2-styryl-4-oxazolecarboxylic acid methyl ester

Activated manganese dioxide is a closely related oxidant to Ni02 but less commonly used. Meguro, Fujita, and co-workers described oxidation of oxazolines using Mn02 in their synthesis of antidiabetic agents. For example, the serine-derived P-hydroxyamide 21 was cyclized to the oxazoline 22 with polyphosphoric acid. Oxidation of 22 with activated manganese dioxide afforded 2-styryl-4-oxazolecarboxylic acid methyl ester, 23 (Scheme 1.4). 

Further work firom Shiori s group described the total synthesis of 1191a, but not via their original strategy. Originally, the authors focused on an oxazole-containing linear precursor to the pyran fragment, which was to be prepared fi om 2-styryl-4-oxazolecarboxylic acid methyl ester 1426 (Scheme 1.366). Preparation of... 

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See also in sourсe #XX -- [ , ]

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