The Photochemical Behaviour of 5,5-Dimethyl-2(5H)-furanone

The photochemical behaviour of the title compound 2c was investigated in various solvents. In benzene and t-butanol photodimerization affords the cis-anti-cis HH- and HT-dimers (H = head, T = tail). In acetonitrile, cyclohexane and 2-propanol, photoreduction competes with photodimerization. The photoreduction products are hydrodimers, solvent adducts and the saturated lactone (the 2H-reduction product). In acetonitrile and cyclohexane H-abstraction by the β-C-atom of the C?C bond is the predominant reduction process. In 2-propanol, solvent adducts to the α- and β-C-atoms are formed in equal amounts. In xanthone-sensitized irradiations the ratio of HH- to HT-dimer is the same as on direct irradiation and the relative rates of conversion of 2c to products in different solvents are also similar under both conditions.     

Cyclohexenones by the photoannelation of alkenes with 2,2-dimethyl-3(2H)-furanone

The photoaddition of alkenes to 2,2-dimethyl-3(2H)-furanone affords products which can be efficiently elaborated to cyclohexenones by two different methods.     

Efficient Isomerization for Preparing thans-2,2-Dimethyl-3-(2,2-dichloroethenyl) cyclopropanecarbonyl Chloride

2,2-Dimethyl-3-(2,2-dichloroethecyclopropanecarbonylchloride(hereafterreferredtoaspermethricacidchloride)isausefulintermediateforthepreparationofsomesyntheticpyrethroids,suchaspermethrinandcypermethrin.Permethricacidchloridehasageometricalisomericpair,oiLyandtrans,owingtoitscyclopropanering.Itisknownthat,ingeneral,theestersderivedfromtheirans-isomerarelesstoxictomammalsthanthosederivedfromtheets-isomerl--3.Thepermethricacidproducedindustriallyisalwaysinformsofmixturesoftrans-andets-isomers.Ac…     

New Syntheses of Geiparvarin and 2,5-Dimethyl-3(2H)-furanone Via Co2 Mediated Bond Reorganization

A new synthesis of 3(2H)-furanones from 4-hydroxy-2-alkyn-1-one derivatives via CO₂ mediated bond reorganization has been developed to the preparation of an antitumor agent, geiparvarin and a constituent of flavors, 2,5-dimethyl-3(2H)-furanone.     

A Preparative Method for Blocking of Ketone Group in 2,2-Dimethyl-3-(2-Oxopropyl)-Cis-Cyclopropaneacetaldehyde

An efficient three-step procedure for protection of ketone group in 2,2-dimethyl-3-/2-oxopropyl/-cis-cyclopropaneacet-aldehyde 1 is described.     

Asymmetric Photocatalyzed Addition of Cyclic Ammes to the Chiral 5-(l)-Menthyloxy-2(5H)-furanone

Inrecentyears,considerableattentionhasbeenfocusedonthesynthesisandpropertiesofchiralbutenolidesbecauseoftheirmultifunctionalnatureandversatilityonenantioselectivetransformationreactionsl'2.Despiteextensivestudiesofthisresearchworkonasymmetricreactionsbutlittleefforthasbeendevotedtowardsphotochemicalsynthesisofsomechiraly-substituted2-(SH)-furanones'.Amongthepreviouswork,thetertiaryammesusedinthephotocatalysedconjugateadditionsto5-substituted2(5H)foranoneswerethefirstexamples",andthesecondaryc…     

Oxidative Addition of N-Aminophthalimide and 3-Amino-2-methylquinazolin-4(3H)-one to Conjugated Azocyclopentenes and Azocyclohexenes

The oxidation of N-aminophthalimide and 3-amino-2-methylquinazolin-4(3H)-one in the presence of conjugated azocyclopentenes, azocyclohexenes, and 3-arylazocyclohexen-2-ones gives adducts at the carbon-carbon double bond corresponding to C-azoaziridines and/or bicyclic 2H-1,2,3-triazoles.     

Reactions of γ-acyloxy-β-ketophosphonates: New routes to 3(2h)- and 2(3h)-dihydrofuranones

Depending on the reaction conditions, γ-acyloxy-β-ketophosphonate anions can undergo either an intramolecular Wittig-like condensation or an unexpected rearrangement which affords an enol ester product.     

