1-Acylamino-1-azadienes as an alternative to 1-dimethylamino-1-azadienes in the preparation of 1,8-diazaanthracene-2,9,10-triones.

The aza-analogues of 1,4-naphthoquinones are potent substrates and inhibitors of plasmodial thioredoxin and glutathione reductases and of human erythrocyte glutathione reductase

“…38 The methyl-substituted analogues, 2, 39 3, 40,41 and 4, 42 which were previously prepared from oxidation of aminoquinoline derivatives, were obtained here by cycloadditions of an 1-azadiene 43 with bromo-quinone partners; indeed, although 1-azadienes are not that reactive-for a discussion of relevant factors see ref. 44-the cycloaddition of acroleine-N,Ndimethylhydrazone 45 proceeded with 5-methyl-, 46,47 6-methyl, 48,49 and 5,6-dimethyl- 50 2-bromobenzoquinones to produce the desired quinones (2 and 3 < 10%; 4, 40%).…”

New Types of Reactivity of α,β‐Unsaturated N,N‐Dimethylhydrazones: Chemodivergent Diastereoselective Synthesis of Functionalized Tetrahydroquinolines and Hexahydropyrrolo[3,2‐b]indoles

“…indoles as major products through a fully diastereoselective ABB'C fourcomponent domino process that generates two cycles, three stereocenters, two CÀC bonds, and two CÀN bonds in a single operation. Keywords: domino reactions • heterocycles • Lewis acids • multicomponent reactions • stereoselectivity this type of reaction requires the unsaturated imines to be electron rich, the imines have to be modified by the introduction of electron-releasing groups on the nitrogen atom, normally dimethylamino, [9] and in some other cases acetylamino [10] or 1-tert-butyldimethylsilyloxy, [11] substituents to compensate for the electron-withdrawing effect of the nitrogen atom. We reasoned that the same electron-releasing effect should be expected to increase the electron density of the C2 À C3 bond of the hydrazone sufficiently to allow its participation in Povarov-type chemistry.…”

Structure-Antitumor Activity Relationships of Aza- and Diaza-Anthracene-2,9,10-Triones and Their Partially Saturated Derivatives

“…Compounds 5 and 6 were prepared using hetero Diels–Alder chemistry [ 33 , 34 , 35 , 36 , 37 ]. The starting materials were, on the one hand, the unsaturated dimethylhydrazones 9 , obtained [ 38 , 39 ] from N , N -dimethylhydrazine and the corresponding aldehydes, which are commercially available with the exception of 2-methyl-2-hexenal, synthesized using a literature procedure [ 40 ] ( Table 1 ).…”

“…The hetero Diels–Alder reactions performed were usually regioselective, according to the previous experience of our group in similar reactions [ 33 , 46 ], and afforded only the 1,8-diazanthracene-2,9,10-trione structure. The selectivity of the process towards the C 6 end can be attributed to the combination of two electronic factors: the conjugation of the carbonyl at C-5 with the lactam nitrogen and the deficiency created at C 8 =O as a consequence of its conjugation with the C 2 =O group and the existence of an intramolecular hydrogen bond with N 1 -H [ 33 ]. In one case, as shown in Scheme 3 , the reaction of 1-(4-tolyl)-1- H -2,5,8-quinolinetrione ( 8h ) with azadiene 9b afforded significant amounts of the regioisomer 1,5-diaza adduct 11 ( 5p : 11 = 2:1).…”

“…Method D: reaction according to method B, followed by oxidation with activated manganese dioxide. b Data obtained from reference [ 33 ]. c Data obtained from reference [ 34 ].…”