Organic Syntheses, CV 9, 212
[[4H-4a,7-Methanooxazirino[3,2-i][2,1]benzisothiazole, tetrahydro-8,8-dimethoxy-9,9-dimethyl-, 3,3-dioxide], [2R-(2α,4aα,7α,8aR)]- and [4H-4a,7-Methanooxazirino[3,2-i][2,1]benzisothiazole, 8,8-dichlorotetrahydro-9,9-dimethyl-, 3,3-dioxide, [2R-(2α,4aα,7α,8aR)]]
Submitted by Bang-Chi Chen
1, Christopher K. Murphy
1, Anil Kumar
1, R. Thimma Reddy
1, Charles Clark
1, Ping Zhou
1, Bryan M. Lewis
1, Dinesh Gala
2, Ingrid Mergelsberg
3, Dominik Scherer
3, Joseph Buckley
2, Donald DiBenedetto
2, and Franklin A. Davis
1,4.
Checked by Thanh H. Nguyen and Albert I. Meyers.
1. Procedure
A.
(−)-(3-Oxocamphorylsulfonyl)imine. A
2-L, single-necked, round-bottomed flask, equipped with a
condenser and
magnetic stirring bar, is charged with
42.6 g (0.2 mol) of (−)-(camphorylsulfonyl)imine (Note
1),
30.0 g (0.27 mol) of selenium dioxide (Note
2), and
500 mL of reagent grade acetic acid (Note
3). The mixture is stirred at reflux for 14 hr (Note
4), and the black
selenium metal that separates is removed by suction filtration of the hot reaction mixture using a
250-mL porcelain filter funnel. The funnel, flask and residue are washed with
50 mL of acetic acid. Removal of solvent using a
rotary evaporator gives
43.0–47.0 g of crude
(−)-(3-oxocamphorylsulfonyl)imine as a dark orange solid that is dried under reduced pressure overnight in a
desiccator (Note
5) and (Note
6). This product is suitable for further reaction without purification.
B.
(+)-[(7,7-Dimethoxycamphoryl)sulfonyl]imine. A
500-mL, single-necked, round-bottomed flask, equipped with a condenser, magnetic stirring bar, and
nitrogen inlet, is charged with
22.8 g (0.1 mol) of the crude (−)-(3-oxocamphorylsulfonyl)imine prepared above,
125 mL of trimethyl orthoformate,
68 mL of methanol, and
5 mL of concd sulfuric acid. The mixture is heated to 85–90°C in an
oil bath (Note
7) and (Note
8). After heating for 4 hr, during which time precipitation of the product is observed, the reaction mixture is cooled to room temperature, and an additional
30 mL of trimethyl orthoformate and
10 mL of methanol are added. Heating is continued for an additional hour, after which the reaction mixture is cooled to room temperature and transferred with the aid of
250 mL of methylene chloride to a
500-mL separatory funnel. The solution is washed successively with water (100 mL), aqueous
20% sodium bicarbonate solution (100 mL), water (4 × 100 mL), and
brine (100 mL), and dried over anhydrous
magnesium sulfate. Filtration and removal of the solvent under reduced pressure affords
22.8–23.0 g (
83–85%) of the crude
(+)-(7,7-dimethoxy camphorylsulfonyl)imine as a light pink solid, mp
179–184°C ((Note
9) and (Note
10)). This product is suitable for further reaction without purification.
C.
