We recently reported the successful introduction of the isopropyl group into the aromatic ring of 5-methoxy-1-tetralone and 7-methoxy-1-tetralone using 2-propanol (2PrOH) and polyphosphoric acid (PPA). These results have now prompted us to carry out the isopropylation of 6-methoxy-1-tetralone (1) as a possible route to 5-isopropyl-6methoxy-1-tetralone (3) and 7-isopropyl-6-methoxy (4) respectively (Scheme 1). The tetralone 3 and tetralone 4 are potential intermediates for the preparation of the bioactive phenolic diterpenes Totarol 5 and Sempervirol 6 respectively (Scheme 1). These compounds were originally isolated from the wood of Tetraclinis articulata and from the resin of Cupressus sempervirens respectively. Recently Totarol 5 has also been discovered in the Chilean Podocarpaceae, juniperus and Mediterranean propolis. It has been approved for use as an antimicrobial additive in toothpaste and acne treatments and for prophylaxis of schistosomiasis and fascioliasis in humans, sheep, goats and cattle. The antibacterial activity of Totarol 5 and anthelmintic activity of Sempervirol 6 are well documented. In the event, to a mixture of commercially available PPA and 2-PrOH heated to 75–80 C we added the tetralone 1 and the mixture was heated for 5 h to obtain a viscous material. This contained a mixture of recovered tetralone 1 and three products of different intensities (but distinct Rf values) as evidenced in thin layer chromatography. Chromatographic purification afforded tetralones 2, 3 and 4 in yields of 10%, 20% and 32% respectively (Scheme 1). The structures of the tetralones 2, 3 and 4 were ascertained by H NMR and C NMR spectroscopy (see Experimental Section). When the isopropylation experiment was carried out by heating the reaction mixture at 100–110 C for 10h, the tetralone 4

中文翻译：

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6-甲氧基-1-四氢萘酮的异丙基化

我们最近报道了使用 2-丙醇 (2PrOH) 和多磷酸 (PPA) 将异丙基成功引入 5-甲氧基-1-四氢萘酮和 7-甲氧基-1-四氢萘酮的芳环中。这些结果现在促使我们进行 6-甲氧基-1-四氢萘酮 (1) 的异丙基化反应，作为制备 5-异丙基-6甲氧基-1-四氢萘酮 (3) 和 7-异丙基-6-甲氧基 (4) 的可能途径分别（方案1）。四氢萘酮 3 和四氢萘酮 4 分别是制备具有生物活性的酚类双萜 Totarol 5 和 Sempervirol 6 的潜在中间体（方案 1）。这些化合物最初分别从 Tetraclinis articulata 的木材和 Cupressus sempervirens 的树脂中分离出来。最近还在智利罗汉松科、杜松和地中海蜂胶中发现了 Totarol 5。它已被批准用作牙膏和痤疮治疗中的抗菌添加剂，以及预防人类、绵羊、山羊和牛的血吸虫病和片吸虫病。Totarol 5 的抗菌活性和 Sempervirol 6 的驱虫活性已得到充分证明。在这种情况下，将市售 PPA 和 2-PrOH 的混合物加热到 75-80 摄氏度，我们添加四氢萘酮 1，并将混合物加热 5 小时以获得粘性材料。这包含回收的四氢萘酮 1 和三种不同强度（但不同 Rf 值）的产品的混合物，如薄层色谱所示。色谱纯化得到四氢萘酮 2、3 和 4，产率分别为 10%、20% 和 32%（方案 1）。四氢萘酮2的结构，3 和 4 由 H NMR 和 C NMR 光谱确定（见实验部分）。当通过将反应混合物在 100-110°C 加热 10 小时进行异丙基化实验时，四氢萘酮 4