A Novel Reagent for Radioiodine Labeling of New Chemical Entities (NCEs) and Biomolecules

Radioiodine labeling of peptides and proteins is routinely performed by using various oxidizing agents such as Chloramine T, Iodobeads, and Iodogen reagent and radioactive iodide (I−), although some other oxidizing agents were also investigated. The main objective of the present study was to develop and test a novel reagent, inorganic monochloramine (NH2Cl), for radioiodine labeling of new chemical entities and biomolecules which is cost-effective, easy to make and handle, and is selective to label amino acids, peptides, and proteins. The data presented in this report demonstrate that the yields of the non-radioactive iodine labeling reactions using monochloramine are >70% for an amino acid (tyrosine) and a cyclic peptide (cyclo Arg-Gly-Asp-d-Tyr-Lys, cRGDyK). No evidence of the formation of N-chloro derivatives in cRGDyK was observed, suggesting that the reagent is selective in iodinating the tyrosine residue in the biomolecules. The method was successfully translated into radioiodine labeling of amino acid, a peptide, and a protein, Bovine Serum Albumin (BSA).

Reactivity and mechanisms of hydridic hydrogen of B-H in ammonia borane towards acetic acids: the ammonia B-monoacyloxy boranes

The non-classical acid-base neutralization reactions of ammonia borane (NH3•BH3, AB) with acetic acids are moderate, affected by the strengths of acetic acid and its chloro derivatives, the concentrations and ratios...

Trifluoromethyl derivatives of pentagon-fused C60: 1809C60(CF3)n (n = 10, 12, 14, 16)

The structural chemistry of trifluoromethyl derivatives of non-IPR 1809C60 is discussed and compared with related chloro derivatives for the first time.

Structural Studies of Giant Empty and Endohedral Fullerenes

Structure elucidations of giant fullerenes composed of 100 or more carbon atoms are severely hampered by their extremely low yield, poor solubility and huge numbers of possible cage isomers. High-temperature exohedral chlorination followed by X-ray single crystal diffraction studies of the chloro derivatives offers a practical solution for structure elucidations of giant fullerenes. Various isomers of giant fullerenes have been determined by this method, specially, non-classical giant fullerenes containing heptagons generated by the skeletal transformations of carbon cages. Alternatively, giant fullerenes can be also stabilized by encapsulating metal atoms or clusters through intramolecular electron transfer from the encapsulated species to the outer fullerene cage. In this review, we present a comprehensive overview on synthesis, separation and structural elucidation of giant fullerenes. The isomer structures, chlorination patterns of a series of giant fullerenes C2n (2n = 100-108) and heptagon-containing non-classical fullerenes derived from giant fullerenes are summarized. On the other hand, giant endohedral fullerenes bearing different endohedral species are also discussed. At the end, we propose an outlook on the future development of giant fullerenes.

4-(azulen-1-yl)-2,6-diphenylchalcogenopyrylium Perchlorates; Synthesis and Characterization

2,6-Diphenyl substituted thio- and seleno-pyrylium salts with azulen-1-yl moieties in 4-position were prepared from phenylacetylene going through chalcogenopyrones and 4-chloro-chalcogenopyrylium salts as intermediates. The final step of synthesis involves the electrophile substitution in 1-position of azulenes with the obtained chloro-derivatives and the products isolation as stable perchlorates. The electronic and magnetic spectra of products are presented and compared with those of the corresponding pyrylium salts.

Synthesis, Antitumor Activity, and Docking Analysis of New Pyrido[3’,2’:4,5]furo(thieno)[3,2-d]pyrimidin-8-amines

Continuing our research in the field of new heterocyclic compounds, herein we report on the synthesis and antitumor activity of new amino derivatives of pyrido[3’,2’:4,5](furo)thieno[3,2-d]pyrimidines as well as of two new heterocyclic systems: furo[2–e]imidazo[1,2-c]pyrimidine and furo[2,3-e]pyrimido[1,2-c]pyrimidine. Thus, by refluxing the 8-chloro derivatives of pyrido[3’,2’:4,5]thieno(furo)[3,2-d]pyrimidines with various amines, the relevant pyrido[3’,2’:4,5]thieno(furo)[3,2-d]pyrimidin-8-amines were obtained. Further, the cyclization of some amines under the action of phosphorus oxychloride led to the formation of new heterorings: imidazo[1,2-c]pyrimidine and pyrimido[1,2-c]pyrimidine. The possible antitumor activity of the newly synthesized compounds was evaluated in vitro. The biological tests evidenced that some of them showed pronounced antitumor activity. A study of the structure–activity relationships revealed that the compound activity depended mostly on the nature of the amine fragments. A docking analysis was also performed for the most active compounds.

The Synthesis of α-Hydroxy- and α-Chlorophosphonic Acid Derivatives Starting from Benzaldehydes and Phosphorous Acid or Dimethyl Phosphite

The addition of phosphorous acid on the C=O group of substituted benzaldehydes in the presence of hydrochloric acid in water affords a mixture of the corresponding α - chlorophosphonic acid and α-hydroxyphosphonic acid. The selectivity towards the α-chloro derivatives may be increased to 92% by the excess of HCl applying forcing conditions. α- Hydroxyphosphonic acids may be synthesized better in yields of 83-92% by the hydrolysis of the corresponding dimethyl α-hydroxyphosphonates. α-Chlorophosphonic acids may also be obtained in yields of 66-79% from α -hydroxyphosphonic esters by reaction with thionyl chloride followed by hydrolysis. The α -chlorophosphonic acids and esters are useful intermediates for other phosphonic derivatives.