Reaction #2069938

Reaction equation

3-amino-4,6-dihydro-pyrrolo[3,4-c]pyrazole-1,5-dicarboxylic acid 5-tert-butyl ester 1-ethyl ester

DIEA

(COCl)2

2-naphthalen-2-yl-propionic acid

→

title compound

Yield 93.0%

3-(2-Naphthalen-2-yl-propionylamino)-4,6-dihydro-pyrrolo[3,4-c]pyrazole-1,5-dicarboxylic acid 5-tert-butyl ester 1-ethyl ester

Yield 93.0%

Solvents

THF

THF

DCM

DMF

ethyl acetate cyclohexane

DCM

Conditions

Workup

1. 1
   ConcentrationThe reaction mixture was concentrated under vacuum
2. 2
   Concentrationconcentrated
3. 3
   Otherto reach r.t.
4. 4
   workup.STIRRINGstirred overnight
5. 5
   FiltrationThe mixture was filtered
6. 6
   Otherthe solution evaporated to dryness under vacuum
7. 7
   workup.DISSOLUTIONThe resulting residue was dissolved in DCM
8. 8
   Washthe obtained solution was washed with brine
9. 9
   Dryingdried over sodium sulfate
10. 10
    Filtrationfiltered
11. 11
    Otherevaporated to dryness
12. 12
    OtherThe crude product was purified by flash-chromatography (eluent

Procedure

To a solution of 2-naphthalen-2-yl-propionic acid (1.48 g. 7.4 mmol) in DCM (40 ml) and DMF cat., (COCl)2 (0.83 ml, 9.65 mmol) in DCM (10 ml) was added dropwise. The mixture was stirred at r.t. for 30 min. The reaction mixture was concentrated under vacuum, reconstituted twice with toluene and concentrated. A solution of the obtained acyl-chloride in THF (40 ml) was added slowly to a mixture of 3-amino-4,6-dihydro-pyrrolo[3,4-c]pyrazole-1,5-dicarboxylic acid 5-tert-butyl ester 1-ethyl ester (2.0 g, 6.75 mmol) and DIEA (5.8 ml, 33.3 mmol) in THF (40 ml) at 0-5° C. The reaction was allowed to reach r.t. and stirred overnight. The mixture was filtered and the solution evaporated to dryness under vacuum. The resulting residue was dissolved in DCM and the obtained solution was washed with brine, dried over sodium sulfate, filtered and evaporated to dryness. The crude product was purified by flash-chromatography (eluent:ethyl acetate/cyclohexane 3/7 then 4/6) to give 3.0 g (93% yield) of the title compound as a white solid.

Source