 6.27 (s, 1H), 4.81 (d, 1H, J = 8.9 Hz), 3.80 (s,
3H), 2.04 (broad s, 3H), 1.49 (d, 1H, J = 8.9 Hz). 13C NMR
(CDCl3) δ: 158.0, 147.1, 146.1, 135.7, 126.5, 120.4, 113.1,
110.7, 79.0, 55.6, 13.7. GC–MS: 177 (10), 176 (87), 175
(18), 162 (11), 161 (100), 160 (33), 159 (18), 146 (15), 145
(40), 133 (23), 131 (12), 118 (17), 117 (16), 116 (19), 115
(60), 105 (13), 103 (20), 102 (11), 91 (13), 79 (11), 77 (24),
63 (17), 51 (16). HR-MS calcd. for C11H12O2: 176.0837;
found: 176.0841.
1
100%) of the crude bromide, as a brown solid, resulted. H
NMR (CDCl3) δ: 7.22–7.32 (m, 3H), 3.85 (s, 3H), 3.72 (d,
1H, J = 18 Hz), 3.41 (d, 1H, J = 18 Hz), 1.95 (s, 3H). 13C
NMR (CDCl3) δ: 200.4, 160.0, 141.8, 133.8, 127.1, 125.3,
106.7, 60.3, 55.7, 45.8, 27.0. GC–MS: 256 (19), 254 (18),
176 (58), 175 (100), 174 (22), 161 (96), 148 (20), 147 (41),
146 (10), 133 (29), 132 (23), 131 (41), 117 (16), 115 (32),
105 (10), 104 (11), 103 (42), 102 (14), 91 (36), 89 (14), 79
(19), 78 (29), 77 (77), 76 (18), 75 (17), 74 (20), 65 (13), 64
(10), 63 (45), 62 (15), 51 (34), 50 (13). HR-MS calcd. for
C11H11O2Br: 253.9942; found: 253.9934. A mixture of
20.5 g (79 mmol) of crude bromoindanone, 12.1 g
(139 mmol) LiBr, and 10.4 g (140 mmol) Li2CO3 in 175 mL
of DMF was heated between 135–140 °C for 3 h under a ni-
trogen atmosphere. After cooling, the mixture was poured
into 300 mL of water and extracted three times with ether.
The combined ether layers were washed twice with water
and dried with MgSO4. Evaporation of the ether produced
10.4 g of thick red oil that contained crystals. This material
was purified by flash chromatography on silica gel produc-
ing 3.60 g (21 mmol, 26%) of bright orange needles: mp 82–
General method for the preparation of esters 1a–c and
2a–c
The corresponding acid chloride (4 mmol) in 5 mL of dry
benzene was added to a solution of the corresponding
indenol (2 mmol) and pyridine (4 mmol) in 10 mL of dry
benzene. The solution was stirred overnight at room temper-
ature, then 50 mL of water was added, and the two layers
were separated. The benzene layer was washed twice with
10% aqueous HCl and once with saturated aqueous sodium
bicarbonate and finally with water. The esters were purified
by column chromatography on silica gel. The yields were
50–75%. Solid samples were recrystallized and oils were
bulb-to-bulb distilled.
1
84 °C. H NMR (CDCl3) δ: 7.06 (q, 1H, J = 1.8 Hz), 6.97
(d, 1H, J = 2.4 Hz), 6.78 (d, 1H, J = 7.9), 6.67 (dd, 1H, J1 =
2.4, J2 = 7.9 Hz), 3.77 (s, 3H), 1.81 (d, 3H, J = 1.8 Hz). 13C
NMR (CDCl3) δ: 198.6, 160.1, 144.1, 136.6, 134.9, 132.7,
121.6, 116.1, 110.9, 55.6, 10.0. GC–MS: 175 (12), 174
(100), 159 (40), 131 (92), 115 (10), 103 (74), 102 (21), 77
(64), 76 (21), 75 (20), 63 (25), 62 (12), 51 (18). HR-MS
calcd. for C11H10O2: 174.0681; found: 174.0675.
2-Methyl-1-indenyl acetate, 1a
bp 87–91 °C at 2–3 mmHg (1 mmHg = 133.322 Pa). UV
(methanol) λmax (nm) (⑀ ((mol L–1)–1 cm–1)): 266 (7130), 306
1
(952). H NMR (CDCl3) δ: 7.04–7.36 (m, 4H), 6.40 (s, 1H),
6.13 (s, 1H), 2.16 (s, 3H), 1.97 (s, 3H). 13C NMR (CDCl3) δ:
171.4, 144.4, 143.7, 142.1, 129.3, 128.8, 125.1, 124.2,
120.3, 78.4, 21.0, 14.0. GC–MS: 188 (15), 147 (11), 146
(100), 145 (29), 131 (68), 129 (21), 128 (74), 127 (16), 117
(10), 115 (31). HR-MS calcd. for C12H12O2: 188.0837;
found: 188.0843.
Indenol syntheses
Indenols
3 were prepared from the corresponding
indenones using Luche’s reagent (18). The yields were 60–
95%.
2-Methyl-1-indenol 3a
mp 84–86 °C. H NMR (CDCl3) δ: 7.09–7.50 (m, 4H),
6.33 (broad s, 1H), 4.84 (broad s, 1H), 2.07 (broad s, 3H),
1.66 (broad s, 1H). 13C NMR (CDCl3) δ: 148.3, 145.2,
143.0, 128.5, 127.0, 124.9, 123.3, 120.1, 78.9, 13.8. GC–
MS: 146 (86), 145 (38), 132 (10), 131 (100), 129 (13), 128
(22), 127 (14), 117 (15), 116 (11), 115 (46), 103 (31), 91
5-Methoxy-2-methyl-1-indenyl acetate, 1b
UV (methanol) λmax (nm) (⑀ ((mol L–1)–1 cm–1)): 279
1
1
(2880, 306 (1560). H NMR (CDCl3) δ: 7.27 (d, 1H, J =
7.9 Hz), 6.71 (d, 1H, J = 2.4 Hz), 6.59 (dd, 1H, J1 = 2.4,
J2 = 7.9 Hz), 6.38 (broad s, 1H), 6.07 (broad s, 1H), 3.79 (s,
3H), 2.17 (s, 3H), 1.98 (broad s, 3H). 13C NMR (CDCl3) δ:
171.6, 160.7, 145.5, 134.1, 129.1, 125, 109.4, 107.2, 78.1,
© 2003 NRC Canada