反応 #345498

反応方程式

2-chloroanthracene

N-methylformanilide

phosphorus oxychloride

→

2-chloro-9-formylanthracene

収率 56.9%

溶媒

o-dichlorobenzene

反応条件

後処理

1. 1
   温度The resulting bright yellow mixture was heated gradually over 1.5 h to 9° C. at which point an exotherm
2. 2
   温度ensued raising the reaction temperature to 115° C
3. 3
   その他The heat was removed until the exotherm
4. 4
   その他(45 min)
5. 5
   温度after which time the mixture was heated for 9 h at 90° C.
6. 6
   温度cooled
7. 7
   その他The cooled reaction mixture
8. 8
   その他precipitating a dark brown tar
9. 9
   その他The aqueous layer was decanted away from the tar
10. 10
    抽出extracted with methylene chloride (5×2 L)
11. 11
    workup.DISSOLUTIONto redissolve the tar
12. 12
    洗浄The methylene chloride solution was washed with 3N hydrochloric acid (4×1.5 L)
13. 13
    乾燥dried over magnesium sulfate
14. 14
    ろ過The extracts were filtered
15. 15
    ろ過pressure-filtered through a bed of silica gel
16. 16
    洗浄eluting with methylene chloride until all of the desired compound
17. 17
    その他had been recovered
18. 18
    濃縮The eluent was concentrated on the rotary evaporator
19. 19
    その他to give a slurry of bright yellow crystals (in o-dichlorobenzene)
20. 20
    ろ過The crystals were collected by filtration
21. 21
    洗浄washed with diethyl ether (2×500 ml)
22. 22
    その他vacuum dried

実験手順

N-methylformanilide (2.45 kg, 18.12 mol) was treated with phosphorus oxychloride (2.66 kg, 17.35 mol) over a 40 min period at ambient temperature. The intermediate Vilsmeier complex was stirred for 2 h at room temperature, then treated with 2-chloroanthracene (described in Example 1a) (963 g, 4.53 mol), and o-dichlorobenzene (1.0 L). The resulting bright yellow mixture was heated gradually over 1.5 h to 9° C. at which point an exotherm ensued raising the reaction temperature to 115° C. The heat was removed until the exotherm subsided (45 min), after which time the mixture was heated for 9 h at 90° C., then cooled. TLC analysis (silica gel; ethyl acetate: hexane 1:4) showed a small amount of unreacted anthracene (Rf 0.90), a small amount of the 3-chloro isomer (Rf 0.65), and the 2-chloro isomer (Rf 0.58) as the major component. The cooled reaction mixture was poured into ice/water (27 L) precipitating a dark brown tar. The aqueous layer was decanted away from the tar and extracted with methylene chloride (5×2 L). The combined extracts were used to redissolve the tar. The methylene chloride solution was washed with 3N hydrochloric acid (4×1.5 L), followed by water (2 L), then dried over magnesium sulfate. The extracts were filtered, then pressure-filtered through a bed of silica gel, eluting with methylene chloride until all of the desired compound had been recovered. The eluent was concentrated on the rotary evaporator to give a slurry of bright yellow crystals (in o-dichlorobenzene). The crystals were collected by filtration, washed with diethyl ether (2×500 ml), then vacuum dried to afford 619.7 g (56.9%) of the desired 2-chloro-9-formylanthracene (mp 148°-150° C.). NMR (CDCl3) 11.35 (s, 1H), 9.02 (d, J=0.9 Hz, 1H), 8.81 (d, J=8.9 Hz, 1H), 8.56 (s, 1H), 7.98 (m, 1H), 7.90 (d, J=8.9 Hz, 1H), 7.66 (m, 1H), 7.53 (m, 1H), 7.42 (m, 1 H).

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