Showing papers on "Benzopyrans published in 1984"
TL;DR: In this paper, simple benzopyrans with a fused γ-lactone unit were prepared from an o-disubstituted arene by direct intramolecular alkoxycarbonylation/lactonization promoted by palladium diacetate; the process gives high yields and moderate stereoselectivity, favoring the cis lactone over trans by a factor of 5:1.
59 citations
13 citations
12 citations
TL;DR: A two-step process for synthesizing 2H-1-benzopyrans from phenols and β-halopropionaldehyde acetals is described in this article.
8 citations
3 citations
TL;DR: In this paper, the structures of two benzofuro[3,2-b][1]benzopyrans, the furan (6) and the 2-methylfuran (7a), and 2-ethylfuron (7b), related to cannabinol have been totally synthesized for the first time.
Abstract: Four cannabinoids, the furan (6), the 2-methylfuran (7a), the 2-ethylfuran (7b), and the 2,3-dimethylfuran (11), related to cannabinol have been totally synthesized for the first time. The structures of two of three benzofuro[3,2-b][1]benzopyrans, the furan (6) and the 2-methylfuran (7a), recently isolated from cannabis resin smoke, were thereby confirmed. The earlier proposed structure of the third furan, as being the 2,3-dimethylfuran (11), was shown to be incorrect. The structure of 2-ethylfuran (7b) is now proposed for this cannabinoid. The key step in the syntheses of the furan (6) and the 2,3-dimethylfuran (11) was an internal site-specific base-catalysed cyclization of the intermediate aryloxyacetaldehyde (3) and 3-aryloxybutan-2-one (8), respectively. The 2-alkylated furans (7a) and (7b) have been synthesized in good yield by a highly selective lithiation of the furan (6) followed by treatment with an alkyl iodide.
3 citations
Patent•
12 May 1984
2 citations
TL;DR: Les derives acyloxy du titre sont prepares par chauffage d'anhydrides d'acides et de benzoyl-3 chromannone-2 en presence de triethylamine; ils sont ensuite transformes en derives acylamino par action de nitrile en presence of H 2 SO 4
Abstract: Les derives acyloxy du titre sont prepares par chauffage d'anhydrides d'acides et de benzoyl-3 chromannone-2 en presence de triethylamine; ils sont ensuite transformes en derives acylamino par action de nitrile en presence d'H 2 SO 4
1 citations