2270-59-9

Basic information

• Product Name: 5-BROMO-2-METHYL-2-PENTENE
• Synonyms: 5-BROMO-2-METHYL-2-PENTENE;5-BROMO-2-METHYLPENT-2-ENE;Homoprenyl bromide;NSC 244464;Prenylmethyl bromide;5-Bromo-2-methyl-2-pentene 97%;2-Pentene,5-bromo-2-methyl-
• CAS NO: 2270-59-9
• Molecular Formula: C₆H₁₁Br
• Molecular Weight: 163.06
• EINECS: -0
• Product Categories: Alkenyl;Halogenated Hydrocarbons;Organic Building Blocks
• Mol File: 2270-59-9.mol
• Article Data: 35

Chemical Properties

• Melting Point: -102.35°C (estimate)
• Boiling Point: 152-154 °C(lit.)
• Flash Point: 73 °F
• Appearance: /
• Density: 1.217 g/mL at 25 °C(lit.)
• Vapor Pressure: 4.44mmHg at 25°C
• Refractive Index: n20/D 1.476(lit.)
• Storage Temp.: 2-8°C
• Water Solubility: Slightly miscible with water.
• BRN: 1735749
• CAS DataBase Reference: 5-BROMO-2-METHYL-2-PENTENE(CAS DataBase Reference)
• NIST Chemistry Reference: 5-BROMO-2-METHYL-2-PENTENE(2270-59-9)
• EPA Substance Registry System: 5-BROMO-2-METHYL-2-PENTENE(2270-59-9)

Safety Data

• Hazard Codes: Xi
• Statements: 10-36/37/38
• Safety Statements: 26-36
• RIDADR: UN 1993 3/PG 2
• WGK Germany: 3
• F: 10-23
• HazardClass: 3
• PackingGroup: III
• Hazardous Substances Data: 2270-59-9(Hazardous Substances Data)

Usage

Uses

5-Bromo-2-methyl-2-pentene acts as a synthetic reagent, which is useful in the formation of sesqueterpenoid. It is also employed in the preparation of geranlol-3-14C. Further, it is used in the preparation of penifulvin A, which is a sesquiterpenoid with a novel dioxa-fenestrane structure.

InChI:InChI=1/C6H11Br/c1-6(2)4-3-5-7/h4H,3,5H2,1-2H3

Synthetic route

2-cyclopropyl-2-propanol (930-39-2) → 1-bromo-4-methylpent-3-ene (2270-59-9)

Conditions	Yield
With magnesium bromide In diethyl ether for 3h; Heating;	93%
With magnesium bromide In diethyl ether for 8h; Heating;	89%
With hydrogen bromide; lithium bromide In water at 0℃; for 0.75h;	87%

Cyclopropyl methyl ketone (765-43-5) + methylmagnesium bromide (75-16-1) → 1-bromo-4-methylpent-3-ene (2270-59-9)

Conditions	Yield
Stage #1: Cyclopropyl methyl ketone; methylmagnesium bromide In tetrahydrofuran for 1h; Reflux; Inert atmosphere; Stage #2: With sulfuric acid In tetrahydrofuran; water at 10℃; for 0.5h; Inert atmosphere;	88%
Stage #1: Cyclopropyl methyl ketone; methylmagnesium bromide In tetrahydrofuran at 20℃; Inert atmosphere; Reflux; Stage #2: With sulfuric acid In tetrahydrofuran at 10℃;	85%
With sulfuric acid In diethyl ether for 1h;	85%

4-methylpent-3-en-1-ol (763-89-3) → 1-bromo-4-methylpent-3-ene (2270-59-9)

Conditions	Yield
With pyridine; phosphorus tribromide In diethyl ether for 8h; Ambient temperature;	82%
With hydrogen bromide
With pyridine; phosphorus tribromide
Multi-step reaction with 2 steps 1: pyridine 2: 56 percent / LiBr / acetone / 4 h / Heating View Scheme

4-methylpent-3-enyl 4-methylbenzenesulfonate (783-86-8) → 1-bromo-4-methylpent-3-ene (2270-59-9)