(+)-[(7,7-Dichlorocamphoryl)sulfonyl]imine. A
1-L, three-necked, round-bottomed flask, equipped with a
mechanical stirrer or magnetic stirring bar,
thermometer, and
250-mL pressure-equalizing addition funnel with a nitrogen inlet, is placed under a
nitrogen atmosphere and charged with a solution of
50 g (0.235 mol) of (−)-(camphorsulfonyl)imine (Note
1) in
250 mL of ethyl acetate. To this solution is added
71 g (0.47 mol) of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) (Note
11) over 30 min, and the reaction mixture is stirred for 30 min at room temperature. To the resulting mixture is then added
51.5 g (0.26 mol) of 1,3-dichloro-5,5-dimethylhydantoin (Note
12) in portions over 90 min while maintaining the reaction temperature at 20–25°C by cooling with an
ice-water bath. When the reaction is complete, typically 30–60 min as determined by HPLC or TLC (Note
13) and (Note
14), 400 mL of water is slowly added while keeping the temperature at 20–25°C. The pH of the reaction mixture is adjusted to 7–7.5 by the addition of
25 mL of concd hydrochloric acid, and the
ethyl acetate solvent is removed on the rotary evaporator at a maximum bath temperature of 60°C (Note
15). The resulting suspension is stirred for 1 hr at room temperature, then the solids are collected by suction filtration, washed with 500 mL of water, and dried in a
draft oven at 50°C to a constant weight affording
62.0–63.0 g (
94–95%) of white solid
(+)-(7,7-dichlorocamphorylsulfonyl)imine (mp
170–175°C) (Note
16) and (Note
17). This product is suitable for further reaction without purification.
D.
(+)-(2R,8aR)-[(8,8-Dimethoxycamphoryl)sulfonyl]oxaziridine (
1). In a
500-mL, three-necked, Morton flask, equipped with a mechanical stirrer with a
Teflon stirring blade and stirrer bearing, a thermometer, and a 250-mL pressure-equalizing addition funnel, is charged with
20.9 g (0.077 mol) of crude (+)-(7,7-dimethoxy camphorylsulfonyl)imine,
175 mL of methylene chloride, and 1.6 g of Aliquat 336 (Note
18). The reaction mixture is cooled in an
ice bath to 0°C, efficient stirring is initiated, and a solution of
63 g (0.38 mol) of potassium carbonate in 120 mL of water is added at 0–10°C followed by
27.2 g (0.114 mol) of 32% peracetic acid (Note
19) dropwise such that the temperature is maintained at 3–5°C. After the addition is completed, the reaction mixture is allowed to warm to room temperature and stirred until reaction is complete (typically 40 hr) as determined by
1H NMR (Note
4) and (Note
20). On completion,
0.6 g of sodium sulfite is added, the reaction mixture is stirred for 30 min, and
5 mL of aqueous 30% sodium hydroxide is introduced. The reaction mixture is transferred to a 500-mL separatory funnel with the aid of
50 mL of methylene chloride, the phases are separated, and the aqueous phase is extracted twice with
50 mL of methylene chloride. The combined organic extracts are washed successively with a saturated solution of
sodium bicarbonate (50 mL) and water (2 × 50 mL), and then dried over anhydrous
magnesium sulfate. The solvents are removed under reduced pressure while maintaining the temperature below 40°C which affords an off-white solid that is suspended in
100 mL hexane and collected by suction. The solids are washed on the filter with two additional
100-mL portions of hexane to give
15.1 g of
(+)-(2R,8aR)-[(8,8-dimethoxycamphoryl)sulfonyl]oxaziridine (1) having mp
184–186°C (dec.) and
[α]25D +91.6° (CHCl
3,c 3.39) (Note
21). A second crop is obtained by evaporating the filtrate to dryness and repeating the process which affords a total of
19.2–19.8 g (
86–90%) of the oxaziridine (mp
184–186°C (dec.)). The product may be used as obtained for oxidations, but may be further purified, if desired, by recrystallization from
1400 mL of 95% ethanol.
This oxaziridine can also be prepared in

4 hr by oxidation of the corresponding imine using
3-chloroperbenzoic acid (Note
22).
The antipode, (−)-(2S,8aR)-[(8,8-dimethoxycamphoryl)sulfonyl]oxaziridine, (mp 189°C (dec.); [α]20D −91.3° (CHCl3, c 0.5)) was prepared in a similar manner starting from (+)-(camphorylsulfonyl)imine.
