Thionyl Chloride → Methyl 7-Phthalimido-3alpha-methyl-3beta-hydroxycepham-4-carboxylate
Reaction equation
[C:1]1(=[O:26])[N:5]([CH:6]2[C:19](=[O:20])[N:8]3[CH:9]([C:15]([O:17][CH3:18])=[O:16])[C:10]([CH3:14])([CH3:13])[S:11](=O)[C@H:7]23)[C:4](=[O:21])[C:3]2=[CH:22][CH:23]=[CH:24][CH:25]=[C:2]12.S(Cl)(Cl)=[O:28]>C(Cl)(Cl)(Cl)Cl>[C:4]1(=[O:21])[N:5]([CH:6]2[C:19](=[O:20])[N:8]3[CH:9]([C:15]([O:17][CH3:18])=[O:16])[C@:10]([CH3:14])([OH:28])[CH2:13][S:11][C@H:7]23)[C:1](=[O:26])[C:2]2=[CH:25][CH:24]=[CH:23][CH:22]=[C:3]12Participants
4
Procedure
A solution of methyl 6-phthalimido-2,2-dimethylpenam-3-carboxylate-1-oxide (2.25 g., 6 mmol) and thionyl chloride (0.47 ml., 6.5 mmol) in 90 ml. dry carbon tetrachloride was refluxed for 1 hour, cooled and evaporated in vacuo to dryness. An nmr spectrum of the crude product showed a 2:3:3 mixture of methyl 7-phthalimido-3α-methyl-3β-hydroxycepham-4-carboxylate, methyl 6-phthalimido-2β-chloromethylpenam-2α-methyl-3-carboxylate, and methyl 6-phthalimido-2α-chloromethylpenam-2β-methyl-3-carboxylate, respectively. The products were separated by chromatography on silica gel and fully characterized by spectroscopy.