5208-93-5

Basic information

• Product Name: 3-methyl-1-(2,6,6-trimethylcyclohex-1-en-1-yl)penta-1,4-dien-3-ol
• Synonyms: 3-methyl-1-(2,6,6-trimethylcyclohex-1-en-1-yl)penta-1,4-dien-3-ol;3-Methyl-1-(2,6,6-Trimethylcyclohex-1-En-Yl)Pwnta-1,4-Dien-3-Ol(ForIsotretinoin);Vinyl-beta;3-Methyl-1-(2,6,6-trimethylcyclohex-1-en-yl)penta-1,4-dien-3-ol;3-Methyl-1-(2,6,6-trimethylcyclohex-1-en-yl) pwnta-1,4-dien-3-ol;VINYI-β-IONOL/3-MTHYL-1-1(2,6,6-TRIMETHYLCYCLOHEX-1-EN-1-YL)PENTA-1,4-DIEN-3-OL;3-Methyl-1-(2,6,6-trimethyl-1-cyclohexen-1-yl)-1,4-pentadien-3-ol;1,4-Pentadien-3-ol, 3-methyl-1-(2,6,6-trimethyl-1-cyclohexen-1-yl)-
• CAS NO: 5208-93-5
• Molecular Formula: C₁₅H₂₄O
• Molecular Weight: 220.35046
• EINECS: 226-006-5
• Product Categories: (intermediate of isotretinoin)
• Mol File: 5208-93-5.mol
• Article Data: 2

Chemical Properties

• Boiling Point: 315℃
• Flash Point: 116℃
• Appearance: /
• Density: 0.948
• Vapor Pressure: 3.76E-05mmHg at 25°C
• Refractive Index: 1.533
• Storage Temp.: 2-8°C
• PKA: 13.93±0.29(Predicted)
• Water Solubility: 151mg/L at 25℃
• CAS DataBase Reference: 3-methyl-1-(2,6,6-trimethylcyclohex-1-en-1-yl)penta-1,4-dien-3-ol(CAS DataBase Reference)
• NIST Chemistry Reference: 3-methyl-1-(2,6,6-trimethylcyclohex-1-en-1-yl)penta-1,4-dien-3-ol(5208-93-5)
• EPA Substance Registry System: 3-methyl-1-(2,6,6-trimethylcyclohex-1-en-1-yl)penta-1,4-dien-3-ol(5208-93-5)

Safety Data

• Hazardous Substances Data: 5208-93-5(Hazardous Substances Data)

Usage

Flammability and Explosibility

Nonflammable

InChI:InChI=1/C15H24O/c1-6-15(5,16)11-9-13-12(2)8-7-10-14(13,3)4/h6,9,11,16H,1,7-8,10H2,2-5H3/b11-9+

Synthetic route

4-(2,6,6-trimethyl-1-cyclohexen-1-yl)-3-buten-2-one (79-77-6) + vinylmagnesium chloride (3536-96-7) → 2-vinyl-β-ionol (5208-93-5)

Conditions	Yield
In tetrahydrofuran at 0 - 10℃; for 2h;	90%

(E)-β-ionone (79-77-6) + vinyl magnesium bromide (1826-67-1) → 2-vinyl-β-ionol (5208-93-5)

Conditions	Yield
at 0 - 20℃; for 10h; Grignard Reaction;	58%

2-vinyl-β-ionol (5208-93-5) + Benzenesulfinic acid (618-41-7) → 1-Benzolsulfonyl-3-methyl-5-(2',6',6'-trimethyl-cyclohex-1-enyl)-penta-2,4-dien (50464-14-7)

Conditions	Yield
In water at 40℃; Temperature; Microwave irradiation;	99%

3-methyl-4-oxobut-2-enyl acetate (14918-80-0) + 2-vinyl-β-ionol (5208-93-5) → Retinol acetate (127-47-9)

