1204-38-2

Usage

Synthesis Reference(s)

Journal of Heterocyclic Chemistry, 29, p. 387, 1992 DOI: 10.1002/jhet.5570290217

Upstream product

• 141-97-9 ethyl acetoacetate 
• 18735-93-8 4,7-dimethyl-3,4-dihydropyrano[4,3-b]pyran-2,5-dione 
• 675-10-5 4-hydroxy-6-methyl-2-pyron 
• 67977-10-0 2,2-difluoro-4,7-dimethyl-5-oxo-(5H)-pyrano[4,3-d][1,3,2]-(2H)-dioxaborine 
• 108-24-7 acetic anhydride 
• 3385-34-0 ethyl isodehydroacetate 
• 64-17-5 ethanol 
• 142231-08-1 ethyl 7,7-dichloro-1,5-dimethyl-3-oxo-2-oxabicyclo<4.2.0>oct-4-ene-6-carboxylate 

Relevant academic research and scientific papers

A new method for annulation of the α-pyrone ring

New derivatives of coumarin, containing annulated α-pyrone rings, were obtained by reaction of the borate complexes of three isomeric acyl(hydroxy)coumarins with acid anhydrides. It was shown that the borate complex of 3-acetyl-4-hydroxy-2-pyrone also condenses with acetic anhydride to form a derivative containing a new annulated α-pyrone ring.

Lewis acid mediated condensation reactions of α,β-unsaturated acids with 4-hydroxy-2-pyrones. A concise structural assignment of Fleischmann's α,α-bispyrone and Praill's α,γ-bispyrone

Unambiguous assignments of Fleischmann's α,α-bispyrone 3 and Praill's α,γ-bispyrone 6 have been carried out by exploring Lewis acid mediated condensation reactions of α,β-unsaturated carboxylic acids with 4-hydroxy- 2-pyrones. This protocol is shown to be useful for synthesis of a BCDE-ring tetracyclic analog of arisugacin. (C) 2000 Elsevier Science Ltd.

A Reinvestigation of Bicarbonate Induced Oligomerization of Ethyl Acetoacetate: One-pot Biomimetic Synthesis of Dimethylcoumarin, Trimethylcoumarin and Condensed Coumarin Derivatives

In addition to the previously reported products dehydroacetic acid (1) and a pyranopyran derivative, presently revised as 4,7-dimethyl-2H-pyrano-13,2-c]-2H-pyran-2,5-dione (2), seven new polysubstituted coumarin derivatives have been synthesised by NaHCO3 catalyzed self-condensation of ethyl acetoacetate. The new products have been characterized as 3-acetyl-6-carboethoxy-5-hydroxy-4,7-dimethylcoumarin (3), 5-hydroxy-4,7-dimethylcoumarin (4), 3-acetyl-6-carboethoxy-4,5,7-trimethylcoumarin (5), 6-carboethoxy-4,5,7-trimethylcoumarin (6), 9-carboethoxy-10-hydroxy-2,4,8-trimethylbenzo-[3,4]-coumarin (7) and 8-carboethoxy-3,7,9-trimethylfurano-[3,2-c]-coumarin (8) based on their 1H and 13C nmr, and mass spectral studies in conjunction with the mechanistic rationale of their formation and some chemical evidence. In the same way the remaining new product is tentatively assigned 3″-carboethoxy-7,9,10,10′-tetramethyl-tetrahydrofurano-[2,4-de]- 4′,10′-dihydro-[5,6]-naphthopyran-2,5-dione (9) structure. Transformations of 3 to 4, 5 to 6 (minor), 6-carboethoxy-4,5,7-trimethylcoumarin (10) and 4,5,7-trimethylcoumarin (11), and 6 to 11 have been effected by heating with conc. H2SO4. Use of 60% H2SO4 increased the yield of 11. Decarboxylation of 10 affords 11. Sodium bicarbonate mediated self-condensation of methyl acetoacetate affords the methyl ester 12 of 10. Oxidation of the 4-methylcoumarins 6, 11 and 12 with SeO2 gives the corresponding 4-formyl and 4-hydroxymethyl derivatives. The one-pot monosubstrated oligomerization of ethyl acetoacetate thus demonstrates a simple biomimetic type synthesis of a number of new dimethylcoumarin and trimethylcoumarin derivatives.

Novel Transformation of Two Kinds of Chloinated Photo Cycloadducts of 2-Pyrone-5-carboxylate

Novel reactions of 7,7-dichloro- and 7,7,8-trichloro-3-oxo-2-oxabicyclooct-4-ene-6-carboxylates 5 with 1,8-diazabicycloundec-7-ene (DBU) in alcohol gave pyranopyran-2,5-diones 8 via (Z)-(2H-pyran-2-on-3-yl)butenoates 7.On the other hand, the same treatment of 7,7,8-trichloro-2-oxo-3-oxabicyclooct-4-ene-5-carboxylate 6b afforded 2-oxo-3-oxabicyclooct-4,7-diene-5-carboxylate 14 via cyclobutene formation and Sn2' displacement by attack of the alkoxy anion.