[NH2:1][C:2]1[CH:3]=[C:4]([C:8]2[O:9][C:10]3[C:11]([N:16]=2)=[N:12][CH:13]=[CH:14][CH:15]=3)[CH:5]=[CH:6][CH:7]=1.[CH3:17][N:18]([CH2:20][CH:21]=O)[CH3:19].C(OC(OCC)CN(C)C)C.[BH4-].[Na+]>O.C(O)C>[CH3:17][N:18]([CH3:19])[CH2:20][CH2:21][NH:1][C:2]1[CH:3]=[C:4]([C:8]2[O:9][C:10]3[C:11]([N:16]=2)=[N:12][CH:13]=[CH:14][CH:15]=3)[CH:5]=[CH:6][CH:7]=1A mixture of 1.1 g., (0.005 mole) of 2-(3-aminophenyl)oxazolo[4,5-b]pyridine and 50 ml. of ethanol is reacted with dimethylaminoacetaldehyde [from 0.96 g. (0.006 mole) dimethylaminoacetaldehyde diethylacetal] by gentle heating to complete the intermediate Schiff base formation. The mixture is then cooled and 60 mg., (0.0015 mole) of sodium borohydride is added, and the mixture allowed to stir overnight at room temperature. Water is added, the solvents are removed in vacuo, and the residue is distributed between water and methylene chloride. The organic layer is dried and concentrated in vacuo to give crude 2-[3-(2-dimethylaminoethyl)aminophenyl]oxazolo[4,5-b]pyridine, purified via column chromatography using an alumina column with an ethylacetate-ether mixture (v/v 0-60% ethylacetate) as eluant.
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