Hydrochloric Acid → Isopropyl 2-methyl-5,6-dioxo-2,3,5,6-tetrahydronaphtho[1,2-b][1,4]oxathiine-2-carboxylate

HRID 563124Notes

Reaction equation

HRID 563124 reaction equation
[SH-:1].[Na+].[CH3:3][C:4]1([C:7](OC)=O)CO1.Cl.FC(F)(F)[C:14]([OH:16])=[O:15].[C:19]1(=[O:30])[C:28]2[C:23](=[CH:24][CH:25]=[CH:26][CH:27]=2)[CH:22]=[CH:21][C:20]1=[O:29].[CH:31]([OH:34])([CH3:33])[CH3:32]>O>[CH3:32][C:31]1([C:14]([O:16][CH:4]([CH3:7])[CH3:3])=[O:15])[O:34][C:22]2[C:23]3[C:28]([C:19](=[O:30])[C:20](=[O:29])[C:21]=2[S:1][CH2:33]1)=[CH:27][CH:26]=[CH:25][CH:24]=3

Participants

7

Reactant 5

HCID 313Hydrochloric AcidHCID 3776IsopropanolHCID 28015Sodium hydrosulfideHCID 3525005Methyl 2-methylglycidateHCID 67005934Naphthalene-1,2-dione trifluoroacetic acid

Product 1

HCID 25263982Isopropyl 2-methyl-5,6-dioxo-2,3,5,6-tetrahydronaphtho[1,2-b][1,4]oxathiine-2-carboxylate

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

To round bottom flask containing sodium hydrosulfide (0.582 g, 10.4 mmol) in isopropanol (20 mL) was added methyl 2-methyloxirane-2-carboxylate (1.0 mL, 9.44 mmol). The reaction mixture was stirred at room temperature for 2.5 hours. To the reaction mixture was then added water (20 ml) and the pH adjusted to 2 with 2 N HCl. The reaction mixture was extracted with diethyl ether (3×50 mL). The organic extracts were combined, dried with sodium sulfate and concentrated under reduced pressure. The resulting crude isopropyl 3-mercapto-2-methyl-2-propanoate obtained was used in the next reaction with naphthalene-1,2-dione trifluoroacetic acid as outlined for example 21. The final desired product isopropyl 2-methyl-5,6-dioxo-2,3,5,6-tetrahydronaphtho[1,2-b][1,4]oxathiine-2-carboxylate was obtained as a dark red solid (overall yield 5% for the three steps). M.p.=168-169° C.; 400 MHz 1H NMR (CDCl3) δ: 8.06 (dd, J=7.7, 1.1 Hz, 1H), 7.83 (dd, J=7.7, 0.9 Hz, 1H), 7.66 (td, J=7.7, 1.4 Hz, 1H), 7.49 (td, J=7.5, 1.1 Hz, 1H), 5.08 (septuplet, J=6.3 Hz, 1H), 3.35 (d, J=13.2 Hz, 1H), 3.03 (d, J=13.2 Hz, 1H), 1.86 (s, 3H), 1.27 (d, J=6.3 Hz, 3H), 1.26 (d, J=6.3 Hz, 3H); LCMS: 333 [M+H]; Calc. for C17H16O5S: C, 61.43; H, 4.85; N, 0. Found C, 61.93; H, 4.92; N, 0.04.

Workup

  1. extractionThe reaction mixture was extracted with diethyl ether (3×50 mL)
  2. dry with materialdried with sodium sulfate
  3. concentrationconcentrated under reduced pressure
  4. customThe resulting crude isopropyl 3-mercapto-2-methyl-2-propanoate obtained

Sources & evidence

ORD record
ord-aedf2ff6e83b430e808021b15128e4b6
Source dataset
uspto-grants-2011_11
Patent number
US08067459B2

Reaction notes

Loading…