E.
(+)-(2R,8aR)-[(8,8-Dichlorocamphoryl)sulfonyl]oxaziridine (
2). A
1-L, three-necked, Morton flask, equipped with a mechanical stirrer with a Teflon stirring blade and stirrer bearing or a magnetic stirring bar, a thermometer, and a 250-mL pressure-equalizing addition funnel is charged with a solution of
48 g (0.17 mol) of (+)-[(7,7-dichlorocamphoryl)sulfonyl]imine in 300 mL of methylene chloride and 3.5 g of Aliquat 336 (Note
18). After cooling the resulting mixture to 0°C with an ice-bath, a solution of
119 g (0.86 mol) of potassium carbonate in 250 mL of water is added to the rapidly stirring reaction mixture while maintaining the temperature between 0–10°C. Then
45 g (0.188 mol) of 32% peracetic acid (Note
19) is added dropwise at such a rate (

30 min) that the temperature is maintained between 0–5°C. When the oxidation is complete, as determined by TLC (normally after stirring overnight) (Note
23),
1.3 g (0.099 mmol) of sodium sulfite is added between 0–10°C. After stirring for 30 min,
8 mL of 30% aqueous sodium hydroxide solution is added and the reaction mixture is warmed to room temperature. The organic phase is separated, the aqueous phase is extracted with
methylene chloride (2 × 25 mL), and the combined organic phases are washed with saturated
sodium bicarbonate solution (25 mL) and water (2 × 25 mL) (Note
24), and dried over anhydrous
sodium sulfate. Approximately
210 mL of methylene chloride is evaporated from the organic phase under reduced pressure while maintaining the bath temperature below 40°C. During removal of the solvent crystallization occurs. The resulting slurry is diluted with
125 mL of hexane, cooled in an ice bath (0–5°C), and stirred for 1 hr. The product is collected by suction filtration, washed with
hexane (100 mL), and dried at a maximum of 40°C in an air draft oven to yield
45.5–48.0 g (
90–95%) of
(+)-(2R,8aR)-[(8,8-dichlorocamphoryl)sulfonyl] oxaziridine (2) (mp
182–186°C; [α]20D +91.4° (CHCl
3,
c 0.5)) ((Note
25) and (Note
26)).
The antipode (−)-(2S,8aR)-[(8,8-dichlorocamphoryl)sulfonyl]oxaziridine (mp 182–186°C; [α]20D −92.3° (CHCl3, c 0.5)) was prepared in a similar manner starting from (+)-(camphorylsulfonyl)imine.
2. Notes
1.
(−)-(Camphorylsulfonyl)imine may be purchased from Aldrich Chemical Company, Inc., or prepared according to reference
5.
3.
Reagent grade acetic acid was purchased from Aldrich Chemical Company, Inc.
4. The progress of the reaction was monitored using
1H NMR by observing the disappearance of the two methyl absorptions of
(−)-(camphorylsulfonyl)imine at δ 0.88, and 1.09 in a sample obtained from a 0.5-mL aliquot which is concentrated to dryness on a rotary evaporator.
5. The crude product is of sufficient purity for the next step even if trace amounts of
acetic acid and
selenium dioxide are present. The material can be purified by crystallization from
chloroform to provide product with mp
189–190°C (Lit.
6 mp
190–191°C) and
[α]20D −178.5° (acetone,
c 2.2).
6. The spectral properties of
(−)-[(3-oxocamphoryl)sulfonyl]imine are as follows:
1H NMR (300 MHz, CDCl
3) δ: 0.95 (s, 3 H), 1.13 (s, 3 H), 1.76–1.87 (m, 1 H), 1.92–2.02 (m, 1 H), 2.16–2.36 (m, 2 H), 2.74 (d, 1 H, J = 4.8), 3.20 (d, 1 H, J = 13.5), 3.42 (d, 1 H, J = 13.5);
13C NMR (75 MHz, CDCl
3) δ: 18.41, 20.19, 22.28, 28.00, 44.65, 50.07, 59.04, 62.74, 181.38, 197.71; IR (KBr) cm
−1: 2950, 1761, 1654, 1340, 1166, 741.
