Studies in claisen rearrangements a novel oxidative rearrangement of 3-aryloxymethyl-(4H)-benzopyrans
TL;DR: In this article, the Oxidative Claisen rearrangement of 3-aryloxymethyl-(2H)-benzopyrans has been shown to yield the normal products.
About: This article is published in Tetrahedron Letters.The article was published on 1983-01-01. It has received 6 citations till now. The article focuses on the topics: Carroll rearrangement & Claisen rearrangement.
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TL;DR: Condensation reactions of dialdehydes and naphthols have been carried out and the structures of the products have been investigated as mentioned in this paper, and Naphthofuronaphthoffuran type compounds have been obtained in the case of using glyoxal and 2-naphthol or dihydroxynaphthalenes Malonaldehyde and glutaraldehyde have resulted methano and propano-dinaphtho[1,3]dioxocins respectively.
20 citations
TL;DR: In this paper, the synthesis of 7a,15a-dlhydro, 15a-methylnaphtho[2,l-b] naphthol [1',2':5,6] pyrano[3,2-e]pyran (II) and 7a 15a -dihydro-7a-mmethyl-15aisopropyi naphTHo [2,1-b], naphthso [1',2' : 5,6]-pyrano [3
8 citations
TL;DR: In this article, a heterocyclic system was obtained from malono-nitrile and o-quinone methides, generated in situ by the thermolysis of phenolic Mannich bases in the presence of 1,8diazabicyclo[5.4.0]undec-7-ene.
Abstract: 5a-Amino-5aH,11H-chromeno[2,3-b]chromene-11a(12H)-carbonitriles were synthesized from malono-nitrile and o-quinone methides, generated in situ by the thermolysis of phenolic Mannich bases in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene. It was also shown that this heterocyclic system can be obtained from 2-amino-4H-chromene-3-carbonitriles and the aforementioned o-quinone methides.
7 citations
TL;DR: In this article, the thermal Claisen rearrangement of the allyl ethers has been studied in refluxing N,N-dimethylaniline (DMA) and neat at 185 °C under an N2 atmosphere.
Abstract: Thermal Claisen rearrangement of the allyl ethers (3) and (12) of the isomeric 2-acetyl-1-hydroxy- and 1-acetyl-2-hydroxy-naphthalenes (1) and (2) has been studied by heating each in refluxing N,N-dimethylaniline (DMA) and neat at 185 °C under an N2 atmosphere. 2-Acetyl-4-allyl-1-hydroxynaphthalene (4), the sole product isolated from (3), was isolated in 56 and 88% yield respectively under the two sets of conditions. The rearrangement of the allyl ether (12) gave 3-acetyl-1-allyl-2-hydroxynaphthalene (13)(18%) and 2-acetoxy-1-allylnaphthalene (14)(23%) in N,N-DMA while in the neat rearrangement it gave (14) as the major product (70%) along with 1-allyl-2-hydroxynaphthalene (17)(20%). The rearrangement of the allyl ether (7), obtained on further allylation of (4), furnished 2,4-diallyl-1-hydroxynaphthalene (8), (15%) and (4)(15%) in DMA while it gave 1-acetoxy-2,4-diallylnaphthalene (9) as the sole product (67%) in the neat rearrangment. The rearrangement of the allyl ether (15), obtained by further allylation of (13), in DMA gave 3-acetyl-1,1-diallylnaphthalen-2(1H)-one (16)(20%) along with (13)(6%). The various rearrangement products have been characterised by their spectroscopic data (UV, IR, 1H NMR, and EI-MS) and the reactions rationalised by the allowed sigmatropic shifts such as [3,3] allyl, [1,5] acetyl followed by loss of allyl or acetyl groups. The significant differences noticed in the reactions of the isomeric series of allyl ethers are consistent with the greater fixed double-bond character of the naphthalene system compared to that of benzene as well as the positional isomerism that exists in the allyl ethers. The above Claisen rearrangement studies result in the isolation of some interesting naphthylallyl derivatives with orhto-hydroxyacetophenone units which form useful synthetic intermediates for preparing several naphthyl-α- and γ-pyrone derivatives of pharmacological activity.
5 citations
TL;DR: In this article, a method for the preparation of polycondensed chromeno[2,3-b]chromenes was developed based on the formal [3+3] cycloaddition reaction between 1H-benzo[f]chromene-2-carbaldehydes and 2-naphthols.
Abstract: A method for the preparation of polycondensed chromeno[2,3-b]chromenes was developed based on the formal [3+3] cycloaddition reaction between 1H-benzo[f]chromene-2-carbaldehydes and 2-naphthols. In the case of resorcinol, the bisannulation product formed with the participation of both hydroxy groups was isolated.
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229 citations
42 citations
TL;DR: In this article, a successful Claisen rearrangement of a number of 1,4-diaryloxy-2-butynes is reported, which offers a facile synthetic route to tetracyclic derivatives resembling the naturally occurring pterocarpans.
29 citations