Mercaptoacetaldehyde, diethyl acetal

Malonic ester syntheses, 30, 7 Malononitrile, 37, 53 Malonyl dichloride, 33, 20 Mandelic acid, 36, 3 Mandelic acid, />-bromo, 35,11 Mannich reaction, with acetone, 37,18 Mercaptoacetaldehyde, diethyl ACETAL, 35, 51... 

The michael addition of mercaptoacetaldehyde diethyl acetal 87 and 9-cyanononenal 86 in the presence of triethylamine gave the adduct 88 quantitatively. 1-Tributyl-phosphoranylidene-2-heptanone was reacted with the aldehyde and produced the conjugated enone 89, which ketalizated with four equivalents of ethylene glycol and catalytic amounts of p-toluenesulfonic acid in refluxing benzene to the bis-dioxolane 90. Surprisingly, the isomeric bisdioxolane with the double bond at positions C13 14 was not detected. 

Mannich reaction, with acetone, 37, 18 Mercaptoacetaldehyde, diethyl ACETAL, 35, SI... 

The 2-thiobenzoyl acetaldehyde diethyl acetal (17.2 g) was dissolved in 100 ml THF followed by the addition of 6 g NaOH in 20 ml H20. The mixture was refluxed under N2 for 15 h, then cooled and diluted with water (200 ml) and the product extracted with ether (3 x 200 ml). The extract was dried, the solvent removed in vacuo and the residue distilled to yield 7.1 g of mercaptoacetaldehyde diethylacetal. 

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