Conditions	Yield
With lithium bromide In acetone for 4h; Heating;	56%

2,5-dibromo-2-methylpentane (52278-94-1) → 1-bromo-4-methylpent-3-ene (2270-59-9)

Conditions	Yield
With pyridine at 60 - 100℃; under 150 Torr;
With Potassium benzoate; acetic acid

2,5-dibromo-2-methylpentane (52278-94-1) + Potassium benzoate (582-25-2) + acetic acid (64-19-7) → 1-bromo-4-methylpent-3-ene (2270-59-9)

2-cyclopropyl-2-propanol (930-39-2) → 2,5-dibromo-2-methylpentane (52278-94-1) + 1-bromo-4-methylpent-3-ene (2270-59-9)

Conditions	Yield
With hydrogen bromide at 10 - 15℃; for 0.133333h;

2-cyclopropyl-2-propanol (930-39-2) → 1-bromo-4-methylpent-3-ene (2270-59-9) + 1-bromo-4-methylpent-4-ene (41182-50-7)

Conditions	Yield
With hydrogen bromide In pentane

4-butanolide (96-48-0) + methyl magnesium iodide (917-64-6) → 1-bromo-4-methylpent-3-ene (2270-59-9)

Conditions	Yield
With carbon tetrabromide; triphenylphosphine 1) ether, 4 h, 2) CH2Cl2, ice cooling, 5 min; Yield given. Multistep reaction;

2-cyclopropyl-2-propanol (930-39-2) + HBr → 1-bromo-4-methylpent-3-ene (2270-59-9)

4-methyl-1,4-pentanediol (1462-10-8) → 1-bromo-4-methylpent-3-ene (2270-59-9)

Conditions	Yield
Multi-step reaction with 2 steps 1: pyridine; phosphorus (III)-bromide 2: pyridine / 60 - 100 °C / 150 Torr View Scheme
Multi-step reaction with 2 steps 1: HBr 2: potassium benzoate; glacial acetic acid View Scheme
Multi-step reaction with 2 steps 1: benzene; phosphorus (III)-bromide 2: pyridine / 60 - 100 °C / 150 Torr View Scheme

5-Hydroxy-2-pentanone (1071-73-4) → 1-bromo-4-methylpent-3-ene (2270-59-9)

Conditions	Yield
Multi-step reaction with 3 steps 1: diethyl ether 2: pyridine; phosphorus (III)-bromide 3: pyridine / 60 - 100 °C / 150 Torr View Scheme
Multi-step reaction with 3 steps 1: diethyl ether 2: benzene; phosphorus (III)-bromide 3: pyridine / 60 - 100 °C / 150 Torr View Scheme

ethyl 4-methyl-3-pentenoate (6849-18-9) → 1-bromo-4-methylpent-3-ene (2270-59-9)

Conditions	Yield
Multi-step reaction with 2 steps 1: sodium; propan-2-ol 2: hydrogen bromide View Scheme

1-bromo-4-methylpent-3-ene (2270-59-9) + 4-methylsalicylaldehyde (698-27-1) → C14H20O2

Conditions	Yield
Stage #1: 1-bromo-4-methylpent-3-ene With iodine; magnesium In diethyl ether for 1h; Reflux; Stage #2: 4-methylsalicylaldehyde In diethyl ether for 0.5h; Reflux;	100%

1-bromo-4-methylpent-3-ene (2270-59-9) + piperidin-2-ylmethanol (3433-37-2) → (+/-)-<1-(4-methyl-3-pentenyl)-2-piperidyl>methanol (167750-59-6)

Conditions	Yield
With potassium carbonate In toluene at 110℃; for 72h;	99%

5-(4’-hydroxyphenyl)-10,15,20-triphenylporphyrin + 1-bromo-4-methylpent-3-ene (2270-59-9) → C50H40N4O

Conditions	Yield
With potassium carbonate In N,N-dimethyl-formamide at 60℃; for 1h; Williamson Ether Synthesis; Darkness; Inert atmosphere;	99%

