1,1,3,3-Tetraethoxy-2-methylpropane → 6-methyl-1H,3H-2,4,7a,8-tetraaza-cyclopenta[a]indene-2-carboxylic acid tert-butyl ester

HRID 1478992Notes

Reaction equation

[C:1]([O:5][C:6]([N:8]1[CH2:15][C:14]2[C:10](=[N:11][NH:12][C:13]=2[NH2:16])[CH2:9]1)=[O:7])([CH3:4])([CH3:3])[CH3:2].C(O[CH:20](OCC)[CH:21]([CH3:29])[CH:22](OCC)OCC)C>CC(O)=O.O>[C:1]([O:5][C:6]([N:8]1[CH2:15][C:14]2=[C:13]3[N:12]([N:11]=[C:10]2[CH2:9]1)[CH:22]=[C:21]([CH3:29])[CH:20]=[N:16]3)=[O:7])([CH3:4])([CH3:2])[CH3:3]

Participants

Conditions

Temperature: 50 °C

Procedure

A mixture of 3-amino-2,6-dihydro-4H-pyrrolo[3,4-c]pyrazole-5-carboxylic acid tert-butyl ester (5 g; 22.3 mmol; 1 eq.) and 1,1,3,3-tetraethoxy-2-methylpropane (4.32 mL; 22.3 mmol; 1 eq.) in AcOH (50 mL) was stirred at 50° C. for 20 hours then diluted with water (250 mL). The precipitate was filtered off and dried to afford the title compound (3.5 g, 57%) as a pale beige solid. 1H NMR (DMSO-d6) δ 8.98-8.95 (m, 1H), 8.43 (d, J=2.1 Hz, 1H), 4.61-4.54 (m, 4H), 2.31 (s, 3H), 1.47 (s, 9H). HPLC (max plot) 99.7%; Rt 3.27 min. UPLC/MS: (MS+) 275.0 ([M+H]+).

Workup

filtrationThe precipitate was filtered off
customdried

Sources & evidence

ORD record: ord-ccedeb49729a40d68219d5de3779fed9
Source dataset: uspto-grants-2016_08
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09403835B2

Reaction notes

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