O-Methyl-α-ketophenylacetohydroximoyl chloride ( 1 ) was prepared by the reaction of
O-methyl-α-methoxyphenylacetohydroximoyl chloride ( 5 ) with
N-bromosuccinimide and concentrated hydrobromic acid. Reaction of 1 with ethylenediamine gave 3-phenyl-5,6-dihydro-2(1
H)-pyrazinone-
O-methyloxime ( 6 ). 3-Phenyl-5,6-cyclohexano-5,6-dihydro-2(1
H)-pyrazininone-
O-methyloxime ( 7 ) was prepared by reaction of 1 with
trans-1,2-diaminocyclohexane. The X-ray structure of 6 has been determined. The crystals are orthorhombic, space group Pbca with a = 10.264(3), b = 18.262(4), c = 23.530(4)Å, V = 4411(2)Å
3, and Z = 16. The structure, which was refined to R = 0.038 using 1652 observed reflections, shows the amidoxime moiety to be the
Z configuration. Reaction of benzohydroximoyl chloride with aziridine gave (
Z)-aziridinylbenzaldoxime ( 16a ). Ultraviolet irradiation of a benzene solution of 16a gave a mixture of the
Z and
E isomers 16a and 16b . The
E isomer 16b underwent thermal isomerization to 16a at 100°. Reaction of 16a with dimethyl sulfate in sodium hydroxide solution gave (
Z)-
O-methylaziridinylbenzaldoxime ( 17a ). Photoisomerization of a hexane solution of 17a gave a mixture of the
Z and
E isomers 17a and 17b which were separated by preparative glc. The isomers 17a and 17b are resistant to thermal
Z = E isomerization. The mechanisms of thermal isomerization of benzamidoximes are discussed.
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