7-Chloro-2-phenyl-1 -phthalazinone

The isolation of chloro heterocycles is not always necessary. Chlorination with POCI3 and amination can be combined in a one-pot reaction as exemplified by the reaction of 4-phenyl-1-(2//)-phthalazinone (83) with POCI3 in the presence of excess neopentylamine in boiling xylene to furnish 84 in 77% yield (85EUPI5%52). 

Tetrachlorobicyclo[4.2.0]octa-l(6),2,4-triene-7,8-dione (124) with hydrazine hydrochloride gave 5,6,7,8-tetrachloro-l(2H)-phthalazinone (125, R = H) (EtOH, reflux, 24 h 71%) or with phenylhydrazine gave 5,6,7,8-tetra-chloro-2-phenyl-l(2H)-phthaIazinone (125, R = Ph) (H2SO4, EtOH, reflux, 2 h 79%) the same substrate (124) was converted into its monophenylhy-drazone (126) (PhNHNHa, H2SO4, EtOH, reflux, briefly 46%) and thence... 

Chloro-3-phenyl-l,3-dihydro-l-isobenzofuranone (210) and iVA -dimethylhy-drazine gave (via an unisolated intermediate) 4-hydroxy-2,3-dimethyl-4-phenyl-3,4-dihydro-l(2fl)-phthalazinone (211) (EtaN, PhH, 20°C, 24 h. 

Phenyl-l(2/i/)-phthalazmone (3) gave l-chloro-4-phenylphthalazine (4) (POCI3, 85°C, 4h 79%) 4-p-dimethylaminophenyl-4-phenyl-3,4-dihy-dro-l(27/)-phthalazinone (5) gave l-chloro-4-p-dimethylaminophenyl-4-phe-nyl-3,4-dihydrophthalazine (6) (PCX ls, 80°C, 6h 58%) and thence 1-chloro-4-phenylphthalazine (4) (POCI3, reflux, 6h 71% note nuclear oxidation by loss of PhNMc2) " as might be expected, the substrate (5) also afforded... 

Hydroxyethyl)-3-methyl-l,4(2//,3/l)-phthalazinedione (27, R = OH) gave 2-(2-chloroethyl)-8-methyl-l,4(2//,3/l)-phthalazinedione (27, R = Cl) (SOCI2, CHCI3, reflux, 16 h 75%) " likewise, 7-hydroxymethyl- gave 7-chloro-methyl-2-phenyl-l(2//)-phthalazinone (neat SOCI2, reflux, 1 h 78%)." "... 

Chloro-2-phenyl-l(2//)-phthalazinone with -aminoacetophenone gave 4- -acetylanilino-2-phenyl-l(2//)-phthalazinone (52) [synthon, EtONa in EtOH, reflux, 5 h (presumably to form a sodio derivative ) substrate, reflux, 10 h 75%]. 25... 

Chloro-2-phenyl- gave 2-phenyl-6- p[(2-phenylpyrazol-3-yl)sulfamoyl]phe-nylsulfamoyl -4-(A( -phenylureido)-l(2//)-phthalazinone (90) [PhHNC(=0)... 

Chloro-2-phenyl-1 (2/7)-phthalazinone gave 7 -ethylthio-2-phenyl-1 (2 /)-phthala-zinone (113) (C iSEt, MejNCHO, reflux, 15 h 71%). "... 

Chloromethyl-4-phenyl-1 (2H)-phthalazinone 1 -Chloro-4-methyl-7-nitrophthalazine 7-Chloro-2-methyl- 1-oxo-1,2-dihydro-6-phthalazinesulfonamide 7-Chloro-3-methyl-4-oxo-3,4-dihydro-6-phthalazinesulfonamide 7-Chloro-2-methyl-1 -oxo-1,2-dihydio-6-phthalazinesulfonyl chloride... 

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