A 1,3,4-thiadiazole library was constructed by solid-phase organic synthesis. The key step of this solid-phase synthesis involves the preparation of polymer-bound 2-amido-5-amino-1,3,4-thiadiazole resin by the cyclization of thiosemicarbazide resin using p-TsCl as the desulfurative agent, followed by the functionalization of resin by alkylation, acylation, alkylation/acylation, and Suzuki coupling reaction. Both the alkylation and acylation reactions chemoselectively occurred at the 2-amide position of 2-amido-5-amino-1,3,4-thiadiazole resin and the 5-amine position of 2-amido-5-amino-1,3,4-thiadiazole resin, respectively. Finally, these functionalized 1,3,4-thiadiazole resins were treated with trifluoroacetic acid in dichloromethane, …show more content…
Lee et al. compared the binding affinity of compounds containing 1,3,4-oxadiazole or 1,3,4-thaidiazole in the same chemical structure toward CB1 receptor in the process of development of obesity drug.9 Both 1,3,4-oxadiazoles and 1,3,4-thiadiazoles were also used for the development potent antibacterial agent by Kumar et al.10 Asai et al. reported dramatic difference in the binding affinity between 1,3,4-oxadiazole and 1,3,4-thiadiazole toward signal transducers and activators of transcription.11 Because of these biologically interesting properties of 1,3,4-thiadiazole and 1,3,4-oxadiazole, these core skeletons have been targeted for synthesis by organic and medicinal chemists, and as a result, many synthetic methodologies have been developed in the literature.12 Among these synthetic methodologies, solid-phase synthesis effectively facilitates the generation of various 1,3,4-thiadiazoles and 1,3,4-oxadiazoles in a short time.13 In our own research area, we have developed solid-phase synthetic methodology to produce 1,3,4-oxadiazoles and 1,3,4-thiadiazoles.14 However, unfortunately our methodology was limited to synthesize diverse 1,3,4-thiadiazole derivatives. It was only suitable to generate p-nitro substituted 1,3,4-thiadiazoles (Scheme 1a). To improve over
This experiment investigates an oxidative coupling reaction in an to synthesise triphenylimidazole dimer from 2,4,5-triphenyl-1H-imidazole. The resulting compound was investigated for both photochromic and piezochromic properties by way of formation of a stable radical, utilizing visual observations and UV-Vis as a means of distinction. Both the oxidative coupling reaction and the dimers interaction with light are depicted in the reactions in figure 1.
Azacitidine was first synthesized by Piskala and Sorm in 1964 [Piskala A, Sorm F. (1964). Collect Czech Chem. Commun., 29: 2060-2076]. It was developed as a nucleoside antimetabolite specifically used for the treatment of acute myelogenous leukemia (Cihak, 1974;Sorm et al., 1964).
Abstract: This procedure demonstrates the nitration of methyl benzoate to prepare methyl m-nitrobenzoate. Methyl benzoate was treated with concentrated Nitric and Sulfuric acid to yield methyl m-nitrobenzoate. The product was then isolated and recrystallized using methanol. This reaction is an example of an electrophilic aromatic substitution reaction, in which the nitro group replaces a proton of the aromatic ring. Following recrystallization, melting point and infrared were used to identify and characterize the product of the reaction.
An air-dried glass reaction vessel equipped with a magnetic stir bar was charged with, in order: 1,4-dioxane (15 mL), t-amyl alcohol (3 mL),2-bromo-3-chloro-5-methyl-6-(thiophen-2-yl)-5H-pyrrolo [2,3-b]pyrazine (0.84 g, 2.5 mmol), Pd(OAc)2 (0.057 g, 0.25 mmol), xantphos (0.25 g, 0.43 mmol), Cs2CO3 (1.66 g, 5 mmol) and tert-butyl carbamate (0.3 g, 2.5 mmol). The suspension was refluxed at 90 oC for 3 h. Once the reaction was complete by TLC, it was diluted with EA and filtered through a bed of celite. The filtrate was concentrated in vacuum. The residue was purified by silica chromatography (25% EA:hexane) to afford desired product as a crystalline solid.
