Two New 2‐(2‐Phenylethyl)chromen‐4‐ones from Aquilaria sinensis (Lour.) Gilg

Abstract

Two new compounds, 8-chloro-6-hydroxy-2-(2-phenylethyl)chromen-4-one (1) and 8-chloro-6hydroxy-2-[2-(4-methoxyphenyl)ethyl]chromen-4-one (2), were isolated from the Aquilaria sinensis (Lour. ) Gilg. Their structures were elucidated on the basis of spectroscopic methods including 1D-and 2 D-NMR analysis.

2-(2-Phenylethyl)chromone Derivatives in Chinese Agarwood “Qi-Nan” from Aquilaria sinensis

“…Compound 6 was identified as 2-[2-(2-hydroxyphenyl) ethyl]chromone, being reported only in the synthesis of 6,6-bisbenzannulated spiroketals [45]. It was isolated as a natural product for the first time and given the name qinanone F. The structures of the other known compounds were identified as 2-(2phenylethyl)chromone (7) [16], 2-[2-(4-methoxyphenyl)ethyl] chromone (8) [16], 6-hydroxy-2-(2-phenylethyl)chromone (9) [46], 6-hydroxy-2-[2-(4-methoxyphenyl)ethyl]chromone (10) [47], 6-hydroxy-2-[2-(2-hydroxyphenyl)ethyl]chromone (11) [48], 6-hydroxy-2-[2-(3-methoxy-4-hydroxyphenyl)ethyl]chromone (12) [49], and 6-hydroxy-2-[2-(3-hydroxy-4-methoxyphenyl)ethyl]chromone (13) [15], by comparing their spectroscopic data with those reported in the above references. Qinanone A (1) was obtained as colorless needle crystals with the molecular formula C 18 H 16 O 4 as established by the HREIMS molecular peak at m/z 296.1050 [M] + (calcd.…”

“…2 Tables 1, 2 and [8, 9, 11-15, 44, 50]. A few of these were found in other genera [44,50], but most were in agarwoods from Aquilaria species [9,[11][12][13][14][15]. Therefore this Chinese agarwood "Qi-Nan" may possess a different biosynthetic pathway to yield these unsubstituted chromone rings.…”

Three New Sesquiterpenoids and One New Sesquiterpenoid Derivative from Chinese Eaglewood

“…The key NOESY correlations of H-4/H-5, H-10/H-5 were observed, which disclosed that Me-11 and Me-12 were α-oriented while H-5 was β-oriented. The relative configuration of OH-1 was determined by the NOESY correlation of between OH-1 (δ H 4.13, in DMSO-d 6 ) and Me-12 ( Figure 3). Thus, the structure of compound 4 was elucidated to be 1α-hydroxy-4α,10α-dimethyl-5βH-octahydro-azulen-8-one (Figure 1).…”

“…Research on the chemical components of the eaglewood began half a century ago. So far, a large number of compounds have been reported from this resin wood, including aromatics [2,3], sesquiterpenes [4], chromone derivatives [5][6][7][8], triterpenes, and diterpenes [9]. Some of them showed certain anti-microbial, anti-inflammation, neuroprotective, and anti-depressant activities.…”

Synthesis and Transformation of Halochromones

“…Some 6-and 8-mono-and 6,8-dichloro derivatives have been identified in Streptomyces strains [34][35][36] and recently three pestalochromones from Pestalotiopsis were isolated [37]. Halochromones also occur in higher plants, where 6-chloroapigenin was found in Equisetum arvense [38] and recently two 8-chloro-2-(2-phenylethyl)chromones were obtained from Aquilaria sinensis [39]. The versatility of halochromones as reactive organic intermediates allows the preparation of a whole series of other heterocyclic systems [40,41].…”