抄録
The ring carbon at 1-position in 1-(methylsulfonyl) phthalazine (I) is active to nucleophilic reagents, same as that in 1-(methylsulfonyl)-4-phenylphthalazine, and reacts with sodium methoxide, butylamine, aniline, hydrazine, and hydroxylamine to form 1-methoxy-(VIa), 1-butylamino-(VIb), 1-anilino-(VIc), 1-hydrazino-(VId), and 1-hydroxylaminophthalazine (VIe). VIa to VIe were identified with samples synthesizes from 1-chlorophthalazine (II) and the above reagents (Table I). I also reacts with active methylene compounds such as ethyl cyanoacetate, ethyl acetoacetate, phenylacetonitrile, diethyl malonate, malononitrile, and acetonitrile to form ethyl α-cyano-1-phthalazineacetate (VIIIa), ethyl α-acetyl-1-phthalazineacetate (VIIIb), α-phenyl-1-phthalazineacetonitrile (VIIIc), diethyl 1-phthalazinemalonate (VIIId), and 1-phthalazinemalononitrile (VIIIe). The reaction of I and phenylacetonitrile afforded, besides VIIIc, a structurally unknown substance of mp 244-246°, while the reaction of I and acetonitrile produced a minute amount of a substance assumed to be bis (1-phthalazinyl) acetonitrile (VIIIg') and not the anticipated 1-phthalazineacetonitrile (VIIIg) (Tables II and III). I differs from 1-(methylsulfonyl)-4-phenylphthalazine in its reaction with ketone carbanion and the phenyl group in 4-position was found to affect the direction of this reaction. Reaction of I in dehyd. benzene, in the presence of sodium amide, with ketones afforded 1-(1-phthalazinyl)-2-propanone (Xc) and 2-(1-phthalazinyl)-3-pentanone (Xd) in respective yield of 8% and 14% from the reaction with acetone and diethyl ketone, same as in the reaction of II with these ketones. Reaction of I with acetophenone, propiophenone, and cyclohexanone failed to produce the expected compounds and only XIVa-x, XIVb, and XIVe were obtained (Table VI). The same reaction of I with ketones in the presence of sodium hydroxide also produced XIVa-e and not the anticipated Xa-e. Prolonged reaction of I and acetophenone also gave XIVa-x, besides XIVa. The structure of XIVa-x is now being examined (Table VII). The structure of XVa to XVe was presumed from the analytical values and from IR, UV, NMR, and mass spectral data of XIVa to XIVe and the compounds (XVa to XVe) obtained by conversion of their -SO2CH3 group with -CN. For example, XIVd was assumed to be 2-[1, 2-dihydro-2-(1-phthalazinyl)-4-(methylsulfonyl)-1-phthalazinyl]-3-pentanone and XVd to be 3, 4-dihydro-4-(1-methyl-2-oxobutyl)-3-(1-phthalazinyl)-1-phthalazinecarbonitrile (Chart 3).
