Dimethylformamide → HCID 13393792, compound
Reaction equation
[CH3:1][O:2][C:3]1[C:12]([O:13][CH3:14])=[C:11]([O:15][CH3:16])[CH:10]=[C:9]2[C:4]=1[C:5](=O)[CH2:6][CH:7]([C:17]1[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=1)[O:8]2.P(Cl)(Cl)([Cl:26])=O.CN(C)[CH:31]=[O:32]>>[Cl:26][C:5]1[C:4]2[C:9](=[CH:10][C:11]([O:15][CH3:16])=[C:12]([O:13][CH3:14])[C:3]=2[O:2][CH3:1])[O:8][CH:7]([C:17]2[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=2)[C:6]=1[CH:31]=[O:32]Participants
4
Procedure
As in example 1, but using 15 g 5,6,7-trimethoxyflavanone, 150 ml dimethylformamide and 26 ml phosphorous oxychloride. Reaction time is forty eight hours at room temperature. After hydrolysis and usual work up, the residual solid is purified by preparative HPLC and the best fractions are crystallised in hexane. 4-chloro-3-formyl-5,6,7-trimethoxyflav-3-ene is obtained as yellow crystals; m.p. 84°-87° C.