Dimethylformamide dimethyl acetal → 1-(2'6'-Diethylphenyl)-4-methylamino-1,2-dihydro-1,3,5-triazin-2-one hydrochloride

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Reaction Steps

To a suspension of 22.8 g. (80.0 mmol) of 1-(2',6'-diethylphenyl)-3-methylamidinourea hydrochloride in CH3CN (100 ml.) are added 19.1 g. (160.0 mmol) of DMF-DMA and the reaction mixture is heated at reflux for 3 hours. The CH3CN is removed under reduced pressure and the residue partitioned between CHCl3 and H2O. The layers are separated and the aqueous layer extracted with CHCl3 (1×100). The combined CHCl3 extracts are washed with H2O (1×100 ml.), dried (MgSO4) and concentrated under reduced pressure to give an off-white solid, which by NMR confirms the desired free base. The solution is dissolved in H2OH and acidified with HCl/MeOH and the MeOH removed under reduced pressure to give an off-white solid which is crystallized from CH3CN to give after vacuum drying over the weekend (105° C., house vacuum) 16.7 g. (71%) of crude product. The material is recrystallized from CH3CN (a hot filtration is necessary to remove some undissolved solid) to give 11.0 g. (47%) of desired product as a white crystalline solid.

Provenance & Evidence