Oxygen → 2-Azetidinone, 1-(2,2-dimethoxyethyl)-

To a solution of 2.2 mmol of lithium diisopropylamide in 15 ml tetrahydrofuran at -78° was added dropwise 0.43 g (2 mmol) of N-(2,2-dimethoxyethyl)-2-carbethoxy azetidine in 3 ml of tetrahydrofuran. After stirring at -78° for 30 minutes, the deep yellow anion was silylated in the usual way and warmed to room temperature. Removal of all volatiles by rotary evaporation with a high vacuum pump gave a purple residue which was redissolved in dichloromethane. Internal photooxidation using 5 g of Photox (trademark for photoconductive lead-free zinc oxides available from The New Jersey Zinc Co.) as the sensitizer required less than 5 minutes for oxygen uptake. The mixture was then filtered free of sensitizer and worked up by aqueous extraction in the usual manner. The pink residue obtained was applied to a 17×2 cm neutral alumina column. Elution with 10:3 ethyl acetate-hexane yielded 0.18 g (56%) of pale yellow liquid, which by NMR analysis was greater than 90% pure. Comparison of its spectral properties (IR, NMR) with those of an authentic known sample confirmed the identity of the product as the expected beta-lactam.

1. customRemoval of all volatiles
2. customby rotary evaporation with a high vacuum pump
3. customgave a purple residue which
4. customless than 5 minutes
5. filtrationThe mixture was then filtered free of sensitizer
6. extractionworked up by aqueous extraction in the usual manner
7. customThe pink residue obtained
8. washElution with 10:3 ethyl acetate-hexane

ORD record

ord-dbf392eb780a4f0c96ccfb6465f47d1d

Source dataset

uspto-grants-1980_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04190579