ABSTRACT
This review covers the literature information on the chemistry of hydrazonoyl halides with different substrates to give heterocyclic compounds. From the foregoing survey, it seems this provides a useful and convenient strategy for the synthesis of numerous heterocyclic derivatives. The subject of such reactions is still ongoing and undoubtedly will provide new fused functionalized compounds of both industrial and biological interest. A literature survey revealed that a great deal of interest has been focused on the synthesis of functionalized heterocyclic compounds due to their wide range of biological activities, such as contact dermatitis, anthelmintic, antiviral, antimicrobial, herbicidal, and anti-cancer. On the other hand, hydrazonoyl halides are interesting synthons for valuable bioactive heterocyclic compounds. The reaction of hydrazonoyl halides with various types of substrates gave a huge number of different heterocyclic systems. In this review, we collected all reactions of hydrazonoyl halides with different moieties and classified them as aryl diazo of monoheterocycles, aryldiazo of 5,5-bis-heterocycles, aryldiazo of 5,6-bis-heterocycles, aryldiazo of 6,6-bis-heterocycles, aryldiazo of 5,5,6-tri-heterocycles, aryldiazo of 5,6,6-tri-heterocycles, aryldiazo of 6,6,6-tri-heterocycles, hetero annulation of bisheterocycles, hetero annulation of tri-heterocycles, hetero-annulation of tetra-heterocycles, synthesis of spiro-heterocycles, heterocyclic ring transformations, and 1,3-dipolar cycloaddition reactions catalyzed by transition metals using hydrazonoyl halides as substrates.Most reaction types have been successfully applied and used in the production of biologically active compounds. The aim of the present survey is to consider in the reader the opportunity interactions and biological activities of hydrazonoyl halides. The information of several artificial paths and varied physics-chemical factors of such heterocycles made a special consideration of chemists in different fields to yield a combinatorial library and carry out thorough efforts in the search for hydrazonoyl halides.
ABSTRACT
The objective of this work was to computationally predict the melting temperature and melt properties of thermosetting monomers used in aerospace applications. In this study, we applied an existing voids method by Solca. to examine four cyanate ester monomers with a wide range of melting temperatures. Voids were introduced into some simulations by removal of molecules from lattice positions to lower the free-energy barrier to melting to directly simulate the transition from a stable crystal to amorphous solid and capture the melting temperature. We validated model predictions by comparing melting temperature against previously reported literature values. Additionally, the torsion and orientational order parameters were used to examine the monomers' freedom of motion to investigate structure-property relationships. Ultimately, the voids method provided reasonable estimates of melting temperature while the torsion and order parameter analysis provided insight into sources of the differing melt properties between the thermosetting monomers. As a whole, the results shed light on how freedom of molecular motions in the monomer melt state may affect melting temperature and can be utilized to inspire the development of thermosetting monomers with optimal monomer melt properties for demanding applications.
ABSTRACT
Synthetic aromatic polymers are ubiquitous and indispensable to modern life, industry, and the global economy. The direct functionalization of these materials remains a considerable challenge on account of their unreactive aromatic C-H bonds and robust physical properties. Here, we demonstrate that homogeneous gold catalysis offers a mild, chemoselective, and practical approach to functionalize high-volume commodity aromatic polymers. Utilizing a gold-catalyzed intermolecular hydroarylation between a methyl ester functionalized alkyne, methyl propiolate, and nucleophilic arenes within polystyrene (PS) results in direct functionalization of phenyl rings with 1,2-substituted methyl acrylate functional groups. The reactivity and functionalization depend on the steric and electronic environment of the catalyst, counterion pairing, and method of activation. The reactivity is broad in scope, enabling the functionalization of arenes within commercial polysulfone (PSU) and waste polyethylene terephthalate (PET). These reactions open new opportunities to chemically transform aromatic polymers and modify their physical properties.
