Diethyl squarate → HCID 54525291, compound

HRID 963449Notes

Reaction equation

HRID 963449 reaction equation
C(O[C:4]1[C:5](=[O:12])[C:6](=[O:11])[C:7]=1[O:8][CH2:9][CH3:10])C.[NH2:13][C@@H:14]([C:16]([CH3:19])([CH3:18])[CH3:17])[CH3:15]>C(O)C>[CH2:9]([O:8][C:7]1[C:6](=[O:11])[C:5](=[O:12])[C:4]=1[NH:13][C@H:14]([CH3:15])[C:16]([CH3:19])([CH3:18])[CH3:17])[CH3:10]

Participants

4

Reactant 2

HCID 123228Diethyl squarateHCID 5324845(R)-3,3-Dimethyl-2-aminobutane2×

Product 1

HCID 54525291HCID 54525291, compoundYield 74%

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent2×

Procedure

A solution of 3,4-diethoxy-3-cyclobutene-1,2-dione (10 g, 59 mmol) and (R)-2-amino-3,3-dimethylbutane (353 mL of a 0.2M solution in absolute ethanol, 71 mmol) was stirred at room temperature for 24 hours. Another portion of (R)-2-amino-3,3-dimethylbutane (150 mL of a 0.2M solution in absolute ethanol, 30 mmol) was added and the resulting solution was stirred at room temperature for 24 hours. The slurry was filtered, and the filtrate concentrated under reduced pressure. The resulting solid was trituated with hexane:ethyl acetate (150:5 mL), then washed with hexane to give 9.78 g (74%) of (R)-3-ethoxy-4-(1,2,2-trimethyl-propylamino)-cyclobut-3-ene-1,2-dione as a white solid: 1H NMR: (DMSO-d6): δ 8.72 and 8.50 (two d, 1H, rotamers), 4.65 (m, 2H), 3.90 and 3.42 (two m, 1H, rotamers), 1.37 and 1.35 (two overlapping t, 3H, rotamers), 1.10 (two overlapping d, 3H, rotamers), 0.85 and 0.84 (two s, 9H, rotamers) ppm. IR (KBr): 3150, 2950, 1800, 1700 cm-1 ; MS (m/z): 225 (M+).

Workup

  1. filtrationThe slurry was filtered
  2. concentrationthe filtrate concentrated under reduced pressure
  3. washethyl acetate (150:5 mL), then washed with hexane

Sources & evidence

ORD record
ord-9dec054052484814a4df84bfc615c3aa
Source dataset
uspto-grants-1998_06
Patent number
US05763474

Reaction notes

Loading…