5436-21-5

Basic information

• Product Name: Acetylacetaldehyde dimethyl acetal
• Synonyms: FEMA 3381;FADMA;FORMYLACETONE DIMETHYL ACETAL;KBA;1,1-DIMETHOXY BUTANONE-3;1,1-DIMETHOXY-3-BUTANONE;AADMA;ACETYLACETALDEHYDE DIMETHYL ACETAL
• CAS NO: 5436-21-5
• Molecular Formula: C₆H₁₂O₃
• Molecular Weight: 132.16
• EINECS: 226-605-1
• Product Categories: Pharmaceutical Intermediates
• Mol File: 5436-21-5.mol
• Article Data: 22

Chemical Properties

• Melting Point: -82 °C
• Boiling Point: 70-73 °C20 mm Hg(lit.)
• Flash Point: 121 °F
• Appearance: Clear colorless to yellow/Liquid
• Density: 0.996 g/mL at 25 °C(lit.)
• Vapor Pressure: 1.35mmHg at 25°C
• Refractive Index: n20/D 1.414(lit.)
• Storage Temp.: Flammables area
• Water Solubility: decomposes
• BRN: 1702372
• CAS DataBase Reference: Acetylacetaldehyde dimethyl acetal(CAS DataBase Reference)
• NIST Chemistry Reference: Acetylacetaldehyde dimethyl acetal(5436-21-5)
• EPA Substance Registry System: Acetylacetaldehyde dimethyl acetal(5436-21-5)

Safety Data

• Hazard Codes: F
• Statements: 10
• Safety Statements: 16
• RIDADR: UN 1989 3/PG 3
• WGK Germany: 2
• RTECS: EL7592500
• TSCA: Yes
• HazardClass: 3
• PackingGroup: III
• Hazardous Substances Data: 5436-21-5(Hazardous Substances Data)

Usage

Chemical Properties

Clear colorless to yellow liquid

Uses

Different sources of media describe the Uses of 5436-21-5 differently. You can refer to the following data:
1. Acetaldehyde dimethyl acetal is used as a flavoring agent. It is also used in the preparation of (R)-4,4-dimethoxy-2-butanol, pyrazoles and pyrimidines. Further, it is used in the preparation of N,N-diethyl-[2-(4-fluorophenyl)-5-methylpyrazolo[1,5-a]-pyrimidin-3-yl]acetamide and acetoacetaldehyde.
2. 4,4-Dimethoxy-2-butanone (β-ketobutyracetal) may be used in the preparation of:(R)-4,4-dimethoxy-2-butanolpyrazoles and pyrimidines[7,16-dihydro- 6,15( 17)-dimetbyldibenzo[b,i]-[1,4,8,11]tetrilazacyclotetradecinato-N5,N9,N14,N18]nickel{II)

Synthesis Reference(s)

The Journal of Organic Chemistry, 41, p. 3765, 1976 DOI: 10.1021/jo00885a028Tetrahedron Letters, 28, p. 6657, 1987 DOI: 10.1016/S0040-4039(00)96938-7

General Description

4,4-Dimethoxy-2-butanone (Acetylacetaldehyde dimethylacetal) is a ketone.

InChI:InChI=1/C6H12O3/c1-5(7)4-6(8-2)9-3/h6H,4H2,1-3H3

Synthetic route

methanol (67-56-1) + trans-4-methoxy-3-buten-2-one (51731-17-0) → acetylacetaldehyde dimethyl acetal (5436-21-5)

Conditions	Yield
pyrrolidine; methanesulfonic acid at 20℃; for 28h; oxy-Michael reaction;	99%

3-butenal dimethyl acetal (72380-56-4) → acetylacetaldehyde dimethyl acetal (5436-21-5)

Conditions	Yield
With tert.-butylhydroperoxide; C21H19N5Pd(2+)*2BF4(1-) In decane; acetonitrile at 70℃; for 24h; Temperature; Wacker Oxidation;	95%