7. Within 30 min of heating to 85–90°C, vigorous evolution of gas ensues.
8. The reaction was monitored using
1H NMR by observing the disappearance of the two methyl absorptions at δ 0.95 and 1.13 of
(−)-(3-oxocamphorylsulfonyl)imine.
9. This material can be purified by crystallization from
absolute ethanol to give product with mp
186–7°C and
[α]20D +7.2° (CHCl
3,
c 3.6).
10. The spectral properties of
(+)-[(7,7-dimethoxycamphoryl)sulfonyl]imine are as follows:
1H NMR (300 MHz, CDCl
3) δ: 0.94 (s, 3 H), 1.04 (s, 3 H), 1.73–2.02 (m, 4 H), 2.29 (d, 1 H, J = 1.4), 2.93 (d, 1 H, J = 13.3), 3.12 (d, 1 H, J = 13.3), 3.30 (s, 3 H), 3.39 (s, 3 H);
13C NMR (75 MHz, CDCl
3) δ: 20.4, 20.5, 20.6, 29.2, 46.0, 48.8, 50.3, 50.5, 52.0, 64.2, 103.0, 188.8; IR (KBr) cm
−1: 1620, 1340, 1160.
11.
DBU was purchased from Fluka Chemie AG, Air Products, or Aldrich Chemical Company, Inc.
13. HPLC conditions were as follows: C
18-Novapak (Waters), 5μ; UV detector at 210 nm; mobile phase:
acetonitrile/water (55/45) at a flow rate of 1 mL/min. Alternately, this reaction can be monitored by TLC: R
f = 0.42 using CH2Cl2 and
10% molybdophosphoric acid in
ethanol as the developer.
14. During the reaction, the suspended solids dissolve giving a clear solution.
15. In the event that foaming takes place a few drops of
2-octanol are added.
16. This solid can be purified by crystallization from
2-propanol to give product with mp
177–179°C, and
[α]20D +7.9° (CHCl
3,
c 2.1),
[α]20D +97.8° (CH
3CN,
c 1).
17. The spectral properties of
(+)-[(7,7-dichlorocamphoryl)sulfonyl]imine are as follows:
1H NMR (300 MHz, CDCl
3) δ: 1.12 (s, 3 H), 1.17 (s, 3 H), 1.75–1.93 (m, 1 H), 1.96–2.20 (m, 2 H), 2.23–2.38 (m, 1 H), 2.75 (d, 1 H, J = 3.5), 3.24 (d, 1 H, J = 13.5), 3.42 (d, 1 H, J = 13.5);
13C NMR (75 MHz, CDCl3) δ: 21.8, 25.1, 27.4, 47.8, 50.8, 61.2, 64.1, 81.9, 189.2.
20. The reaction was monitored using
1H NMR by observing the disappearance of the two
methyl absorptions at δ 0.94 and 1.04 of
(−)-(7,7-dimethoxycamphoryl sulfonyl)imine.
21. The spectral properties of
(+)-(2R,8aR)-[(8,8-dimethoxycamphoryl)sulfonyl]oxaziridine are as follows:
1H NMR (300 MHz, CDCl
3) δ:1.02 (s, 3H), 1.28 (s, 3H), 1.70–1.95 (m, 4 H), 2.24 (d, 1 H, J = 4.0), 3.03 (d, 1 H, J = 14), 3.23 (s, 3 H), 3.24 (d, 1 H, J = 14), 3.30 (s, 3 H);
13C NMR (75 MHz, CDCl
3) δ: 20.5, 21.6, 28.1, 45.1, 47.4, 50.5, 50.8, 52.9, 54.6, 97.6, 102.8; IR (KBr) cm
−1: 1356, 1165.
