640-21-1

Basic information

• Product Name: 1,2-DIBROMO-3,3-DIMETHYLBUTANE
• Synonyms: 1,2-DIBROMO-3,3-DIMETHYLBUTANE;3,3-DIMETHYL-1,2-DIBROMOBUTANE
• CAS NO: 640-21-1
• Molecular Formula: C₆H₁₂Br₂
• Molecular Weight: 243.97
• Mol File: 640-21-1.mol
• Article Data: 12

Chemical Properties

• Boiling Point: 73 °C3 mm Hg(lit.)
• Flash Point: 183 °F
• Appearance: /
• Density: 1.61 g/mL at 25 °C(lit.)
• Vapor Pressure: 0.128mmHg at 25°C
• Refractive Index: n20/D 1.5053(lit.)
• CAS DataBase Reference: 1,2-DIBROMO-3,3-DIMETHYLBUTANE(CAS DataBase Reference)
• NIST Chemistry Reference: 1,2-DIBROMO-3,3-DIMETHYLBUTANE(640-21-1)
• EPA Substance Registry System: 1,2-DIBROMO-3,3-DIMETHYLBUTANE(640-21-1)

Safety Data

• Hazard Codes: Xn
• Statements: 20/21/22-36/37/38
• Safety Statements: 26-36/37/39
• WGK Germany: 3
• Hazardous Substances Data: 640-21-1(Hazardous Substances Data)

Usage

InChI:InChI=1/C6H12Br2/c1-6(2,3)5(8)4-7/h5H,4H2,1-3H3

Synthetic route

tert-butylethylene (558-37-2) → 1,2-dibromo-3,3-dimethylbutane (640-21-1)

Conditions	Yield
With bromine for 0.133333h; Phase-vanishing reaction with phase screen; Neat (no solvent); Darkness;	94%
With carbon tetrabromide; bromine In tetrachloromethane; ethanol 1.) -20 deg C, 2.5 h; 2.) up to r. t., overnight;	89%
With bromine In hexane at 20℃;	88%

tert-butylethylene (558-37-2) + N-bromo-1,8-naphthalenedicarboximide (105089-47-2) → 1,2-dibromo-3,3-dimethylbutane (640-21-1) + N-(2-bromo-3,3-dimethylbutyl)-1,8-naphthalenedicarboximide (105089-49-4)

Conditions	Yield
In dichloromethane at 17℃; Irradiation;	A 4.1% B 68%

methanol (67-56-1) + tert-butylethylene (558-37-2) → 1,2-dibromo-3,3-dimethylbutane (640-21-1) + 2-bromo-1-methoxy-3,3-dimethyl-butane (26356-14-9)

Conditions	Yield
With bromine unter Lichtausschluss;

tert-butylethylene (558-37-2) → 1,4-dibromo-2,3-bis-bromomethyl-but-2-ene (30432-16-7) + 3,3-dimethylbutyl bromide (1647-23-0) + 1,2-dibromo-3,3-dimethylbutane (640-21-1)

Conditions	Yield
With bromine
With bromine for 2h;
With bromine In chloroform at -78℃; for 5h;

N-Bromosuccinimide (128-08-5) + tert-butylethylene (558-37-2) → Succinimide (123-56-8) + N-(2-bromo-3,3.-dimethyl-1-butyl)succinimide (72323-45-6) + 1,2-dibromo-3,3-dimethylbutane (640-21-1)

Conditions	Yield
In dichloromethane; benzene at 14 - 15℃; Irradiation;	A 0.58 mmol B 0.12 mmol C 0.33 mmol

2,2-dimethyl-3-butyne (917-92-0) → 3,3-dimethylbutyl bromide (1647-23-0) + 1,2-dibromo-3,3-dimethylbutane (640-21-1)

Conditions	Yield
With organoaluminiumhydride; water; bromine 2) -40 to 20 deg C; Yield given. Multistep reaction. Yields of byproduct given;

tert-butylethylene (558-37-2) + ethanol (64-17-5) → 1,2-dibromo-3,3-dimethylbutane (640-21-1) + 2-bromo-1-ethoxy-3,3-dimethylbutane (73694-80-1)

Conditions	Yield
With 2,6-di-tert-butyl-4-methyl-phenol; N,N'-dibromo-2,5-piperazinedione (NBP) In dichloromethane for 0.5h; Ambient temperature; Irradiation;	A 20 % Chromat. B 11 % Chromat.

tert-butylethylene (558-37-2) + C16H36N(1+)*C4H4BrNO2*Br(1-) (103191-58-8) → 1,2-dibromo-3,3-dimethylbutane (640-21-1)