2-methyl-propan-1-ol (78-83-1) + (Z)-4-methoxybut-3-en-2-one (57155-06-3) → acetylacetaldehyde dimethyl acetal (5436-21-5) + 4-isobutoxy-but-3-en-2-one (85716-38-7) + 4-isobutoxy-4-methoxybutan-2-one

Conditions	Yield
for 10h; Heating; Yields of byproduct given;	A n/a B 90% C n/a

2-(Trimethylsilyloxy)propene (1833-53-0) + trimethyl orthoformate (149-73-5) → acetylacetaldehyde dimethyl acetal (5436-21-5)

Conditions	Yield
With zinc(II) chloride In ethyl acetate at 20 - 25℃; for 2h;	87%
dodecacarbonyltetrarhodium(0) In benzene at 100℃; for 18h;	48%

3-oxobutyraldehyde (625-34-3) + trimethyl orthoformate (149-73-5) → acetylacetaldehyde dimethyl acetal (5436-21-5)

Conditions	Yield
With tropylium tetrafluoroborate In acetonitrile at 70℃; for 5h; Inert atmosphere; Green chemistry; chemoselective reaction;	69%

1-methoxy-buten-3-yne (2798-73-4) → acetylacetaldehyde dimethyl acetal (5436-21-5)

Conditions	Yield
With water; mercury(II) sulfate In diethylene glycol at 80℃; for 0.5h;	14%

methanol (67-56-1) + 1-methoxy-buten-3-yne (2798-73-4) → acetylacetaldehyde dimethyl acetal (5436-21-5)

Conditions	Yield
With sulfuric acid
With mercury(II) sulfate In water
With sulfuric acid; water

methanol (67-56-1) + tetrachloromethane (56-23-5) + 4-chloro-3-buten-2-one (7119-27-9) → acetylacetaldehyde dimethyl acetal (5436-21-5)

Conditions	Yield
at -15 - -10℃;
at -15 - -10℃;

methanol (67-56-1) + 4-chloro-3-buten-2-one (7119-27-9) → acetylacetaldehyde dimethyl acetal (5436-21-5)

Conditions	Yield
With sodium hydroxide at -15 - -10℃;
With sodium hydroxide at -15 - -10℃;

methanol (67-56-1) + 1-methoxy-3-methylsulfanyl-buta-1,2-diene (56699-02-6) → acetylacetaldehyde dimethyl acetal (5436-21-5)

Conditions	Yield
With mercury dichloride

3-oxobutyraldehyde (625-34-3) + methanol (67-56-1) → acetylacetaldehyde dimethyl acetal (5436-21-5) + trans-4-methoxy-3-buten-2-one (51731-17-0)

Conditions	Yield
Product distribution; other β-ketoaldehydes, other alcohols, var. solvents;

methanol (67-56-1) + 4-methoxy-3-buten-2-one (4652-27-1) → acetylacetaldehyde dimethyl acetal (5436-21-5)

methanol (67-56-1) + acetone (67-64-1) + formic acid ethyl ester (109-94-4) → acetylacetaldehyde dimethyl acetal (5436-21-5)

Conditions	Yield
Yield given. Multistep reaction;

methanol (67-56-1) + 1-methoxy-buten-3-yne (2798-73-4) + sulfuric acid (7664-93-9) → acetylacetaldehyde dimethyl acetal (5436-21-5)

1,1,3,3-tetramethoxy-butane (5744-65-0) + water (7732-18-5) → acetylacetaldehyde dimethyl acetal (5436-21-5)

Conditions	Yield
at 50 - 60℃;

methanol (67-56-1) + 1,1-dimethoxy-but-2-yne (22022-34-0) + mercury(II) sulfate → acetylacetaldehyde dimethyl acetal (5436-21-5)

methanol (67-56-1) + hydroxymethylenacetone sodium → acetylacetaldehyde dimethyl acetal (5436-21-5)

