| Abstract: | Two new cyclobutanoid amides, piperarborenine A (=1,1′‐{(1α,2α,3β,4β)‐2,4‐bis(3,4‐dimethoxyphenyl)cyclobutane‐1,3‐diyl]dicarbonyl}bis5,6‐dihydropyridin‐2(1H)‐one]; 1 ) and piperarborenine B (=1,1′‐{(1α,2α,3β,4β)‐2‐(3,4‐dimethoxyphenyl)‐4‐(3,4,5‐trimethoxyphenyl)cyclobutane‐1,3‐diyl]dicarbonyl}bis5,6‐dihydropyridin‐2(1H)‐one]; 2 ) were isolated from the stem of Piper arborescens, besides two known cyclobutanoid amides, piperarboresine (=1,1′‐{(1α,2α,3β,4β)‐2‐(7‐methoxy‐1,3‐benzodioxol‐5‐yl)‐4‐(3,4,5‐trimethoxyphenyl)cyclobutane‐1,3‐diyl]dicarbonyl}bis5,6‐dihydropyridin‐2(1H)‐one]; 3 ) and piplartine‐dimer A (=1,1′‐{(1α,2α,3β,4β)‐2,4‐bis(3,4,5‐trimethoxyphenyl)cyclobutane‐1,3‐diyl]dicarbonyl}bis5,6‐dihydropyridin‐2(1H)‐one]; 4 ). The structures of the two new compounds were determined by spectral analyses. |