1-bromo-4-methylpent-3-ene (2270-59-9) + diethyl malonate (105-53-3) → diethyl 2,2-bis(4-methylpent-3-enyl)malonate (336885-03-1)

Conditions	Yield
With potassium hydroxide; trifluorormethanesulfonic acid In dimethyl sulfoxide at 50℃; for 3h;	98%
Stage #1: diethyl malonate With sodium hydride In N,N-dimethyl-formamide for 0.5h; Stage #2: 1-bromo-4-methylpent-3-ene In N,N-dimethyl-formamide for 18h; Further stages.;	66%

1-bromo-4-methylpent-3-ene (2270-59-9) → lithium cyclopentylmethanesulfinate

Conditions	Yield
Stage #1: 1-bromo-4-methylpent-3-ene With lithium In diethyl ether at 0℃; for 2h; Inert atmosphere; Stage #2: With sulfur dioxide In diethyl ether; pentane at -78 - 20℃; for 2h; Inert atmosphere; Schlenk technique;	98%

1-bromo-4-methylpent-3-ene (2270-59-9) + 2-Mercaptobenzothiazole (149-30-4) → 2-(4-methyl-pent-3-enylsulfanyl)-benzothiazole (864948-23-2)

Conditions	Yield
With tetra-(n-butyl)ammonium iodide; sodium hydride In N,N-dimethyl-formamide at 20℃; for 1.5h;	97%

1-bromo-4-methylpent-3-ene (2270-59-9) + 4-piperidone hydrochloride (41979-39-9) → 1-(4-methyl-3-pentenyl)-4-piperidone (203321-74-8)

Conditions	Yield
With potassium carbonate; potassium iodide In acetonitrile at 80℃; for 7h; Alkylation;	97%

1-bromo-4-methylpent-3-ene (2270-59-9) + phenol (108-95-2) → 1-(4-methylpent-3-enyloxy)benzene (88626-76-0)

Conditions	Yield
With potassium carbonate In N,N-dimethyl-formamide at 60℃; for 1h; Williamson Ether Synthesis; Darkness; Inert atmosphere;	97%
With potassium carbonate In acetone for 8h; Reflux;

α-picoline (109-06-8) + 1-bromo-4-methylpent-3-ene (2270-59-9) → 2-(5-methylhex-4-en-1-yl)pyridine (139367-31-0)

Conditions	Yield
Stage #1: α-picoline With n-butyllithium In tetrahydrofuran; hexane at -78 - 0℃; for 0.5h; Inert atmosphere; Stage #2: 1-bromo-4-methylpent-3-ene In tetrahydrofuran; hexane at -78℃; for 1h; Inert atmosphere;	96%
With n-butyllithium 1.) THF, -78 deg C, 2.) THF, 3 h; Yield given. Multistep reaction;

1-bromo-4-methylpent-3-ene (2270-59-9) + (S)-1-Pyrrolidin-2-yl-methanol (23356-96-9) → N-(4-methyl-3-pentenyl)-(S)-prolinol (166317-94-8)

Conditions	Yield
With potassium carbonate In toluene at 110℃; for 72h;	96%

1-bromo-4-methylpent-3-ene (2270-59-9) + diethyl hydrazodicarboxylate (4114-28-7) → Diethyl 1-(3-methyl-2-buten-1-yl)-1,2-hydrazinedicarboxylate

Conditions	Yield
Stage #1: diethyl hydrazodicarboxylate With sodium hydride In tetrahydrofuran; N,N-dimethyl-formamide; mineral oil at 0℃; for 0.5h; Stage #2: 1-bromo-4-methylpent-3-ene In tetrahydrofuran; N,N-dimethyl-formamide; mineral oil at 20℃; for 24h;	96%

1-bromo-4-methylpent-3-ene (2270-59-9) + 2,4-Dimethoxybenzaldehyde (613-45-6) → C15H22O3

Conditions	Yield
Stage #1: 1-bromo-4-methylpent-3-ene With iodine; magnesium In diethyl ether for 1h; Reflux; Stage #2: 2,4-Dimethoxybenzaldehyde In diethyl ether at 0℃; for 18h;	95%

