(4-oxoazetidin-2-yl) acetate

反応条件: temp:0.00; pressure:0.00; stir:

反応条件: temp:0.00; pressure:0.00; stir:

反応条件: temp:0.00; pressure:0.00; stir:

反応条件: temp:0.00; pressure:0.00; stir:

反応条件: temp:0.00; pressure:0.00; stir:

反応条件: temp:0.00; pressure:0.00; stir:

反応条件: temp:0.00; pressure:0.00; stir:

反応条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

実験手順: To a cold (0°-5°) oxygen-free 1 N NaOH solution (803 ml.) was added over 20 minutes thioacetic acid (57 ml., 61 g., 0.803 mole). The resulting solution was added in ca 20 minutes to a cold (10°) oxygen-free solution of 4-acetoxyazetidinone (94 g., 0.730 mole) in water (300 ml.). The pH of the resulting solution was immediately adjusted to 7.4 with solid NaHCO3. The cooling bath was removed and the solution was stirred for 2.75 hours. The mixture was then extracted with chloroform, the combined organic extracts washed with water (150 ml.) and dried over sodium sulfate. Concentration on a rotary evaporator left a yellow oil (95.3 g., 90%) which solidified to a yellow solid on cooling and seeding. This solid was found identical (by IR, NMR and TLC) to the product obtained in Preparation 1. The cooling bath was removed The mixture was then extracted with chloroform the combined organic extracts washed with water (150 ml.) dried over sodium sulfate Concentration on a rotary evaporator left a yellow oil (95.3 g., 90%) which on cooling obtained in Preparation 1

反応条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

実験手順: To a cold (0°-5° C.) oxygen-free 1 N NaOH solution (27.5 ml.) was added thioacetic acid (2.09 g., 27.5 mmole) at such a rate that the temperature was maintained between 0°-5° C. The resulting solution was added dropwise (over 20 min.) to a cold (0.5° C.) oxygen-free aqueous solution (11 ml.) of 4-acetoxy-2-azetidinone (3.23 g., 25 mmole) [prepared in Liebigs Ann. Chem., 539 (1974)]. The reaction mixture was stirred under a nitrogen atmosphere for 0.5 hr. at 0°-5° C. and for 2-2.5 hr. at 23°-25° C. before being extracted with chloroform (4×25 ml.). The organic extracts were combined, washed with water (10 ml.), dried over anhydrous Na2SO4 and concentrated to a yellow syrup, 3.3 g., 91% yield. The title product was found to be identical to the sample prepared by Clauss in Liebigs Ann. Chem., 539 (1974). δ (ppm, CDCl3), 7.2 (1H, NH), 5.23 (1H, dd, Jcis =2.8, Jtrans =5.0, H-H), 3.55 (1H, ddd, Jgem =15.2, JHNH =2.0, H-3 trans), 2.95 (1H, ddd, Jgem =15.2, Jcis =2.8, JHNHSl, H-3 cis) and 2.36 (3H, s, methyl). was maintained between 0°-5° C at 0°-5° C. and for 2-2.5 hr at 23°-25° C. before being extracted with chloroform (4×25 ml.) washed with water (10 ml.) dried over anhydrous Na2SO4 concentrated to a yellow syrup, 3.3 g prepared by Clauss in Liebigs Ann

反応条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

実験手順: A solution of 42.9 g of sodium hydroxide in 500 ml of water was made up under nitrogen and cooled to room temperature, 108 ml of allyl mercaptan were added and the mixture stirred under nitrogen for 30 minutes. 138.7 g of 4-acetoxyazetidin-2-one were added to the mixture over 10 minutes under nitrogen and the reaction mixture was stirred overnight. The reaction was checked for completion by T.L.C. (hexane-ethyl acetate) and extracted into dichloromethane (6×250 ml). The organic layer was washed with water (2×250 ml), dried over magnesium sulphate and evaporated in vacuo to dryness. Purification, over silica gel and elution with hexane-ethyl acetate afforded the above product as a yellow oil. (112.1 g, 73% of the theoretical yield). νmax=1769, 1778 (sh) cm-1. the reaction mixture was stirred overnight (hexane-ethyl acetate) and extracted into dichloromethane (6×250 ml) The organic layer was washed with water (2×250 ml) dried over magnesium sulphate evaporated in vacuo to dryness Purification over silica gel and elution with hexane-ethyl acetate

反応条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

実験手順: To a cold (0°-5°) oxygen-free 1N NaOH solution (803 ml.) was added over 20 minutes thioacetic acid (57 ml., 61 g., 0.803 mole). The resulting solution was added in ca 20 minutes to a cold (10°) oxygen-free solution of 4-acetoxyazetidinone (94 g., 0.730 mole) in water (300 ml.). The pH of the resulting solution was immediately adjusted to 7.4 with solid NaHCO3. The cooling bath was removed and the solution was stirred for 2.75 hours. The mixture was then extracted with chloroform, the combined organic extracts washed with water (150 ml.) and dried over sodium sulfate. Concentration on a rotary evaporator left a yellow oil (95.3 g., 90%) which solidified to a yellow solid on cooling and seeding. This solid was found identical (by IR, NMR and TLC) to the product obtained in Preparation 1. The cooling bath was removed The mixture was then extracted with chloroform the combined organic extracts washed with water (150 ml.) dried over sodium sulfate Concentration on a rotary evaporator left a yellow oil (95.3 g., 90%) which on cooling obtained in Preparation 1

反応条件: temp:0.00; pressure:0.00; stir: