The key intermediate of eudesmane sesquiterpenoid analogue 2c was synthesized with high regioselectivity via Diels-Alder reaction from the dienophile 2-methoxyl-6-methyl-1,4-benzoquinone and the diene 1-methoxyl-3-isopropyl-1, 4-butadiene.
One-pot reaction was reported for the synthesis of 5-aryl diketo-1H-tetrazols (2). Meanwhile, 1-methyl-1-methoxyethyl (MME) as protective group of tetrazole was firstly reported. The protective and deprotective reactions were performed in moderate conditions and the new method leads to simplified process and increased productivity. Six novel 5-aryl diketo-1H-tetrazol compounds were synthesized by using this method for further biological screening.