Sodium Chloride → (6R,7R)-2,2-dimethyl-7-phthalimido-1-aza-3-oxabicyclo[4.2.0]octan-8-one

HRID 851397Notes

Reaction equation

HRID 851397 reaction equation
B(F)(F)F.CCOCC.[OH:10][CH2:11][CH2:12][C@H:13]1[NH:16][C:15](=[O:17])[C@@H:14]1[N:18]1[C:22](=[O:23])[C:21]2=[CH:24][CH:25]=[CH:26][CH:27]=[C:20]2[C:19]1=[O:28].CO[C:31](OC)([CH3:33])[CH3:32].[Cl-].[Na+].C(=O)(O)[O-].[Na+]>ClCCl>[CH3:32][C:31]1([CH3:33])[O:10][CH2:11][CH2:12][C@H:13]2[N:16]1[C:15](=[O:17])[C@@H:14]2[N:18]1[C:19](=[O:28])[C:20]2=[CH:27][CH:26]=[CH:25][CH:24]=[C:21]2[C:22]1=[O:23]

Participants

7

Reactant 5

HCID 5234Sodium ChlorideHCID 64952,2-Dimethoxypropane2×HCID 8000Boron trifluoride etherateHCID 516892Sodium BicarbonateHCID 53834571(3R,4R)-4-(2-hydroxyethyl)-3-phthalimidoazetidin-2-one

Product 1

HCID 53799173(6R,7R)-2,2-dimethyl-7-phthalimido-1-aza-3-oxabicyclo[4.2.0]octan-8-one

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

Boron trifluoride etherate (5 μl) was added to a suspension of (3R,4R)-4-(2-hydroxyethyl)-3-phthalimidoazetidin-2-one (126 mg) and 2,2-dimethoxypropane (74 μl) in dichloromethane (3 ml) at ambient temperature. The mixture was stirred for two hours. Additional dimethoxypropane (50 μl) was added and the mixture was stirred for an additional 1.5 hours. The resulting solution was poured into a saturated aqueous solution of sodium chloride and sodium bicarbonate and extracted twice with dichloromethane. The combined extracts were dried over magnesium sulfate and evaporated to give a crystalline solid. Chromatography on silica gel (4 g; eluting with 3% acetone in dichloromethane) and washing the crystals with ether afforded 100 mg of (6R,7R)-2,2-dimethyl-7-phthalimido-1-aza-3-oxabicyclo[4.2.0]octan-8-one: IR (CH2Cl2): 1770 and 1720 cm-1 ; NMR (CDCl3) δ: 1.56 (s, 3H), 1.81 (s, 3H), 1.7-2.0 (m, 2H), 3.7-4.1 (m, 3H), 5.01 (d, J=2 Hz, 1H), and 7.5-7.9 (m, 4H).

Workup

  1. stirringthe mixture was stirred for an additional 1.5 hours
  2. extractionextracted twice with dichloromethane
  3. dry with materialThe combined extracts were dried over magnesium sulfate
  4. customevaporated
  5. customto give a crystalline solid
  6. washChromatography on silica gel (4 g; eluting with 3% acetone in dichloromethane) and washing the crystals with ether

Sources & evidence

ORD record
ord-4dcf50b180fa498fab81594fe5b341ee
Source dataset
uspto-grants-1983_05
Patent number
US04383945

Reaction notes

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