Polyamides from trans-4-octen-1,8-dioic and trans-2-trans-6-octadien-1,8-dioic acids

Novel polyamides from trans-4-octen-1,8-dioic acid (4-OD) and trans-2-trans-6-octadien-1,8-dioic acid (2,6-ODD) ad linear aliphatic diamines or piperazine were prepared in good yields by low-temperature polycondensation. The polymers obtained were investigated by infrared spectroscopy, x-ray diffraction, and differential scanning calorimetry. Polyamides from 4-OD show high molecular weights and crystallinities and T_m above 500°K, whereas those from 2,6-ODD are very weakly crystalline and decompose without melting in nitrogen at temperatures higher than 550°K. DSC studies revealed in the case of 4-OD polymers with odd diamines, a multiple peak phenomenon in the melting region, strongly dependent from the heating rate. Some hypotheses consistent with this behavior are briefly discussed, and it is concluded that the phenomenon arises from melt recrystallization occurring during the DSC scan.     

Syntheses and structural, physical, and theoretical studies of the novel isostructural Mo9 cluster compounds Ag(2.6)CsMo9Se11, Ag(4.1)ClMo9Se11, and h-Mo9Se11 with tunnel structures

The new isostructural compounds Ag(2.6)CsMo9Se11 (1) and Ag(4.1)ClMo9Se11 (2) were prepared by solid-state reaction in evacuated sealed silica tubes at 1200 degrees C and 860 degrees C, respectively. By topotactic reduction-oxidation reaction of Ag(4.1)ClMo9Se11 with I2, we also obtained the metastable compound h-Mo9Se11 (3). The three compounds crystallize in the hexagonal space group P6(3)/m, Z = 2, (1) a = 10.0472(2) A, c = 11.9548(2), (2) a = 10.0321(2) A, c = 11.8734(2) A, and (3) a = 9.4204(2) A, c = 12.1226(2) A. Their crystal structures were determined from single-crystal X-ray diffraction data and consist of interconnected Mo9Se11 units forming an original and unprecedented three-dimensional framework in which large tunnels are occupied randomly by a part of the Ag+ and the Cl- ions in 2 and the Cs+ ions in 1, the remaining Ag+ in 1 being localized in mirror planes around the 3-fold axis. First-principle calculations allow the understanding of the variation of the atomic distances. Electrical resistivity measurements carried out on single crystals of Ag(2.6)CsMo9Se11 and Ag(4.1)ClMo9Se11 in which the number of electrons per Mo9 cluster is different indicate that the former is semiconducting whereas the latter is semimetallic.     

Equilibrium studies of the diorganotin(IV) complexes with some amino acids and related compounds

The interaction of dimethyltin(IV) and diethyltin(IV) cations with water and some amino acids and related compounds was investigated at 25 degrees C and ionic strength 0.1 M NaNO(3) using a potentiometric technique. The results showed the formation of 11 and 12 (organotin:ligand) complexes and the corresponding stability constants were determined. The participation of different ligand functional groups in binding to organotin is discussed. The effect of the pK(a) value of the respective ligand on the stability constant of its complex species was elucidated. The concentration distribution of the complexes in solution was evaluated.     

Rearrangement during cyclisation of some 3-(2-pyrrolyl) propionic acids and related compounds

Cyclisation of the title compounds leads to mixtures of the expected 4H-cyclopental[b]pyrrol-4-ones (1), the corresponding 6-ones (3) by a single rearrangement, and the cyclopenta[c]pyrrol-4-ones (4) by a double rearrangement, the proportions depending upon the substituents.The ¹H NMR spectra of 2-methyl-4H-cyctopenta[b]thiophen-6-one (3f) shows 6J long range $\text{CH}{}_3\text{CH}{}_2$ coupling, but this is absent in the corresponding pyrroles (3c,d). The ¹³C spectra of 1 and 3 cannot be interpreted on the basis of substituent chemical shifts in pyrroles and thiophens, and are clearly -CH = CH-X (X = NMe, NPh, S) bridged derivatives of cyclopent-2-enone.     