Conditions	Yield
With sulfuric acid; benzene

methanol (67-56-1) + sodium-compound of acetoacetaldehyde → acetylacetaldehyde dimethyl acetal (5436-21-5)

Conditions	Yield
With hydrogenchloride

methanol (67-56-1) + 1,4-dimethyl-cyclohexa-1,4-diene (4074-22-0) → acetylacetaldehyde dimethyl acetal (5436-21-5) + (3R,5S)-3,5-Dimethoxy-3-methyl-[1,2]dioxolane

Conditions	Yield
With toluene-4-sulfonic acid; ozone In chloroform-d1 at -78℃; Title compound not separated from byproducts;

methanol (67-56-1) + Methyl formate (107-31-3) + acetone (67-64-1) → acetylacetaldehyde dimethyl acetal (5436-21-5)

Conditions	Yield
Stage #1: Methyl formate; acetone With sodium methylate In diethyl ether at 20℃; for 3h; Stage #2: methanol With sulfuric acid at 20℃; for 12h;

acetone (67-64-1) + trimethyl orthoformate (149-73-5) → acetylacetaldehyde dimethyl acetal (5436-21-5)

Conditions	Yield
Stage #1: trimethyl orthoformate With boron trifluoride diethyl etherate In dichloromethane at -40 - 0℃; for 0.5h; Stage #2: acetone With N-ethyl-N,N-diisopropylamine In dichloromethane at -78 - 20℃; for 1h;

methanol (67-56-1) + methyl vinyl ketone (78-94-4) → acetylacetaldehyde dimethyl acetal (5436-21-5) + 1-methoxybutan-3-one (6975-85-5)

Conditions	Yield
With carbon dioxide; oxygen; sodium phosphate; copper(l) chloride; palladium dichloride at 50℃; under 90007.2 Torr; for 12h;	A 83.2 % Chromat. B 12.8 % Chromat.
With carbon dioxide; polystyrene-supported benzoquinone; oxygen; palladium dichloride at 50℃; under 60004.8 Torr; for 12h;	A 76.8 % Chromat. B 13.4 % Chromat.

methanol (67-56-1) + methyl vinyl ketone (78-94-4) → acetylacetaldehyde dimethyl acetal (5436-21-5)

Conditions	Yield
With carbon dioxide; oxygen; palladium dichloride at 50℃; under 105011 Torr; for 15h;	88.6 % Chromat.

methanol (67-56-1) + 3-oxo-butyraldehyde; sodium enolate (41125-09-1, 14975-15-6, 926-59-0) → acetylacetaldehyde dimethyl acetal (5436-21-5) + 4-methoxy-3-buten-2-one (4652-27-1)

Conditions	Yield
With hydrogenchloride at 20℃; for 4h;

Methyl formate (107-31-3) + acetone (67-64-1) → acetylacetaldehyde dimethyl acetal (5436-21-5)

Conditions	Yield
Stage #1: Methyl formate; acetone With sodium methylate In methanol at 40℃; for 5h; Stage #2: With sulfuric acid In methanol at 30℃; for 5h;	195.6 g

methanol (67-56-1) + methyl ethynyl ketone (1423-60-5) + benzyl azide (622-79-7) → acetylacetaldehyde dimethyl acetal (5436-21-5) + 1-(1-benzyl-1H-1,2,3-triazol-4-yl)ethan-1-one (80819-67-6)

Conditions	Yield
With DBN; oxygen; copper(II) acetate monohydrate at 0 - 20℃; for 3h;

acetylacetaldehyde dimethyl acetal (5436-21-5) → 1,1-dimethoxybutan-3-ol (39562-58-8)

Conditions	Yield
With sodium tetrahydroborate In tetrahydrofuran; methanol at 0 - 20℃; for 0.5h;	100%
With sodium tetrahydroborate In ethanol for 2h; Ambient temperature;	84%
With methanol; sodium tetrahydroborate In tetrahydrofuran at 0 - 20℃; for 2h;	79%

