70728-93-7

Basic information

• Product Name: 2,2'-dibroMo-4,4'-di-tert-butylbiphenyl
• Synonyms: 2,2'-dibroMo-4,4'-di-tert-butylbiphenyl;2,2'-Dibromo-4,4'-di-tert-butyl-1,1'-biphenyl
• CAS NO: 70728-93-7
• Molecular Formula: C₂₀H₂₄Br₂
• Molecular Weight: 424.21256
• Mol File: 70728-93-7.mol
• Article Data: 6

Chemical Properties

• Appearance: /
• CAS DataBase Reference: 2,2'-dibroMo-4,4'-di-tert-butylbiphenyl(CAS DataBase Reference)
• NIST Chemistry Reference: 2,2'-dibroMo-4,4'-di-tert-butylbiphenyl(70728-93-7)
• EPA Substance Registry System: 2,2'-dibroMo-4,4'-di-tert-butylbiphenyl(70728-93-7)

Safety Data

• Hazardous Substances Data: 70728-93-7(Hazardous Substances Data)

Usage

General Description

2,2'-dibromo-4,4'-di-tert-butylbipheny is a chemical compound with the molecular formula C20H22Br2. 2,2'-dibroMo-4,4'-di-tert-butylbiphenyl is a brominated derivative of the biphenyl molecule, with two bromine atoms attached to the 2 and 2' positions of the biphenyl structure. Additionally, it contains two tert-butyl groups, which are bulky and sterically hindered, attached to the 4 and 4' positions of the biphenyl. This chemical is commonly used as a flame retardant and is known for its thermal stability and resistance to oxidation, making it suitable for use in various industrial applications. However, it is important to handle this compound with care due to its toxicity and potential environmental hazards.

Synthetic route

4,4'-di-tert-butylbiphenyl (1625-91-8) → 2,2′-dibromo-4,4′-di-tert-butylbiphenyl (70728-93-7)

Conditions	Yield
Stage #1: 4,4'-di-tert-butylbiphenyl With iron In dichloromethane Stage #2: With bromine In dichloromethane at 0℃; for 2h;	78%
With bromine; iron In dichloromethane at 30℃; for 3h; Inert atmosphere;	75%
With bromine; iron In dichloromethane at 20℃; for 2h;	63%

4,4'-di-tert-butylbiphenyl (1625-91-8) → 2-bromo-4,4'-di-tert-butylbiphenyl (70728-89-1) + 2,2′-dibromo-4,4′-di-tert-butylbiphenyl (70728-93-7)

Conditions	Yield
With n-butyllithium; potassium tert-butylate; bromine In hexane	A 49% B 36%

2,2′-dibromo-4,4′-di-tert-butylbiphenyl (70728-93-7) + dibutyltin chloride (683-18-1) → 3,7-di-tert-butyl-5,5-dibutyl-5H-dibenzo[b,d]stannole (121772-26-7)

Conditions	Yield
Stage #1: 2,2′-dibromo-4,4′-di-tert-butylbiphenyl With n-butyllithium In diethyl ether; hexane at 20℃; for 2h; Stage #2: dibutyltin chloride In diethyl ether at 20℃;	85%
With t-buthyl lithium In diethyl ether prepn. of 4,4'-bis(t-butyl)-2,2'-dilithio-biphenyl in ether at 0°Cstirring at room temp. for 5h, this soln. was added to di-n-butyltindichloride in ether(1h, room temp.); after 2h hydrolyse, etherlayer over Na2SO4, evapn., crystn. from methanol, elem.anal., IR, NMR;	68%
Stage #1: 2,2′-dibromo-4,4′-di-tert-butylbiphenyl With n-butyllithium In diethyl ether at -196.16 - 20℃; for 2h; Inert atmosphere; Stage #2: dibutyltin chloride In diethyl ether at 20℃; Inert atmosphere;	42.6%

n-butyllithium (109-72-8, 29786-93-4) + 2,2′-dibromo-4,4′-di-tert-butylbiphenyl (70728-93-7) + dimesitylfluoroborane (436-59-9) → lithium 3,3’-di-tert-butyl-5,5-dimesityl-5H-dibenzo[b,d]borol-5-ide

