Hydrochloric Acid → 2-(6-methylpyridin-2-yl)-5,6-dihydro-4H-pyrrolo[1,2-b]pyrazole-3-carboxylic acid

HRID 2221145Notes

Reaction equation

[O-]CC.[Na+].C1(C)C=CC=CC=1.C([O:14][C:15](=[O:32])[CH2:16][C:17]([C:25]1[CH:30]=[CH:29][CH:28]=[C:27]([CH3:31])[N:26]=1)=[N:18][N:19]1[CH2:23][CH2:22][CH2:21][C:20]1=O)C.Cl>O>[CH3:31][C:27]1[N:26]=[C:25]([C:17]2[C:16]([C:15]([OH:14])=[O:32])=[C:23]3[CH2:22][CH2:21][CH2:20][N:19]3[N:18]=2)[CH:30]=[CH:29][CH:28]=1

Participants

Conditions

Temperature: 100 °C

Procedure

Add sodium ethoxide (90 g, 1.32 mol), toluene (5 L) and 3-[6-methyl-(pyridin-2-yl)]-3-(2-oxo-pyrrolidin-1-ylimino)-propionic acid ethyl ester (Preparation 2-B; 201 g, 0.661 mol) to a 22 L flask equipped with a mechanical stirrer, nitrogen inlet and a reflux condenser. Heat the mixture at 100° C. for 24 h then cool to room temperature. Add water (4 L) and adjust the pH to 4 with concentrated hydrochloric acid. Separate the organic layer and extract the aqueous portion with 10% isopropyl alcohol in chloroform (3×4.5 L). Combine the organic layers, dry (sodium sulfate), filter, and concentrate in vacuo to yield the subtitled product 138 g (86%) as a yellow solid in 78% purity by HPLC analysis. MS ES+ m/e 244 (M+1).

Workup

customequipped with a mechanical stirrer, nitrogen inlet and a reflux condenser
temperaturethen cool to room temperature
customSeparate the organic layer
extractionextract the aqueous portion with 10% isopropyl alcohol in chloroform (3×4.5 L)
dry with materialCombine the organic layers, dry (sodium sulfate)
filtrationfilter
concentrationconcentrate in vacuo

Sources & evidence

ORD record: ord-5ec45f30964247f08e181fdf7a87e300
Source dataset: uspto-grants-2008_05
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07368445B2

Reaction notes

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