We describe a new route for the synthesis of (S)-N-Boc-5-oxaproline. This building block is a key element for the chemical synthesis of proteins with the α-ketoacid-hydroxylamine (KAHA) ligation. The new synthetic pathway to the enantiopure oxaproline is based on a chiral amine mediated enantio...

Several new Grignard reagents based on substituted cyclobutanes have been generated and added to cyclobutanones to yield mono- to trimethylated [1,1′-bicyclobutyl]-1-ols. Mono- to trimethylated spiro[3.4]octan-5-ols have been prepared from the parent ketone via alkylation and/or addition reacti...

Carbon-11 labeled alkyl iodides such as ethyl, propyl and butyl iodides are useful precursors for labeling various tracers for positron emission tomography. In the standard preparing process, which consists of the reaction of Grignard reagents with 11CO2 followed by reduction with lithium alumin...

The paper presents the developed method for purification of ammonium perrhenate solutions by ion-exchange method on strongly acidic cation-exchange resin C160. The developed method is characterized by high, over 95% efficiency of sorption of potassium, sodium, calcium, iron, magnesium and lead i...

A pharmacologic and toxicologic investigation of potassium perrhenate and rhenium trichloride showed that these compounds exhibited the same delayed acute toxicity previously reported for other rare elements. Rhenium trichloride was 10 times more toxic than potassium perrhenate but the latter co...

Single crystals of ammonium perrhenate (NH4ReO4) and potassium perrhenate (KReO4) when γ-irradiated at 77 K gave new paramagnetic centers. The paramagnetic centers formed at 77 K are identified as ReO3 and O− in both the samples. However, when temperature variation studies were carried out, it ...

A series of twenty 2-aryl-4H-chromen-4-one (flavones) derivatives (3a–3s) were synthesized and tested for hMAO inhibitory activity. Fifteen compounds (3a, 3c, 3e–3h, 3j–3p, 3r, 3s) were found to be selective towards MAO-B, while 3d was selective towards MAO-A, and 3b, 3i and 3q were non-selec...

New methods for the synthesis of (E)-3-halo-2-styryl-4H-chromen-4-ones were established. The reaction of these compounds with hydrazine hydrate afforded new and unexpected 3(5)-aryl-5(3)-[2-(2-hydroxyphenyl)-2-hydrazonoethyl]-1H-pyrazoles, which upon acid hydrolysis gave 3(5)-aryl-5(3)-[2-(2-hyd...

Publisher SummaryAzodicarbonyl compounds contain a carbonyl function on both sides of the azo bond, in contrast to aliphatic and aromatic azo compounds, possess a highly reactive N=N group. Reactions in which one or both, of the nitrogen atoms of the azo group are retained in the final heterocyc...

Four secondary alcohols of different steric environment reacted with five carboxylic acids of different acidity in the presence of N,N,N′,N′-tetramethylazodicarboxamide and tributylphosphine to give the corresponding epi-esters in better yield than with diethyl azodicarboxylate-triphenylphosph...

Two rearrangement reactions caused by the thermal instability of samarium organometallics leading to mixtures of disproportionation products have been studied. Dicyclopentadienylsamarium acetate rearranges into triscyclopentadienylsamarium and samarium acetate, while dicyclopentadienyl samarium ...

In this study, Au-Ce0.5Zr0.5O2 (Au-CeZr) and Sm modified AuCeZr catalysts were synthesized by organic deposition-precipitation method using gold acetate and samarium acetate as Au and Sm precursors and tetrapropyl ammonium hydroxide as precipitating agent. The synthesized nanocrystalline Au-CeZr...

Isothermal decomposition of un-irradiated and pre-γ-irradiated samarium acetate has been investigated at different temperatures between 613 and 633 K. Irradiation was observed to enhance the rate of decomposition without modifying the mechanism of thermal decomposition. Thermal decomposition of...

A general and highly selective method for the synthesis of carbohydrate-derived (Z)-vinyl halides and silanes is described. This reaction takes place through a β-elimination process of sugar-derived α-halomethylcarbinol acetates promoted by samarium diiodide. Starting materials have been easil...

Tachykinins constitute an important class of neuropeptides which exhibit a wide variety of biological functions. They are responsible for exciting neurons and evoking behavioral responses. These peptides have a common C-terminal pentapeptide sequence and their biological activity depends on the ...

SummaryThe hypotensive and antidipsogenic effects of eledoisin, physalaemin and some synthetic eledoisin- or physalaemin-like peptides were studied in conscious rats, respectively after intravenous or intracerebroventricular administration.The effects of the peptides were compared to the hypoten...

Diverse C-terminal heptapeptide derivatives related to substance P, kassinin, physalaemin, neurokinin A and B were synthesized and the contracting activities on the guinea pig ileum as well as rat duodenum were compared. In the partial sequence of C-terminal of tachykinin peptides, -I-II-Phe- II...

SummaryThe hypotensive and dipsogenic effects of eledoisin, physalaemin and some synthetic eledoisin- or physalaemin-like peptides were studied in conscious pigeons, respectively after intravenous or intracerebroventricular administration. The effects of the peptides were compared to the hypoten...

Substance P carboxy-terminal heptapeptide ([pGlu5]SP5−11) showed a similar potency on the salivation and amylase release in anaesthetized rats to that of substance P. In an in-vitro experiment using parotid slices, the rate of amylase release by [pGlu5]SP5−11 was significantly higher than by sub...

The effect of eledoisin fragments and eledoisin-related peptides was studied in vivo on dog, rabbit and cock blood pressure, on rabbit uterus and on guinea pig brocchospasm, and in vitro on guinea pig seminal vesicles. The following conclusions were drawn: (1) At least six amino acids are necess...