5-Methylene-2 -furanones

There is lots of current interest in doubly oxidized deoxyribose. A recent article by Roginskaya et al. [77] detected 5-methylene-2-furanone (5-mF) release in irradiated DNA. The production of 5-mF involves Cl chemistry. To produce 5-mF one needs a doubly oxidized site. 

Roginskaya M., Bernhard W.A., Marion R.T., Razskazovskiy Y, The Release of 5-Methylene-2-Furanone from Irradiated DNA Catalyzed by Cationic Polyamines and Divalent Metal Cations, Radiat. Res., 2005,163,79-84. 

MD approach. See Molecular dynamics approach (MD approach) Mechanistic studies. Cl -radical generation, 130—133 P-Mercaptoethanol (BME), 127—130,175 Metal coordination, 83 2-Methyl-1,4-napthoquinone (MD), 125 5-Methylene-2-furanone, 130 Microscopic constants, 43—48 MM. See Molecular mechanics (MM) MnPy. See Manganese porphyrins (MnPy) Molecular dynamics approach (MD approach), 206... 

Bromo-5-methylene-2(5//)-furanone 133 was obtained from the /3-angelica lactone 129 by using mild simple methods that combine bromination and dehy-drobromination or debromination processes accomplished in a convenient order, as illustrated in Scheme 41 (94T12457). 

The 5-methylene-2(5//)-furanone 216 was found to be a good dienophile in Diels-Alder reactions with acyclic dienes (R = H, 2-Me, 2,3-di-Me, 1-Me, 1,3-di-Me). The reaction took place specifically at the cxo-cyclic double bond to give the corresponding spiro adducts 217 in good yields (Scheme 59) (90JOC3060). 

Thermal cycloadditions of butadiene to 3-bromo- 133 and 3-methoxy-5-methylene-2(5//)-furanones 220 were studied (95TL749). These systems contain substituents at C3 capable of stabilizing also a possible radical intermediate, influencing hereby the rate and/or the course of the reaction. Thus, the reaction of 133 and 220, respectively, with butadiene at 155°C afforded mixtures of the expected 1,4-cycloadducts 221 and 222, respectively, and of the cyclobutane derivatives... 

Optically active dihydro-2-methylene-2(3//)-furanones fused to 5- and 6-membered carbocyclic rings were synthesized with 64-92% ee using the intramolecular reaction between chiral 2-alkoxy-carbonylallylsilanes and aldehydes80. 

S)-Dihydro-3-methylene-5-(2-methylpropyl)-2(3//)-furanone Typical Procedure9 ... 

S-[3-terl-buto.xycarh 61% d.r. iantijsyn) >70 30... 

The possibility of a biradical mechanism was suggested using the MNDO and AMI semiempirical methods, for the addition of protoanemonin (5-methylene-2(5Z/)-furanone) to butadiene105 and to several substituted dienes106. Experimental evidence for this kind of mechanism has recently been published133. A biradical mechanism has also been considered for the dimerization of butadiene96. For this reaction, CASSCF calculations... 

The kinetics and mechanisms of the oxidation of DNA, nucleic acid sugars, and nucleotides by [Ru(0)(tpy)(bpy)] and its derivatives have been reported. " The Ru =0 species is an efficient DNA cleavage agent it cleaves DNA by sugar oxidation at the 1 position, which is indicated by the termini formed with and without piperidine treatment and by the production of free bases and 5-methylene-2(5//)-furanone. Kinetic studies show that the I -C— activation is rate determining and a hydride transfer mechanism is proposed. The Ru =0 species also oxidizes guanine bases via an 0x0 transfer mechanism to produce piperidine-labile cleavages. 

A. 2(SH)-Furanone. A 6-L, three-necked, round-bottomed flask equipped with two condensers, a dropping funnel and a 12 x 55 mm magnetic stirring bar is charged with 480 g (5 mol) of furfural (Note 1) and 2.0 L of methylene... 

S. Furyt phoaphopodiohtoridate. A 1-L flask, protected from moisture by a calcium chloride tube. Is charged with 42 g (0.5 mol) of 2(5H)-furanone, 85 g (0.55 mol) of phosphoryl chloride and 100 iri. of methylene chloride. A solution of 65 g (0.5 mol) of ethyl d1 isopropyl amine In 60 mL of methylene chloride Is added dropwlse during 4 hr at ambient temperature (Note 9). The resulting mixture Is stirred overnight (12 hr), after which 6.5 g of the amine... 

Materials Employed. 2,5-dimethyl-4-hydroxy-3(2H)-furanone (DMHF) of high purity was provided by International Flavors and Fragrances (IFF). L-cystine, injectable grade, was purchased from Ajinomoto Company, Tokyo, Japan. Reagent grade methylene chloride was purchased from Aldrich Chemical Company, and was freshly distilled prior to use. Spectral grade glycerol was obtained from a commercial source. 

Purify the crude product by chromatography using pentane ether (4 1). Pure 5-(4-chlorophenyl)-4,5-dihydro-3-methylene(3H)-furanone (1.87 g, 90%) is obtained and characterized by 1H and 13C NMR. 

Vicinally donor-acceptor-substituted olefins usually are rather unreactive species. Nevertheless cyclopropanation of 2,2-dimethyl-3(2 H)-furanone 70 could be executed with dimethyl oxosulfonium methylide as a methylene source. The bicyclic compound 71 is formed in modest yield accompanied by the spiro epoxide as a second product in almost equal amounts. Carbinols 72 derived from 71 by alkyl lithium addition can be nitrosated and photolyzed to suffer a Barton fragmentation. The resulting y-oxoaldehydes are directly cyclized to afford the 2-substituted cyclopentenones 73 in good yield 41. ... 

Single-photon emission computed tomography Tricarbonyltris(2-methoxyisobutyl isonitrile)99mTc complex Hexakis(2-ethoxy-isobutylisonitrile)99mTc complex trans[(l,2-Bis(dihydro-2,2,5,5-tetramethyl-3(2H)furanone-4-methylene-imino)ethane) bis(tris(3-methoxy-l-propyl)phosphine)]99mTc complex Hexakis(2-methoxyisobutyl isonitrile)"mTc complex [l,2-Bis bis(2-ethoxyethyl)phosphino ethane]20299mTc complex... 

The 2-rhenafuran-3-ol 39 is in equUibrium with the corresponding 37/-furanone 40 (A eq = 1-5) while the equilibrium constant is much more on the side of the furanone when the ring Re is replaced by Mn or in the absence of the metal heteroatom. For example, no 5-methyl-2-furanol (41) is detected in the rearrangement of y-methylene-y-bntyrolactone (42) to a-angehcalactone (43). Understanding the contribution to aromaticity of Re in the 2-rhenafurans (39, 40) and the exocyclic and endocyclic methylene groups in 42 and 43 would be most instructive. 

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