Diethyl squarate → HCID 10813912, compound

HRID 849279Notes

Reaction equation

HRID 849279 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.[CH2:13]([O:15][P:16]([CH2:21][CH2:22][NH:23][CH2:24][CH2:25][CH2:26][NH:27][C:28]([O:30][C:31]([CH3:34])([CH3:33])[CH3:32])=[O:29])(=[O:20])[O:17][CH2:18][CH3:19])[CH3:14]>C(O)C>[C:31]([O:30][C:28](=[O:29])[NH:27][CH2:26][CH2:25][CH2:24][N:23]([CH2:22][CH2:21][P:16]([O:15][CH2:13][CH3:14])([O:17][CH2:18][CH3:19])=[O:20])[C:4]1[C:5](=[O:12])[C:6](=[O:11])[C:7]=1[O:8][CH2:9][CH3:10])([CH3:34])([CH3:32])[CH3:33]

Participants

4

Reactant 2

HCID 123228Diethyl squarateHCID 10903865HCID 10903865, compound

Product 1

HCID 10813912HCID 10813912, compound

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent2×

Procedure

To a solution of 3,4-diethoxy-3-cyclobutene-1,2-dione (45 g, 0.265 mole; Aldrich 31,077-8) in absolute ethanol (1.2 L) under nitrogen was added dropwise a solution of N-[3-(t-butyloxycarbonylamino)propyl]-2-aminoethylphosphonic acid diethyl ester (80 g, 0.24 mole) in absolute ethanol (600 mL) and the reaction mixture was stirred at ambient temperature 15 hr. The reaction mixture was concentrated in vacuo and the residue was put on a pad of silica gel (6"×4") and eluted first with a mixture of methylene chloride/hexane 1:1 to remove excessive 3,4-diethoxy-3-cyclobutene-1,2-dione and finally with 10% methanol/methylene chloride to yield the title compound after evaporation as a viscous oil (107 g, 96%). NMR: (CDCl3, 400 MHz): 1.34 (t, 6H), 1.43 (s, 9H), 1.46 (t, 3H), 1.80 (m, 2H), 2.12 (m, 2H), 3.14 (m, 2H), 3.49 (t, 1H), 3.66 (m, 1H), 3.73 (t, 1H), 3.90 (m, 1H), 4.10 (m, 4H), 4.74 (m, 4H), 5.05 (br, H).

Workup

  1. concentrationThe reaction mixture was concentrated in vacuo
  2. washeluted first with a mixture of methylene chloride/hexane 1:1
  3. customto remove excessive 3,4-diethoxy-3-cyclobutene-1,2-dione

Sources & evidence

ORD record
ord-a53235377a044e18b9310dc8964a98b3
Source dataset
uspto-grants-2000_01
Patent number
US06011168

Reaction notes

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