Conditions	Yield
Stage #1: 2-vinyl-β-ionol With toluene-4-sulfonic acid; triphenylphosphine In toluene at 12℃; Inert atmosphere; Sealed tube; Stage #2: 3-methyl-4-oxobut-2-enyl acetate In toluene at 12℃; Temperature; Inert atmosphere; Sealed tube;	92.8%

2-vinyl-β-ionol (5208-93-5) + triphenylphosphine hydrobromide (6399-81-1) → [3-methyl-5-(2,6,6-trimethylcyclohexen-1-yl)penta-2,4-dien-1-yl]triphenylphosphanium bromide

Conditions	Yield
In methanol at 20℃; Inert atmosphere;	77%

2-vinyl-β-ionol (5208-93-5) → oxovinylionol (67777-14-4) + tert-butylperoxyvinylionol (1432964-99-2)

Conditions	Yield
With tert.-butylhydroperoxide; copper(II) acetylacetonate hydrate In pyridine; water at 40℃; for 10h; Reagent/catalyst; Concentration; Time; Temperature; Solvent;	A 46.6% B 5.9%

2-vinyl-β-ionol (5208-93-5) → oxovinylionol (67777-14-4)

Conditions	Yield
Stage #1: 2-vinyl-β-ionol With tert.-butylhydroperoxide; 1,10-Phenanthroline; cobalt(II) 2-ethylhexanoate In water at 68 - 72℃; Stage #2: With piperidine In water at 70℃; for 12h; Reagent/catalyst; Time; Solvent; Concentration; Temperature;	43.2%

tert.-butylhydroperoxide (75-91-2) + 2-vinyl-β-ionol (5208-93-5) → oxovinylionol (67777-14-4) + tert-butylperoxyvinylionol (1432964-99-2)

Conditions	Yield
With cobalt(II) bromide In pyridine; water at 40℃; for 10h; Reagent/catalyst; Time; Temperature; Concentration;	A 16.9% B 42.8%

2-Methoxypropene (116-11-0) + 2-vinyl-β-ionol (5208-93-5) → 2-[(E)-3-(1-methoxy-1-methyl-ethoxy)-3-methyl-penta-1,4-dienyl]-1,3,3-trimethyl-cyclohexene (1196448-69-7)

Conditions	Yield
phosphoric acid In acetone at -20 - 0℃; Inert atmosphere;

2-vinyl-β-ionol (5208-93-5) → 1-(4-hydroxy-3-oxo-2,6,6-trimethyl-1-cyclohexen-1-yl)-3-methyl-3-trimethylsiloxy-1,4-pentadiene (1432965-26-8) + C21H38O3Si2 (1432965-13-3)

Conditions	Yield
Multi-step reaction with 2 steps 1.1: tert.-butylhydroperoxide; cobalt(II) 2-ethylhexanoate; 1,10-Phenanthroline / water / 68 - 72 °C 1.2: 12 h / 70 °C 2.1: tetrabutylammomium bromide; triethylamine / acetonitrile / 24 h / 20 - 25 °C / Reflux View Scheme
Multi-step reaction with 2 steps 1: cobalt(II) bromide / water; pyridine / 10 h / 40 °C 2: tetrabutylammomium bromide; triethylamine / acetonitrile / 24 h / 20 - 25 °C / Reflux View Scheme
Multi-step reaction with 2 steps 1: copper(II) acetylacetonate hydrate; tert.-butylhydroperoxide / water; pyridine / 10 h / 40 °C 2: tetrabutylammomium bromide; triethylamine / acetonitrile / 24 h / 20 - 25 °C / Reflux View Scheme

2-vinyl-β-ionol (5208-93-5) → 3-methyl-5-(2,6,6-trimethyl-4-hydroxy-1-cyclohexene-3-carbonyl)-2,4-pentadiene-1-bromotriphenylphosphine (84592-32-5)

