Rare A-Type, New Spiro-Type, and Highly Oligomeric Proanthocyanidins from Pinus massoniana

Abstract

<div>Isolation of underivatized PACs led to three new, structurally unique PACs (<b>1</b>-<b>3</b>) from pine bark. Pinutwindoublin (<b>1</b>) is the first known trimer with double A-type interflavanyl linkages (2α→O→5,4α→6 and 2α→O→7,4α). Pinuspirotetrin (<b>2</b>) represents the first PAC tetramer with a heterodimeric framework consisting of one spiro-type and one A-type dimer. Pinumassohexin (<b>3</b>) was elucidated as a mixed A + B type hexamer that consists of the tetramer, peanut procyanidin E, and an A-type dimer (<b>5</b>).</div>

Rare A-Type, Spiro-Type, and Highly Oligomeric Proanthocyanidins from Pinus massoniana

“…The preprint of this article is available at https://doi.org/10.26434/chemrxiv.12168168.v1. The raw NMR data (FIDs) are made available at https://doi.org/10.7910/DVN/CI2ODS.…”