22. Biphasic basic oxidation using
technical grade (50–60%) 3-chloroperbenzoic acid affords this oxaziridine in

4 hr: In a
2-L, three-necked, Morton-flask equipped with a mechanical stirrer was placed
22.6 g (0.083 mol) of crude (+)-[(7,7-dimethoxycamphoryl)sulfonyl]imine,
42.6 g (0.13 mol) of 3-chloroperoxybenzoic acid (50–60%) in 450 mL of methylene chloride, and
450 mL of saturated potassium carbonate solution. The reaction mixture was stirred vigorously until the oxidation was complete as indicated by TLC (Note
27) at which time 500 mL of water was added, the organic layer was separated and the aqueous layer was extracted with
methylene chloride (2 × 500 mL). The combined organic extracts were washed with saturated
sodium sulfite (300 mL) and water (300 mL), and dried over anhydrous
magnesium sulfate.
23. The reaction was monitored by TLC using silica gel plates (Kieselgel-60F, 254 nm, Merck), developing with CH
2Cl
2; for visualization spray with
5% molybdophosphoric acid in
ethanol and heat.
24. The aqueous phases are monitored with Merckoquant 10011 test strips for their peroxide content prior to their disposal. The residual peroxide is neutralized (<1 ppm, the detection limit of the paper) by the addition of saturated
sodium sulfite solution.
25. The spectral properties of
(+)-(2R,8aR)-[(8,8-dichlorocamphoryl)sulfonyl]oxaziridine are as follows:
1H NMR (300 MHz, CDCl
3) δ: 1.16 (s, 3 H), 1.48 (s, 3 H), 1.86–2.18 (m, 3 H), 2.30–2.40 (m, 1 H), 2.73 (d, 1 H, J = 3.9), 3.23 (d, 1 H, J = 14), 3.45 (d, 1 H, J = 14);
13C NMR (75 MHz, CDCl
3) δ: 21.9, 23.31, 25.3, 26.8, 47.3, 49.4, 54.6, 62.5, 86.1, 99.1.
27. A 1-mL aliquot was removed from the organic layer, diluted with
2 mL of methylene chloride, and analyzed by TLC eluting with
methylene chloride (I
2 visualization); imine R
f = 0.34, oxaziridine R
f = 0.51.
Waste Disposal Information
All toxic materials were disposed of in accordance with "Prudent Practices in the Laboratory"; National Academy Press; Washington, DC, 1995.
In the Radex study, samples of oxaziridine 2 were heated in open glass tubes at 60°C/hr from ambient temperature to 260°C under atmospheric conditions. It was found that there is a strong exotherm with an onset at 165°–190°C (neat), at 135–158°C upon addition of stainless steel, and at 73°–84°C upon addition of FeCl3 · H2O. Furthermore, the onset temperature in the FeCl3 · H2O study was found to be dependent on the concentration of ferric ion. In each case as the exotherm occurred, each sample frothed violently out of the sample tube as a gas was produced.
3. Discussion
(−)-[(3-Oxocamphoryl)sulfonyl]imine has been prepared independently by Glahsl and Herrmann in
70% yield in a similar manner using
dioxane as solvent, but the reaction required two weeks for completion.
7 The submitters observed that using
acetic acid as the solvent dramatically reduces the time to

14 hr and improves the yield to
90%.
6 (+)-[(7,7-Dimethoxycamphoryl)sulfonyl]imine has been prepared in a similar manner in
70% yield.
8 This procedure affords this material in
83–88% yield.
6 Chlorination of the aza enolate of
(+)-(camphorylsulfonyl)imine, prepared by treatment with
sodium bis(trimethylsilyl)amide, with
N-chlorosuccinimide affords
(+)-[(7,7-dichlorocamphoryl)sulfonyl]imine in
74% yield.
