hydroxylamine hydrochloride under standard (basic) condi-
tions. The three ketoximes for which the ketones were not avail-
130.0, 130.8, 131.1, 135.8, 137.7, 140.4, 141.6, 152.7; m/z (%)
285 (29, Mϩ), 255 (19), 177 (6) 163 (11), 151 (7), 106 (1), 91
(100), 77 (6), 65 (7), 51 (4).
able commercially viz., Me C(Me CH)C᎐O, (Me C) C᎐O and
᎐
᎐
2
3
2
3
Me C(1-Ad)C᎐O, were prepared by syringe addition (∼1 cm3
᎐
3
minϪ1) of t-butyllithium (30 cm3 of 1.7 M, 0.051 mol) to 0.050
mol of the alkyl nitrile under nitrogen according to the liter-
ature method.6,18,19 The mixture was stirred until the reaction
was complete (TLC, 1–3 h) and then ethanol (5 cm3) was added,
followed by acetic acid (3 cm3). Ethanol (65 cm3) and O-benzyl-
hydroxylamine hydrochloride (8.0 g) were added and the
solution was refluxed for 5–8 h. Purification was by column
chromatography (hexane/ethyl acetate, 3 : 1) and final yields of
these hindered O-benzyloxime ethers were ca. 80%.
Pentan-3-one, 2,4-dimethyl oxime
δH 1.14 (d, J = 7 Hz, 6H), 1.18 (d, J = 7 Hz, 6H), 2.54–2.61 (m,
1H), 3.18–3.25 (m, 1H), 8.86 (br, s, 1H); δC 19.2, 21.7, 27.9, 31.1,
169.2; m/z (CI) 130.1.
Pentan-3-one, 2,4-dimethyl-, O-(phenylmethyl)oxime 2f
Clear liquid, δH 1.12 (d, J = 7 Hz, 6H), 1.15 (d, J = 7 Hz, 6H),
2.53–2.56 (m, 1H), 3.05–3.09 (m, 1H), 5.07 (s, 2H), 7.30–7.39
(m, 5H); δC 19.4, 21.6, 28.6, 31.7, 75.8, 127.8, 128.3, 128.6,
139.0, 169.2; m/z (%) 219 (18, Mϩ), 202 (6), 177 (3), 128 (2). 91
(100), 77 (10), 65 (9); m/z (CI) 220.1692. C14H22NO requires
220.1701.
General procedure: ethanone, 1-phenyl-, O-(phenylmethyl)oxime,
2b
O-Benzylhydroxylamine hydrochloride (3.19 g, 0.02 mol) was
suspended in anhydrous pyridine (40 cm3) at room temperature
(∼80% dissolved), and acetophenone (2.33 cm3, 0.02 mol) was
added to the suspension in one portion via syringe. The solution
turned clear immediately after the addition. The solution was
stirred at room temperature overnight, and the progress of the
reaction was monitored by TLC (hexane : ethyl acetate = 5 : 1)
and GC-MS. Upon completion, the reaction mixture was
poured into distilled water (50 cm3), extracted with EtOAc
(2 × 50 cm3), and the combined organic phases were washed
several times with saturated, aqueous CuSO4 solution to
remove any traces of pyridine. It was then dried (MgSO4) and
concentrated on a rotavap and purified by column chromato-
graphy (hexane : ethyl acetate = 5 : 1) to give 2b as a colorless
liquid (3.90 g, 87%). Note that if the reaction was conducted at
room temperature, then both isomers of 2b could be observed
by GC-MS and 1H NMR; but if the reaction was refluxed
for 6 h, only one isomer was obtained. In the case of benzo-
phenone, refluxing for 8 h was required for the reaction
instead of room temperature.
Pentan-3-one, 2,2,4-trimethyl-, O-(phenylmethyl)oxime 2g
(mixture of 2 isomers, 3 : 2 ratio)
Clear liquid, δH 1.13–1.27 (m, 15H), 2.53–2.68 (m, 1H), 5.03
and 5.05 (s, s, 2H), 7.30–7.40 (m, 5H); δC 19.3, 22.9, 27.9, 28.7,
29.9, 31.4, 38.4, 76.0, 76.1, 127.7, 128.4, 128.5, 128.5, 139.0,
169.4; m/z (%) (EI) 233 (3, Mϩ), 216 (2), 191 (2), 174 (1), 142 (1),
115 (1), 105 (1), 91 (100), 77 (10), 65 (8), 57 (17), 51 (7); m/z (CI)
234.1823. C15H24NO requires 234.1858.
Pentan-3-one, 2,2,4,4-tetramethyl-, O-(phenylmethyl)oxime 2h24
Clear liquid, δH 1.27 (s, 9H), 1.39 (s, 9H), 5.10 (s, 2H), 7.3–7.6
(m, 5H); δC 29.9, 30.3, 38.7, 40.0, 75.9, 127.5, 128.3, 128.7,
138.8, 168.3; m/z (CI) 248.1945. C16H26NO requires 248.2014.
