l,l-Dialkyl-1H-diazirino[l,2-b]phthalazine-3,S-d~ones isomerize in boiling toluene into 2-(l-alken-l-yl)-4-hydroxy-l(2H)-phthalazinones and react with enamines and ynamines to yield derivatives of pyrazolo[l,2-b]-and indazolo[l,2-b]phthalazinediones.The thermal conversions of 1-(2,4-dinitropheny1)-3,3-dialkyl-and 1-(2,4-dinitropheny1)-2,3,3-trialkyldiaziridines into 2,4-dinitrophenylhydrazones and 2-alkyl-6-nitrobenzotriazole 1-oxides, respectively, and the addition of 3,3-dialkyl-and 1,3,3-trialkyldiaziridines to electrophilic acetylenes have been the subjects of earlier reports in this series.1$2 In the present paper the synthesis and reactions of 1-alkyl-and 1,l-dialkyl-1H-diazirino[l,2-b lphthalazine-3,8-diones (1-7) and the related systems 8 and 9 are described. These versatile compounds are thermally isomerized into 2-(1 -alken-1-yl) -4-hydroxy-1 -( 2H)phthalazinones and react with ynamines and enamines to give pyrazolo[l,2-b]-and indazolo[l,2-b]phthalazinediones. Reactions with I nitrones are presented in the following paper.Resultswere prepared by the addition of phthaloyl chloride to ethereal solutions of 3,3-dialkyldiaziridines containing triethylamine (Scheme I, Table I). The l-alkyllH-diazirino[l,2-b]phthalazine-3,8-diones 6 and 7 were synthesized by generating the 3-alkyldiaziridines in The Scheme I EtBN o-C,H,(COCl), + HN-NHvTable I 1-Alkyl-and 1,l-Dialkyl-1H-diazirino [ 1,2-b]phthalazine-3,8-dionesa Compd b R1 R2 Yield,c % Mp, OC 1 Me Me 58 98-99 2 Et Et 35 70-71 3 n -P r n -P r 47 108-109 4 -(CH2)5-75 110-111 5 Me Et 71 76-77 6 H n -Pr 61 71-72.5 110-111 7 H t -Bu 51 a Satisfactory analytical data for C, H, and N were obtained for all compounds listed in the table. Ed. Compounds 1-7 were recrystallized from cyclohexane. c Yields are reported on the basis of recrystallized products.situ from the corresponding chloral adducts, R b m C H ( O H ) C H C C l 3 , in the presence of o-phthaloyl chloride. Compounds 8 and 9 were made in much the same / \ manner as 1-5 by employing the appropriate diacid chlo-R' R2 ride and 3,3-~entamethylenediaziridine.The structures of 1-9 were assigned on the basis of elemental analyses, nmr spectroscopy, and by the hydrolysis H+* $r + ~1~2~0 of 2,4, and 7 into 4-hydroxy-l(2H)-phthalazinone (10) and the corresponding carbonyl compounds 3-pentanone, cyclohexanone, and pivalaldehyde, respectively (Scheme I). The nmr spectrum of l,l-dimethyl-lH-diazirino[1,2-0 1-7 10 blphthalazine-3,B-dione (1) taken in C6D6 shows two peaks a t 6 1.45 and 1.25 for the two methyl groups on the diaziridinyl carbon. On heating to about 60" the two peaks coalesce to a broad singlet which on further heating to 75O becomes a sharp singlet a t 6 1.55. If the temperature is lowered to 40° the two signals for the methyl groups reappear. The temperature variance of the nmr spectrum of 1 indicates inversions of the nitrogen atoms (Scheme 11) and is of some interest, since the N-aroyl moieties are perforce cis to 0 R1 0 CH,OH-H,O OH 0 8 9 3187
Reaction of 1,1-dialkyl-l/f-diazirino[l,2-6]phthalazine-3,8-diones with nitrones in refluxing benzene gave 2,4,5]oxatriazino [4,[5][6]phthalazine-6,ll-diones. The latter compounds are hydrolyzed in aqueous methanol to 4-hydroxy-l(2ff )-phthalazinone, ketones,, and nitrones. It!was! also shown that 2-isopropenyl-4-hydroxy-1 (2/f)-phthalazinone reacted with nitrones in benzene to also form Iff-[l,2,4,5]oxatriazino[4,5-6 jphthalazine-6,11 -diones in low yields.Recently reported reactions of 1,1-dialkyl-lff -diazirino[l,2-6 ]phthalazine-3,8-diones suggest that these substances are prone to form azomethine imines as reaction intermediates.1 It appears, for example, that 1,1-dimethyllff-diazirino[l,2-6]phthalazine-3,8-dione (1) in boiling toluene or benzene is converted to 2, which then adds to enamines or ynamines to give 3 and 4, respectively, or in the absence of these reagents rearranges to 5 (Scheme I).1 Scheme I 4 3The present paper deals with the reaction of 1,1-dialkyl-
Aus den 3,3‐Dialkyl‐diaziridinen (I) erhält man mit 0‐Phthaloylchlorid (II) die tricyclischen Kondensate (III), deren isomere Formen diskutiert werden und die bei der Behandlung mit Säuren unter Eliminierung von Phthalazin (IV) zu den Ketonen (V) gespalten werden.
Die aus Phthaloylchlorid und Diaziridinen erhaltenen Addukte (I) reagieren mit den "Nitronen (II) zu den Additionsprodukten (III).
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