1. Introduction
Heterocyclic chemistry is the branch of chemistry dealing with the synthesis, properties and applications of heterocycles. The name comes from the greek word “heteros” which means “different”. Any of a class of organic compounds whose molecules contain one or more rings of atoms with at least one atom (the heteroatom) being an element other than carbon, most frequently oxygen, nitrogen, or sulfur [1].
The most common heterocycles are classified in aliphatic and aromatic molecule. The aliphatic heterocycles are similar to the open chain analogues, ethers, amines and sulfides. These aromatic compounds follow the Huckel’s rule which states that cyclic conjugated and planar systems having (4n+2) π electrons are aromatic. Those having five or six-membered rings and containing heteroatoms of nitrogen (N), oxygen (O), or sulfur (S). The best known of the simple heterocyclic compounds are pyridine, pyrrole, furan, and thiophene. A molecule of pyridine contains a ring of six atoms-five carbon atoms and one nitrogen atom. Pyrrole, furan, and thiophene molecules each contain five-membered rings. other important molecule of quinoline, isoquinoline, 1-8 naphthyridine have a two ring heterocyclic system The history of
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For example, A short time later the first medicinal chemistry related application of the U-4CR was realized, with the one step preparation of the local anesthetic Xylocain [10]. With tremendous foresight, Ugi also recognized that the reaction was ideally suited to probe structure-activity relationships via the synthesis of ‘large collections of compounds’, now referred to as libraries [11]. Today, with the emergence of combinatorial chemistry and high-speed parallel synthesis, the multi-component reaction (MCR) is widely employed for the rapid assembly of arrays with high molecular diversity
...e 3. Both letters A and B within the structure of trans-9-(2-phenylethenyl) anthracene, that make up the alkene, have a chemical shift between 5-6 ppm and both produce doublets because it has 1 adjacent hydrogen and according to the N + 1 rule that states the number of hydrogens in the adjacent carbon plus 1 provides the splitting pattern and the number of peaks in the split signal, which in this case is a doublet.1 Letters C and D that consist of the aromatic rings, both are multiplets, and have a chemical shift between 7-8 ppm. 1H NMR could be used to differentiate between cis and trans isomers of the product due to J-coupling. When this occurs, trans coupling will be between 11 and 19 Hz and cis coupling will be between 5 and 14 Hz, showing that cis has a slightly lowered coupling constant than trans, and therefore have their respective positions in a product. 2
Discussion and Conclusions: Interpreting these results have concluded that relative reactivity of these three anilines in order of most reactive to least reactive go; Aniline > Anisole > Acetanilide. Aniline, has an NH2 , the most active substituent , and adds to any ortho/para position available on the ring. This data is confirmed with the product obtained, (2,4,6 tribromoaniline, mp of 108-110 C). As for anisole, it has a strongly activating group attached, OMe an alkoxy group, and it added in two of the three available spots, both ortho. The results conclude: (2,4-Dibromoanisol mp 55-58 C ). Acetanilide has a strong activating group attached, acylamino group, but this group is large and the ortho positions are somewhat hindered so the majority of the product obtained added at the para position, results conclude: (p-bromoacetanilide mp 160-165 C). Since all the substituents attached to the aromatic rings were activators the only products able to be obtained were ortho/para products.
Discussion The reaction of (-)-α-phellandrene, 1, and maleic anhydride, 2, gave a Diels-Alder adduct, 4,7-ethanoisobenzofuran-1,3-dione, 3a,4,7,7a-tetrahydro-5-methyl-8-(1-methylethyl), 3, this reaction gave white crystals in a yield of 2.64 g (37.56%). Both hydrogen and carbon NMR as well as NOESY, COSY and HSQC spectrum were used to prove that 3 had formed. These spectroscopic techniques also aided in the identification of whether the process was attack via the top of bottom face, as well as if this reaction was via the endo or exo process. These possible attacks give rise to four possible products, however, in reality due to steric interactions and electronics only one product is formed.
First is Synthesis. Synthesis is a reaction in which two different substances are combined to create one substance. In a lab, slime was made as an example of a synthesis reaction. Combining
and Gram-negative bacteria.[139] Mannich reaction also plays a significant role in bioactive skeleton target synthesis. Chernov et al. reported the synthesis of alkaloid-like molecules 22 and 23 from lambertianic acid via Mannich-type intramolecular ring closure reaction (Figure 6).[140]
Zhang X., Tang H., Ye C. and Liu M. (2006). Structure-based drug design: NMR-based approach for ligand-protein interactions. Drug Discovery Today: Technologies. 3 (3), pp. 241-245.