Adamantan-1-yl-2,2-dimethylpropan-1-one O-(phenylmethyl)-
oxime 2j
White solid, mp 65–83 ЊC, δH 1.37 (s, 9H), 1.68 (bs, 6H), 2.02
(bs, 9H), 5.08 (s, 2H), 7.25–7.45 (m, 5H); δC 29.1, 30.2, 37.0,
Ethanone, 1-phenyl-, O-(phenylmethyl)oxime 2b20,21
40.5, 46.2, 48.9, 75.8, 128.0, 128.2, 128.3, ᎐C and one quat-C
᎐
not obs.; m/z (%) 325 (Mϩ, 5), 283 (12), 234 (10), 177 (30),
135 (100), 107 (10), 93 (15), 91 (70), 79 (23), 77 (20), 57 (18);
m/z (CI) 326.2574. C22H32NO, requires 326.2583.
Clear liquid, δH 2.30 (s, 3H). 5.27 (s, 2H), 7.33–7.46 (m, 8H),
7.66–7.68 (m, 2H); δC 13.0, 76.3, 126.2, 128.2, 128.3, 128.4,
128.7, 129.2, 136.7, 138.3, 155.1; second isomer δH 2.22 (s, 3H),
5.13 (s, 2H), ArH overlapped by 1st. isomer; δC 21.9, 76.0,
126.3, 127.7, 127.9, 128.1, 128.5, 129.1, 134.7, 138.5, 154.3; m/z
(electrospray) 226.1. C15H16NO requires 226.1.
Cyclohexanone, O-(phenylmethyl)oxime 2k20
Clear liquid, δH 1.58–1.70 (m, 6H), 2.23 (m, 2H), 2.53 (m, 2H),
5.09 (s, 2H), 7.30–7.40 (m, 5H); δC 25.7, 25.9, 26.0, 27.2, 32.4,
75.3, 127.7, 128.0, 128.5, 138.5, 161.0; m/z (CI) 204.1344.
C13H18NO requires 204.1310.
2-Propanone, O-(phenylmethyl)oxime 2a20,22
Clear liquid, δH 1.90 (s, 3H), 1.92 (s, 3H), 5.10 (s, 2H), 7.30–7.38
(m, 5H); δC 16.2, 22.3, 75.6, 128.0, 128.3, 128.7, 138.7, 155.6;
m/z (electrospray) 164.0. C10H14NO requires 164.1.
Bicyclo[3.3.1]nonan-9-one oxime 1l
Hydroxylamine hydrochloride (50.3 mg, 0.724 mmol) was dis-
solved in anhydrous pyridine (4 cm3) at room temperature, and
bicyclo[3.3.1]nonan-9-one (100 mg, 0.724 mmol) was added to
the stirred solution in one portion. The solution was stirred at
room temperature overnight, and the progress of the reaction
was monitored by TLC (hexane : ethyl acetate = 4 : 1) and GC-
MS. Upon completion, the reaction mixture was worked up as
described for 2b and recrystallization from hexane at Ϫ20 ЊC
afforded the oxime (95 mg, 86%) as white crystals: δH 1.52–1.60
(m, 2H), 1.84–1.94 (m, 8H), 1.95–2.11 (m, 2H), 2.51 (m, 1H),
3.54 (m, 1H), 7.52–7.60 (bs, 1H); δC 21.4, 28.8, 32.1, 33.5, 36.3,
167.9; m/z (electrospray) 154.1. C9H16NO requires 154.2.
Methanone, diphenyl-, O-(phenylmethyl)oxime 2c23
White solid, mp 54–55 ЊC; δH 5.26 (s, 2H), 7.3–7.49 (m, 15H);
δC 76.9, 127.9, 128.3, 128.5, 128.6, 128.7, 129.2, 129.7, 133.8,
136.9, 138.6, 157.5; m/z (CI) 288.1347. C20H18NO requires
288.1310.
Indan-1-one, O-(phenylmethyl)oxime 2d
δH 2.96–3.11 (m, 4H), 5.29 (s, 2H), 7.26–7.53 (m, 8H), 7.79 (d,
J = 7 Hz, 1H); δC 26.9, 28.8, 76.4, 121.9, 125.7, 127.9, 128.0,
128.2, 128.5, 130.5, 136.2, 138.4, 148.6, 163.5; m/z (%), 237 (27,
Mϩ), 220 (3), 207 (5), 146 (2), 130 (4), 115 (11), 103 (5), 91 (100),
77 (11), 65 (9), 51 (8).
Bicyclo[3.3.1]nonan-9-one, O-(phenylmethyl)oxime 2l
White solid, mp 48–49 ЊC; δH 1.50–1.60 (m, 2H), 1.80–1.91 (m,
8H), 1.92–2.09 (m, 2H), 2.51 (m, 1H), 3.53 (m, 1H), 5.10 (s,
2H), 7.30–7.40 (m, 5H); δC 21.3, 30.0, 32.3, 33.7, 36.2, 75.1,
127.6, 127.9, 128.4, 138.8, 168.2; m/z (CI) 244.1797. C16H22NO
requires 244.1788.
Fluoren-9-one, O-(phenylmethyl)oxime 2e
White solid, mp 59 ЊC, δH 5.55 (s, 2H), 7.30–7.58 (m, 9H), 7.63–
7.70 (m, 2H), 7.84 (d, J = 7 Hz, 1H), 8.34, (d, J = 7 Hz, 1H);
δC 120.0, 120.1, 121.9, 128.0, 128.2, 128.3, 128.4, 128.7, 129.6,
O r g . B i o m o l . C h e m . , 2 0 0 4 , 2, 4 1 5 – 4 2 0
419