Diethyl malonate, condensation with acetone

Diethyl malonate, condensation with acetone, 50, 39 Diethyl 5-methylcoprost-3-en-yl phosphate, 52, 109 Diethyl phosphorochloridate,... 

A Knoevenagel condensation/Michael addition sequence has been reported by Barbas III and coworkers (Scheme 2.70) [158] using benzaldehyde, diethyl malonate, and acetone in the presence of the chiral amine (S)-l-(2-pyrrolidinyl-methyl)-pyrrolidine (2-301). As the final product the substituted malonate 2-302 was isolated in 52% yield with 49% ee. 

The condensation of 5-acetyl derivative 404 instead of the corresponding 5-formyl compound, with ethyl acetoace-tate, ethyl benzoylacetate, and diethyl acetone-1,3-dicarboxylate, by heating in the absence of base gave the respective 6-acylpyrido[2,3-4]pyrimidin-7(8//)-ones 406. The reaction of 404 with diethyl malonate afforded the 6-carboxylate 407 <2005RCB784>. Reaction of 405 with triethyl phosphonoacetate yielded 408 <2001W02001070741>. 

Ketones do not condense readily with malonic ester. The condensation of acetone and diethyl malonate is brought about by heating for 24 hours with acetic anhydride and zinc chloride. The yield of diethyl isopropyl-idenemalonate is 52%. ° Under similar conditions methyl ethyl ketone condenses to the extent of only 19%. ° ... 

The catalytic activity of the NHs-grafted mesoporous silica, FSMN, was examined in some base-catalysed condensations (eqn. 1). The results were listed in Table 1. The FSMN catalyst used here was FSMN-5 that was prepared by the pre-activation at 1073 K followed by NH3-treatment at 973 K. The Aldol condensation of benzaldehyde and acetone did not proceed in this condition (entry 1). The Knoevenagel condensation of benzaldehyde and diethyl malonate (entry 2) did not occurred. On the other hand, the reactions with malononitrile (entry 3) and with ethyl cyanoacetate (entry 4) were catalysed by the FSMN-5. This shows that the NHa-grafted mesoporous silica would function as base catalyst. 

Ketones can also be condensed with malonic acid by the Knoevenagel method for example, 3-methyl-2-butenoic acid is formed in 60% yield when malonic acid is heated with acetone in pyridine containing a little piperidine 909 when diethyl ketone is used in this synthesis the yield falls to 35%, and the reaction fails (yield 5%) with cyclohexanone. However, in such cases condensation of ketones with malonic acid is successful if piperidine acetate is used as catalyst. 

Quinoxaline-2-carboxaldehyde has been converted into the 2-carboxylic acid by oxidation with potassium permanganate in acetone and reduced to the 2-hydroxymethyl compound by treatment with formalin and potassium hydroxide. It also undergoes other typical reactions of aromatic aldehydes such as benzoin formation on reaction with potassium cyanide - and condensation reactions with malonic acid and its diethyl ester and Schiff base formation. Acid-catalyzed reaction of quinoxaline-2-carboxaldehyde with ethylene glycol gives the cyclic acetal the diethylacetal has been prepared by reaction of 2-dibromomethylquinoxaline with sodium ethoxide. " An indirect preparation of the oxime 11 is achieved by treatment of 2-nitromethyl-quinoxaline (10) with diazomethane followed by thermolysis of the resulting nitronic ester. 

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