Hexane → trans-N-(4'-chlorophenyl)-2,2-diethoxy-3,6-dimethyl-4-ethoxy-3,4-dihydro-2H-pyran-5-carboxamide

HRID 487752Notes

Reaction equation

HRID 487752 reaction equation
[Cl:1][C:2]1[CH:7]=[CH:6][C:5]([NH:8][C:9](=[O:18])[C:10](=[CH:14][O:15][CH2:16][CH3:17])[C:11](=[O:13])[CH3:12])=[CH:4][CH:3]=1.[CH2:19]([O:21][C:22]([O:25][CH2:26][CH3:27])=[CH:23][CH3:24])[CH3:20].CCCCCC>C1(C)C=CC=CC=1>[Cl:1][C:2]1[CH:3]=[CH:4][C:5]([NH:8][C:9]([C:10]2[C@@H:14]([O:15][CH2:16][CH3:17])[C@H:23]([CH3:24])[C:22]([O:25][CH2:26][CH3:27])([O:21][CH2:19][CH3:20])[O:13][C:11]=2[CH3:12])=[O:18])=[CH:6][CH:7]=1

Participants

5

Reactant 3

HCID 8058HexaneHCID 1408411-Propene, 1,1-diethoxy-HCID 54471103N-(4'-Chlorophenyl)-2-ethoxymethylene-3-oxobutanamide

Product 1

HCID 86746200trans-N-(4'-chlorophenyl)-2,2-diethoxy-3,6-dimethyl-4-ethoxy-3,4-dihydro-2H-pyran-5-carboxamideYield 31.1%

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Procedure

N-(4'-Chlorophenyl)-2-ethoxymethylene-3-oxobutanamide (1.3 g) was stirred in toluene (10 ml) whilst 1,1-diethoxyprop-1-ene (2 g) was added dropwise. The mixture was stirred at room temperature for 40 hours and evaporated to dryness. The residual gum was purified by medium pressure liquid chromatography on K60 silica using ethyl acetate/petroleum ether b.p. 60°-80° C. 15/85 v/v as eluting solvent to give two stereoisomers. The first isomer after trituration with n-hexane gave trans-N-(4'-chlorophenyl)-2,2-diethoxy-3,6-dimethyl-4-ethoxy-3,4-dihydro-2H-pyran-5-carboxamide (0.6 g), m.p. 104°-106° C. The n.m.r. spectrum (deuterochloroform) showed the --CH(OEt)-- signal at 4.0 ppm (doublet of quartets 1H, J=3 Hz and 1 Hz), consistent with the trans-configuration. The second isomer, after trituration with n-hexane, gave cis-N-(4'-chlorophenyl)-2,2-diethoxy-3,6-dimethyl-4-ethoxy-3,4-dihydro-2H-pyran-5-carboxamide (0.1 g), m.p. 125°-7° C. The n.m.r. spectrum (deuterochloroform) showed the --CH(OEt)-- signal at 4.5 ppm (doublet of quartets, 1H, J=7 Hz and 1 Hz) consistent with the cis-configuration.

Workup

  1. additionwas added dropwise
  2. customevaporated to dryness
  3. customThe residual gum was purified by medium pressure liquid chromatography on K60 silica
  4. wash15/85 v/v as eluting solvent
  5. customto give two stereoisomers

Sources & evidence

ORD record
ord-b671c6cb7d114e6193c6c0eb3bac63ff
Source dataset
uspto-grants-1994_03
Patent number
US05296613

Reaction notes

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