New Pyrrole Alkaloids with Bulky N‐Alkyl Side Chains Containing Stereogenic Centers from Lycium chinense. Issue 8 (12th August 2013)

• Record Type: Journal Article
• Authors: Joung Youn, Ui; Kil, Yun‐Seo; Nam, Joo‐Won; Jin Lee, Yoo; Kim, Jinwoong; Lee, Dongho; Lee, Je‐Hyun; Seo, Eun‐Kyoung
• Is Part Of: Helvetica chimica acta. Volume 96:Issue 8(2013:Aug.)
• Page Start: 1482
• Page End: 1487
• Publication Date: 2013-08-12
• Subjects: Chemistry -- Periodicals; Chemistry, Analytical -- periodicals; Chimie -- Périodiques; 540
• DOI: 10.1002/hlca.201200608
• Languages: English
• ISSNs: 0018-019X

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>Four new pyrrole alkaloids, methyl 2‐[2‐formyl‐5‐(methoxymethyl)‐1<italic>H</italic>‐pyrrol‐1‐yl]propanoate (<bold>1</bold>), methyl 2‐[2‐formyl‐5‐(methoxymethyl)‐1<italic>H</italic>‐pyrrol‐1‐yl]‐3‐(4‐hydroxyphenyl)propanoate (<bold>2</bold>), dimethyl 2‐[2‐formyl‐5‐(methoxymethyl)‐1<italic>H</italic>‐pyrrol‐1‐yl]butanedioate (<bold>3</bold>), and dimethyl 2‐[2‐formyl‐5‐(methoxymethyl)‐1<italic>H</italic>‐pyrrol‐1‐yl]pentanedioate (<bold>4</bold>), were isolated from the AcOEt extract of the fruits of <italic>Lycium chinense</italic><sc>Miller</sc> (Solanaceae). The stereogenic center C(2) in the bulky <italic>N</italic>‐alkyl side chain in each of <bold>1</bold>–<bold>4</bold> seems to hold the H‐atoms of nearby CH₂ groups, CH₂(7′) and CH₂(3) (if R≠H), leading to two different chemical shifts in the ¹H‐NMR spectrum due to their diastereotopic characteristics. In the ¹H‐NMR data of each of <bold>2</bold>–<bold>4</bold>, the enhancement of HC(2) signal was inhibited by the R group, probably due to steric hindrance, and its chemical shift was influenced by the anisotropy effect. The structures of <bold>1</bold>–<bold>4</bold> were elucidated by analysis of various spectroscopic data, including 1D‐ and 2D‐NMR.</p> </abstract>