9 The procedure described here uses inexpensive
DBU and
1,3-dichloro-5,5-dimethylhydantoin to give this imine in
95% yield and is applicable to large scale preparations.
10
Oxidation of (+)-[(7,7-dimethoxycamphoryl)sulfonyl]imine (
96%)
6 and
(+)-[(7,7-dichlorocamphoryl)sulfonyl]imine (
98%)
10 with
3-chloroperbenzoic acid has been reported. The procedure described here uses less hazardous and less expensive
peracetic acid with the aid of Aliquat 336.
10 However, this system requires 40 hr vs. 4 hr using
3-chloroperbenzoic acid for oxidation of
(+)-[(7,7-dimethoxycamphoryl)sulfonyl]imine to the oxaziridine.
N-Sulfonyloxaziridines are an important class of selective, neutral, and aprotic oxidizing reagents.
11 12 Enantiopure N-sulfonyloxaziridines have been used in the asymmetric hydroxylation of enolates to enantiomerically enriched α-hydroxy carbonyl compounds,
9,11,12,13,14 the asymmetric oxidation of sulfides to sulfoxides,
15,16 selenides to selenoxides,
17 sulfenimines to sulfinimines,
18 and the epoxidation of alkenes.
19
(+)-(2R,8aR)-[(8,8-Dimethoxycamphoryl)sulfonyl]oxaziridine (
1) and
(+)-(2R,8aR)-[(8,8-dichlorocamphoryl)sulfonyl]oxaziridine (
2) are most effective for the hydroxylation of 2-substituted 1-tetralone enolates to 2-substituted 2-hydroxy-1-tetralones. The former oxaziridine,
1, gives higher ee's (>90%) with tetralones having an 8-methoxy group, while the dichloro reagent
2 is more effective with those enolates lacking this substituent. For example (+)-
1 has been employed in highly enantioselective syntheses of (+)- and
(−)-5,7-O-dimethyleucomol (>96% ee),
20 the AB-ring segments for γ-rhodomycinone and α-citromycinone (94% ee),
6 and
(R)-(−)-2-acetyl-5,8-dimethoxy-1,2,3,4-tetrahydro-2-naphthol (>95% ee), a key intermediate in the synthesis of anthracyclinones.
21 The asymmetric synthesis of the AB ring of aklavinone (>95% ee)
22 and the homoisoflavanoids
(+)-O-trimethylsappanone (94% ee) and
(+)-O-trimethylbrazilin (92% ee) used oxaziridine (+)-
2. Some representative examples using these reagents are given in the Table.
TABLE
ASYMMETRIC HYDROXYLATION OF TETRALONE AND PROPIOPHENONE ENOLATES USING (CAMPHORYLSULFONYL)OXAZIRIDINES 1 AND 2
|
Oxaziridine |
Ketone (X=H) |
Base |
Temp. (°C) |
α-Hydroxy Tetralone (X=OH) |
%Yielda |
%ee (Config.) |
Ref. |
|
(+)−1 |
|
NHMDSa |
−78 |
66 |
36(R) |
6,9,22 |
(+)−2 |
NHMDS |
−78 |
66 |
>95(R) |
6,9,22 |
(+)−1 |
|
NHMDS |
−78 |
58 |
60(R) |
6,22 |
LDAb |
0 |
66 |
94(R) |
|
(+)−2 |
LDA |
−78 |
55 |
73(R) |
|
(+)−1 |
|
NHMDS |
−78 |
75 |
77(R) |
20 |
LDA |
−78 |
72 |