1-phenylpyrazol-5-amine (826-85-7) + acetylacetaldehyde dimethyl acetal (5436-21-5) → 6-methyl-1-phenyl-1H-pyrazolo[3,4-b]pyridine (59026-68-5)

Conditions	Yield
zinc(II) chloride In hydrogenchloride; ethanol for 1h; Heating;	100%

acetylacetaldehyde dimethyl acetal (5436-21-5) + 1,3-diphenyl-1H-pyrazol-5-amine (5356-71-8) → 6-Methyl-1,3-diphenyl-1H-pyrazolo[3,4-b]pyridine (84647-18-7)

Conditions	Yield
zinc(II) chloride In hydrogenchloride; ethanol for 1h; Heating;	100%

acetylacetaldehyde dimethyl acetal (5436-21-5) + 1-methyl-3-phenyl-1H-pyrazol-5-amine (10199-50-5) → 1,6-Dimethyl-3-phenyl-1H-pyrazolo[3,4-b]pyridine (116835-07-5)

Conditions	Yield
zinc(II) chloride In hydrogenchloride; ethanol for 1h; Heating;	100%

acetylacetaldehyde dimethyl acetal (5436-21-5) + 4-amidinopyridine hydrochloride (6345-27-3, 42518-06-9, 61875-64-7) → 4-(4-methylpyrimidin-2-yl)pyridine (182416-44-0)

Conditions	Yield
In 1,4-dioxane Heating;	100%
In 1,4-dioxane Reflux; Inert atmosphere;	62%

acetylacetaldehyde dimethyl acetal (5436-21-5) + methylamine (74-89-5) → 1-methylamino-1-butenone (20082-88-6)

Conditions	Yield
In methanol at 20℃; for 12h; Inert atmosphere;	100%

acetylacetaldehyde dimethyl acetal (5436-21-5) + C15H24N2O2 → C21H36N2O4

Conditions	Yield
Stage #1: acetylacetaldehyde dimethyl acetal; C15H24N2O2 With acetic acid In tetrahydrofuran at -10 - -5℃; for 1h; Stage #2: With sodium cyanoborohydride In tetrahydrofuran at 0 - 10℃; for 2h;	100%

(-)-3-amino-5-(5-fluoro-2-methylphenyl)-2-cyclohexenon-1-one + acetylacetaldehyde dimethyl acetal (5436-21-5) → (-)-7-(5-fluoro-2-methylphenyl)-4-methyl-7,8-dihydroquinolin-5(6H)-one (239132-05-9)

Conditions	Yield
With sodium methylate; potassium carbonate In water; toluene	98.8%

acetylacetaldehyde dimethyl acetal (5436-21-5) + thiourea (17356-08-0) → 2-mercapto-6-methylpyrimidine (35071-17-1, 774119-15-2)

Conditions	Yield
With hydrogenchloride In water at 50℃;	95%
With hydrogenchloride In methanol at 50℃; Rate constant; temperature 60 or 70 deg C, water as solvent;

acetylacetaldehyde dimethyl acetal (5436-21-5) + 3-Chloro-2-methylpropene (563-47-3) → 1,1-Dimethoxy-3,5-dimethyl-hex-5-en-3-ol (124538-13-2)

Conditions	Yield
With manganese; zinc(II) chloride In tetrahydrofuran at 60℃;	95%

1,2,3-Benzotriazole (95-14-7) + acetylacetaldehyde dimethyl acetal (5436-21-5) → 4,4-di(benzotriazol-1-yl)-2-butanone

Conditions	Yield
With PF-5080; toluene-4-sulfonic acid for 22h; Heating;	95%

acetylacetaldehyde dimethyl acetal (5436-21-5) + dimethyl amine (124-40-3) → 4-dimethylamino-3-buten-2-one (1190-91-6)

