3-Phenyl-4-7?-2,5-dihydro-2-furanones

Similarly, (A )-( )-3-(2-methoxymethyl-l-pyrrolidinyl)-l-phenylpropene118 121, after lithia-tion and addition of acetone, acidic hydrolysis and oxidation of the intermediate lactol, gives (5)-dihydro-5,5-dimethyl-4-phenyl-2(3/f)-furanone with 98% ee and 54% overall yield. Thus, these sequences constitute asymmetric homoaldol addition. 

The natural products as- and fra t-whisky lactones 95 have been prepared from the furanones 94 (92-93% yield), which were themselves obtained from ak-3-phenyl-6-butyl-3,6-dihydro-l,2-dioxin 92 and a chiral malonate ester 93 in 54% yield <20060L463> chromatographic separation on silica gel provided the pure (3R,43, 53)- and (33, 4i ,5R)-diastereomers of 94 which were converted into two nature-identical and two non-natural isomers of 95. 

The assignment of (/ )-2,3-dihydro-2-phenylfuran rests on Jones oxidation which furnished (ft)-dihydro-5-phenyl-2(3//)-furanone [(/ )-24]80. The configuration of the corresponding S-enantiomer (obtained by yeast reduction of 4-oxo-4-phenylbutanoic acid) was established by correlation with ethyl (S)-3-hydroxy-3-phenylpropanoate (of known configuration, obtained itself by a baker s yeast reduction) by a sequence featuring an Arndt -Eistert homologization as the key step (see also p 403)19. 

C. Kinetioally-controlled formation of the cis l4RS, RS> isomer of 4,5-dihydro-5-iodomethyl-4-phenyl-S(3H)-furanone. A mixture of 10 g (0.057 mol)... 

Conversion of lodolactones into the corresponding epoxy esters- is often one of the major steps in their utilization for the purposes of stereo-control. Methanolysis of the cis isomer of 4,5-dihydro-5-iodomethyl-4-phenyl-2(3H)-furanone to methyl (3RS,4RS)-4,5-epoxy-3-phenylpentanoate is a representative procedure for this transformation. 

Phenyl-4-pentenoic acid (3) is converted to the corresponding mercury derivative 7 by treatment with mercury(II) acetate in methanol26. After demercuration with sodium borohydride in sodium hydroxide, dihydro-5-methyl-4-phenyl-2(3//)-furanone (8) is obtained as an 85 15 mixture of trans/cis-isomers in 45 % yield. 

In the 3-phenyl-2(3 )-benzofuranone series, we find a long-known spasmolytic compound, 3-(2-diethylamino)ethyl-3-phenyl-2(3fI)-benzo-furanone (Amolanone), which also has analgesic properties. A novel compound, 2-(l-succinyloxy)ethyl-3-methyl-5-(2-oxo-2,5-dihydro-4-furyl)benzofuran or Benfurodil (25) (clinical name Eudilat), is a vasodilator and cardiotonic. 

Figure 5.2.11. Cellulose pyrolysate obtained at 59(P C and separated on a methyl silicone with 5% phenyl silicone type column. 1 acetic anhydride, 2 pentanal, 3 2-hydroxybutanedialdehyde, 4 1,4-dioxadiene, 5 tetrahydro-2-furanmethanol, 6 2-(hydroxymethyl)-furan, 7 3-methyl-2-hexanone, 8 2-methoxy-2,3-dihydrofuran, 9 2(5H)-furanone, 10 1-acetyloxypropan-2-one, 11 hydroxycyclopentenone, 12 5-methylfurfural, 13 2,3-dihydro-5-methylfuran-2-one, 14 1-cyclopentylethanone, 15 2-hydroxy-3-methyl-2-cyclopenten-1-one, 16 3,5-dimethylcyclopentan-1,2-dione, 17 unknown, 18 3-ethyl-2,4(3H,5H)-furandione, 19 6-methyl-1,4-dioxaspiro[2,4]heptan-5-one, 20 1-hydroxy-3,6-dioxabicyclo[3.2.1]octan-2-one, 21 1,4 3,6-dianhydro-a-D-glucopyranose, 22 5-(hydroxymethyl)-furfural, 23 4-cyclopenten-1,2,3-triol, 24 5-ethyl-3-hydroxy-4-methyl-tetrahydrofuran-2-one, 25 levoglucosan, 26 1,6-anhydro-p-D-glucofuranose.

Treatment with HCl/EtOH gave 4,5-dihydro-3-hydroxy-4,4,5,5-tetramethyl-3-phenyl-2(3tf)-furanone. 

Dihydro-5-pentyl-2(3h)-furanone 9,10-Dihydrophenanthrene 2,3-Dihydro-2-phenyl-4W-1-benzopyran-4-one 4,5-Dihydro-2-(phenylmethyl)-1//-imidazole, monohydrochloride... 

STEREOCOKTROLLED lOOOLACTONIZATION OF ACYCLIC OLEFINIC ACIDS THE TRANS AND CIS ISOMERS OF 4,5-DIHYDRO-5-IODOMETHYL-4-PHENYL-2(3H)-FURANONE... 

Dihydro-4 -naphtho[l,2-6]pyran-... — Dihydro-5-phenyl-2(3 0-furanone... 

Dihydro-1-phenyl-5W-tetrazole-5-thione Dihydro-5-propyl-2(3W)-furanone 2,3-Dihydro-6-propyl-2-thioxo-4(1/y)-pyrimidinone 1,7-Dihydro-6W-purine-6-thione 3.4-Dihydro-2W-pyran 3.6-Dihydro-2/fpyran Dihydro-2W-pyran-2.6(3W)-dione... 

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