Arylation of adamantanamines: II. Palladium-catalyzed amination of dihalobenzenes with adamantylalkanamines

Palladium-catalyzed arylation of various (1-adamantyl)alkanamines with isomeric (ortho, meta, and para) bromochloro- and dibromobenzenes was studied. Optimal catalytic systems were found for the synthesis of mono- and diamination products, and the dependences of their yields on the nature of the initial amine and dihalobenzene and on the amount of base were examined. Side amination products were isolated, and paths of their formation were analyzed.     

Amination of 2-chloro-and 2,4-dichloropyrimidines by polyamines

A study was carried out on the amination of 2-chloro-and 2,4-dichloropyrimidines by linear polyamines and oxadiamines under catalytic and noncatalytic conditions. The reaction of excess polyamine with 2-chloropyrimidine gives the corresponding 2-aminopyrimidines, while the reaction of polyamines with excess of 2-chloropyrimidine gives di-, tri-, and tetraarylated derivatives. The reaction of 2,4-dichloropyrimidine with diamines was studied with different ratios of the starting reagents. The ratios of the products of substitution at pyrimidine C-2 and C-4 were found. Dedicated to Academician B. A. Trofimov on the occasion of his seventieth jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1418–1431, September, 2008.     

Palladium‐Catalyzed Amination of 3,5‐Dihalopyridines – a Convenient Route to New Polyazamacrocycles

Pd‐Catalyzed amination of 3,5‐dibromo‐ and 3,5‐dichloropyridine ( 1a and 1b , resp.) with linear polyamines 2 leads to the formation of a new family of pyridine‐containing macrocycles 3 with an ‘exo’‐oriented pyridine N‐atom (Schemes 1 and 2). The dependence of the macrocycle yield on the nature of the halogen atom, the length of the polyamine chain and C/N atom ratio, and the composition of the catalytic system is studied. The synthesis of mono‐ and bis(5‐halopyridin‐3‐yl)‐substituted polyamines 4, 5, 8, 9 , and of 3,5‐bis(polyamino)‐substituted pyridines 6 is described (Schemes 3 and 4), and the use of these compounds as intermediates on the way to the macrocycles 7, 16 , and 18 with larger cavity (‘cyclodimers’ and ‘cyclotrimers’) is demonstrated (Schemes 5–10).     

THE EFFECT OF ACIDS ON THE INFRARED SPECTRA OF SCHIFF BASES—II. IMINES CONTAINING THE C=C-C=N AND C=C-C=C-C=N UNITS

Abstract— The Fourier-transform infrared spectra of chloroform-d solutions of conjugated imines CH₃CH=CHCH=NCH(CH₃)₂ and CH₃CH₂CH=CHCH=CHCH=NCH(CH₃)₂ and the related protonated species with HCl, HBr, HI, trichloro, dichloro, monobromo and monochloroacetic acids or propionic acid are presented. The effects of conjugation and protonation are examined. The results show that conjugation slightly increases the basicity of the Schiff bases. HCl, HBr and HI protonate the Schiff bases completely. The carboxylic acids protonate partially depending on their p K _a, values. When the Schiff base contains two (or more) C=C bonds conjugated with C=N, the main C=C stretching band undergoes a strong intensification showing that sizeable dipole moment variations occur along the conjugated chain.     

Synthesis of macrocycles containing two pyridine and two polyamine moieties via Pd-catalyzed amination

The synthesis of macrocycles containing two pyridine and two polyamine fragments was carried out by the Pd-catalyzed amination of 2,6-dihalopyridines using polyamines and dioxadiamine. Two alternative approaches were elaborated and compared: via intermediate formation of N^α,N^ω-bis(6-halopyridin-2-yl)polyamines or via 2,6-bis(polyamino)substituted pyridines. The yields of linear and cyclic products were shown to be strongly dependent on the nature of the starting polyamines and that of the halogen atom.     

A pairwise chemical genetic screen identifies new inhibitors of glucose transport

Oxidative phosphorylation (OXPHOS) and glycolysis are the two main pathways that control energy metabolism of a cell. The Warburg effect, in which glycolysis remains active even under aerobic conditions, is considered a key driver for cancer cell proliferation, malignancy, metastasis, and therapeutic resistance. To target aerobic glycolysis, we exploited the complementary roles of OXPHOS and glycolysis in ATP synthesis as the basis for a chemical genetic screen, enabling rapid identification of novel small-molecule inhibitors of facilitative glucose transport. Blocking mitochondrial electron transport with antimycin A or leucascandrolide A had little effect on highly glycolytic A549 lung carcinoma cells, but adding known glycolytic inhibitors 2-deoxy-D-glucose, iodoacetate or cytochalasin B, rapidly depleted intracellular ATP, displaying chemical synthetic lethality. Based on this principle, we exposed antimycin A-treated A549 cells to a newly synthesized 955 member diverse scaffold small-molecule library, screening for compounds that rapidly depleted ATP levels. Two compounds potently suppressed ATP synthesis, induced G1 cell-cycle arrest and inhibited lactate production. Pathway analysis revealed that these novel probes inhibited GLUT family of facilitative transmembrane transporters but, unlike cytochalasin B, had no effect on the actin cytoskeleton. Our work illustrated the utility of a pairwise chemical genetic screen for discovery of novel chemical probes, which would be useful not only to study the system-level organization of energy metabolism but could also facilitate development of drugs targeting upregulation of aerobic glycolysis in cancer.     

Arylation of adamantanamines: III. Palladium-catalyzed arylation of adamantane-1,3-diyldimethanamine and 2,2′-(adamantane-1,3-diyl)diethanamine

Palladium-catalyzed arylation of adamantane-1,3-diyldimethanamine and 2,2′-(adamantane-1,3-diyl) diethanamine with isomeric bromochloro- and dibromobenzenes was studied. The yields of N,N′-diarylation products depend on the initial diamine and dihalobenzene structure. Side reactions were revealed, which reduced the yield of the target products. The arylation of 2,2′-(adamantane-1,3-diyl)diethanamine gives the corresponding N,N′-diaryl derivatives with better yield. The possibility for synthesizing unsymmetrical N,N′-diaryl derivatives of 2,2′-(adamantane-1,3-diyl)diethanamine was demonstrated.     

Palladium-catalyzed amination of isomeric dihalobenzenes with 1- and 2-aminoadamantanes

Palladium-catalyzed amination of isomeric bromochloro- and dibromobenzenes with 1- and 2-aminoadamantanes was studied. The best yields of the corresponding monoamination products were obtained in the reactions of 2-aminoadamantane with bromochlorobenzenes. The arylation of 1-aminoadamantane was successful in the presence of donor phosphine ligand. The amination of o- and m-dibromobenzenes was strongly complicated by formation of diamination products. Conditions ensuring predominant formation of the latter were found. The arylation of 2-aminoadamantane was accompanied by oxidation of the initial amine and reduction of aryl halide.