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The synthesis of substituted 3‐oxo‐pyrimido[1,2‐b]indazoles from 3‐aminoindazoles and ketones has been established. It involves one molecule of 3‐aminoindazoles and two molecules of ketones via a [3+2+1] three‐component annulation process. 3‐Oxo‐pyrimido[1,2‐b]indazoles exhibit strong yellow fluorescence in various solvents. A wide range of products have anti‐oxidant activities. Cytotoxicity studies indicate that compounds 3 a, 3 aa and 3 ab have obvious effects on both HCT116 and A549 cancer cell lines. [ABSTRACT FROM AUTHOR]

An unprecedented eco-friendly multi-component domino reaction for the synthesis of novel N,O-acetals is reported. The protocol involves sequential coupling, [1,5]-hydride transfer and hetero-Diels–Alder cyclization. This new strategy enables direct α,β-difunctionalization of cyclic amines utilizing enamines generated in situ. The methodology features high atom and step economy, excellent regioselectivity, a simple work-up procedure and molecular diversity. [ABSTRACT FROM AUTHOR]

An efficient and regioselective cyclization for construction of pyrazolo[3,4‐b]pyridines and methylene‐bridged bis(pyrazolo[1,5‐a]pyrimidines) has been established. It involves a [3+2+1] annulation of 3(5)‐aminopyrazole, N,N‐dimethylethanolamine (DMEA), with 1,2‐insertion of aryl methyl ketones or 2,1‐insertion of aryl alkynes. DMEA is oxidized through C(sp3)‐H activation to provide a single or triple carbon source. [ABSTRACT FROM AUTHOR]

An organophotoelectrocatalytic method for the C(sp2)–H alkylation of heteroarenes with unactivated C(sp3)–H compounds through dehydrogenation cross-coupling has been developed. The C(sp2)–H alkylation combines organic catalysis, photochemistry and electrochemistry, avoiding the need for external metal-reagents, HAT-reagents, and oxidants. This protocol exhibits good substrate tolerance and functional group compatibility, providing a straightforward and powerful pathway to access a variety of alkylated heteroarenes under green conditions. [ABSTRACT FROM AUTHOR]

Hydrogen atom transfer from commonly used solvents to nitroarenes occurred. Such solvents required C(sp3)H‐C(sp3)H bond adjacent to oxygen atoms, such as 1,4‐dioxane, tetrahydrofuran, alkanol, ethylene glycol, glycerol and bis(2‐methoxyethyl) ether. The transformation was transition‐metal free and the reduced nitroarenes were trapped by naphthols and their analogues at ortho‐position. The protocol provided a favourable and efficient route to access ortho‐arylaminonaphthols and a possible mechanism is depicted. [ABSTRACT FROM AUTHOR]

A simple and efficient approach for the synthesis of N,N'-methylenebisamides through a Selectfluor-mediated oxidative reaction of aromatic amides and N,N-dimethylpropanamide (DMP) is described. Remarkable results clearly reveal that DMP plays a dual role in this reaction, as both a one-carbon source and an environment-friendly solvent. Moreover, the process provides new strategies for the synthesis of bisamides with advantages of operationally simple, insensitive to atmospheric conditions, and good to high yields. Key words: amides, methylenebisamides, Selectfluor, DMP, methylene. Nous derivons une approche simple et efficace pour effectuer la synthese de N,N'-methylenebisamides par une reaction d'oxydation assuree par le Selectfluor entre des amides aromatiques et le N,N-dimethylpropanamide (DMP). Les resultats, remarquables, revelent clairement que le role du DMP est double dans cette reaction, car il agit a la fois comme une source de methylene et comme solvant sans danger pour l'environnement. De plus, cette methode constitue une nouvelle strategie pour effectuer la synthese de bisamides en offrant les avantages d'etre simple sur le plan pratique, d'etre insensible aux conditions atmospheriques et de produire des rendements allant de bons a eleves. [Traduit par la Redaction] Mots-cles : amides, methylenebisamides, Selectfluor, DMP, methylene., Introduction Amides and polyamides, the important biological and medicinal scaffolds, have been widely occurred among numerous biologically active compounds, natural products, (1) pharmaceuticals, polymers, (2) and peptides. (3) In particular, [...]

Methyl substituted 3-hydroxypyridin-4([.sup.1]H)-ones have been synthesized. The p[K.sub.a] values and [Fe.sup.3+] affinity constants of these ligands were studied. The introduction of an electron-donating methyl group at a different position of pyridinone ring markedly influences the p[K.sub.a] values of 3-hydroxy and 4-oxo groups. The p[Fe.sup.3+] values were also affected and are in the range of 17.6-20.7. The findings can be used to guide a design of 3-hydroxypyridin-4-ones with desirable p[K.sub.a] and p[Fe.sup.3+] values. Key words: iron chelators, 3-hydroxypyridin-4-ones, methyl substituted, p[Fe.sup.3+], electron-donating group, p[K.sub.a]. Resume : Nous avons synthetise des 3-hydroxypyridin-4([.sup.1]H)-ones substituees par un groupe methyle. Nous avons etudie les p[K.sub.a] de ces ligands et leurs constantes d'affinite pour le [Fe.sup.3+]. La position d'un groupe methyle electrodonneur sur le noyau pyridinone influence considerablement les valeurs de p[K.sub.a] des groupes 3-hydroxy et 4-oxo, et modifie egalement les valeurs de p[Fe.sup.3+], qui se situent dans un intervalle de 17,6 a 20,7. Ces resultats peuvent permettre d'orienter la conception de 3-hydroxypyridin-4-ones qui poss-dent des valeurs souhaitables de p[K.sub.a] et de p[Fe.sup.3+]. [Traduit par la Redaction] Mots-cles : chelateurs du fer, 3-hydroxypyridin-4-ones, substitue par un groupe methyle, p[Fe.sup.3+], groupe electrodonneur, p[K.sub.a]., Introduction Deferiprone (6) is an orally active iron-selective chelator that is widely used to treat systemic iron overload associated with regular blood transfusion. (1,2) It is highly effective at removing [...]

A metal‐free 1,4‐allylation of azadienes with allyltrimethylsilanes catalyzed by B(C6F5)3 has been developed. The high Lewis acidity, good thermal stability, and good hydrolytic stability of the catalyst make this reaction efficient and operationally simple. In contrast to the previously reported 1,2‐allylation of α,β‐unsaturated imines, the 1,4‐allylation of azadienes is described here for the first time. Benzofuran‐, indene‐, dihydronaphthalene‐, chromene‐, and benzothiophene‐based allyl arylmethanes have been obtained in up to 95 % yield. [ABSTRACT FROM AUTHOR]