Conditions	Yield
In water at 25℃; for 4h;	95%

acetylacetaldehyde dimethyl acetal (5436-21-5) + 4-methoxybenzamidine hydrochloride (51721-68-7) → 4-methyl-2-(4-methoxyphenyl)pyrimidine

Conditions	Yield
With sodium methylate In methanol at 50℃; for 14h; Inert atmosphere;	95%

acetylacetaldehyde dimethyl acetal (5436-21-5) + dimethyl amine (124-40-3) → (E)-4-(dimethylamino)but-3-en-2-one (2802-08-6)

Conditions	Yield
With triethylamine In water at 25℃; for 4h;	95%
In methanol at 20℃; for 4h;	90%

acetylacetaldehyde dimethyl acetal (5436-21-5) + benzamidine monohydrochloride (1670-14-0) → 4-methyl-2-phenylpyrimidine (34771-48-7)

Conditions	Yield
With sodium methylate In methanol at 45 - 50℃; for 6h;	91.3%

N-(3-(((2,6-difluorophenyl)amino)sulfonyl)-1H-1,2,4-triazol-5-yl)amine (113171-12-3) + acetylacetaldehyde dimethyl acetal (5436-21-5) → N-(2,6-difluorophenyl)-5-methyl[1,2,4]triazolo[1,5-a]pyrimidine-2-sulfonamide (98967-40-9)

Conditions	Yield
With hydrogenchloride; sodium hydroxide; sodium carbonate; sodium chloride In water	91%

acetylacetaldehyde dimethyl acetal (5436-21-5) + trimethyl orthoformate (149-73-5) → 1,1,3,3-tetramethoxy-butane (5744-65-0)

Conditions	Yield
With toluene-4-sulfonic acid In methanol at 20℃; for 24h;	90%
With sulfuric acid

acetylacetaldehyde dimethyl acetal (5436-21-5) + 3-(β-ionilidene)-1-propyne (103633-89-2) → (6E,8E)-1,1-Dimethoxy-3,7-dimethyl-9-(2,6,6-trimethyl-cyclohex-1-enyl)-nona-6,8-dien-4-yn-3-ol (74352-13-9, 77871-12-6, 77871-15-9)

Conditions	Yield
With n-butyllithium In tetrahydrofuran at -60℃;	90%
With n-butyllithium In tetrahydrofuran; hexane for 1h; -60 deg C to room t.;	90%

acetylacetaldehyde dimethyl acetal (5436-21-5) + 1-ethoxy-1-(tert-butyldimethylsilyloxy)ethene (42201-84-3) → 3-(tert-Butyl-dimethyl-silanyloxy)-5,5-dimethoxy-3-methyl-pentanoic acid ethyl ester

Conditions	Yield
With bis-(pentafluoro phenyl) dibromo stannane In dichloromethane at -78℃; for 3h;	90%

acetylacetaldehyde dimethyl acetal (5436-21-5) + methyl allylcarbamate (19364-21-7) → Allyl-((E)-3-oxo-but-1-enyl)-carbamic acid methyl ester (219826-40-1)

Conditions	Yield
With toluene-4-sulfonic acid In chloroform Heating;	90%
With toluene-4-sulfonic acid In chloroform for 27h; Heating;	90%

2,6-Diaminopyridine (141-86-6) + acetylacetaldehyde dimethyl acetal (5436-21-5) → 2-amino-7-methyl-1,8-naphthyridine (1568-93-0)

Conditions	Yield
With phosphoric acid In water at 90℃; for 3h;	90%
In various solvent(s) Cyclization;	79%
With phosphoric acid at 90℃; for 24h;	72%

2-methyl-1H-indole (95-20-5) + acetylacetaldehyde dimethyl acetal (5436-21-5) → 2-methyl-3-(3-phenyl)indole (1157851-94-9)

Conditions	Yield
With 4-n-butyl-4-(3-sulfopropyl)thiomorpholinium 1,1-dioxide trifluoromethane sulfonate In neat (no solvent) at 60℃; for 15h; Green chemistry;	90%

acetylacetaldehyde dimethyl acetal (5436-21-5) + 2-(diethoxymethyl)formamidine hydrochloride → 2-(diethoxymethyl)-4-methylpyrimidine

