Monomethyl malonate

Reaction of (T)-(-)-2-acetoxysuccinyl chloride (78), prepared from (5)-mahc acid, using the magnesiobromide salt of monomethyl malonate afforded the dioxosuberate (79) which was cyclized with magnesium carbonate to a 4 1 mixture of cyclopentenone (80) and the 5-acetoxy isomer. Catalytic hydrogenation of (80) gave (81) having the thermodynamically favored aH-trans stereochemistry. Ketone reduction and hydrolysis produced the bicycHc lactone acid (82) which was converted to the Corey aldehyde equivalent (83). A number of other approaches have been described (108). 

The reaction of amino acid imidazolides with the potassium salt of monomethyl malonate in the presence of one equivalent of MgCl2, CoCl2, or MnCl2 results in the formation of jS"keto-y-aminocarboxylates.[64]... 

The synthesis of the representative compound of this series, 1,4-dihydro-l-ethyl-6-fluoro (or 6-H)-4-oxo-7-(piperazin-l-yl)thieno[2/,3/ 4,5]thieno[3,2-b]pyridine-3-carboxylic acid (81), follows the same procedure as that utilized for compound 76. Namely, the 3-thienylacrylic acid (77) reacts with thionyl chloride to form the thieno Sjthiophene -carboxyl chloride (78). Reaction of this compound with monomethyl malonate and n-butyllithium gives rise to the acetoacetate derivative (79). Transformation of compound 79 to the thieno[2 3f 4,5]thieno[3,2-b]pyhdone-3-carboxy ic acid derivative (80) proceeds in three steps in the same manner as that shown for compound 75 in Scheme 15. Complexation of compound 75 with boron trifluoride etherate, followed by reaction with piperazine and decomplexation, results in the formation of the target compound (81), as shown in Scheme 16. The 6-desfluoro derivative of 81 does not show antibacterial activity in vitro. 

A methanolic solution of isopropylidene (3-methyl-6-oxopiperidin-2-yli-dene)malonate (537) was boiled overnight in the presence of sodium methylate to give monomethyl malonate (1627) in 86% yield (86JST319). The half ester (1627) was decarboxylated at 150°C to afford methyl (3-methyl-6-oxopiperidin-2-ylidene)acetate (1628) in 95% yield. 

Methanolic MeONa (3M, 0.12 ml) is added to the V-benzylquininium or quinidinium chloride (0.162 g, 0.36 mmol) in dry THF (2 ml) at room temperature. The mixture is stirred at room temperature for 10 min and the Meldrum s acid derivative (0.3 mmol) in dry PhMe (13 ml) is added at -50°C. The course of the reaction is monitored by GLC. On completion, the mixture is stirred for a further 15 min at -50°C and aqueous itric acid (3%, 30 ml) is added. The aqueous phase is separated, and extracted with Et20 (3 x 20 ml). The combined extracts are washed with brine (20 ml) and dried (Na2S04). Evaporation of the Et20 under reduced pressure gives the monomethyl malonic ester. 

The reaction with monomethyl malonate in acetic acid, which does not occur at 0-10°C, proceeds smoothly when sonication is applied (Allegretti et al. 1993). From cyclohexene, only the cis ring fusion in bicyclic lactone is observed the product is formed at 80% yield for 15 min at 10°C. The overall transformation, in brief, is shown in Scheme 6.16. The stereoselectivity of the sonochemical process probably reflects the enhanced reaction rate, which does not allow equilibration processes to take place. 

Potassium monomethyl malonate Propanedioic acid, monomethyl ester, potassium salt (9) (38330-80-2)... 

The C-acylation reactions of magnesium monomethyl malonate proceed in the presence of acid- and base-sensitive functionality, as illustrated in the reaction sequence shown belowH ... 

A. Potaasium monomethyl malonate. Dimethyl malonate Note 1, 264.2 g,... 

A unique preparation of ketenes is by thermal decomposition of malonic anhydrides, which form ketenes and carbon dioxide (Scheme 7.47). Ketene, methylketene, and dimethylketene are formed by this methodology. Surprisingly, the monomethyl malonic anhydride is the most reactive and the dimethyl is the slowest. 

B-hydroxy-acid using monomethyl malonate followed by enolization... 

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