反応 #949900

反応方程式

2-chloroanthracene

N-methylformanilide

phosphorus oxychloride

→

2-chloro-9-anthraldehyde

収率 56.9%

溶媒

o-dichlorobezene

反応条件

後処理

1. 1
   温度The resulting bright yellow mixture was heated gradually over 1.5 h to 90° 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
    濃縮The eluate was concentrated on the rotary evaporator
18. 18
    その他to give a slurry of bright yellow crystals (in o-dichlorobenzene)
19. 19
    ろ過The crystals were collected by filtration
20. 20
    洗浄washed with diethyl ether (2×500 ml)
21. 21
    その他vacuum dried

実験手順

N-methylformanilide (2.45 kg, 18.12 moles) was treated with phosphorus oxychloride (2.66 kg, 17.35 moles) 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 (963 g, 4.53 moles), and o-dichlorobezene (1.0 L). The resulting bright yellow mixture was heated gradually over 1.5 h to 90° 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 passed through. The eluate 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-anthraldehyde (mp 148°-150° C.). 1H NMR (CDCl3): δ11.35 (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, 1H).

出典