methyl 3-oxothiolane-2-carboxylate

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

Procedure: 2-Methoxycarbonyl-3-oxotetrahydrothiophene (2 g) was dissolved in acetonitrile (20 ml) with heating and stirring. Hydroxylamine hydrochloride (0.8 g) was added to the refluxing solution and the mixture was refluxed for 11/2hour. After cooling, ether (50 ml) was added and the precipitated straw-coloured solid was filtered off. The solid was dissolved in water and basified with 4M ammonia solution and extracted with dichloromethane (2×25 ml). The combined extracts were washed with water and with brine and dried over sodium sulphate. Filtration and evaporation gave an oil which solidified on cooling and was crystallised from petrol ether bp 60°-80° to afford the title compound, 1.34 g (73%); mp 62°-63°. with heating the mixture was refluxed for 11/2hour After cooling the precipitated straw-coloured solid was filtered off The solid was dissolved in water and basified with 4M ammonia solution extracted with dichloromethane (2×25 ml) The combined extracts were washed with water and with brine dried over sodium sulphate Filtration and evaporation gave an oil which on cooling was crystallised from petrol ether bp 60°-80°

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

Procedure: using isopropyl 2-chloro-4-fluoro-5-ureidobenzoate and methyl 3-oxotetrahydrothiophene-2-carboxylate there is obtained isopropyl 2-chloro-4-fluoro-5-{3-[2-(methoxycarbonyl)-4,5-dihydro-thien-3-yl]ureido}-benzoate, m.p. 161°-163° C.,

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

Procedure: Lithium metal (2.70 g, 390.15 mmol) was added to 500 mL of methanol in an ice-bath. Then at rt methyl 3-(2-methoxy-2-oxoethylthio)propanoate (50.0 g, 260.10 mmol) was added dropwise to the solution. The reaction mixture was stirred overnight. The resulting reaction mixture was evaporated to remove the solvent. The mixture was neutralized to pH=7-8 with 3N HCl and extracted with dichloromethane. The organic layers were combined, washed with brine, dried over anhydrous Na2SO4, filtered and evaporated. The crude residue obtained contained the target as the only isolable product. Purification by column chromatography on silica gel (eluent: PE/EA=20/1-5/1) provided methyl 3-oxo-tetrahydrothiophene-2-carboxylate as a colourless oil (18.0 g, 43%). The resulting reaction mixture was evaporated to remove the solvent extracted with dichloromethane washed with brine dried over anhydrous Na2SO4 filtered evaporated The crude residue obtained Purification by column chromatography on silica gel (eluent: PE/EA=20/1-5/1)

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

Procedure: 2-Methoxycarbonyl-3-oxotetrahydrothiophene (2 g) was dissolved in acetonitrile (20 ml) with heating and stirring. Hydroxylamine hydrochloride (0.8 g) was added to the refluxing solution and the mixture was refluxed for 11/2hour. After cooling, ether (50 ml) was added and the precipitated straw-coloured solid was filtered off. The solid was dissolved in water and basified with 4M ammonia solution and extracted with dichloromethane (2×25 ml). The combined extracts were washed with water and with brine and dried over sodium sulphate. Filtration and evaporation gave an oil which solidified on cooling and was crystallised from petrol ether bp 60°-80° to afford the title compound, 1.34 g (73%); mp 62°-63°. with heating the mixture was refluxed for 11/2hour After cooling the precipitated straw-coloured solid was filtered off The solid was dissolved in water and basified with 4M ammonia solution extracted with dichloromethane (2×25 ml) The combined extracts were washed with water and with brine dried over sodium sulphate Filtration and evaporation gave an oil which on cooling was crystallised from petrol ether bp 60°-80°

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

Procedure: Following a procedure similar to that described in Example 1B hereinabove, methyl 3-oxo-2,3,4,5-tetrahydrothiophene-2-carboxylate is reacted with 5-(2-eicosyl)resorcinol to give 1,2-dihydro-7-(2-eicosyl)-9-hydroxy-4-oxo-4H-thieno [2,3-c][1]-benzopyran.

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

Procedure: Following a procedure similar to that described in Example 1B hereinabove, methyl 3-oxo-2,3,4,5-tetrahydrothiophene-2-carboxylate is reacted with 5-(1-cyclohexylethyl) resorcinol to give 7-(1-cyclohexylethyl)-1,2-dihydro-9-hydroxy-4-oxo-4H-thieno[2,3-c][1]benzopyran.

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

Procedure: Following a procedure similar to that described in Example 1B hereinabove, methyl 3-oxo-2,3,4,5-tetrahydrothiophene-2-carboxylate is reacted with 5-(1-pentyl)resorcinol to give 1,2-dihydro-9-hydroxy-4-oxo-7-(1-pentyl)-4H-thieno[2,3-c][1]benzopyran.

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

Procedure: Following a procedure similar to that described in Example 1B hereinabove, methyl 3-oxo-2,3,4,5-tetrahydrothiophene-2-carboxylate is reacted with 5-(3-cyclopropyl-2-propyl)resorcinol to give 7-(3-cyclopropyl-2-propyl)-1,2-dihydro-9-hydroxy-4-oxo-4H-thieno[2,3-c][1]benzopyran.

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

Procedure: Following a procedure similar to that described in Example 1B hereinabove, methyl 3-oxo-2,3,4,5-tetrahydrothiophene-2-carboxylate is reacted with 5-(3-cyclopropyl-2-propyl)resorcinol to give 7-(3-cyclopropyl-2-propyl)-1,2-dihydro-9-hydroxy-4-oxo-4H-thieno[2,3-c][1]benzopyran.

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

Procedure: Following a procedure similar to that described in Example 1B hereinabove, methyl 3-oxo-2,3,4,5-tetrahydrothiophene-2-carboxylate is reacted with 5-(2-heptyl)resorcinol to give 1,2-dihydro-7-(2-heptyl)-9-hydroxy-4-oxo-4H-thieno [2,3-c][1]benzopyran.

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

Procedure: Following a procedure similar to that described in Example 1B hereinabove, methyl 3-oxo-2,3,4,5-tetrahydrothiophene-2-carboxylate is reacted with 5-(3-cyclopropyl-2-propyl)resorcinol to give 7-(3-cyclopropyl-2-propyl)-1,2-dihydro-9-hydroxy-4-oxo-4H-thieno[2,3-c][1]benzopyran.

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

Procedure: Following the procedure similar to that described in Example 1B hereinabove, methyl 3-oxo-2,3,4,5-tetrahydrothiophene-2-carboxylate is reacted with 5-methylresorcinol to give 1,2-dihydro-9-hydroxy-7-methyl-4-oxo-4H-thieno[2,3-c][1]benzopyran.