2-Bromo-9H-fluorene → HCID 21504075, compound

Temperature

-2 °C

To a mechanically stirred solution of commercially available 2-bromofluorene (79.1 g 90% pure, 71.19 g at 100% purity, 0.29 mol) in 350 mL dichloromethane, in a 1-liter 3-neck round-bottomed flask, cooled in a ice-salt bath, tin(IV)chloride (60 mL, 133.56 g, 0.513 mol) was added. Maintaining the temperature at −2° C., over a period of 20 minutes, dichloromethyl methyl ether (33 mL, 41.94 g, 0.365 mol) was added dropwise, stirred near 0 to −1° C. for 1.5 hours, and then allowed to warm to room temperature over a period of 3 hours. The mixture was poured into crushed ice, and methylene chloride was allowed to evaporate. The product slurry was then filtered and washed with water. The dry crude product (mixture of two aldehydes) weighed 87.9 g, m.p. 138-144° C. This was stirred with 750 mL of 10% toluene-heptane at reflux for 2 hours, cooled and filtered at room temperature, 73.5 g, m.p. 161-170° C. This was dissolved in 400 mL hot toluene (hazy solution; tin salts might be still present) diluted with 300 mL heptanes, and the slurry was kept at reflux for 3 hours, cooled and collected at room temperature, 59.0 g, m.p. 176-179° C. A recrystallization by dissolution in toluene (600 mL), clarification while hot, and dilution with heptanes (300 mL) delivered 50 g of pure 7-bromo-9H-fluorene-2-carbaldehyde, m.p. 177-180° C. The yield is 57 or 63% based on assumed purity of 100% or 90% for the sample of 2-bromofluorene used. Mass spec: m/z 272, 274 (M+). Anal Calcd for C14H9BrO: C, 61.57%; H, 3.32%; Br, 29.26%. Found: C, 61.53%; H, 3.44%; Br, 29.22%. 1H NMR (CDCl3), δ ppm: 3.94 (s, 2H), 7.53-7.56 (dd, 1H), 7.68-7.72 (m, 2H), 7.85-7.91 (m, 2H), 8.03 (s, 1H), and 10.04 (s, 1H). 13C NMR: 36.57 (1 sp3C), 120.19, 122.23, 122.46, 125.82, 128.55, 129.81, 130.40, 135.32, 139.21, 143.28, 146.45, 146.72, and 191.90 (13 sp2C).

1. temperatureto warm to room temperature over a period of 3 hours
2. additionThe mixture was poured
3. customto evaporate
4. filtrationThe product slurry was then filtered
5. washwashed with water
6. customThe dry crude product (mixture of two aldehydes)
7. stirringThis was stirred with 750 mL of 10% toluene-heptane
8. temperatureat reflux for 2 hours
9. temperaturecooled
10. filtrationfiltered at room temperature
11. dissolutionThis was dissolved in 400 mL hot toluene (hazy solution; tin salts might be still present)
12. additiondiluted with 300 mL heptanes
13. temperatureat reflux for 3 hours
14. temperaturecooled
15. customcollected at room temperature
16. customA recrystallization
17. dissolutionby dissolution in toluene (600 mL)

ORD record

ord-a8229576cac7448a8a94ec56a9981ca3

Source dataset

uspto-grants-2013_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08471035B1