Reaction #8810

Reaction equation

7-benzyl-5,6,7,8-tetrahydro-3H-pyrido[3,4-d]pyrimidin-4-one

N,N-diethylaniline

POCl3

→

7-benzyl-4-chloro-5,6,7,8-tetrahydro-pyrido[3,4-d]pyrimidine

Conditions

Workup

1. 1
   OtherAfter evaporation of the excess of POCl3
2. 2
   workup.ADDITIONthe residue was poured into ice, dichloromethane
3. 3
   workup.ADDITIONwas added
4. 4
   ExtractionThe product was extracted with dichloromethane
5. 5
   Otherdried
6. 6
   Concentrationconcentrated

Procedure

To a mixture of 7-benzyl-5,6,7,8-tetrahydro-3H-pyrido[3,4-d]pyrimidin-4-one 3a (1.0 g, 4.14 mmol) and N,N-diethylaniline (0.37 g, 2.48 mmol) was slowly added POCl3 (12 mL). The mixture was heated to 80° C. for 20 h. After evaporation of the excess of POCl3, the residue was poured into ice, dichloromethane was added and the mixture was made basic (pH=11) with solid Na2CO3. The product was extracted with dichloromethane, dried, and concentrated. Flash column chromatography with 20% ethyl acetate:hexane gave 0.46 g of 7-benzyl-4-chloro-5,6,7,8-tetrahydro-pyrido[3,4-d]pyrimidine 4a as a yellow oil.

Source