A condensed synthesis of dihydro-3(2H)-furanone

A straight forward synthesis of dihydro-3(2h)-furanone is described. An attempted preparation of the oxetan-3-one precursor 10 by this method gave, instead, the ring enlargement product 11.     

2,2-Dimethyl-5-(5-r-2-furfurylidene)-1,3-dioxane-4,6-diones

2,2-Dimethyl-5-(5-methyl-2-furfurylidene)-1,3-dioxane-4,6-dione crystals were subjected to an x-ray diffraction study. The unit cell of the crystal contains two symmetrically independent A and B molecules that exist in the x-cis conformation, which is stabilized by conjugation between the heteroring and, possibly, an intramolecular hydrogen bond.See [1] for Communication 1.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1453–1456, November, 1988.     

Electrochemical synthesis of 3,5-diphenyl-2(3H)-furanone

From electrochemical reduction of phenacyl bromide, 3,5-diphenyl-2(3H)-furanone was obtained as a side-product and its structure was determined by chemical and spectral techniques.     

Synthesis and Photochemistry of 2,2-Dimethyl-3(2H)-thiophenone,a Ketonic Tautomer of 3-Hydroxythiophene. Preliminary Communication

On irradiation (λ = 366 nm), the 4-thia-2-cyclopentenone 3a behaves in complete analogy to the oxa-enone 3c undergoing regio- and stereospecific cyclodimerization, regiospecific cycloaddition with 2-methylpropene and cycloaddition with 2,3-dimethyl-2-butene to afford cyclobutane derivatives. In contrast, the 4 -aza-2-cyclopentenone 3b does not undergo the above-mentioned reactions but only slow photodecomposition.     

Photochemistry of 2,2-Dimethyl-2H-Furo[3,4-b]Pyran-4,7(3H, 5H)-Dione

Irradiation (λ > 340 nm) of the title compound 2a in t-BuOH affords 3,3,10,10-tetramethyl-2,8-dioxatricyclo-[4.3.2.0^1,6]undecane-5,9-dione (3) via photoextrusion of 2-methylpropene and subsequent photocycloaddition of 2a to the alkene. The same regioisomer 3 is formed selectively and in much higher yields on irradiating 2a in the presence of excess 2-methylpropene. Irradiation of 3 (λ = 300 nm) in t-BuOH in the presence of the same alkene gives a 6:1 mixture of spirooxetanes 7a and 7b but not α-cleavage products. In 2-propanol, 2a is photoreduced to a 2:1 mixture of diastereoisomeric hydrodimers 9 .     

2(5H)-furanone in the vilsmeier—haak reaction. Synthesis of β-substituted furans. Molecular structures of 3-dimethylaminomethylene-5-formyl-2(3H)-furanone and dimethylammonium 3,5-di(2,2-dimethyl-4,6-dioxo-1,3-dioxan-5-ylidenemethyl)-2-furanolate

The reaction of 2(5H)-furanone with the Vilsmeier-Haak-Arnold reagent and subsequent addition of concentrated aqueous HClO₄ to the reaction mixture give (3-dimethylaminomethylen-2-oxo-3H-5-furanyl)methylenimmonium perchlorate, whose hydrolysis under various conditions leads to 3-dimethylaminomethylene-5-formyl-2(3H)-furanone or to the potassium salt of 5-hydroxy-2,4-furandicarbaldehyde. The reaction of these products with CH-acids was studied. The structures of the key compounds of this work have been proved by the method of X-ray diffraction analysis.Kuban State Technological University. 350072 Krasnodar, Russia; email:gemm18803@yahoo.com. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 24–34, January, 1999.     

Synthesis and Some Transformations of (2,2-Dimethyl-4-propyltetrahydro-2H-pyran-4-yl)acetonitrile

Russian Journal of General Chemistry - Removal of the ethoxycarbonyl group in ethyl cyano-(2,2-dimethyl-4-propyltetrahydro-2H-pyran-4 -yl)acetate afforded the corresponding...     

On the mechanism of a novel 3(2H)-Furanone-2(5H)-furanone rearrangement

The isolation of a stable intermediate product and the mechanism of a novel 3(2H)-furanone-2(5H)-furanone rearrangement that led to the facile preparation of a new class of γ-lactone amides 2 and 4 are discussed.     

Selective Noncatalytic Hydration of N-(1,1-Dimethyl-2-propynyl)-acetamide to N-(1,1-Dimethyl-2-oxopropyl)acetamide

Russian Journal of Organic Chemistry -