The synthesis of .525 g of para-methoxyacetophenone and .49 g of para-chlorobenzaldehyde using 95% ethanol and catalytic aqueous sodium hydroxide yielded .587 g (61.7% yield) of chalcone 1. The product of chalcone 1 was then confirmed through several different tests. Testing with TLC showed that the product contained a pure substance with only one dot present. The melting point was tested and showed similar characteristics to that of the literature melting points2. The 1H-NMR was analyzed and the key characteristics of the integration values and chemical shifts were comparable to that of the desired chalcone 1 product. Infrared spectroscopy (IR) supported the claim due to the fact that the product’s wavelengths displayed peaks representing characteristics found in the chalcone 1 product. Mass spectrometry was used to confirm the presence of chlorine in our product and to analyze the cation fragments and compare to potential structures. Lastly, this experiment implemented the green chemistry concepts of using safer solvents and a high atom economy while aiming to achieve a high yield product.
Recently, several chemical synthetic cross-linkers have also been developed having superior cross-linking properties [27]. In particular, 4-aminoethanol-N-hydroxyethanyl-1,8- naphthalimide (AHN), a dual-hydroxyl naphthalimide derivative that have been utilized in fluorescent labeling and as the chemical cross-linking agent but with less toxicity [28].
Nuclear Reactions is a process altering the energy, structure, or composition of atomic nuclei. In a reaction two nuclei or nuclear particles collide to produce a completely different product than the original nuclear particles. Although this is exceptionally rare occurrence a principal reaction includes 2 particles colliding. In most cases the particles will just collide and separate, this process is known as elastic collision, which is not a nuclear reaction. Confused with and similar to the Nuclear Reaction, a Chemical reaction only involves the atoms electrons. In an actual Nuclear Reaction only the atoms nucleus is involved.
I have always been inspired by the workings of chemistry and mathematics. My studies of these subjects have developed my understanding and have made me pursue my interest in these two topics. I want to take up chemistry as it involves a large amount of mathematics which I value and understand to be challenging, yet very enjoyable, as there is always an alternative route to obtain the answer. Additionally, I am drawn to the course because it is a mixture of all these exacting subjects, forming a degree that is very demanding and stimulating. Chemists are constantly thinking of new ways to produce viable drugs containing different isomers to improve the pharmaceutical sector using mathematical equations. Chemistry is about innovation, applying information to new areas and how to do things better than they were before, the degree appeals to and fascinates me.
There are four different types of hydrocarbons each having a different homologous series (formula for carbon chain). These being an alkane (formula = CnH2n+2), alkene (formula = CnH2n), alkyne (formula = CnH2n-2), and an alkanol which has the same formulae as an alkane only that is has a hydroxide molecule which replaces one of the hydrogen atoms (refer to figure 3 and
Baran and his team showed that they could use their new method to directly append a strained-ring molecule favored by pharmaceutical chemists—propellane, so-called because its structure resembles a propeller—to existing larger drug molecules. ‘We can make that five-carbon ring structure of propellane click onto a wide range of drug molecules of a type known as secondary amines—we call that a propellerization reaction,’ said Lopchuck.”
Lasix is a brand of the drug furosemide. Lasix tablets are also called water tablets because furosemide, which is the active pharmaceutical ingredient in them acts as a diuretic which gets rid of excess fluid from the body. Who can use the drug? People with high blood pressure use the medication to control their condition.
Organic chemistry is the study of carbon and its compounds (Alcin). Carbon is less than one percent of all matter.Carbon is part of every living thing (Gangson). Carbon makes up eighteen percent of all the matter in living things. (Alcin). The average human body has about 16 kilograms of carbon in some form of this element. Carbon is a part of DNA and proteins. (Robertson).
There are numerous methods on quinolinone synthesis have been reported (Liu et al., 2012). Still, Friedlander reaction remains simplest and the finest method, various methods have been listed by Jose et al., (Jose et al., 2009 & Maguire et al., 1994) for the synthesis of quinolines and quinolinones. Friedlander annulations are carried out in aqueous or alcoholic solutions in the presence of a base or acid under reflux conditions at 150 - 220 °C. Though, the aforementioned synthetic strategies involve unsafe conditions, expensive palladium or phosphine reagents and lower yields, in addition to ending up with quinoline derivatives instead of quinolinones. Hence, it is very essential to overcome these difficulties and to find simple process for the synthesis of quinolin-2(1H)-one. We paved the way to develop inexpensive, solvent free, simple process, less hazardous, Eco-friendly, highly efficient Friedlander annulations of aminobenzophenones reaction with different 1,3-diones (with active hydrogen) in the presence of ZnO NPs (Scheme 1). Although, there are many reports on ZnO NPs in organic conversion reactions (Krishnakumar et al., 2012). Synthesized the ZnO NPs by using existing procedure (Siva Kumar et al., 2013) and Characterized by XRD, SEM,