Conditions	Yield
Multi-step reaction with 3 steps 1.1: cobalt(II) bromide / water; pyridine / 10 h / 40 °C 2.1: tetrabutylammomium bromide; triethylamine / acetonitrile / 24 h / 20 - 25 °C / Reflux 3.1: hydrogen bromide / dichloromethane / 0.67 h / -5 - 0 °C 3.2: 20 h / 1 °C / Reflux View Scheme
Multi-step reaction with 3 steps 1.1: copper(II) acetylacetonate hydrate; tert.-butylhydroperoxide / water; pyridine / 10 h / 40 °C 2.1: tetrabutylammomium bromide; triethylamine / acetonitrile / 24 h / 20 - 25 °C / Reflux 3.1: hydrogen bromide / dichloromethane / 0.67 h / -5 - 0 °C 3.2: 20 h / 1 °C / Reflux View Scheme
Multi-step reaction with 3 steps 1.1: tert.-butylhydroperoxide; cobalt(II) 2-ethylhexanoate; 1,10-Phenanthroline / water / 68 - 72 °C 1.2: 12 h / 70 °C 2.1: tetrabutylammomium bromide; triethylamine / acetonitrile / 24 h / 20 - 25 °C / Reflux 3.1: hydrogen bromide / dichloromethane / 0.67 h / -5 - 0 °C 3.2: 20 h / 1 °C / Reflux View Scheme

2-vinyl-β-ionol (5208-93-5) → C23H32O2 + C23H32O2

Conditions	Yield
Multi-step reaction with 2 steps 1.1: methanol / 20 °C / Inert atmosphere 2.1: n-butyllithium / tetrahydrofuran; hexane / 0.53 h / -20 °C / Inert atmosphere 2.2: 4 h / -20 - 20 °C / Inert atmosphere View Scheme

2-vinyl-β-ionol (5208-93-5) + triphenylphosphine (603-35-0) → β-Jonylidenaethyl-triphenyl-phosphonium-chlorid (1062-12-0)

Conditions	Yield
With hydrogenchloride In water at 53℃; under 150015 Torr; for 1.5h; Temperature; Pressure; Autoclave; Inert atmosphere;
Stage #1: 2-vinyl-β-ionol With triethylamine In methanol for 0.166667h; Large scale; Stage #2: triphenylphosphine With hydrogenchloride; 2,6-di-tert-butyl-4-methyl-phenol In methanol; water Time; Inert atmosphere; Reflux; Large scale;

Upstream product

• 79-77-6 4-(2,6,6-trimethyl-1-cyclohexen-1-yl)-3-buten-2-one 
• 3536-96-7 vinylmagnesium chloride 
• 79-77-6 (E)-β-ionone 
• 1826-67-1 vinyl magnesium bromide 

Downstream Products

• 50464-14-7 1-Benzolsulfonyl-3-methyl-5-(2',6',6'-trimethyl-cyclohex-1-enyl)-penta-2,4-dien 
• 127-47-9 Retinol acetate 
• 67777-14-4 3-[3-hydroxy-3-methyl-penta-1,4-dienyl]-2,4,4-trimethyl-cyclohex-2-en-1-one 
• 1432964-99-2 tert-butylperoxyvinylionol 
• 84592-32-5 3-methyl-5-(2,6,6-trimethyl-4-hydroxy-1-cyclohexene-3-carbonyl)-2,4-pentadiene-1-bromotriphenylphosphine 
• 1196448-69-7 2-[(E)-3-(1-methoxy-1-methyl-ethoxy)-3-methyl-penta-1,4-dienyl]-1,3,3-trimethyl-cyclohexene 
• 1062-12-0 β-Jonylidenaethyl-triphenyl-phosphonium-chlorid 

Relevant articles and documents

Short, convergent synthesis of locked retinals

We report a short and convenient synthesis of two configurationally locked retinals that are important for applications in the context of optogenetics. The C11-C15 cyclopentyl fragments of both retinals were obtained by palladium-catalysed alkoxycarbonylation and merged with the rest of the carbon skeleton through Wittig olefination. The preparation of the required and known ylide precursor was revisited and optimised. This synthetic route enables gram-scale preparation of both retinal derivatives.