Conditions	Yield
With C16H36N(1+)*C4H4BrNO2*Br(1-) In acetonitrile for 3h; Mechanism; Heating; var. bromino reagent;

tert-butylethylene (558-37-2) → 1,2-dichloro-3,3-dimethyl-butane (26120-63-8) + 1,2-dibromo-3,3-dimethylbutane (640-21-1) + 2-bromo-1-chloro-3,3-dimethylbutane + 1-bromo-2-chloro-3,3-dimethylbutane

Conditions	Yield
With bromine chloride In dichloromethane at 0℃; Yield given. Yields of byproduct given. Title compound not separated from byproducts;

1,2-dibromo-3,3-dimethylbutane (640-21-1) → 2,2-dimethyl-3-butyne (917-92-0)

Conditions	Yield
With 18-crown-6 ether; potassium tert-butylate In Petroleum ether at 60℃; for 2h;	91%
With potassium hydroxide; tetraoctyl ammonium bromide In Petroleum ether at 90℃; for 6h;	86%
With potassium tert-butylate; 18-crown-6 ether In Petroleum ether	84%
With potassium hydroxide; 2,5-dimethyl-2,5-hexanediol at 100℃; for 0.75h;	80%
With potassium tert-butylate Heating;

1,2-dibromo-3,3-dimethylbutane (640-21-1) → 2,2-dimethyl-3-butyne (917-92-0) + 2-Bromo-3,3-dimethyl-1-butene (33693-77-5) + 1-bromo-3,3-dimethylbut-1-ene (13352-80-2)

Conditions	Yield
With potassium hydroxide; Aliquat 336 In xylene Heating;	A 91% B n/a C n/a

1,2-dibromo-3,3-dimethylbutane (640-21-1) + carbon monoxide (201230-82-2) + benzene (71-43-2) → 2,2,3,3-Tetramethyl-1-indanon (10474-33-6)

Conditions	Yield
With aluminium trichloride at 19 - 21℃; for 2.5h;

1,2-dibromo-3,3-dimethylbutane (640-21-1) + 3,5-dimethoxybenzoic acid (1132-21-4) → 3-t-butyl-9-hydroxy-2-oxaspiro<4.5>dec-8-ene-1,7-dione + 1-(2-bromo-3,3-dimethylbutyl)-3-hydroxy-5-oxocyclohex-3-ene-1-carboxylic acid

Conditions	Yield
With hydrogenchloride; ammonia; lithium Yield given. Multistep reaction. Yields of byproduct given;

1,2-dibromo-3,3-dimethylbutane (640-21-1) + potassium acetate (127-08-2) → monobromopseudobutylethylene

Conditions	Yield
at 200℃;

1,2-dibromo-3,3-dimethylbutane (640-21-1) + Bromoform (75-25-2) → 1,1,2-tribromo-2-(tert-butyl)cyclopropane (87619-26-9)

Conditions	Yield
Stage #1: 1,2-dibromo-3,3-dimethylbutane With sodium methylate In dichloromethane for 24h; Heating; Stage #2: Bromoform With sodium hydroxide; N-benzyl-N,N,N-triethylammonium chloride at 20℃;	6.97 g

1,2-dibromo-3,3-dimethylbutane (640-21-1) → 2-Bromo-3,3-dimethyl-1-butene (33693-77-5) + (E)-1-bromo-3,3-dimethyl-1-butene (38203-90-6)

Conditions	Yield
With sodium methylate In dichloromethane for 24h; Heating; Title compound not separated from byproducts;

Upstream product

• 558-37-2 tert-butylethylene 
• 105089-47-2 N-bromo-1,8-naphthalenedicarboximide 
• 103191-58-8 C₁₆H₃₆N⁽¹⁺⁾*C₄H₄BrNO₂*Br^(1-) 
• 64-17-5 ethanol 
• 917-92-0 3,3-Dimethylbut-1-yne 
• 128-08-5 N-Bromosuccinimide 
• 67-56-1 methanol 

Downstream Products

• 917-92-0 3,3-Dimethylbut-1-yne 
• 33693-77-5 2-Bromo-3,3-dimethyl-1-butene 
• 13352-80-2 1-bromo-3,3-dimethylbut-1-ene 

Relevant articles and documents

Complexes between N-Bromosuccinimide and Quaternary Ammonium Bromides and Their Role in the Addition of Bromine to Olefins

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Removal of water - a factor influencing the synthesis of alkynes in a phase-transfer catalyzed β-elimination reaction

Acetylene derivatives 4 were synthesized from the corresponding vicinal bromo compounds 2 in the phase-transfer catalyzed hydrogen bromide β-elimination reaction using solid potassium hydroxide as a base, xylene as a solvent, and a phase-transfer catalyst. The yields of the synthesized acetylene derivatives 4 were substantially improved when water formed in the process had been removed.

ANOMALOUS BROMINATION OF ALKYLIDENEDIALUMINIUM COMPOUNDS

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