- Synthesis and properties of (1,3-dioxolan-2-yl)furans
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Reaction of formylfurancarboxylates with excess ethylene glycol in the presence of p-toluenesulfonic acid gives rise to (1,3-dioxolan-2-yl)furancarboxylates. Reduction of these products with lithium aluminum hydride proceeds with preservation of the dioxolane ring. Except for 5-(1,3-dioxolan-2-yl)(hydroxymethyl)-2-methyl-3-furan, the obtained alcohols are unstable. Chlorides derived from them decompose under conditions of the Michaelis-Becker reaction, and no phosphorylation products are formed. By contrast, the above-mentioned stable alcohol by treatment with thionyl chloride in the presence of pyridine is converted to a fairly stable chloromethylfuran. The latter compound reacts with sodium diethyl phosphite in benzene to form the corresponding phosphonate that exists as a 1:4 mixture of two spectroscopically discernible conformers.
- Pevzner
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- Indirect support for a stepwise carbonium ion pathway operating in (4+3)-cycloaddition reactions between furanoxonium ions and 1,3-dienes
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Treatment of solutions of the furfuryl alcohol 6 in dichloromethane- methanol with buta-1,3-diene or cyclohexa-1,3-diene or with cyclopentadiene in the presence of trifluoroacetic acid leads to the corresponding substituted furyl tetrahydrofurans, 8, 12 and 15 respectively, rather than to the products 10, 13 and 16 anticipated from intermolecular (4+3)-type cycloaddition reactions. These outcomes provide indirect experimental support for a stepwise carbonium ion pathway operating in (4+3)-cycloaddition reactions between furanoxonium ions and 1,3-dienes. Alongside other results, the outcomes also highlight a limitation to (4+3) cycloadditions in cycloheptene ring synthesis when the precursors contain hydroxyl groups capable of intercepting any carbonium ion intermediates leading to O-heterocyclic by-products. Georg Thieme Verlag Stuttgart New York.
- Palframan, Matthew J.,Pattenden, Gerald
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- INDAZOLES AND AZAINDAZOLES AS LRRK2 INHIBITORS
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The present invention is directed to indazole and azaindazole compounds which are inhibitors of LRRK2 and are useful in the treatment of CNS disorders.
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Page/Page column 77
(2021/01/29)
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- Synthesis of (2-Ethoxy-2-oxoethylthio)methyl Derivatives of Furoic Acids and Attempts of Their Intramolecular Cyclizations under the Conditions of the Claisen Reaction
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Abstract: Based on reactions of phosphorylated derivatives of halomethylfuroic acid esters with thioglycolic acid ester in the presence of bases, a method for the synthesis of mono-and bisphosphosphorylated esters of (2-ethoxy-2-oxoethylthio)methyl derivatives of furoic acids, containing an ester group in the position adjacent to the sulfide moiety was developed. Obtained compounds are relatively easily metallized with potassium tert-butylate, but intramolecular cyclization proceeds smoothly only in the case of 5-(diethoxyphosphorylmethyl)-2-(ethoxycarbonylmethylthiomethyl)furan-3-carboxylic acid. The resulting 1,3-dicarbonyl derivative of 7H-thiopyrano[3,4-b]furan is hydrolytically unstable, but its enol O-methyl ether is stabile. Alkaline hydrolysis of the latter compound was studied, and it was shown that it proceeds at the ester as well as at the phosphonate group.
- Pevzner, L. M.,Stepanova, N. P.
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p. 166 - 181
(2020/04/15)
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- ISOXAZOLE DERIVATIVES
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The invention relates to new isoxazoline compounds of formula (I) wherein the variables have the meaning as indicated in the claims; in free form and in salt form; and optionally the enantiomers and geometrical isomers thereof. The compounds of formula (1
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Page/Page column 35
(2012/09/22)
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- NEW BRADYKININ B1 ANTAGONISTS
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The invention relates to compounds of formula (I) where in R1, R1a, R1b, R2, R3 and X, X1, X2, X3 have the meaning as cited in the description and the claims. Said compounds are useful as Bradykinin B1 antagonists. The invention also relates to pharmaceutical compositions, the preparation of such compounds as well as the production and use as medicament.
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Page/Page column 126-127
(2010/04/03)
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- Gold catalysis: Dihydroisobenzofurans and isochromanes by the intramolecular furan/alkyne reaction
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A series of furyl alcohols and homofuryl alcohols was synthesized by reduction of furfurals or reaction of furyllithium compounds with epoxides and subsequent propargylation. The gold-catalyzed cycloisomerization of these products furnished dihydroisobenzofurans and isochromanes. Crystal structure analyses proved the sequence of the substituents for both classes of products. Unsaturated dicarbonyl compounds as side-products show the mechanistic relationship to the analogous platinum-catalyzed reactions. Neither ester groups, even on the 4-position of the furan ring, nor aryl bromides hinder the catalysis by gold. In the case of a substrate with an allyl ether in the side chain, a side-product, which provides evidence for a reaction of the alkyne with an inverse regioselectivity, was observed.
- Stephen,Hashmi,Woelfle,Ata, Filiz,Hamzic, Melissa,Salathe, Ralph,Frey, Wolfgang
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p. 2501 - 2508
(2007/10/03)
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- Conversion of formyl into cyano groups in kojic acid derivatives and analogues
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It has been revealed that N,N-dimethylhydrazones (1a-c, 3a,b) derived from kojic acid analogs, such as substituted furans (3a,b), 4-pyrones (1a,b) and 4-pyridine (1c), on oxididation with 3-chloroperoxybenzoic acid afford the corresponding nitriles (2a-c,
- Mlochowski, Jacek,Giurg, Miroslaw,Uher, Michal,Korenova, Anna,Vegh, Daniel
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- PREPARATION OF FURAN DERIVATES FROM PENTOSES AND HEXOSES. STUDY OF THE ANHYDRIZATION OF THE TETRAHYDROXYLATED CHAIN AT α POSITION
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The reaction of pentoses and hexoses with active methylene compounds in presence of an ethanolic solution of a Lewis acid or mixtures of aquenous acids leads to polyfunctional furanic derivatives in wich a polyhydroxylated chain exists in α position.When
- Ballesteros, Juan Sanchez,McPhee, Derek James,Hernandez, Dolores Hernandez
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p. 176 - 180
(2007/10/02)
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