Conditions	Yield
Stage #1: n-butyllithium; 2,2′-dibromo-4,4′-di-tert-butylbiphenyl In tetrahydrofuran; diethyl ether at -78 - 25℃; for 5h; Schlenk technique; Inert atmosphere; Stage #2: dimesitylfluoroborane In tetrahydrofuran; diethyl ether at 25℃; Schlenk technique; Inert atmosphere;	81%

3,3,3-trifluoro-2-phenylpropene (384-64-5) + 2,2′-dibromo-4,4′-di-tert-butylbiphenyl (70728-93-7) → 3,9-di-tert-butyl-7-fluoro-6-phenyl-5H-dibenzo[a,c][7]annulene

Conditions	Yield
Stage #1: 2,2′-dibromo-4,4′-di-tert-butylbiphenyl With n-butyllithium; cerium(III) chloride; N,N,N,N,-tetramethylethylenediamine In tetrahydrofuran at 20℃; for 0.25h; Inert atmosphere; Stage #2: 3,3,3-trifluoro-2-phenylpropene In tetrahydrofuran at 20 - 55℃; for 4.25h; Inert atmosphere;	80%

n-butyllithium (109-72-8, 29786-93-4) + 2,2′-dibromo-4,4′-di-tert-butylbiphenyl (70728-93-7) + bis(p-tolyl)boron chloride (13272-74-7) → lithium 3,3’-di-tert-butyl-5,5-ditolyl-5H-dibenzo[b,d]borol-5-ide

Conditions	Yield
Stage #1: n-butyllithium; 2,2′-dibromo-4,4′-di-tert-butylbiphenyl In tetrahydrofuran; diethyl ether at -78 - 25℃; for 5h; Schlenk technique; Inert atmosphere; Stage #2: bis(p-tolyl)boron chloride In tetrahydrofuran; diethyl ether at 25℃; Schlenk technique; Inert atmosphere;	77%

2,2′-dibromo-4,4′-di-tert-butylbiphenyl (70728-93-7) → 2,2',7,7'-tetra-tert-butyl-9,9'-spirobi[9H-9-silafluorene] + 4,4'-di-tert-butylbiphenyl (1625-91-8)

Conditions	Yield
Stage #1: 2,2′-dibromo-4,4′-di-tert-butylbiphenyl With magnesium In tetrahydrofuran; ethylene dibromide at 20℃; for 16h; Stage #2: With (teeda)*H2SiCl2 In tetrahydrofuran; dichloromethane at 20℃; for 48h;	A 74% B n/a

2,2′-dibromo-4,4′-di-tert-butylbiphenyl (70728-93-7) + dimethyl(phenyl)(3,3,3-trifluoropropan-1-en-2-yl)silane (535975-23-6) → (3,9-di-tert-butyl-7-fluoro-5H-dibenzo[a,c][7]annulen-6-yl)dimethyl(phenyl)silane

Conditions	Yield
Stage #1: 2,2′-dibromo-4,4′-di-tert-butylbiphenyl With n-butyllithium; cerium(III) chloride; N,N,N,N,-tetramethylethylenediamine In tetrahydrofuran at 20℃; for 0.25h; Inert atmosphere; Stage #2: dimethyl(phenyl)(3,3,3-trifluoropropan-1-en-2-yl)silane In tetrahydrofuran at 20 - 55℃; for 4.25h; Inert atmosphere;	72%

n-butyllithium (109-72-8, 29786-93-4) + 2,2′-dibromo-4,4′-di-tert-butylbiphenyl (70728-93-7) + (mesityl)(tolyl) methoxyborane → lithium 3,3’-di-tert-butyl-5-mesityl-5-tolyl-5H-dibenzo[b,d]borol-5-ide

Conditions	Yield
Stage #1: n-butyllithium; 2,2′-dibromo-4,4′-di-tert-butylbiphenyl In tetrahydrofuran; diethyl ether at -78 - 25℃; for 5h; Schlenk technique; Inert atmosphere; Stage #2: (mesityl)(tolyl) methoxyborane In tetrahydrofuran; diethyl ether at 25℃; Schlenk technique; Inert atmosphere;	62%

