Caffeoyl esters of threonic acid and its lactone from Viguiera Pazensis

two caffeoyl esters of sugar derivatives: 3-o-caffeoyl-2-c-methyl-d-threono-1,4-lactone, 4-o-caffeoyl-2-c-methyl-d-threonic acid, along with the previously known compounds: 2-c-methyl-d-threono-1,4-lactone, caffeic acid, carabrone, 5,7,3'-trihydroxy-4'-methoxyflavone, and 5,7,3'-trihydroxy-6,4'-dimethoxyflavone were isolated from the aerial parts of viguiera pazensis. their structures were elucidated by application of various spectroscopic methods, including 1d and 2d nmr spectroscopy.