Topic
Pyran
About: Pyran is a research topic. Over the lifetime, 5275 publications have been published within this topic receiving 48482 citations. The topic is also known as: oxine & pyran.
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TL;DR: Magnesium oxide (MgO) as a highly effective heterogeneous base catalyst effectively catalyzes the three component reaction of aryl aldehydes, malononitrile and α-hydroxy or α-amino activated C-H acids as mentioned in this paper.
Abstract: Magnesium oxide (MgO) as a highly effective heterogeneous base catalyst effectively catalyzes the three component reaction of aryl aldehydes, malononitrile and α-hydroxy or α-amino activated C–H acids such as 1,3-cyclohexanedione, dimedone, 4-hydroxy-6-methylpyrone, 4-hydroxycoumarin, 1,3-dimethylbarbituric acid and 1,3-dimethyl-6-amino uracil to the formation of the corresponding pyran annulated heterocyclic systems The catalyst is inexpensive and easily obtained, stable and storable, easily recycled and reused for several cycles with consistent activity
178 citations
Patent•
09 Sep 1985
TL;DR: In this article, 6-[2.6]-pyrrol-1-yl)alkyl]pyran-2-ones and corresponding ring-opened hydroxy-acids derived therefrom are potent inhibitors of the enzyme 3-hydroxy-3-methylglutarylcoenzyme A reductase.
Abstract: 6-[2-(Substituted-pyrrol-1-yl)alkyl]pyran-2-ones and the corresponding ring-opened hydroxy-acids derived therefrom are potent inhibitors of the enzyme 3-hydroxy-3-methylglutarylcoenzyme A reductase (HMG-CoA reductase), and are thus useful hypolipidemic and hypocholesterolemic agents. Pharmaceutical compositions containing such compounds, and a method of treatment employing such pharmaceutical compositions are also disclosed.
166 citations
TL;DR: In this paper, a unique synthesis of functionalised α-tetralones has emerged from cyclic and acyclic carbon nucleophiles with 2 substituted 1,3-oxazinanes.
166 citations
TL;DR: Proline has been used as a mild, efficient and neutral catalyst for synthesis of various 4H-benzo[b]pyran derivatives via a one-pot three-component condensation of aromatic aldehydes, active methylene compounds, and dimedone in aqueous media as discussed by the authors.
Abstract: (S)-Proline has been used as a mild, efficient and neutral catalyst for synthesis of various 4H-benzo[b]pyran derivatives via a one-pot three-component condensation of aromatic aldehydes, active methylene compounds, and dimedone in aqueous media. This method offers the advantages of proceeding and neutral and mild conditions, giving high to excellent yields of the products and simple workup.
166 citations
TL;DR: A general regiospecific synthesis of dibenzo[b,d]pyran-6-one derivatives 1a,c and 8a-i related to ellagic acid is described in this article.
Abstract: A general regiospecific synthesis of dibenzo[b,d]pyran-6-one derivatives 1a,c and 8a-i related to ellagic acid is described (Scheme I, Table I). The sequence involves directed ortho metalation-boronation of benzamides 4 to give the arylboronic acids 5, which, upon palladium-catalyzed cross-coupling with alkoxybromobenzenes 6 leads to the biphenylamides 7. BBr 3 demethylation followed by acid-catalyzed cyclization affords pyranone 8. In this manner, the naturally occurring dibenzopyranones 1a, autumnariol (1c), and the heterocyclic analogue 13 (Scheme III) were efficiently prepared
161 citations