2-methylfuran

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Pentachlorocyclopropane (100 g, 0.467 mol) is added to a suspension of potassium hydroxide (31.4 g, 0.56 mol) in 1,4-dioxane (3600 ml) and the mixture is stirred at room temperature for 30 minutes and then heated to 65° C. for a further 30 minutes. 2-Methylfuran (38.36 g, 0.467 mol) is added to the reaction mixture, the temperature is raised to 85-90° C. and the mixture is stirred for 16 hours. The reaction mixture is cooled to room temperature, filtered through a plug of diatomaceous earth and the filtrate evaporated under reduced pressure to give (1R*,5S*)-2,3,4,4-tetrachloro-1-methyl-8-oxabicyclo[3.2.1]octa-2,6-diene (83 g), used without further purification in the next step. heated to 65° C. for a further 30 minutes the temperature is raised to 85-90° C. the mixture is stirred for 16 hours The reaction mixture is cooled to room temperature filtered through a plug of diatomaceous earth the filtrate evaporated under reduced pressure

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:-10.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: t-BuLi (1.7 m solution in hexane, 7.9 ml, 14.6 mmol) was added dropwise under constant stirring under a nitrogen atmosphere to a solution of 2-methylfuran (1.0 g, 12 mmol) in THF (20 ml) at -78° C. The solution was then warmed to -10° C. and stirring continued for 45 min. The solution was then added to a solution of zinc chloride (27 ml of a 0.5M solution in THF) at -30° C. and then warmed to room temperature where stirring continued for 1 hr. resulting in a pale yellow clear solution. The solution was then transferred via a steel canula under nitrogen to a solution of N-(5-bromothiophene-2-sulfonyl)pyrrole (Example 33A, 3.5 g, 12 mmol) and tetrakis(triphenylphosphine)-palladium (0) (693 mg, 0.6 mmol) in THF (15 ml) at -78° C. The solution was then warmed to room temperature and stirred for a period of 2 hours. Purification by column chromatography using 2% ethyl acetate gave 680 mg of N-[5-(2-methyl-5-furyl)thiophene-2-sulfonyl]pyrrole as a pale yellow powder (19% yield). warmed to room temperature where stirring continued for 1 hr resulting in a pale yellow clear solution The solution was then warmed to room temperature stirred for a period of 2 hours Purification by column chromatography

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A solution of n-BuLi (83 mL, 133.0 mmol, 1.2 eq, 1.6 M in hexanes) was added to a stirred solution of 2-methylfuran (10 mL, 110.8 mmol, 1 eq) in THF (85 mL) at 0° C. under inert atmosphere. The reaction mixture was stirred for 4 h at room temperature then cooled to 0° C. Ethylene oxide (8.3 mL, 166.3 mmol, 1.5 eq) was added dropwise and the reaction mixture was allowed to warm to room temperature overnight. After quenching with saturated aqueous NH4Cl, the resulting layers were separated and the aqueous layer was extracted with Et2O (2×). The combined organic layers were dried over Na2SO4 and concentrated under reduced pressure. Distillation at atmospheric pressure (170-185° C.) gave 10.13 g (80.3 mmol, 72%) of 5-methyl-2-furanethanol (2f(2)) as a light yellow oil: then cooled to 0° C to warm to room temperature overnight After quenching with saturated aqueous NH4Cl the resulting layers were separated the aqueous layer was extracted with Et2O (2×) The combined organic layers were dried over Na2SO4 concentrated under reduced pressure Distillation at atmospheric pressure (170-185° C.)

Conditions: temp:-70.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 24 ml (60 mmol, 1.5 eq) of a 2.5 M solution of n-butyllithium in hexane were added dropwise to a solution of 5.0 g (60 mmol, 1.5 eq) of 2-methylfuran in 100 ml of tetrahydrofuran cooled to −70° C. The reaction medium was stirred and allowed to return to ambient temperature for 2 hours. The reaction medium was cooled to −70° C. and then 6.0 g (40 mmol, 1 eq) of 2-methyltetrahydrofuran-2-carbaldehyde at 77% were added. The reaction medium was stirred at ambient temperature for 3 hours. The reaction medium was treated with a saturated ammonium chloride solution and extracted with ethyl acetate. The organic phases were combined, washed with a saturated sodium chloride solution, filtered over magnesium sulfate and evaporated. 5.21 g of (5-methylfuran-2-yl)-(2-methyltetrahydrofuran-2-yl)methanol were obtained. Yield=66%. TLC/SiO2: heptane/EtOAc (60/40), developing with KMnO4. The reaction medium was cooled to −70° C. The reaction medium was stirred at ambient temperature for 3 hours extracted with ethyl acetate washed with a saturated sodium chloride solution filtered over magnesium sulfate evaporated

