2,2-dimethyl-5-phenyl-1,3-dioxane-4,6-dione

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

Procedure: A solution of 25 g (135.1 mmol) N,N-dimethylammonium iodide and 11.91 g (54.1 mmol) 2,2-dimethyl-5-phenyl-[1,3]dioxane-4,6-dione in 585 ml abs. methanol was heated to 65° C. and the reaction was allowed to continue over night at 65° C. The reaction mixture was allowed to cool down to room temperature and the solvent was removed under reduced pressure. The residue was treated with diethyl ether, extracted with a satured NaHCO3 solution and brine and dried over MgSO4. The solvent was removed under reduced pressure and 9.01 g (quant.) of 2-phenyl acrylic acid methyl ester was isolated as a colourless oil. The compound was used without further purification. to continue over night at 65° C the solvent was removed under reduced pressure The residue was treated with diethyl ether extracted with a satured NaHCO3 solution and brine dried over MgSO4 The solvent was removed under reduced pressure

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

Procedure: A solution of 25 g (135.1 mmol) N,N-dimethylammonium iodide and 11.91 g (54.1 mmol) 2,2-dimethyl-5-phenyl-[1,3]dioxane-4,6-dione in 585 ml abs. methanol was heated to 65° C. and the reaction was allowed to continue over night at 65° C. The reaction mixture was allowed to cool down to room temperature and the solvent was removed under reduced pressure. The residue was treated with diethyl ether, extracted with a satured NaHCO3 solution and brine and dried over MgSO4. The solvent was removed under reduced pressure and 9.01 g (quant.) of 2-phenyl acrylic acid methyl ester was isolated as a colourless oil. The compound was used without further purification. to continue over night at 65° C the solvent was removed under reduced pressure The residue was treated with diethyl ether extracted with a satured NaHCO3 solution and brine dried over MgSO4 The solvent was removed under reduced pressure

Conditions: temp:25.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To 11.8 g (50 mmol) of phenylmalonic acid diethyl ester in 23 ml. of acetic anhydride there are added 0.5 ml. of concentrated H2SO4 and 20 ml. of acetone. The mixture is stirred at 25° C for 8 hours, water (250 ml.) is then added thereto and the mixture is stirred for 30 minutes. The obtained precipitate is washed with 250 ml. of water up to pH 6.5, dried under reduced pressure and dissolved in 100 ml. of chloroform. The organic solution is dried over anhydrous sodium sulfate, most of the solvent is evaporated under reduced pressure and 100 ml. of petroleum ether (50°-70° C) is added thereto. The suspension is stirred for 30 minutes and filtered. The precipitate is washed with 20 ml. of petroleum ether (50°-70° C) and dried over P2O5 under reduced pressure to yield 2.2-dimethyl-5-phenyl-1.3-dioxane-4.6-dione with the same characteristics as the compound described by P. J. Scheuer in J.A.C.S. 80, 4933-38 (1958). the mixture is stirred for 30 minutes The obtained precipitate is washed with 250 ml of water up to pH 6.5, dried under reduced pressure dissolved in 100 ml The organic solution is dried over anhydrous sodium sulfate, most of the solvent is evaporated under reduced pressure and 100 ml of petroleum ether (50°-70° C) is added The suspension is stirred for 30 minutes filtered The precipitate is washed with 20 ml of petroleum ether (50°-70° C) and dried over P2O5 under reduced pressure

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

Procedure: When an equivalent amount of 2.2-tetramethylene-5-phenyl-1.3-dioxane-4.6-dione prepared in the example 3 is substituted for 2.2-dimethyl-5-phenyl-1.3-dioxane-4.6-dione and the reaction with 6-aminopenicillanic acid is carried out as disclosed in the example 1, 6-(α-carboxy-α-phenylacetamido)penicillanic acid (carbenicillin) is obtained.

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

Procedure: A solution of 25 g (135.1 mmol) N,N-dimethylammonium iodide and 11.91 g (54.1 mmol) 2,2-dimethyl-5-phenyl-[1,3]dioxane-4,6-dione in 585 ml abs. methanol was heated to 65° C. and the reaction was allowed to continue over night at 65° C. The reaction mixture was allowed to cool down to room temperature and the solvent was removed under reduced pressure. The residue was treated with diethyl ether, extracted with a satured NaHCO3 solution and brine and dried over MgSO4. The solvent was removed under reduced pressure and 9.01 g (quant.) of 2-phenyl acrylic acid methyl ester was isolated as a colourless oil. The compound was used without further purification. to continue over night at 65° C the solvent was removed under reduced pressure The residue was treated with diethyl ether extracted with a satured NaHCO3 solution and brine dried over MgSO4 The solvent was removed under reduced pressure