YC‐1, an activation inductor of soluble guanylyl cyclase

The crystal structure of 1‐benzyl‐3‐(5‐hydroxy­methyl‐2‐furyl)­indazole, C₁₉H₁₆N₂O₂, showed that the furan O and indazole N atoms lie on the same face of the mol­ecule. The crystal packing consists of intermolecular hydrogen bonding, and indazole–indazole and indazole–phenyl interactions.     

A convenient synthesis of dihydro- and tetrahydro-1,3-thiazine derivatives from β-aryl-β-amino acids

A facile synthesis of 2-alkyl-4-aryl-5,6-dihydro-4H-1,3-thiazines and cis-2-alkyl-4-aryl-3,4,5,6-tetrahydro-2H-1,3-thiazines with potential therapeutic interest was achieved starting from readily accessible β-aryl-β-amino acids.     

Synthesis of 5-arylthiazoles. Comparative study between Suzuki cross-coupling reaction and direct arylation

A facile synthetic route to the new thiazol-5-ylboronic acid pinacol ester was described herein. Its reactivity toward Suzuki cross-coupling reaction was studied to provide various 5-arylthiazoles. A comparative study between Suzuki cross-coupling reactions and palladium-catalyzed C5–H direct arylation on thiazole ring was achieved.     

Microencapsulation of bisphenol-A bis (diphenyl phosphate) and influence of particle loading on thermal and fire properties of polypropylene and polyethylene terephtalate

Microencapsulated flame retardant, bisphenol-A bis (diphenyl phosphate) (BDP), with a silane shell was prepared by sol–gel process with the goal of incorporating them in polymeric matrices by melt blending to improve the flame retardancy of isotactic polypropylene (iPP) and polyethylene terephtalate (PET). The influence of the loading content on thermal transitions has been studied by differential scanning calorimetry (DSC), the thermal stability of the polymer/microcapsules composites has been assessed by thermogravimetric analysis (TGA) and cone calorimetry has been used to study the fire reaction. It was noticed that the microcapsules have a limited influence on the thermal transitions of iPP matrix, but a decrease of the melting and glass transition temperatures was detected for the PET microcomposites. TGA results showed that the addition of microcapsules could improve char formation of the PET systems both in nitrogen and in air atmospheres, whereas only a small improvement of the thermal stability was detected in oxidative atmosphere for the iPP samples. Furthermore, cone calorimeter experiments show that the incorporation of microcapsules in the iPP gives almost no improvement in the iPP fire reaction. However, the microcapsules act as flame retardant in PET reducing the heat release rate during the combustion and the total heat evolved. Therefore, microcapsules can act as a char promoter agent to enhance the fire resistance in the case of PET.     

Mechanical memory effect in isotropic polyethylene terephthalate fiber crystallized from the glassy state

Preoriented yarns (POY fiber) of polyethylene terephthalate spun at low speed shrink crystallize above T_g and show no orientation. It is shown that the kinetics of crystallization and the morphology (long period) are dependent on the molecular weight and on the spinning velocity. These differences observed in isotropic spun fibers are explained by the disentanglement of the chains, which depends on the mechanical history of the melt state. It is emphasized that these memory effects indicate that the time for the spun melt to recover its equilibrium properties is longer than the terminal time ι_t. Similar conclusions were obtained for polyethylene melts subjected to temperature jumps.     

2‐(6‐Bromo­pyridin‐2‐yl)‐6‐methyl‐[1,3,6,2]­diox­aza­borocane,a new stable (pyridin‐2‐yl)­boronic acid derivative

The crystal structure of the first reported non‐substituted N‐methyl­diox­aza­borocane confirms that the presence of a methyl group attached to the N atom introduces an NB bond length that is longer than that in a simple diox­aza­borocane ring. The presence of more N atoms in the vicinity of the B atom in the title compound [systematic name: 6a‐(6‐bromo­pyridin‐2‐yl)‐3a‐methyl‐2,3,4,5‐tetra­hydro‐1,6‐dioxa‐3a‐aza‐6a‐borapentalene], C₁₀H₁₄BBrN₂O₂, does not modify significantly any structural parameter in the diox­aza­borocane ring. On the other hand, a small asymmetry appears in the bond angles of the pyridine C atom next to the B atom.     

Chain orientation in natural rubber, Part II: 2H-NMR study

Stress-induced crystallisation (SIC) and stress-induced melting (SIM) in natural rubbers (NR), unfilled and filled with carbon black (CB) have been studied by ²H-NMR measurements. Various materials have been swollen with small amount (< 2%) of deuterated alkane chains. The orientation of the amorphous chains, then the local deformation of the amorphous chains during deformation cycles and during stress relaxation, permits to clarify the SIC and SIM processes during hardening and recovery. By mechanical, WAXS and NMR measurements one determines the same critical draw ratio for appearance λ_A and disappearance λ_E of the crystallites. It is demonstrated that the hysteresis observed by the different techniques (stress σ, crystallinity χ, NMR splitting Δν) are due to the supercooling effect ( λ_A > λ_E, at constant temperature). During hardening at constant strain rate it is found that the local draw ratio remains constant and equal to λ_A, whereas the crystallinity increases linearly with the macroscopic draw ratio λ. The hardening σ ∼ (λ - λ_A)² is then interpreted as a reinforcement effect due to the crystallites, which act as new crosslinks. This confirms the prediction of Flory. In filled rubber the same effects are observed, and the stress amplification factor is determined as a function of the CB content. It is found that the fillers act as nucleation centres for the NR crystallites. The reinforcement of such materials is due principally to this nucleation effect and to the presence of a super network formed by both the NR crystallites and the CB fillers.     

A new approach to determine radiative recombination lifetime in quantum well solar cells

In this paper, the authors present and extend on an existing model, which has been developed to determine the radiative recombination lifetimes in quantum well solar cells. Given the fact that recombination reduces cell performance, the main future use of this new model is to aid in optimisation of cell designs and increase cell efficiency. In this work the authors introduce a coefficient defined as the delta factor which is based on material parameters into the existing model. The introduction of this factor into the existing model has shown an improvement in radiative recombination lifetime determination of approximately 11% when comparison is made with the previous model. This has lead to an overall average improvement in lifetime determination of approximately 9% when comparisons are made between the new model and experimental data. This is a significant improvement in lifetime determination, which will benefit cell designers.     

Pyrrolo[2,1-c][1,4]benzodiazepines. Synthesis of new cyclic amidines and fused[a]triazolo,tetrazolo and oxadiazolo derivatives

We report the practical synthesis of new cyclic amidines from thiolactams and the preparation of fused[a]triazolo, tetrazolo and oxadiazolo derivatives via hydrazidines and oximes, in the pyrrolo[2,1-c]-[1,4]benzodiazepine series.