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: The necessary starting material was prepared from 2-methylfuran (16.4 g) by an analogous procedure to that described for furan itself in Example 14, except that in this case the intermediate lithium salt of 2-methylfuran-5-thiol was reacted in dry ether at -20° C. with methyl 2-chloroacetate. The reaction mixture was stirred for 2 days and then partitioned between water (800 ml) and ether (3×400 ml). The organic layers were dried (MgSO4) and evaporated. The residual oil was distilled to give methyl 2-(2-methylfur-5-ylthio)acetate (40.1 g) b.p. 94°-96° C./0.5 mm; NMR (90 MHz): 2.30 (s,3H), 3.45 (s,2H), 3.70 (s,3H), 5.95 (m,1H), 6.45 (d,1H). partitioned between water (800 ml) and ether (3×400 ml) The organic layers were dried (MgSO4) evaporated The residual oil was distilled

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Hexafluoro-2-butyne (21.0 g, 0.13 mol) was transferred into a reaction bottle and 2-methylfuran (12.86 g, 0.157 mol) was added. This resulting mixture bottle was sealed and heated for 15 hr. at 120° C. After cooling, the excess 2-methylfuran was rotoevaporated in vacuo at rt, to give crude title product (29 g, 92%), which was used directly. was added This resulting mixture bottle was sealed heated for 15 hr at 120° C After cooling was rotoevaporated in vacuo at rt

Conditions: temp:90.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 1.88 ml of formalin and 1.07 g of methylfuran were added to a mixture of 4.43 g (15.7 mmol) of 4-(4-methylsulfonylaminobenzoyl)piperidine in free form obtained in Example 17, 1.57 ml of glacial acetic acid and 10 ml of water and the obtained mixture was stirred at 90° C. for 2 h. After cooling, the mixture was neutralized with a 20% aqueous sodium hydroxide solution and extracted with dichloromethane. The organic layer was washed with water and a saturated aqueous common salt solution, dried over magnesium sulfate and concentrated. The solid residue was recrystallized from ethanol/methanol to obtain 4.16 g (yield: 70%) of the intended compound. After cooling extracted with dichloromethane The organic layer was washed with water a saturated aqueous common salt solution, dried over magnesium sulfate concentrated The solid residue was recrystallized from ethanol/methanol

Conditions: temp:90.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 1.88 ml of formalin and 1.07 g of methylfuran were added to a mixture of 4.43 g (15.7 mmol) of 4-(4-methylsulfonylaminobenzoyl)piperidine in free form obtained in Example 17, 1.57 ml of glacial acetic acid and 10 ml of water and the obtained mixture was stirred at 90° C. for 2 h. After cooling, the mixture was neutralized with a 20% aqueous sodium hydroxide solution and extracted with dichloromethane. The organic layer was washed with water and a saturated aqueous common salt solution, dried over magnesium sulfate and concentrated. The solid residue was recrystallized from ethanol/methanol to obtain 4.16 g (yield: 70%) of the intended compound. After cooling extracted with dichloromethane The organic layer was washed with water a saturated aqueous common salt solution, dried over magnesium sulfate concentrated The solid residue was recrystallized from ethanol/methanol

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 2-methylfuran 26 is alkylated with 1,4-dibromobutane in the presence of a strong base, for example, n-butyllithium under anhydrous conditions, to produce 5-(4-bromobutyl)-2-methylfuran 27. The latter is then treated with ethylene or propylene glycol in the presence of an acid catalyst to afford the diketal bromide 28 (n=2 or 3). The bromide 28 is converted with a source of iodine ion, for example, sodium iodide, to the corresponding diketal iodide 29, which in turn is caused to react with triphenylphosphine to give the diketal phosphonium iodide 30. Treatment of the latter with phenyllithium in ether splits out the elements of HI resulting in a red solution of the ylide 25 which is not isolated as such but is used directly in condensation with aldehyde 8 (or 8a or 8b).