2,2′-dibromo-4,4′-di-tert-butylbiphenyl (70728-93-7) + N,N-dimethyl-formamide (68-12-2, 33513-42-7) → 2,2'-diformyl-4,4'-di-tert.-butylbiphenyl

Conditions	Yield
Stage #1: 2,2′-dibromo-4,4′-di-tert-butylbiphenyl With n-butyllithium In tetrahydrofuran; hexane at -78℃; for 2h; Inert atmosphere; Stage #2: N,N-dimethyl-formamide In tetrahydrofuran; hexane at -78 - 20℃; Inert atmosphere;	61%

tetrahydrofuran (109-99-9) + 2,2′-dibromo-4,4′-di-tert-butylbiphenyl (70728-93-7) → 2C16H32LiO4(1+)*C60H72Zr(2-)

Conditions	Yield
Stage #1: tetrahydrofuran; 2,2′-dibromo-4,4′-di-tert-butylbiphenyl With n-butyllithium at -78 - -30℃; Inert atmosphere; Stage #2: With zirconocene dichloride In tetrahydrofuran at -30 - 20℃; Inert atmosphere;	58%

Dichloromethylsilane (75-54-7) + 2,2′-dibromo-4,4′-di-tert-butylbiphenyl (70728-93-7) → 2,7-di-tert-butyl-9H-9-methylsilafluorene (1373161-09-1)

Conditions	Yield
Stage #1: 2,2′-dibromo-4,4′-di-tert-butylbiphenyl With tert.-butyl lithium In diethyl ether; pentane at -78 - 20℃; for 5h; Inert atmosphere; Stage #2: Dichloromethylsilane In diethyl ether; pentane at 0 - 20℃; Inert atmosphere;	58%

2,2′-dibromo-4,4′-di-tert-butylbiphenyl (70728-93-7) + dichlorodiethyldithiocarbamate gold(III) (62109-87-9) → [(5,5′-bis(tert-butyl)-2,2′-biphendiyl)](κ2-S-diethyldithiocarbamate)gold(III)

Conditions	Yield
Stage #1: 2,2′-dibromo-4,4′-di-tert-butylbiphenyl With n-butyllithium In diethyl ether; hexane at -78℃; Stage #2: dichlorodiethyldithiocarbamate gold(III) In diethyl ether; hexane at -78 - 20℃; for 0.75h;	57%

2,2′-dibromo-4,4′-di-tert-butylbiphenyl (70728-93-7) + trimethyltin(IV)chloride (1066-45-1) → 9,9-dimethyl-2,7-di(t-butyl)-9-stannafluorene (1353534-43-6)

Conditions	Yield
Stage #1: 2,2′-dibromo-4,4′-di-tert-butylbiphenyl With n-butyllithium In tetrahydrofuran at -78℃; for 1.26667h; Inert atmosphere; Stage #2: trimethyltin(IV)chloride In tetrahydrofuran at -78 - 20℃; Inert atmosphere;	54%

2,2′-dibromo-4,4′-di-tert-butylbiphenyl (70728-93-7) + boron trichloride (10294-34-5) → 2,8-di-tert-butyl-5-chloro-5H-dibenzo[b,d]borole

Conditions	Yield
Stage #1: 2,2′-dibromo-4,4′-di-tert-butylbiphenyl With n-butyllithium In hexane; benzene for 96h; Inert atmosphere; Heating; Stage #2: boron trichloride In hexane; pentane; benzene at 0 - 25℃; for 12h; Inert atmosphere;	36%

2,2′-dibromo-4,4′-di-tert-butylbiphenyl (70728-93-7) → 2,2'-dibromobiphenyl (13029-09-9)

Conditions	Yield
With aluminium trichloride In benzene

2,2′-dibromo-4,4′-di-tert-butylbiphenyl (70728-93-7) → 4,4'-di-tert-butylbiphenyl (1625-91-8) + 2-bromo-4,4'-di-tert-butylbiphenyl (70728-89-1)

Conditions	Yield
With water; magnesium; ethylene dibromide In tetrahydrofuran at 74.7℃; Product distribution; variation of reagent and conditions;
With magnesium In tetrahydrofuran; ethylene dibromide for 0.5h;	A 57 %Chromat. B 14.5 %Chromat.