1-bromo-4-methylpent-3-ene (2270-59-9) + 3',5'-O-bis(tert-butyldimethylsilyl)-N2-dimethylaminomethylene-2'-deoxyguanosine → 3',5'-O-bis(tert-butyldimethylsilyl)-1-(4-methylpent-3-enyl)-N2-dimethylaminomethylene-2'-deoxyguanosine

Conditions	Yield
Stage #1: 3',5'-O-bis(tert-butyldimethylsilyl)-N2-dimethylaminomethylene-2'-deoxyguanosine With caesium carbonate In tetrahydrofuran at 20℃; for 0.166667h; Stage #2: 1-bromo-4-methylpent-3-ene In tetrahydrofuran at 70℃;	93%

5-Methylfurfural (620-02-0) + 1-bromo-4-methylpent-3-ene (2270-59-9) → 5-methyl-1-(5-methylfuran-2-yl)hex-4-en-1-ol

Conditions	Yield
Stage #1: 1-bromo-4-methylpent-3-ene With magnesium In diethyl ether; ethylene dibromide for 0.5h; Inert atmosphere; Reflux; Stage #2: 5-Methylfurfural In diethyl ether at 0℃; for 1h; Inert atmosphere;	93%

1-bromo-4-methylpent-3-ene (2270-59-9) + 7-chloro-3-(2-(6-cyclopropyl-1H-indol-3-yl)-2-oxoethoxy)-2-naphthamide → 7-chloro-3-(2-(6-cyclopropyl-1-(4-methylpent-3-enyl)-1H-indol-3-yl)-2-oxoethoxy)-2-naphthamide

Conditions	Yield
With potassium carbonate In N,N-dimethyl-formamide at 20℃;	92.2%

1-bromo-4-methylpent-3-ene (2270-59-9) + potassium phtalimide (1074-82-4) → 2-(4-methylpent-3-en-1-yl)isoindoline-1,3-dione (13296-42-9)

Conditions	Yield
In N,N-dimethyl-formamide 1) 80 deg C, 3 h; 2) RT, 3 h;	92%
In N,N-dimethyl-formamide at 110℃; Simmons-Smith Cyclopropanation; Inert atmosphere;	91%
In N,N-dimethyl-formamide at 90℃; for 3h;	81%
In acetonitrile Reflux;	76%

2-nitro-1H-imidazole (527-73-1) + 1-bromo-4-methylpent-3-ene (2270-59-9) → 4-methyl-1-(2-nitro-1H-imidazol-1-yl)-3-pentene (149876-82-4)

Conditions	Yield
With potassium carbonate In N,N-dimethyl-formamide at 75℃; for 48h;	92%
With potassium carbonate	6.2 g (34%)

1-bromo-4-methylpent-3-ene (2270-59-9) + 2-isopropyl-2H-chromene (30447-49-5) → 4-(1-(4-methylpent-3-enyl)-4-methylpent-2-enyl)-phenol

Conditions	Yield
With zirconocene dichloride; butyl magnesium bromide In tetrahydrofuran at 55℃; for 12h; Alkylation;	92%

1-bromo-4-methylpent-3-ene (2270-59-9) → 5-iodo-2-methylpent-2-ene (43161-11-1)

Conditions	Yield
With sodium iodide In acetone at 20℃; for 20h;	92%
With alkali metal iodide Finkelstein reaction;
With sodium iodide In acetone at 20℃; Inert atmosphere;

5-bromo-1H-indole (10075-50-0) + 1-bromo-4-methylpent-3-ene (2270-59-9) → C14H16BrN

Conditions	Yield
Stage #1: 5-bromo-1H-indole With sodium hydride In N,N-dimethyl-formamide; mineral oil at 23℃; for 0.5h; Inert atmosphere; Stage #2: 1-bromo-4-methylpent-3-ene In N,N-dimethyl-formamide; mineral oil at 23℃; for 1h; Inert atmosphere;	92%

diethoxyphosphoryl-acetic acid ethyl ester (867-13-0) + 1-bromo-4-methylpent-3-ene (2270-59-9) → diethyl (1-carbethoxy-5-methyl-4-hexenyl)phosphonate (107554-02-9)

