Carbon Disulfide → Lithium Hexamethyldisilazide

HRID 1980636Notes

Reaction equation

HRID 1980636 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(OC(=O)C)(=O)C>CCCCCC.C1COCC1.C(Cl)(Cl)Cl.O>[CH3:6][Si:7]([CH3:14])([CH3:13])[N-:8][Si:9]([CH3:12])([CH3:11])[CH3:10].[Li+:5]

Participants

9

Reactant 4

HCID 6348Carbon DisulfideHCID 7918Acetic AnhydrideHCID 13838HexamethyldisilazaneHCID 178418339Butyllithium

Product 1

HCID 2733832Lithium Hexamethyldisilazide

Reagents, catalysts & solvents 4

HCID 962WaterSolventHCID 6212ChloroformSolventHCID 8028TetrahydrofuranSolvent2×HCID 8058HexaneSolvent

Procedure

A solution of lithium hexamethyldisilazide was prepared by the addition of 8.66 ml of a 1.6M solution of n-butyllithium in hexane to 2.96 ml of hexamethyldisilazane in 30 ml of dry THF at -10° with stirring under argon. The solution was cooled to -78° and added by cannula to 2.07 g of 4-nitrobenzyl 2-(4-allylthioazetidin-2-on-1-yl) acetate in 15 ml of dry THF at -78°, with stirring, under argon. After 5 minutes 1.11 ml of carbon disulphide were added by syringe. 2.33 ml of acetic anhydride were then added. The solution was allowed to warm to room temperature and evaporated to give an orange oil. The oil was mixed with water (40 ml) and chloroform (40 ml), the organic layer separated and the aqueous layer extracted with additional chloroform (2×40 ml). The combined organic phase was dried (MgSO4) and evaporated to give an orange oil, which was used without further purification as the starting material for Example 16b.

Workup

  1. temperatureThe solution was cooled to -78°
  2. stirringwith stirring, under argon
  3. customevaporated
  4. customto give an orange oil
  5. customthe organic layer separated
  6. extractionthe aqueous layer extracted with additional chloroform (2×40 ml)
  7. dry with materialThe combined organic phase was dried (MgSO4)
  8. customevaporated
  9. customto give an orange oil, which
  10. customwas used without further purification as the starting material for Example 16b

Sources & evidence

ORD record
ord-287b305745d44617a5c40286979996e4
Source dataset
uspto-grants-1985_04
Patent number
US04510086

Reaction notes

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