Carbon Disulfide → Lithium Hexamethyldisilazide

HRID 653174Notes

Reaction equation

HRID 653174 reaction equation
C([Li:5])CCC.[CH3:6][Si:7]([CH3:14])([CH3:13])[NH:8][Si:9]([CH3:12])([CH3:11])[CH3:10].C(=S)=S.C(Cl)(Cl)=O>CCCCCC.O1CCCC1.C1(C)C=CC=CC=1.C(OCC)C.CCCCCC.C(O)(=O)C.C(OCC)C>[CH3:6][Si:7]([CH3:14])([CH3:13])[N-:8][Si:9]([CH3:12])([CH3:11])[CH3:10].[Li+:5]

Participants

11

Reactant 4

HCID 6348Carbon DisulfideHCID 6371PhosgeneHCID 13838HexamethyldisilazaneHCID 178418339Butyllithium

Product 1

HCID 2733832Lithium Hexamethyldisilazide

Reagents, catalysts & solvents 6

HCID 176Acetic AcidSolventHCID 1140TolueneSolventHCID 3283Diethyl EtherSolventHCID 8028TetrahydrofuranSolvent2×HCID 8058HexaneSolventHCID 21584099Diethylether hexaneSolvent

Procedure

A solution of lithium hexamethyldisilazide was prepared by the addition of n-butyllithium in hexane (4.21 ml of a 1.6M solution) to 2.13 ml of hexamethyldisilazane in 10 ml of dry tetrahydrofuran at 0° C. while stirring under nitrogen. The solution was added via a cannula to a solution of 1.08 g of 4-nitrobenzyl 2-(4(R)-ethylthio-3(S)-[1'(R)-dimethyl-{2-methylprop-2-yl}silyloxyethyl]-2-azetidinon-1-yl)acetate in 10 ml of dry tetrahydrofuran at -78° C., with stirring under nitrogen. After 5 minutes, 0.35 ml of carbon disulphide was added by syringe and after a further 90 minutes phosgene in toluene (3.56 ml of a 12.5% solution) was added by syringe. The mixture was stirred for 90 minutes and poured into 50 ml of diethyl ether and 10 ml of 2M acetic acid. The organic layer was separated, washed with water, 12% sodium chloride solution, dried over magnesium sulphate and evaporated to give an orange oil. Chromatography over silica gel using diethyl ether/hexane mixtures as eluent gave 0.485 g of the title compound in purified form.

Workup

  1. stirringwith stirring under nitrogen
  2. additionwas added by syringe
  3. stirringThe mixture was stirred for 90 minutes
  4. customThe organic layer was separated
  5. washwashed with water, 12% sodium chloride solution
  6. dry with materialdried over magnesium sulphate
  7. customevaporated
  8. customto give an orange oil

Sources & evidence

ORD record
ord-a3bb232e4ea7408ca72bf0e03e92e833
Source dataset
uspto-grants-1987_06
Patent number
US04675396

Reaction notes

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