4- Methoxy-3- -furanone

Dipping solution Dissolve 25 mg 2-methoxy-2,4-diphenyl-3(2H)-furanone in 50 ml methanol. 

Ancos and colleagues studied the behavior of 5-methoxy- 163a and (5-ethylthio)-4-pyrrolidin-l-yl-2(5//)-furanones 163b (Y = OMe, SEt) toward aldehydes (91T3171). First, the lithium enolates 164 from these furanones, generated by... 

A versatile synthetic route to enantiomeric ally pure Diels-Alder adducts was deduced and found dependent on the application of enantiomerically pure 5-methoxy-174a (R=Me) and 5-(l-menthyloxy)-2(5//)-furanones 174b (R = menthyl), which were expected to undergo tt-face-selective cycloaddition with dienes. The reaction was effected by heating no Lewis acid catalysts were required (Scheme 55) (88JOC1127). 

The two diastereomers 210a,b are epimeric at the carbon bearing the methoxy group i.e., they are the result of the concurrent endo- and exo-addition of the diene 208 to the 5-menthyloxy-2(5//)-furanone (91TA1247). 

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... 

The reaction of 5-methoxy-2(5//)-furanone 168 with amines was also studied (89T6799). The conjugated addition of ethanolamine to the furanone 168 gave the racemic amino lactone 275 (R = CH2CH20H). Similarly, piperazine reacted with two equivalents of 168 to provide the diadduct 276 as a single diastereomer (no traces of the other isomer were detected). With tryptamine, the reaction was nearly quantitative with the the formation the tran -adduct 277 (R = tryptophanyl) (Scheme 72) (89T6799). 

Various diastereoselective Michael reactions are based on y-bromo-, y-alkyl-, or y-alkoxy-2(5//)-furanones following the trans-face selectivity shown in Section 1.5.2.3.1.2. Thus the lithium enolates of esters such as ethyl propanoate, ethyl a-methoxyacetate and ethyl a-phenylacetate add to methoxy-2(5/f)-furanone with complete face selectivity269-273 (see Section 1.5.2.4.4.2.). 

Although most consumers appreciate the fieriness of chile, capsaicinoids are not perceived through odor or taste receptors but through the nociceptive pain receptors described earlier. The compounds in chile fruit that create the flavor and aroma are produced in the fruit wall. Buttery et al. [90] generated vacuum steam distilled oil from green bell pepper macerate, with well over 40 peaks on subsequent GC/MS analysis. Of these peaks, the major flavor compound associated with bell pepper aroma was 2-methoxy-3-isobutylpyrazine (Fig. 8.1). They also reported several monoterpenoids in abundance, limonene, trans- 3-ocimene, and linalool as well as other aliphatic aldehydes and ketones. The flavor composition of dried red bell pepper powder (sweet paprika) extracted with ether identified 44 key peaks by GC/MS [91]. In these dried samples the key compounds were P-ionone and several furanones. The post-harvest processing and the different fruit maturities as well as possible varietal differences are all causes for the different aromatic profiles. 

Bulaquine is a mixture of 3 -l-4-6(-methoxy-8-quinolinyl) aminopentyl ethylidenedihydro-2-(3H) furanone and it s tautomers. 

Nozaki et al. [23] characterised the production of (+)-mesifuran [2,5-di-methyl-4-methoxy-3(2H)-furanone], an important flavour compound in arctic bramble, but which also occurs in strawberry and pineapple. After lipase-catalysed (Candida antarctica) enantioface-differentiating hydrolysis of the enol acetate, the pure optically active (+)-mesifuran could be obtained. 

Methoxy-2,5-dimethyl-3(2H)-furanone [2H3]methoxy Schieberle and Hofmann, 1997... 

The reaction of 3-benzyloxy-, 5-methoxy-, and 5-nitro-2-aminopyridines and 3-acetyl-4,5-dihydro-2(3//)-furanone in warm toluene in the presence of phosphoryl chloride afforded 3-(2-chloroethyl)-2-methyl-4//-pyrido[l, 2-a]pyrimidin-4-ones 102 (84EUP110435 90EUP368388 92USP5158952). 

It is noteworthy that chiral organic bases such as pyrrolidines and cinchonines or cinchonidines were recently grafted onto a MCM-41 support.1183,1841 These materials catalyse enantioselective Michael-type addition between ethyl 2-oxocy-clopentanecarboxylate and methyl vinyl ketone[183] as well as thiol and 5-methoxy-2(5Z/)-furanone.[184] Although ee was only modest (maximum ee 35 %), these attempts are very promising. 

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... 

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