Hydrochloric Acid → Methyl (3E)-4-methyl-6-(2,6,6-trimethyl-1-cyclohexen-1-yl)-3-hexenoate

HRID 1752173Notes

Reaction equation

HRID 1752173 reaction equation
[CH3:1][CH:2]([CH2:13][CH2:14][C:15]1[C:20]([CH3:22])([CH3:21])[CH2:19][CH2:18][CH2:17][C:16]=1[CH3:23])[CH:3]=[C:4](C(OC)=O)[C:5]([O:7][CH3:8])=[O:6].[Cl-].[Li+].O.CN1CCCC1=O.Cl>>[CH3:1]/[C:2](/[CH2:13][CH2:14][C:15]1[C:20]([CH3:22])([CH3:21])[CH2:19][CH2:18][CH2:17][C:16]=1[CH3:23])=[CH:3]\[CH2:4][C:5]([O:7][CH3:8])=[O:6]

Participants

6

Reactant 5

HCID 313Hydrochloric AcidHCID 962WaterHCID 13387N-methyl-2-pyrrolidoneHCID 433294Lithium ChlorideHCID 24938928Propanedioic acid, 2-[2-methyl-4-(2,6,6-trimethyl-1-cyclohexen-1-yl)butylidene]-, 1,3-dimethyl ester

Product 1

HCID 20663006Methyl (3E)-4-methyl-6-(2,6,6-trimethyl-1-cyclohexen-1-yl)-3-hexenoateYield 100.9%

Conditions

Temperature
130 °C

Procedure

Conjugated malonate 3a (0.5 g, 1.5 mmol), anhydrous lithium chloride (93 mg, 2.2 mmol) and water (53 mg, 3 mmol) in N-methyl-pyrrolidone (2.9 g, 29 mmol) are heated under stirring to 130° C. After 4 h at this temperature the mixture is poured upon 2 M HCl and extracted with tent-butyl methyl ether. The combined organic layers are washed with conc. NaHCO3, conc. NaCl and dried over MgSO4. After filtration and evaporation of the solvent the crude product (0.64 g) is bulb-to-bulb-distilled to give 0.4 g of 4a at 120° C./0.1 mbar. E/Z ratio 82:18. Analytical data of the E-isomer: 1H-NMR (400 MHz, CDCl3): δ 1.0 (s, 6 H), 1.4 (m, 2 H), 1.55 (m, 2 H), 1.6 (s, 3 H), 1.7 (s, 3 H), 1.9 (m, 2 H), 2.1 (4 H), 3.05 (d, 2 H), 3.7 (s, 3 H), 5.35 (t, 1 H) ppm. 13C-NMR (400 MHz, CDCl3): δ 16.35 (t), 19.5 (t), 19.8 (q), 27.5 (t), 28.6 (q, 2 C), 32.8 (t), 33.5 (t), 34.95 (s), 39.8 (t), 40.0 (t), 51.6 (q), 115.0 (d), 127.1 (s), 136.9 (s), 139.9 (s), 172.9 (s). MS (EI): m/z (%) 264 (M+, 4), 249 ([M-15]+, 1), 190 (3), 175 (3), 138 (10), 137 (100), 136 (21), 121 (12), 106 (11), 95 (73), 81 (45), 55 (19), 41 (21). Retention times (GC): 9.47 (Z), 9.56 (α,β), 9.62 (E) min. The mass spectra of the E- and Z-isomers are identical. IR (film): 2972 (m), 2865 (m), 1738 (s), 1434 (m), 1258 (m), 1199 (m), 1148 (m).

Workup

  1. extractionextracted with tent-butyl methyl ether
  2. washThe combined organic layers are washed with conc. NaHCO3, conc. NaCl
  3. dry with materialdried over MgSO4
  4. filtrationAfter filtration and evaporation of the solvent the crude product (0.64 g)
  5. distillationis bulb-to-bulb-distilled

Sources & evidence

ORD record
ord-58bec1f103cc4a06b2390c8a28f4a45c
Source dataset
uspto-grants-2015_10
Patent number
US09163000B2

Reaction notes

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