Methyl 3-bromopropanoate → 2,2-Dimethyl-4,6-dioxo-5-[3-[(triphenylmethyl)thio]propyl]-1,3-dioxane-5-propanoic acid methylester

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Reaction Steps

5 mmol of 2,2-dimethyl-5-[3-[(triphenylmethyl)-thio]-propyl]-1,3-dioxane-5-propanoic-4,6-dione (I) (2.3 g), was dissolved with 20 mmol methyl-3-bromopropionate (3.34g=2.18 ml) and 4.6 ml of 4.37 M methanolic solution of sodium methoxide (20 mmol) in 10 ml of methanol. The reaction mixture was heated to 60° C. overnight after which TLC in hexane/ethylacetate 1:1 detected no starting material. The mixture was then evaporated to dryness and mixed with 40 ml of aqueous 10% KHSO4. The organic material was extracted by 3 portions of EtOAc, the organic layers were combined dried with MgSO4 and evaporated. The residue was crystallized from hexane/ethylacetate to yield 2.1 g (77%) of 2,2-dimethyl-4,6-dioxo-5-[3-[(triphenyl-methyl)thio]propyl]-1,3-dioxane-5-propanoic acid methyl ester (II), 13C-NMR (CDCl3) δ 24.6, 29.4, 29.5, 29.6, 31.4, 32.6, 37.7, 51.9, 52.8, 66.8, 105.7, 126.7, 127.9, 129.5, 144.7, 168.4, 172.0.

Provenance & Evidence