Methyl acetylacetate is an endogenously produced metabolite.

Physicochemical Properties

Molecular Formula	C5H8O3
Molecular Weight	116.12
Exact Mass	116.047
CAS #	105-45-3
Related CAS #	Methyl acetylacetate-13C4;107694-17-7
PubChem CID	7757
Appearance	Colorless to light yellow liquid
Density	1.0±0.1 g/cm3
Boiling Point	169.4±8.0 °C at 760 mmHg
Melting Point	-28 °C
Flash Point	61.6±18.5 °C
Vapour Pressure	1.5±0.3 mmHg at 25°C
Index of Refraction	1.399
LogP	0.19
Hydrogen Bond Donor Count	0
Hydrogen Bond Acceptor Count	3
Rotatable Bond Count	3
Heavy Atom Count	8
Complexity	106
Defined Atom Stereocenter Count	0
SMILES	CC(CC(OC)=O)=O
InChi Key	WRQNANDWMGAFTP-UHFFFAOYSA-N
InChi Code	InChI=1S/C5H8O3/c1-4(6)3-5(7)8-2/h3H2,1-2H3
Chemical Name	methyl 3-oxobutanoate
HS Tariff Code	2934.99.9001
Storage	Powder-20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month
Shipping Condition	Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Biological Activity

ADME/Pharmacokinetics	Absorption, Distribution and Excretion Like other esters, /methyl acetoacetate/ is potentially skin-absorbable. Metabolism / Metabolites Although... similar to other acetates, hydrolysis and metabolic degradation occur rapidly, especially since acetoacetic acid is a common mammalian metabolite.
Toxicity/Toxicokinetics	Non-Human Toxicity Values LD50 Rat oral 3.0 g/kg LD50 Rabbit dermal >10 mL/mg LD50 Rat (male) oral 2.58 g/kg (95% Confidence interval: 2.23 -2.98 g/kg) LD50 Rat (female) oral 3.37 g/kg (95% Confidence interval: 2.92 -3.90 g/kg) For more Non-Human Toxicity Values (Complete) data for METHYL ACETOACETATE (7 total), please visit the HSDB record page.
References	[1]. Gas-phase proton NMR studies of keto-enol tautomerism of acetylacetone, methyl acetoacetate, and ethyl acetoacetate. The Journal of Physical Chemistry, 1985, 89(15): 3347-3352.
Additional Infomation	Methyl acetoacetate appears as a clear colorless liquid. Flash point 158 °F. Denser than water and slightly soluble in water. Vapors heavier than air. Methylacetoacetic acid is an oxo carboxylic acid.

Solubility Data

Solubility (In Vitro)

H2O: 100 mg/mL (861.18 mM) DMSO: 100 mg/mL (861.18 mM)

Solubility (In Vivo)

Solubility in Formulation 1: ≥ 2.5 mg/mL (21.53 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL. Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution. Solubility in Formulation 2: ≥ 2.5 mg/mL (21.53 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly. Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution. Solubility in Formulation 3: ≥ 2.5 mg/mL (21.53 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	8.6118 mL	43.0589 mL	86.1178 mL
	5 mM	1.7224 mL	8.6118 mL	17.2236 mL
	10 mM	0.8612 mL	4.3059 mL	8.6118 mL

*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.