2,2′-dibromo-4,4′-di-tert-butylbiphenyl (70728-93-7) + dimethylsilicon dichloride (75-78-5) → 4,4'-di-tert-butylbiphenyl (1625-91-8) + 2,7-di-tert-butyl-9,9-dimethyl-9H-9-silafluorene

Conditions	Yield
With magnesium; ethylene dibromide In tetrahydrofuran at 74.7℃; Product distribution; variation of reagent and conditions;

2,2′-dibromo-4,4′-di-tert-butylbiphenyl (70728-93-7) + dimethylsilicon dichloride (75-78-5) → 2,7-di-tert-butyl-9,9-dimethyl-9H-9-silafluorene

Conditions	Yield
With tetrahydrofuran; diethyl ether; 0 deg C

2,2′-dibromo-4,4′-di-tert-butylbiphenyl (70728-93-7) + 2,6,2',6'-Tetrabromo-4,4'-di-tert-butyl-biphenyl (180404-94-8) → 2,7,10,15-Tetra-tert-butyl-tetraphenylene + 1,16-Dibromo-3,6,11,14-tetra-tert-butyl-tetraphenylene + 1,8,9,16-Tetrabromo-3,6,11,14-tetra-tert-butyl-tetraphenylene

Conditions	Yield
Yield given. Multistep reaction;

2,2′-dibromo-4,4′-di-tert-butylbiphenyl (70728-93-7) → 2,7,10,15-Tetra-tert-butyl-tetraphenylene

Conditions	Yield
With tert.-butyl lithium; copper(ll) bromide 1.) pentane, ether, -78 deg C, 2 h, 2.) -78 deg C to r.t., 12 h; Yield given. Multistep reaction;

2,2′-dibromo-4,4′-di-tert-butylbiphenyl (70728-93-7) → 2,2',7,7'-tetra-tert-butyl-9,9'-spirobi[9H-9-silafluorene] + 2,7-di-tert-butyl-9H-9-silafluorene (121441-89-2) + 4,4'-di-tert-butylbiphenyl (1625-91-8)

Conditions	Yield
Stage #1: 2,2′-dibromo-4,4′-di-tert-butylbiphenyl With magnesium In tetrahydrofuran; ethylene dibromide for 0.5h; Stage #2: With (teeda)*H2SiCl2 In tetrahydrofuran; dichloromethane; ethylene dibromide	A 65 mg B n/a C n/a

2,2′-dibromo-4,4′-di-tert-butylbiphenyl (70728-93-7) → C80H80

Conditions	Yield
Multi-step reaction with 2 steps 1.1: n-butyllithium / tetrahydrofuran / 1.27 h / -78 °C / Inert atmosphere 1.2: -78 - 20 °C / Inert atmosphere 2.1: bis(tri-t-butylphosphine)palladium(0) / tetrahydrofuran / 120 °C / Microwave irradiation View Scheme

2,2′-dibromo-4,4′-di-tert-butylbiphenyl (70728-93-7) → 3,7-di-tert-butyl-5-chloro-5H-dibenzo[b,d]phosphole

Conditions	Yield
Stage #1: 2,2′-dibromo-4,4′-di-tert-butylbiphenyl With n-butyllithium; N,N,N,N,-tetramethylethylenediamine In diethyl ether; hexane at 0 - 20℃; Inert atmosphere; Stage #2: With diethylphosphoramidous dichloride In diethyl ether; hexane at -78 - 20℃; Inert atmosphere; Stage #3: With hydrogenchloride In diethyl ether; hexane at 0℃; for 1.5h;

2,2′-dibromo-4,4′-di-tert-butylbiphenyl (70728-93-7) → C29H36NOP

Conditions	Yield
Multi-step reaction with 2 steps 1.1: n-butyllithium; N,N,N,N,-tetramethylethylenediamine / diethyl ether; hexane / 0 - 20 °C / Inert atmosphere 1.2: -78 - 20 °C / Inert atmosphere 1.3: 1.5 h / 0 °C 2.1: n-butyllithium / diethyl ether; hexane / 0 - 20 °C / Inert atmosphere 2.2: -78 - 20 °C / Inert atmosphere View Scheme

