Pivaloyl chloride → HCID 70411329, compound

HRID 1074413Notes

Reaction equation

HRID 1074413 reaction equation
[CH3:1][C:2]([CH3:7])([CH3:6])[C:3](Cl)=[O:4].[CH3:8][C:9]1([CH3:27])[O:14][C:13]2[CH:15]=[CH:16][C:17]([C:19]#[N:20])=[CH:18][C:12]=2[C@@H:11]([N:21]2[CH2:25][CH2:24][CH2:23][CH2:22]2)[C@@H:10]1[OH:26]>CN(C)C1C=CN=CC=1.ClCCl>[CH3:8][C:9]1([CH3:27])[O:14][C:13]2[CH:15]=[CH:16][C:17]([C:19]#[N:20])=[CH:18][C:12]=2[C@@H:11]([N:21]2[CH2:22][CH2:23][CH2:24][CH2:25]2)[C@@H:10]1[O:26][C:3](=[O:4])[C:2]([CH3:7])([CH3:6])[CH3:1]

Participants

5

Reactant 2

HCID 62493Pivaloyl chlorideHCID 13223018HCID 13223018, compound

Product 1

HCID 70411329HCID 70411329, compound

Reagents, catalysts & solvents 2

HCID 142844-(Dimethylamino)pyridineCatalystHCID 6344DichloromethaneSolvent2×

Procedure

To a solution of 4-dimethylaminopyridine (0.98 g) in dichloromethane (50 ml) was added 2,2-dimethylpropanoyl chloride (0.69 ml) dropwise and with gentle stirring, followed by crude trans-2,2-dimethyl-4-pyrrolidino-6-cyano-3,4-dihydro-2H-benzo[b]-pyran-3-ol (2.50 g) in dichloromethane (50 ml) during 4 minutes. The resulting red solution was heated under reflux for 40 hours before cooling and evaporation of solvent. The orange residue was taken up in ethyl acetate and washed with water, dried and evaporated leaving a mustard coloured solid (2.97 g) which was separated by chromatography on silica gel (110 g) with mixtures of ethyl acetate and 60°-80° petroleum ether using a gradient elution technique, into crude ester (1.12 g) and starting material (1.13 g). Recrystallization of the crude material from 60°-80° petroleum ether gave trans-2,2-dimethyl-3-(2,2-dimethylpropanoyloxy)-4 pyrrolidino-6-cyano-3,4-dihydro-2H-benzo[b]pyran (0.73 g) as white crystals of m.p. 109°-110° C.; IR absorptions at 1730, 2220 cm-1 ; nmr (CDCl3) δ 1.24 (9H), 1.29 (3H), 1.41 (3H), 1.75 (4H, broad m), 2.73 (4H, broad m), 4.09 (1H, d, J=9), 5.33 (1H, d, J=9), 6.86 (1H, d, J=8), 7.43 (1H, q, J=8, 2), 7.74 (1H, d, J=2). Anal. Calcd. for C21H28N2O3 : C, 70.76; H, 7.92; N,7.86. Found: C, 70.74; H, 8.03, N, 7.76%.

Workup

  1. temperatureThe resulting red solution was heated
  2. temperatureunder reflux for 40 hours
  3. temperaturebefore cooling
  4. customevaporation of solvent
  5. washwashed with water
  6. customdried
  7. customevaporated
  8. customleaving a mustard
  9. customwas separated by chromatography on silica gel (110 g) with mixtures of ethyl acetate and 60°-80° petroleum ether using
  10. washa gradient elution technique
  11. customRecrystallization of the crude material from 60°-80° petroleum ether

Sources & evidence

ORD record
ord-33093166e6a24fcb918241e728ec4333
Source dataset
uspto-grants-1983_07
Patent number
US04391815

Reaction notes

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