1.3- Dioxane-4,6-diones

Dieis-Aider reactions of photoenoi of 2-methylbenzaldehyde with 5-alkylidene-1,3-dioxane-4,6-dione derivatives [48]... 

Alkylidene phenylaminomethylenemalonates (444) were reacted with sodium hydride or lithium hydride in acetonitrile at 40°C for 2 hr. The reaction mixtures were then cooled to 0-20°C, and they were treated with a solution of dialkyl peroxydicarbonate in methylene chloride for 24 hr to give 5-alkoxycarbonyloxy-5-phenyliminomethyl-1,3-dioxane-4,6-diones (1616) in 54-75% yields (80CB2630). 

C-alkylated Meldrum s acid derivatives are cleaved asymmetrically by alkoxide anions in the presence of quininium salts to yield chiral half esters (9.2.2) [11]. Thus, benzylquininium and cinchonidinium salts produce fl-hemi-esters and the cincho-nium and quinidinium salts produce the S-hemi-esters from, for example, 2,2,5-trimethyl-5-pheny 1-1,3-dioxane-4,6-dione. 

Ayras studied the stereochemistry of 2,5-di- and 2,2,5-tri-substituted 1,3-dioxane-4,6-diones (Meldrum s acid derivatives) in CCU (76MI1, 76MI2). 

A. 5-(1-Hydroxyethylidene)-2,2-dimethyl-1,3-dioxane-4,6-dione. A flame-dried, 500-mL, three-necked, round-bottomed flask is equipped with a stir bar, nitrogen inlet adapter, and a pressure-equalizing addition funnel fitted with a rubber septum. The flask is charged with 22.0 g of Meldrum s acid dissolved in 153 mL of methylene chloride, and 24.8 mL of pyridine (Note 1), and the mixture is cooled to -25°C (Note 2). A mixture of 18.3 mL of methylene chloride and 13.1 mL of acetyl chloride is slowly added to the reaction mixture via the addition funnel over 1 hr (Note 3). After the addition of the acetyl chloride is complete, the reaction is slowly warmed over 3 hr to... 

Meldrum s acid Malonic acid, cyclic isopropylidene ester (8) 1,3-Dioxane-4,6-dione, 2,2-dimethyl- (9) (2033-24-1)... 

Acetyl Meldrum s acid See 5-(1-hydroxyethylidene)-1,3-dioxane-4,6-dione... 

Dimethyl-1,3-Dioxane-4,6-dione (Meldrum s Acid) Malonic acid, cyclic isopropylidene ester (8) 1,3-Dioxane-4,6-dione, 2,2-dimethyl- (9) (2033-24-1) Ethylenediammonium diacetate 1,2-Ethanediamine diacetate (9) (38734-69-9) (R)-Citronellal 6-Octenal, 3,7-dimethyl-, (R)-(+)- (8,9) (2385-77-5)... 

Dimethyl-1,3-dioxane-4,6-dione 0.72 g, 5.0 mmol may cause eye, skin, and... 

MELDRUM S ACID 2,2-DIMETHYL-1,3-DIOXANE-4,6-DIONE MALONIC ACID, CYCLIC ISOPROPYLIDENE ESTER 1,3-DIOXANE-4,6-DIONE, 2,2-DIMETHYL- (2033-24-1), 67, 170 69, 33 p-Mentha-6,8-dien-2-one (6485-40-1), 66, 13... 

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