4-BROMO-3,6-DIHYDRO-2H-PYRAN

4-BROMO-3,6-DIHYDRO-2H-PYRAN Property

Boiling point:

184.5±40.0 °C(Predicted)

Density 

1.580±0.06 g/cm3(Predicted)

storage temp. 

Storage temp. 2-8°C

solubility 

Chloroform (Slightly)

form 

Oil

color 

Clear Colorless

Safety

HS Code 

2932990090

Hazard and Precautionary Statements (GHS)

Symbol(GHS)

Signal word

Warning

Hazard statements

H302Harmful if swallowed

H315Causes skin irritation

H319Causes serious eye irritation

H332Harmful if inhaled

H335May cause respiratory irritation

Precautionary statements

P261Avoid breathing dust/fume/gas/mist/vapours/spray.

P264Wash hands thoroughly after handling.

P264Wash skin thouroughly after handling.

P270Do not eat, drink or smoke when using this product.

P271Use only outdoors or in a well-ventilated area.

P280Wear protective gloves/protective clothing/eye protection/face protection.

P302+P352IF ON SKIN: wash with plenty of soap and water.

P305+P351+P338IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continuerinsing.

P332+P313IF SKIN irritation occurs: Get medical advice/attention.

P337+P313IF eye irritation persists: Get medical advice/attention.

P362Take off contaminated clothing and wash before reuse.

P403+P233Store in a well-ventilated place. Keep container tightly closed.

P405Store locked up.

P501Dispose of contents/container to..…

4-BROMO-3,6-DIHYDRO-2H-PYRAN Chemical Properties,Usage,Production

Chemical Properties

4-Bromo-3,6-dihydro-2H-pyran is an organic compound containing a six-membered ring characterized by the substitution of a bromine atom at position 4 and a hydrogen atom on each of the carbon atoms at positions 3 and 6, leaving the carbon atoms at these positions saturated. This structure generally confers on the compound good solubility in organic solvents and, due to the presence of the bromine atom, it may exhibit some activity in chemical reactions, such as participation in substitution or elimination reactions.

Uses

4-Bromo-3,6-dihydro-2H-pyran is a useful reagent for organic synthesis and other chemical processes.

Synthesis

Step 2: 4.79 g (30.0 mmol) of bromine was slowly added dropwise to 78 ml of anhydrous dichloromethane solution containing 8.52 g (27.5 mmol) of triphenyl phosphite at -60 °C. Subsequently 4.5 ml (32.5 mmol) of triethylamine was added and 2.5 g (25.0 mmol) of tetrahydro-4H-pyran-4-one dissolved in 2 ml of dichloromethane was added slowly dropwise. The reaction mixture was slowly warmed to room temperature over a period of about 5 hours and stirring was continued at room temperature for 1 hour. Upon completion of the reaction, all volatile components were removed using a rotary evaporator. The crude product was initially purified by silica gel column chromatography (silica gel 100 g, dichloromethane as mobile phase). After solvent evaporation, the product was further purified by bulb tube distillation (pressure: 8 mbar; temperature: up to 120 °C). Finally, 2.51 g (62% yield) of 4-bromo-3,6-dihydro-2H-pyran was obtained. The structure of the product was confirmed by 1H-NMR (400 MHz, CDCl3, δ/ppm): 6.07 (m, 1H), 4.13 (m, 2H), 3.83 (m, 2H), 2.55-2.50 (m, 2H) and GC/MS (Method L, ESIpos): rt = 2.32 min, m/z = 162/164 [M]+.

References

[1] Patent: CN105503927, 2016, A. Location in patent: Paragraph 0014
[2] Patent: US2013/196964, 2013, A1. Location in patent: Paragraph 1214; 1215; 1216; 1217
[3] Heterocycles, 2015, vol. 91, # 8, p. 1654 - 1659
[4] Patent: CN104004006, 2016, B