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Isopropylidene malonate_Molecular_structure_CAS_2033-24-1)
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Isopropylidene malonate

Catalog No. A15603 Name Alfa Aesar
CAS Number 2033-24-1 Website
M. F. C6H8O4 Telephone
M. W. 144.12532 Fax
Purity 98% Email
Storage Chembase ID: 58237


IUPAC name
IUPAC Traditional name
meldrum's acid
Meldrum's Acid


EC Number 217-992-8
Merck Index 145817
MDL Number MFCD00006638
Beilstein Number 117310
CAS Number 2033-24-1


Purity 98%
Melting Point 92-96°C
GHS Pictograms GHS07
GHS Hazard statements H315-H319-H335
European Hazard Symbols Irritant Irritant (Xi)
GHS Precautionary statements P261-P305+P351+P338-P302+P352-P321-P405-P501A
Risk Statements 36/37/38
RTECS JH0800000
Safety Statements 26-37
TSCA Listed



  • See also: Org. Synth., 77, 114 (1999).
  • Condensation with lactim ethers, catalyzed by Nickel(II) 2,4-pentanedionate, 18811, with alcoholysis of the resulting enamino Meldrum's acids, gives of cyclic ?-enamino esters, useful as alkaloid precursors: J. Org. Chem., 43, 4662 (1978); for an example, see: Org. Synth. Coll., 8, 263 (1993).
  • Malonate ester which is an unusually strong acid (pKa = 9.97) in comparison with, e.g. Diethyl malonate, A15468: J. Am. Chem. Soc., 70, 3426 (1948). The mild conditions required for alkylation, acylation, etc. and the ease with which the products undergo alcoholysis or hydrolysis-decarboxylation make Meldrum's acid a valuable and versatile synthetic intermediate. Reviews: Chem. Soc. Rev., 7, 345 (1978); Heterocycles, 32, 529 (1991); Synlett, 1649 (2004).
  • For phase-transfer alkylation using K2CO3 as base, see: Synthesis, 452 (1982); Bull. Soc. Chim. Belg., 104, 643 (1995). Phase-transfer addition to Michael acceptors also occurs: Synthesis, 224 (1984). Mitsunobu dialkylation with an alcohol and DIAD/Ph3P is also possible: J. Org. Chem., 62, 1617 (1997).
  • Knoevenagel condensation with aldehydes gives ylidene derivatives which are solvolyzed by alcohols to give monoesters of alkylidene or arylidene malonic acids: J. Am. Chem. Soc., 74, 5897 (1952). For diastereoselective condensation with citronellal, followed by intramolecular Diels-Alder reaction, see: Org. Synth. Coll., 8, 353 (1993). With formaldehyde in pyridine gives the stable pyridinium methylide which, on treatment with acid, generates the useful reactive Michael acceptor and dienophile, methylene Meldrum's acid: Synthesis, 215 (1996).
  • With an aryl aldehyde in the presence of triethylamine and formic acid at ambient temperature, in situ reduction to the arylmethyl Meldrum's acid occurs, whereas at 70-80oC, the 3-arylpropionic acid is obtained: Synth. Commun., 25, 3067 (1995).
  • C-Acylation with acyl chlorides occurs in the presence of 2 equivalents of pyridine in high yield. Alcoholysis of the product provides a good route to ?-keto esters: J. Org. Chem., 43, 2087 (1978); Org. Synth. Coll.,7, 359 (1988), also obtainable by reaction of the Na salt with acid anhydrides in DMF: Synthesis, 451 (1982). Alternatively, mild hydrolysis and decarboxylation of the intermediate acyl Meldrum's acid gives the methyl ketone, providing an alternative to organometallic methods for conversion of acyl chlorides to methyl ketones: Synth. Commun., 10, 221 (1980):