Compound 4 was then further modified to gain drug like properties by core ring expansion and maximizing structural diversity by incorporating a iminopyrimidinone core with a thiopene and a pyridine to get compound 5. The iminothiadiazine analog of compound 5 was explored to find compound 7 with better ligand efficiency. Further SAR studies on compound 6 showed that a fluorophenyl attached to the iminothiadiazine connected a picolinamide with a fluorophenyl substituents showed improved biochemical activity and ligand
All reagents and intermediates were obtained from commercial suppliers and used without any further purification. Zinc oxide (99.0%), sulphamic acid (99.0%), acetonitrile (HPLC grade), ethyl acetate (98.0%), anhydrous sodium sulfate (98.0%), and all substrate for ester derivatives were purchased from Sigma-Aldrich and used without any further purification. All solvents were obtained from commercial sources and were distilled with appropriate reagents prior to use it. In the present approach, catalyst zinc sulfamate (Zn(SO3NH2)2 was prepared by using stoichiometry (2:1) amount of sulfamic acid (NH3SO3) and zinc oxide (ZnO). The obtained final zinc sulfamate (Zn(SO3NH2)2 powder was directly used as catalyst for the preparation of benzimidazole
Hydrazino-Pictet-Spengler ligation reaction = In this reaction, the aliphatic and aromatic hydrazines are used as a substrate to undergo pictet-spengler reaction with aldehydic and ketonic group. As described in the above category 7, the various substrates are used for ligation with aldehydic and ketonic groups of the proteins, P. Agarwal and research group developed the Hydrazino-Pictet-Spengler(HIPS) ligation reaction so that the stable protein conjugates can be developed . This strategy can be used in the development of a prodrug delivery system. The advantage of this scheme over the other oxime and hydrazone ligations is that the ligation proceeds very fast near the neutral pH(that is the pH of the normal physiological body) and the product of the HIPS ligation is showing very long stability in human plasma (approx 5 days) as compared to that of oxime-linked conjugate (approx 1 day). This was monitered by protein-fluorophore conjugates by ELISA(42).
as our synthesized compounds are thiadiazole and schiff base derivatives i will start with thiadiazole ,A five-membered heterocyclic ring containing one sulfur and two nitrogen atoms.
1,3,4-thiadiazine can make either by using the heterocycles including thiadiazole and oxathiol or by diels-alder reaction. In addition, synthesis of 1,3,4-thiadiazine
An in situ aqueous oxidative terpolymerization of anthranilic acid, m-aminobenzoic acid,
Pyridazinone are potent medicinal scaffolds and exhibit a full spectrum of biological activities. This review throws light on the detailed synthetic approaches which have been applied for the synthesis of pyridazinone. This has been followed by an in depth analysis of the pyridazinone with respect to their medicinal significance. This follow-up may help the medicinal chemists to generate new leads possessing pyridazinone nucleus with higher
One of the approaches for identification of polypharmacological chemical compounds is “virtual screening of all potential molecular targets of interest for interactions with these chemicals” [171]. Another approach to enable virtual screening of the receptorome attempts to generate a compendium of computational predictors (e.g., QSAR models or structure based models). Consequently, these constructed models can be employed in the virtual screening of chemical libraries for recognition of novel ligands for a panel of molecular targets and “to predict polypharmacological matrices for these all chemicals” incorporated in the chemical database. Finally, a database of models can be built by consolidation of these QSAR or structure based models. This database can be employed in parallel virtual screening of chemical compounds to indentify the interacting partners from all the pre-characterized members of the receptor-ome.
Chemical and pharmaceutical development to assess the feasibility of large-scale synthesis and purification, to assess the stability of the compound under various conditions, and to develop a formulation suitable for clinical studies.
Today’s drug discovery process consists of a methodical and multi-faceted approach, where it takes many years for a drug to reach the market. It is said that the entire drug
In spite of impressive recent advances of synthetic drugs, the approach to develop newer drugs from chemical libraries, however, was proven to be less useful in terms of overall success rate. In recent years, there is a renewed interest on natural product research due to the failure of alternative drug discovery methods to convey many lead compounds in the major therapeutic areas such as immunosuppression, metabolic diseases and anti-infectives. Natural products acquire massive structural and chemical diversity which is incomparable by any synthetic libraries. About 40% of the chemical scaffolds observed in natural products are deficient in today’s medicinal chemistry and thus become complementary to synthetically developed molecules.