Conditions	Yield
Stage #1: diethoxyphosphoryl-acetic acid ethyl ester With potassium tert-butylate In N,N-dimethyl-formamide at 0℃; for 0.166667h; Stage #2: 1-bromo-4-methylpent-3-ene In N,N-dimethyl-formamide at 20℃; for 18h; Further stages.;	91%
	42%
With potassium tert-butylate In N,N-dimethyl-formamide for 1h; Ambient temperature;	42%

1-bromo-4-methylpent-3-ene (2270-59-9) + 4-methoxy-phenyl acetic acid methyl ester (23786-14-3) → methyl 2-(4-methoxyphenyl)-6-methylhept-5-enoate (1350468-24-4)

Conditions	Yield
Stage #1: 4-methoxy-phenyl acetic acid methyl ester With lithium diisopropyl amide In tetrahydrofuran at -78℃; for 0.5h; Stage #2: 1-bromo-4-methylpent-3-ene With N,N,N,N,N,N-hexamethylphosphoric triamide In tetrahydrofuran at -78 - 20℃; for 16h;	91%
Stage #1: 4-methoxy-phenyl acetic acid methyl ester With lithium diisopropyl amide In tetrahydrofuran; diethyl ether at -78℃; for 0.5h; Stage #2: 1-bromo-4-methylpent-3-ene In tetrahydrofuran; N,N,N,N,N,N-hexamethylphosphoric triamide; diethyl ether at -78 - 20℃;	58%

Indole-3-carboxaldehyde (487-89-8) + 1-bromo-4-methylpent-3-ene (2270-59-9) → 1-(4-methyl-3-pentenyl)indole-3-carbaldehyde (192997-21-0)

Conditions	Yield
With potassium carbonate In acetonitrile Heating;	90%

N-hydroxyphthalimide (524-38-9) + 1-bromo-4-methylpent-3-ene (2270-59-9) → 2-(4-methylpent-3-enyloxy)isoindoline-1,3-dione (1177369-84-4)

Conditions	Yield
With 1,8-diazabicyclo[5.4.0]undec-7-ene In acetonitrile at 100℃; for 4h;	90%

1-bromo-4-methylpent-3-ene (2270-59-9) + phenyl(trimethylsiloxy)acetonitrile (25438-37-3) → 5-methyl-1-phenylhex-4-en-1-one (4535-64-2)

Conditions	Yield
Stage #1: phenyl(trimethylsiloxy)acetonitrile With n-butyllithium; diisopropylamine In tetrahydrofuran; hexane at -78℃; for 1h; Inert atmosphere; Stage #2: 1-bromo-4-methylpent-3-ene In tetrahydrofuran; hexane at -78 - 20℃; for 5h; Inert atmosphere;	90%

1-bromo-4-methylpent-3-ene (2270-59-9) + normetazocine (16603-67-1, 16670-83-0, 16670-84-1, 16670-86-3, 16671-00-4, 16808-63-2, 25144-77-8, 25144-78-9, 52079-30-8) → (2S*,6R*,11R*)-6,11-dimethyl-1,2,3,4,5,6-hexahydro-2,6-methano-3-(4-methyl-3-pentenyl)-3-benzazocin-8-ol (74400-52-5, 83377-70-2, 99342-06-0)

Conditions	Yield
With sodium hydrogencarbonate In N,N-dimethyl-formamide at 100℃; for 5h;	89.9%

1-bromo-4-methylpent-3-ene (2270-59-9) + malonic acid dimethyl ester (108-59-8) → dimethyl 2-(4-methylpent-3-en-1-yl)malonate (18776-25-5)

Conditions	Yield
Stage #1: malonic acid dimethyl ester With sodium hydride In tetrahydrofuran at 0℃; Stage #2: 1-bromo-4-methylpent-3-ene With tetra-(n-butyl)ammonium iodide In tetrahydrofuran for 9h; Reflux;	89%
Stage #1: malonic acid dimethyl ester With sodium hydride In tetrahydrofuran; mineral oil at 0℃; for 0.0833333h; Schlenk technique; Inert atmosphere; Stage #2: 1-bromo-4-methylpent-3-ene With tetra-(n-butyl)ammonium iodide In tetrahydrofuran; mineral oil at 0 - 66℃; Schlenk technique; Inert atmosphere;	49%
With sodium methylate In methanol