Conditions	Yield
Stage #1: acetylacetaldehyde dimethyl acetal With sodium hydride In ethanol; mineral oil for 0.5h; Inert atmosphere; Stage #2: 2-(diethoxymethyl)formamidine hydrochloride In ethanol; mineral oil for 4h; Reflux;	90%

acetylacetaldehyde dimethyl acetal (5436-21-5) + 2-chlorobenzimidamide (45743-05-3) → 2-(2-chlorophenyl)-4-methylpyrimidine (1332503-18-0)

Conditions	Yield
With sodium acetate In para-xylene for 13h; Schlenk technique; Inert atmosphere; Reflux;	90%

acetylacetaldehyde dimethyl acetal (5436-21-5) + 2-methylbenzamidine (18636-97-0) → 4-methyl-2-(2-methylphenyl)pyrimidine

Conditions	Yield
With sodium acetate In para-xylene for 10h; Schlenk technique; Inert atmosphere; Reflux;	90%

acetylacetaldehyde dimethyl acetal (5436-21-5) → 1,3,5-triacetylbenzene (779-90-8)

Conditions	Yield
With aluminum (III) chloride In ethanol; acetic acid at 60℃; for 15h;	89%
With water
With water

acetylacetaldehyde dimethyl acetal (5436-21-5) + 5-amino-3-methyl-N-phenylpyrazole-4-carboxamide (96319-19-6) → 2,7-dimethyl-N-phenylpyrazolo<1,5-a>pyrimidine-3-carboxamide (96319-22-1)

Conditions	Yield
With hydrogenchloride In ethanol at 60 - 80℃; for 2h;	89%

Upstream product

• 67-56-1 methanol 
• 4652-27-1 4-methoxy-3-buten-2-one 
• 2798-73-4 1-methoxy-buten-3-yne 
• 4074-22-0 1,4-dimethyl-cyclohexa-1,4-diene 
• 51731-17-0 trans-4-methoxy-3-buten-2-one 
• 124-41-4 sodium methylate 
• 67-64-1 acetone 
• 109-94-4 formic acid ethyl ester 
• 72380-56-4 3-butenal dimethyl acetal 
• 1423-60-5 methyl ethynyl ketone 
• 622-79-7 benzyl azide 
• 625-34-3 3-oxobutyraldehyde 
• 149-73-5 trimethyl orthoformate 
• 107-31-3 Methyl formate 

Downstream Products

• 41995-57-7 4-[2]pyridylamino-but-3-en-2-one 
• 18591-78-1 6-Methyl-s-triazolo<4,3-b>pyridazin 
• 99969-13-8 5-methyl-[1,2,4]triazolo[1,5-a]pyrimidin-2-ylamine 
• 25513-97-7 2-Methylpyrimido<1,2-a>benzimidazol 
• 1721-25-1 1-(2,6-dimethylpyridin-3-yl)ethan-1-one 
• 806606-35-9 2,5-dimethyl-pyrano[3,2-b]pyrrole-3-carboxylic acid ethyl ester 
• 36357-38-7 1-(6-methyl-pyridin-3-yl)-ethanone 
• 127-73-1 N-[4-(4-Methyl-pyrimidin-2-ylsulfamoyl)-phenyl]-acetamide 
• 581-42-0 2.6-dimethylnaphthalene 
• 69225-88-3 (1RS)-1,2,3,4-Tetrahydro-1-(2-oxopropyl)-β-carbolin 
• 31525-67-4 dimethylacetal of 3-methyl-3-hydroxybutyraldehyde 
• 1453-58-3 3-Methylpyrazole 
• 39562-58-8 1,1-dimethoxybutan-3-ol 
• 4652-27-1 4-methoxy-3-buten-2-one 

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