Dichloromethane → 7,7,8a-Trimethyloctahydro-2H-benzo[3,4]cyclobuta[1,2-b]pyran-5(4bH)-one

HRID 2072275Notes

Reaction equation

HRID 2072275 reaction equation
[O:1]=[C:2]1[CH2:9][C:6]([CH3:8])([CH3:7])[CH2:5][C:4]([CH3:10])=[CH:3]1.[O:11]1[CH:16]=[CH:15][CH2:14][CH2:13][CH2:12]1.ClCCl>C(Cl)(Cl)(Cl)Cl>[CH3:7][C:6]1([CH3:8])[CH2:5][C:4]2([CH3:10])[CH:3]([CH:13]3[CH:12]2[O:11][CH2:16][CH2:15][CH2:14]3)[C:2](=[O:1])[CH2:9]1

Participants

5

Reactant 3

HCID 6344DichloromethaneHCID 6544IsophoroneHCID 80803,4-dihydro-2H-pyran

Product 1

HCID 64548777,7,8a-Trimethyloctahydro-2H-benzo[3,4]cyclobuta[1,2-b]pyran-5(4bH)-one

Reagents, catalysts & solvents 1

HCID 5943Carbon TetrachlorideSolvent

Procedure

To a 5-liter round bottomed flask equipped with a quartz immersion well and nitrogen bubbler was added, under nitrogen, 138 g. (1.0 mol.) of isophorone and 498 g. (5.93 mol.) of 3,4-dihydropyran. Enough dichloromethane was added to fill the flask. The solution was bubbled with nitrogen for 1.5 hours and was irradiated with a 450 watt Hanovia medium pressure mercury arc through a Corning 9700 glass filter for 20.5 hours. When the photolysis was completed, the solution was concentrated in vacuo to yield 107.9 g. (0.486 mol.) of a crystalline solid and 80.6 g. of a liquid (0.363 mol.) (Total yield 0.849 mol., 85%). The solid after sublimation and recrystallization had m.p. 111°-112.2° C. IR: 1690 cm-1NMR: (CCl4) 0.92δ (S-3H), 1.12δ (S-3H); 1.32δ (S-3H); 1.35-2.15δ (multiplets 8H); 2.35δ (triplet-2H, J=14Hz); 2.65-2.93δ (M-1H); 3.38-4.20δ (M-2H). The liquid, which had b.p. 101° C./0.3 mm.Hg. was found by glpc to consist of a lower boiling minor component, the solid and a higher boiling product. Redistillation of this fraction gave a fraction, b.p. 85°-90° C./0.1 mm.Hg. which had a NMR (CCl4) spectrum which had methyl singlets at 0.92δ, 1.03δ, 1.10δ and 1.30δ. The singlet at 1.30δ belonged to the solid component, which made up 34% of the mixture. IR: 1695 cm-1.

Workup

  1. additionnitrogen bubbler was added, under nitrogen
  2. customThe solution was bubbled with nitrogen for 1.5 hours
  3. customwas irradiated with a 450 watt Hanovia medium pressure mercury arc through a Corning 9700 glass
  4. filtrationfilter for 20.5 hours
  5. concentrationthe solution was concentrated in vacuo
  6. customto yield 107.9 g
  7. customThe solid after sublimation and recrystallization
  8. distillationRedistillation of this fraction
  9. customgave a fraction, b.p. 85°-90° C./0.1 mm.Hg

Sources & evidence

ORD record
ord-a718e75deedc4926b43cc13b4fa57749
Source dataset
uspto-grants-1977_09
Patent number
US04051076

Reaction notes

Loading…