تفاعل #708771

معادلة التفاعل

water

lithium

2-cyanobenzaldehyde

(1,3-dioxolan-2-yl-methyl)-triphenyl phosphonium bromide

→

2-cyano-(E)-cinnamaldehyde

المردود 45.0%

المذيبات

methanol

dimethylformamide

ظروف التفاعل

المعالجة

1. 1
   درجة الحرارةto cool
2. 2
   استخلاصThe reaction mixture was extracted with diethyl ether (3×120 ml)
3. 3
   غسيلthe combined ether extracts washed with saturated brine
4. 4
   تجفيفdried (MgSO4)
5. 5
   أخرىevaporated
6. 6
   workup.DISSOLUTIONThe residue was dissolved
7. 7
   workup.STIRRINGstirred in tetrahydrofuran (30 ml)
8. 8
   workup.WAIT3M hydrochloric acid (30 ml) for 2 hours
9. 9
   workup.ADDITIONThe mixture was diluted with water (100 ml)
10. 10
    استخلاصextracted with diethyl ether (300 ml)
11. 11
    غسيلThe ether was washed with saturated sodium hydrogen carbonate solution (2×50 ml) and saturated brine
12. 12
    تجفيفdried (MgSO4)
13. 13
    أخرىevaporated
14. 14
    أخرىThe residue was purified by flash column chromatography on silica
15. 15
    غسيلeluting with n-hexane/ethyl acetate (80:20:, by volume)

الإجراء التجريبي

A solution of lithium (77 mg) in methanol (30 ml) was added during 2 hours to a stirred suspension of 2-cyanobenzaldehyde and (1,3-dioxolan-2-yl-methyl)-triphenyl phosphonium bromide (4.71 g) in dimethylformamide (34 ml) at 85° C. The mixture was stirred at 85° C. for 6 hours, allowed to cool and poured into water (450 ml). The reaction mixture was extracted with diethyl ether (3×120 ml) and the combined ether extracts washed with saturated brine, dried (MgSO4) and evaporated. The residue was dissolved and stirred in tetrahydrofuran (30 ml) and 3M hydrochloric acid (30 ml) for 2 hours. The mixture was diluted with water (100 ml) and extracted with diethyl ether (300 ml). The ether was washed with saturated sodium hydrogen carbonate solution (2×50 ml) and saturated brine, dried (MgSO4) and evaporated. The residue was purified by flash column chromatography on silica, eluting with n-hexane/ethyl acetate (80:20:, by volume) to give as a pale yellow solid 2-cyano-(E)-cinnamaldehyde (504 mg, 45%) m.p. 107°-110° C.; NMR: 6.82 (1H, q), 7.69 (5H, m) and 9.81 (1H, d); m/e 157 (M+).

المصدر