Diaziridines. IV. Reaction of some 1,1-dialkyl-1H-diazirino[1,2-b]phthalazine-3,8-diones with nitrones

Abstract

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-

Diaziridines. 5. Reaction of some 1-aroyl- and 1,2-diacyldiaziridines

“…Synthesis of 4',9'-Dihydrospiro[cyclohexane-l,l'(lfl)-diazirino[l,2-c] [3,4]benzodiazocine]-3',10'-dione (7). A solution of 4.62 g (20 mmol) of o -benzenediacetyl chloride16 in 500 ml of dry Et20 and a solution of 6.73 g (60 mmol) of 3,3-pentamethylenediaziridine in 500 ml of dry Et20 were simultaneously added dropwise over 7.5 h to a stirred mixture of 10 g of anhydrous MgS04 in 2.51. of dry Et20 at 5 °C, The reaction mixture was stirred for an additional 19 h and then filtered.…”

“…The difference in thermal behavior of 1 and 3 prompted us to undertake the preparation and thermolysis of a N,N'-diacyldiaziridine similar to 3 but less constrained, namely the benzodiazocine derivative 7. For purposes of comparison with 7 N.-ZV'-diaroyldiaziridines we also prepared several 1-aroyl-2.3.3-trialkyldiaziridines. These substances isomerize in chloroform or acetonitrile to labile 2-aryl-4,5,5-trialkyl-A2-1.3.4-oxadiazolines which react readily with both electrophilic and nucleophilic substrates such as aromatic aldehydes and ynamines.…”

“…Several studies on 1,2 -diaroyldiaziridines have appeared recently. Schmitz and co-workers1 reported the rearrangement of several 1,2-diaroyldiaziridines (1) to ß,/3-diaroylhydrazones (2) (Scheme I) and we2-3 described the reactions of 1,1dialkyl-lif-diazirino[l,2-i>]phthalazine-3,8-diones (3). The latter compounds isomerize to 2-(l-alken-l-yl)-4-hydroxy-1 (2H) -phthalazinones (4) in refluxing toluene and react with ynamines and enamines to give compounds 5 and 6, respectively (Scheme I).…”

Small Ring Compounds and N‐oxides: Cycloadditions and Related Processes

“…At elevated temperatures, phthalohydrazide‐derived diaziridines 56 underwent a C−N bond cleavage, forming azomethine imines 56‐A (Scheme ). These could be intercepted with various 1,3‐dipoles, including nitrones …”