≥96(R) |
|
(+)−2 |
NHMDS |
−78 |
66 |
88(R) |
|
(+)−1 |
|
NHMDS |
0 |
73 |
56(S) |
21 |
LDA |
0 |
|
No Reaction |
|
KHMDSc |
−78 |
70 |
≥95(S) |
|
(+)−2 |
NHMDS |
0 |
63 |
47(S) |
|
(+)−1 |
|
NHMDS |
−78 |
73 |
79(S) |
6,9,22 |
(+)−2 |
NHMDS |
−78 |
70 |
95(S) |
9 |
|
|
This preparation is referenced from:
Appendix
Compounds Referenced (Chemical Abstracts Registry Number)
(−)-(Camphorsulfonyl)imine
(+)-[(7,7-Dimethoxycamphoryl)sulfonyl]imine
(+)-[(7,7-Dichlorocamphoryl)sulfonyl]imine
[4H-4a,7-Methanooxazirino[3,2-i][2,1]benzisothiazole, tetrahydro-8,8-dimethoxy-9,9-dimethyl-, 3,3-dioxide], [2R-(2α,4aα,7α,8aR)]-
[4H-4a,7-Methanooxazirino[3,2-i][2,1]benzisothiazole, 8,8-dichlorotetrahydro-9,9-dimethyl-, 3,3-dioxide, [2R-(2α,4aα,7α,8aR)]
(−)-(3-Oxocamphorylsulfonyl)imine
(−)-(camphorylsulfonyl)imine
(+)-(7,7-dimethoxy camphorylsulfonyl)imine
(+)-(7,7-dichlorocamphorylsulfonyl)imine
(−)-(2S,8aR)-[(8,8-dimethoxycamphoryl)sulfonyl]oxaziridine
(+)-(camphorylsulfonyl)imine
(−)-(2S,8aR)-[(8,8-dichlorocamphoryl)sulfonyl]oxaziridine
(−)-[(3-oxocamphoryl)sulfonyl]imine
DBU
(−)-(7,7-dimethoxycamphoryl sulfonyl)imine
FeCl3 · H2O
(−)-5,7-O-dimethyleucomol
(R)-(−)-2-acetyl-5,8-dimethoxy-1,2,3,4-tetrahydro-2-naphthol
(+)-O-trimethylsappanone
(+)-O-trimethylbrazilin
ethanol (64-17-5)
potassium carbonate (584-08-7)
sulfuric acid (7664-93-9)
hydrochloric acid (7647-01-0)
acetic acid (64-19-7)
ethyl acetate (141-78-6)
methanol (67-56-1)
acetonitrile (75-05-8)
sodium sulfite (7757-83-7)
sodium hydroxide (1310-73-2)
chloroform (67-66-3)
sodium bicarbonate (144-55-8)
sodium sulfate (7757-82-6)
nitrogen (7727-37-9)
selenium dioxide (7446-08-4)
2-propanol (67-63-0)
methyl (2229-07-4)
methylene chloride (75-09-2)
2-Octanol (123-96-6)
Propiophenone (93-55-0)
magnesium sulfate (7487-88-9)
dioxane (5703-46-8)
selenium
tetralone (529-34-0)
peracetic acid (79-21-0)
hexane (110-54-3)
N-chlorosuccinimide (128-09-6)
1,3-dichloro-5,5-dimethylhydantoin (118-52-5)
Molybdophosphoric acid (51429-74-4)
lithium diisopropylamide (4111-54-0)
tricaprylylmethylammonium chloride (5137-55-3)
trimethyl orthoformate (149-73-5)
1,8-diazabicyclo[5.4.0]undec-7-ene (6674-22-2)
(+)-(2R,8aR)-[(8,8-DIMETHOXYCAMPHORYL)SULFONYL]OXAZIRIDINE (131863-82-6)
(+)-(2R,8aR)-[(8,8-DICHLOROCAMPHORYL)SULFONYL]OXAZIRIDINE,
(+)-(2R,8aR)-[(8,8-dichlorocamphoryl)sulfonyl] oxaziridine (127184-05-8)
3-chloroperoxybenzoic acid,
3-chloroperbenzoic acid (937-14-4)
Sodium bis(trimethylsilyl)amide (1070-89-9)
Potassium bis(trimethylsilyl)amide (40949-94-8)
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