Pyrido[1,2-a]benzimidazole, 1,2,3,4-tetrahydro- (6CI,7CI,8CI,9CI) synthesis

12synthesis methods

Product Name:Pyrido[1,2-a]benzimidazole, 1,2,3,4-tetrahydro- (6CI,7CI,8CI,9CI)
CAS Number:5622-83-3
Molecular formula:C11H12N2
Molecular Weight:172.23

675-20-7 Synthesis

675-20-7
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609-73-4 Synthesis

609-73-4
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Pyrido[1,2-a]benzimidazole, 1,2,3,4-tetrahydro- (6CI,7CI,8CI,9CI)

5622-83-3
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Yield:5622-83-3 75%

Reaction Conditions:

Stage #1: piperidin-2-one;o-nitroiodobenzenewith caesium carbonate;palladium(II) trifluoroacetate;2,2'-bis-(diphenylphosphino)-1,1'-binaphthyl in toluene at 80; for 18 h;
Stage #2: with iron;acetic acid in toluene; for 0.5 h;Heating / reflux;
Stage #3: with sodium hydrogencarbonate in water;Product distribution / selectivity;

Steps:

9

Method A applied to 1-lodo-2-nitrobenzene (125 mg, 0.5 mmol) and piperidin-2-one (59 mg, 0.6 mmol) afforded the title compound as pale yellow solid (65 mg, 75%). mp 104-106⁰C. ¹H NMR (DMSO) δ 1.98-2.07 (m, 4 H), 3.16-3.23 (m, 2 H), 4.30 (t, J = 6.9 Hz, 2 H)₁ 7.51-7.56 (m, 2 H), 7.75-7.92 (m, 2 H); ¹³C NMR δ 17.7, 20.5, 22.3, 43.0, 112.3, 114.2, 124.7, 125.6, 131.5, 151.8, 156.6. HRMS (FAB): cal for CnHi₃N₂ [M+H⁺]: 173.1079; found: 173.1071.

References:

WO2009/412,2008,A1 Location in patent:Page/Page column 30-31