1-bromo-4-methylpent-3-ene (2270-59-9) + 2,5-dibenzyloxy-4-methylacetophenone (474842-49-4) → 2-O,5-O-dibenzyl-7-hydroxy-curcuhydroquinone (474842-51-8)

Conditions	Yield
With iodine; magnesium In tetrahydrofuran Inert atmosphere;	89%
Stage #1: 1-bromo-4-methylpent-3-ene With iodine; magnesium In tetrahydrofuran at 65℃; for 0.5h; Stage #2: 2,5-dibenzyloxy-4-methylacetophenone In tetrahydrofuran at 65℃; for 1.5h; Grignard reaction;	81%
Stage #1: 1-bromo-4-methylpent-3-ene With magnesium In tetrahydrofuran at 65℃; for 1h; Stage #2: 2,5-dibenzyloxy-4-methylacetophenone In tetrahydrofuran at 65℃;	70%

1-bromo-4-methylpent-3-ene (2270-59-9) + methyl 2-((tetrahydro-2H-pyran-2-yl)oxy)acetate (135643-82-2) → 2,10-dimethyl-6-[(tetrahydro-2H-pyran-2-yloxy)methyl]-undeca-2,9-dien-6-ol (1008776-29-1)

Conditions	Yield
Stage #1: 1-bromo-4-methylpent-3-ene With magnesium In diethyl ether for 2h; Heating; Stage #2: methyl 2-((tetrahydro-2H-pyran-2-yl)oxy)acetate In diethyl ether at -78 - 20℃; for 3h; Further stages.;	89%

Upstream product

• 52278-94-1 2,5-dibromo-2-methylpentane 
• 582-25-2 Potassium benzoate 
• 64-19-7 acetic acid 
• 6849-18-9 ethyl 4-methyl-3-pentenoate 
• 1071-73-4 5-Hydroxy-2-pentanone 
• 1462-10-8 4-methyl-1,4-pentanediol 
• 930-39-2 2-cyclopropyl-2-propanol 
• 783-86-8 4-methylpent-3-enyl 4-methylbenzenesulfonate 
• 96-48-0 4-butanolide 
• 917-64-6 methyl magnesium iodide 
• 765-43-5 Cyclopropyl methyl ketone 
• 75-16-1 methylmagnesium bromide 
• 763-89-3 4-methylpent-3-en-1-ol 

Downstream Products

• 78-70-6 3,7-dimethylocta-1,6-dien-3-ol 
• 926-56-7 4-methyl-1,3-pentadiene 
• 42272-94-6 5-methylhex-4-ene-1-ol 
• 22410-72-6 (+/-)-lavandulol 
• 69301-57-1 2-(1-Hydroxy-1,5-dimethyl-hex-4-enyl)-5-methyl-phenol 
• 62469-65-2 2-(4-Methylpent-3-enyl)thiophene 
• 62429-57-6 3-(4-methyl-3-pentenyl)thiophene 
• 22544-17-8 1-buthylthio-1-buten-3-yne 
• 82203-08-5 9-methyl-5-thiadeca-3,8-dien-1-yne 
• 82203-09-6 3-bromo-2-(4-methylpent-3-enyl)thiophen 
• 82203-10-9 3-bromo-2,5-bis(4-methylpent-3-enyl)thiophen 
• 477841-80-8 (6R)-2-[(tert-butyldiphenylsilyl)oxy]-7-hydroxy-10-prenyl-7,8-dihydro-α-bisabolene 
• 848566-05-2 6-methyl-2-[2-(triisopropylsilanyloxy)-4-(triisopropylsilanyloxymethyl)phenyl]hept-5-en-2-ol 
• 49749-51-1 (+/-)-3-methyl-3-(4-methyl-3-pentenyl)cyclohexanone 

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