Cysteine Hydrochloride → Ethyl 2-(2,5-dihydroxyphenyl)-1,3-thiazolidine-4-carboxylate

HRID 1069044Notes

Reaction equation

HRID 1069044 reaction equation
Cl.[NH2:2][C@H:3]([C:6]([OH:8])=[O:7])[CH2:4][SH:5].[CH2:9](N(C(C)C)C(C)C)[CH3:10].[OH:18][C:19]1[CH:26]=[CH:25][C:24]([OH:27])=[CH:23][C:20]=1[CH:21]=O>C(O)C>[OH:18][C:19]1[CH:26]=[CH:25][C:24]([OH:27])=[CH:23][C:20]=1[CH:21]1[NH:2][CH:3]([C:6]([O:8][CH2:9][CH3:10])=[O:7])[CH2:4][S:5]1

Participants

5

Reactant 3

HCID 60960Cysteine HydrochlorideHCID 709492,5-DihydroxybenzaldehydeHCID 81531Diisopropylethylamine

Product 1

HCID 9903511Ethyl 2-(2,5-dihydroxyphenyl)-1,3-thiazolidine-4-carboxylate

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent3×

Procedure

To a round bottom flask, equipped with magnetic stirrer, containing 9.25 g (50 mM) ethyl ester of L-cysteine hydrochloride in 75 mL of absolute ethanol was added 8.4 mL (48 mM) ethyldiisopropylamine. A clear solution was obtained after stirring for several minutes with a magnetic stirrer under nitrogen. To this solution was added 6.65 g (49 mM) 2,5-dihydroxybenzaldehyde in 50 mL absolute ethanol, and the reaction mixture was stirred for another 4 hrs. Evaporation to dryness produced a viscous oil, which was dissolved in 20 mL absolute ethanol and loaded on a silica gel column. Elution with ethylacetate/hexane (at molar ratios from 2:8 to 3.5:6.5) produced 5.9 g of the desired product. 1H NMR (DMSO-d6; 1:1 diastereoisomeric mixture at C2) δ; 1.21-1.25 m 3H; 2.95-3.02 m and 3.19-3.22 m, 2H; (3.5 m, 3.76 m 3.90 m and 4.25 m, 2H); 4.15 m, 2H; (5.56 d, J=11.9 Hz and 5.75 d, J=9.9 Hz, 1H); (6.45-6.48 dd, J=2.9 Hz, 8.7 Hz, 6.52-6.55 dd, J=2.9 Hz, 8.7 Hz, 6.57 d, J=8.8 Hz, 6.61 d, J=8.8 Hz 2H); 6.76 dd, J=2.8 Hz, 9.2 Hz, 1H; 8.64 s and 8.75 s, 1H; 9.01 s and 9.19 s 1H.

Workup

  1. customTo a round bottom flask, equipped with magnetic stirrer
  2. customA clear solution was obtained
  3. stirringthe reaction mixture was stirred for another 4 hrs
  4. customEvaporation to dryness
  5. customproduced a viscous oil, which
  6. washElution with ethylacetate/hexane (at molar ratios from 2:8 to 3.5:6.5)

Sources & evidence

ORD record
ord-0001268cccc94b308f6c217649a795df
Source dataset
uspto-grants-2001_06
Patent number
US06251927B1

Reaction notes

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