Pyruvic acid disadvantages

However, the key disadvantage of the reaction described in [199] is observed in the first step—synthesis of unsaturated ketoacids 236 with very low yields (20-30%) [200]. The same authors [201] proposed a multicomponent approach to azolopyr-imidinecarboxylic acids. The reactions of pyruvic acid 239 and aromatic aldehydes 240 with 2-aminobenzimidazole, 5-aminotetrazole 156 and 3-amino-1,2,4-triazole 147 in alcohols, DMF and acetic acid were studied (Scheme 3.67). 

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