2,2′-dibromo-4,4′-di-tert-butylbiphenyl (70728-93-7) → 6-(3,7-di-tert-butyl-5H-benzo[b]phosphindol-5-yl)pyridin-2(1H)-one (1616969-94-8)

Conditions	Yield
Multi-step reaction with 3 steps 1.1: n-butyllithium; N,N,N,N,-tetramethylethylenediamine / diethyl ether; hexane / 0 - 20 °C / Inert atmosphere 1.2: -78 - 20 °C / Inert atmosphere 1.3: 1.5 h / 0 °C 2.1: n-butyllithium / diethyl ether; hexane / 0 - 20 °C / Inert atmosphere 2.2: -78 - 20 °C / Inert atmosphere 3.1: formic acid / 2 h / 20 °C View Scheme

2,2′-dibromo-4,4′-di-tert-butylbiphenyl (70728-93-7) → N-(6-(3,7-di-tert-butyl-5H-benzo[b]phosphindol-5-yl)pyridin-2-yl)pivalamide (1616969-95-9)

Conditions	Yield
Multi-step reaction with 2 steps 1.1: n-butyllithium; N,N,N,N,-tetramethylethylenediamine / diethyl ether; hexane / 0 - 20 °C / Inert atmosphere 1.2: -78 - 20 °C / Inert atmosphere 1.3: 1.5 h / 0 °C 2.1: n-butyllithium / diethyl ether; hexane / 0 - 20 °C / Inert atmosphere 2.2: -78 - 20 °C / Inert atmosphere View Scheme

2,2′-dibromo-4,4′-di-tert-butylbiphenyl (70728-93-7) → C33H38NOP

Conditions	Yield
Multi-step reaction with 2 steps 1.1: n-butyllithium; N,N,N,N,-tetramethylethylenediamine / diethyl ether; hexane / 0 - 20 °C / Inert atmosphere 1.2: -78 - 20 °C / Inert atmosphere 1.3: 1.5 h / 0 °C 2.1: n-butyllithium / diethyl ether; hexane / 0 - 20 °C / Inert atmosphere 2.2: -78 - 20 °C / Inert atmosphere View Scheme

2,2′-dibromo-4,4′-di-tert-butylbiphenyl (70728-93-7) → 3-(3,7-di-tert-butyl-5H-benzo[b]phosphindol-5-yl)isoquinolin-1(2H)-one (1616969-96-0)

Conditions	Yield
Multi-step reaction with 3 steps 1.1: n-butyllithium; N,N,N,N,-tetramethylethylenediamine / diethyl ether; hexane / 0 - 20 °C / Inert atmosphere 1.2: -78 - 20 °C / Inert atmosphere 1.3: 1.5 h / 0 °C 2.1: n-butyllithium / diethyl ether; hexane / 0 - 20 °C / Inert atmosphere 2.2: -78 - 20 °C / Inert atmosphere 3.1: formic acid / 2 h / 20 °C View Scheme

2,2′-dibromo-4,4′-di-tert-butylbiphenyl (70728-93-7) → 3,8-di(tert-butyl)-6-phenylphenanthridine

Conditions	Yield
Multi-step reaction with 3 steps 1: n-butyllithium / diethyl ether; hexane / 2 h / 0 - 20 °C / Inert atmosphere 2: tetrahydrofuran / 3 h / -78 - 20 °C / Inert atmosphere 3: toluene / 36 h / 20 °C / Inert atmosphere View Scheme

Upstream product

• 1625-91-8 4,4'-di-tert-butylbiphenyl 

Downstream Products

• 1625-91-8 4,4'-di-tert-butylbiphenyl 
• 121441-89-2 2,7-di-tert-butyl-9H-9-silafluorene 
• 70728-89-1 2-bromo-4,4'-di-tert-butylbiphenyl 
• 13029-09-9 2,2'-dibromobiphenyl 

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