Sodium hydride → 2-Methyl-4-(6-carbomethoxyhexyl)-5-(3-keto-1-trans-octenyl)-thiazole

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Reaction Steps

To a suspension of 0.45 g of sodium hydride in 5 ml of anhydrous 1,2-dimethoxy-ethane a solution of 4.12 g of 2-oxoheptylphosphonic acid dimethyl ester in 20 ml of 1,2-dimethoxy-ethane was added under stirring at room temperature. The reaction mixture was stirred for an hour, then a solution of 1 g of 2-methyl-4-(6-carbomethoxyhexyl)-thiazole-5-carbaldehyde (XIII, R1 = CH3) prepared according to point (e) of Example 2, in 10 ml of 1,2-dimethoxy-ethane was added dropwise, and stirring was continued for 5 hours. After adding dropwise 30 ml of water under ice-cooling to the reaction mixture, it was extracted with 3 × 20 ml of diethyl ether. The extract was dried on over sodium sulphate and evaporated in vacuo. The evaporation residue was purified by preparative thin layer chromatography, using a silica gel layer as adsorbent and a mixture of 40 % ethyl acetate and 60 % n-heptane as running solvent. The yield was 0.81 g of 2-methyl-4-(6-carbomethoxyhexyl)-5-(3-keto-1-trans-octenyl)-thiazole (Ia, R1 = CH3) of chromatographic purity.

Provenance & Evidence