A 1,4-Anthraquinone derivative from Tectona grandis

Syntheses of chromenes and chromanes via o‐quinone methide intermediates

“…Xiloidone, 3,4‐dihydro‐α‐lapachone ( 11 ) and its isomer, 3,4‐dihydro‐β‐lapachone ( 12 ), are the most representative substances of the chromene‐fused quinone class. These naphthoquinones are minor components in the extract of lapachol ( 13 ) [28–42]. Rodrigues and coworkers obtained 11 and 12 along with lapachol from Tabebuia avellanedae by using supercritical fluid extraction [43].…”

First Synthesis of 9,10‐Dimethoxy‐2‐methyl‐1,4‐anthraquinone: A Naturally Occurring Unusual Anthraquinone

“…In 1989, Singh et al reported the isolation of 1,4‐anthraquinone 3 from the heartwood of Tectona grandis,7 (commonly known as Sagon)8 recorded in traditional medicines, and elucidated its structure by NMR spectroscopic studies. To date, this molecule constitutes the lone example of a natural 1,4‐anthraquinone in which both C9 and C10 are occupied by a methoxy group, whereas other derivatives such as 4 – 7 9,10 are substituted only at C10.…”

2-Methylanthraquinone as a Marker of Occupational Exposure to Teak Wood Dust in Boatyards

“…Analysis and specificity of 2-MeA 2-MeA has been well-known for many years, and it has been quoted several times in the literature as a chemical compound found in teak extracts (Rudman et al, 1958;Schulz and Dietrichs, 1962;Singh et al, 1989;Windeisen et al, 2003;Sumthong et al, 2006).…”

“…toxic, mutagenic or carcinogenic effects). 2-MeA has been identified in both petroleum (Singh et al, 1989) and methanol (Wang et al, 2006) extracts of teak wood. The use of polar extraction solvents appears to be more effective, according to a study of Panamanian teak wood, which yielded ,0.1% w/w 2-MeA following extraction with petroleum ether but 1.5% w/w when extracted with acetone (Windeisen et al, 2003).…”