Synthesis of 12(R),13(S)-oxido-9z-octadecenoic (vernolic) and 13(S)-hydroxy-9z, 11E-octadecadienoic (coriolic) acids

(-)-Vernolic acid was prepared enantiospecifically from a readily available carbohydrate precursor and Isomerized to (+)-coriolic acid using the methylmagnesium salt of     

Dipyridinium tetraisothiocyanatodioxotungstate(VI) and related compounds

Eight tetraisothiocyanatodioxotungstate(VI) salts with general formula, (BH)₂[WO₂(SCN)₄] (where B = pyridine, piperidine, quinoline, isoquinoline, 2-, 3-, and 4-picolines) are reported. These salts have been prepared by the reaction of sodium tungstate dihydrate with ammonium thiocyanate in the presence of HCl and isolated as pyridinium or related salts. The compounds have been characterized by elemental analysis, IR and electronic absorption spectra, conductance and magnetic susceptibility measurements, TGA/DTA, and molecular modelling studies The text was submitted by the authors in English.     

(Alpha-aminoacyl)amino-substituted heterocycles and related compounds

N-Protected-(aminoacyl)benzotriazoles 1a-e, g, i, j, 1a'-c' convert heterocyclic amines of the following series: thiazoles (3a and 3a'), benzothiazoles (3b and 3b'), benzimidazoles (3c and 3c'), thiadiazoles (3d), pyrimidones (9a, b, a'), pyrazoles (11a, b), and pyridines (13a-g, 13d') under microwave irradiation, into N-substituted amides in yields of 40-98% (average 76%). N-Protected peptidoylbenzotriazoles 6a, b similarly afforded C-terminal N-protected dipeptidoyl amides 7a, b (52-60%).     

Di-isophorone and related compounds. Part 9 1-(substituted)aminodi-isophoranes and their cyclodehydration products

The interaction of 1-chlorodi-isophor-2(7)-en-3-one (or its 5,11-bisnorhomologue) with aromatic, heteroaromatic, or saturated heterocyclic amines produces 1-(substituted)aminodi-isophor-2(7)-3n-3-ones by nucleophilic replacement of the bridgehead halogen. Subsequent cyclodehydration affords, in certain examples, substituted 2,3,5,6,7,8-hexahydro-1H,9h-5,8a-methanocycloocta[gh]phenanthridines (2,3-dehydro-1-anilinodi-isophor-2,7-dien-3-ols). Some physical and chemical properties of these novel amines and condensed pentacylic bases are described.Part 8,Allen, A. A., Kurzer, F., Mh. Chem.112, 617 (1978).     

Amino sulfonic acids,peptidosulfonamides and other related compounds

A review with 636 references. The literature on saturated amino sulfonic acids with primary/secondary amino group and their derivatives from XIX century to 2016 is surveyed, focusing mainly on results published in the last two decades. Synthesis of saturated amino sulfonic acids and their derivatives, their occurrence among natural products, as well as their use for design of peptidomimetics, conjugates with various molecules of practical significance, applications as building blocks for drug discovery and for other reasons are discussed.     

Structures of (ester) enolates and related compounds

The side reactions in the anionic polymerization of (meth)acrylates initiated by organolithium compounds raise the question about favorable interactions between organolithium and carbonyl compounds in general and in this polymerization reaction. The results of several crystal structures of lithium(sodium) (ester) enolates without or with other molecules clearly demonstrate the favorable formation of homo- and mixed aggregates, respectively. It is also shown how different gegenions (ZnBr⁺, R₄N⁺, etc.) influence the overall structure and the structure of the anion.     

(11)C] Carbon monoxide in selenium-mediated synthesis of (11)C-carbamoyl compounds

Using either amines, amino alcohols, or alcohols in selenium-mediated synthesis with [(11)C]carbon monoxide, 3 ureas, 6 carbamates, and 1 carbonate were labeled. Tetrabutylammonium fluoride ((TBA)F) was discovered to form a soluble and reactive complex with selenium and drastically increase the radiochemical yields. Of the selected carbamoyl compounds, one was a receptor ligand, one was an enzyme inhibitor, and one was a muscular relaxant pharmaceutical. The (11)C-target compounds were obtained in radiochemical yields ranging from low to almost quantitative and with specific radioactivity up to 1300 GBq/micromol. The radiochemical purity of the final products exceeded 98%. In one case, the corresponding (13)C-substituted compound was produced to verify the position of the (11)C-label. In a typical experiment starting with 16.4 GBq [(11)C]carbon monoxide, 7.0 GBq of LC-purified 5-phenyl-1,3-oxazolidin-[2-(11)C]-2-one was obtained within 20 min from start of the carbonylation reaction (84% decay-corrected radiochemical yield). The presented approach is an interesting alternative to the use of [(11)C]phosgene in labeling chemistry.