1.
Lactam
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A lactam is a cyclic amide. The term is a portmanteau of the words lactone + amide, general synthetic methods exist for the organic synthesis of lactams. Lactams form by the rearrangement of oximes in the Beckmann rearrangement. Lactams form from cyclic ketones and hydrazoic acid in the Schmidt reaction, lactams form from cyclisation of amino acids. Lactams form from intramolecular attack of linear acyl derivatives from the nucleophilic abstraction reaction, in iodolactamization an iminium ion reacts with an halonium ion formed in situ by reaction of an alkene with iodine. At lower temp, β-lactam is the preferred product, at optimum temperatures, a highly useful γ-lactam known as Vince Lactam is obtained. Lactim is a cyclic carboximidic acid compound characterized by an endocyclic carbon-nitrogen double bond and it is formed when lactam undergoes tautomerization. β-Lactam β-Lactam antibiotics, which includes penicillins 2-Pyrrolidone 2-Piperidinone Caprolactam
2.
Amide
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An amide, also known as an acid amide, is a compound with the functional group RnExNR′2. Most common are carboxamides, but many other important types of amides are known, the term amide refers both to classes of compounds and to the functional group within those compounds. Amide can also refer to the base of ammonia or of an organic amine. For discussion of these anionic amides, see Alkali metal amides, the remainder of this article is about the carbonyl–nitrogen sense of amide. The simplest amides are derivatives of ammonia wherein one hydrogen atom has replaced by an acyl group. The ensemble is represented as RCNH2 and is described as a primary amide. Closely related and even more numerous are secondary amides which can be derived from amines and have the formula RCNHR′. Tertiary amides are commonly derived from amines and have the general structure RCNR′R″. Amides are usually regarded as derivatives of carboxylic acids in which the group has been replaced by an amine or ammonia. The lone pair of electrons on the nitrogen is delocalized into the carbonyl, consequently, the nitrogen in amides is not pyramidal. It is estimated that acetamide is described by resonance structure A for 62%, in the usual nomenclature, one adds the term amide to the stem of the parent acids name. For instance, the derived from acetic acid is named acetamide. IUPAC recommends ethanamide, but this and related names are rarely encountered. When the amide is derived from a primary or secondary amine, thus, the amide formed from dimethylamine and acetic acid is N, N-dimethylacetamide. Usually even this name is simplified to dimethylacetamide, cyclic amides are called lactams, they are necessarily secondary or tertiary amides. Functional groups consisting of –PNR2 and –SO2NR2 are phosphonamides and sulfonamides, some chemists make a pronunciation distinction between the two, saying /əˈmiːd/ for the carbonyl–nitrogen compound and /ˈeɪmaɪd/ for the anion. Others replace one of these with /ˈæmᵻd/, while others pronounce both /ˈæmᵻd/, making them homonyms. Compared to amines, amides are very weak bases, while the conjugate acid of an amine has a pKa of about 9.5, the conjugate acid of an amide has a pKa around −0.5
3.
Alpha and beta carbon
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The alpha carbon in organic molecules refers to the first carbon atom that attaches to a functional group, such as a carbonyl. The second carbon atom is called the beta carbon, and the system continues naming in alphabetical order with Greek letters, the nomenclature can also be applied to the hydrogen atoms attached to the carbon atoms. A hydrogen atom attached to a carbon atom is called an alpha-hydrogen atom, a hydrogen atom on the beta-carbon atom is a beta hydrogen atom. Organic molecules with more than one group can be a source of confusion. Generally the functional group responsible for the name or type of the molecule is the group for purposes of carbon-atom naming. For example, the molecules nitrostyrene and phenethylamine are very similar, alpha-carbon is also a term that applies to proteins and amino acids. It is the carbon before the carbonyl carbon. Therefore, reading along the backbone of a protein would give a sequence of –n– etc. The α-carbon is where the different substituents attach to different amino acid. That is, the groups hanging off the chain at the α-carbon are what give amino acids their diversity and these groups give the α-carbon its stereogenic properties for every amino acid except for glycine. Therefore, the α-carbon is a stereocenter for every amino acid except glycine, glycine also does not have a β-carbon, while every other amino acid does. The α-carbon of an acid is significant in protein folding. When describing a protein, which is a chain of amino acids, in general, α-carbons of adjacent amino acids in a protein are about 3.8 ångströms apart. The α-carbon is important for enol- and enolate-based carbonyl chemistry as well, an exception is in reaction with silyl- chlorides, -bromides, and -iodides, where the oxygen acts as the nucleophile to produce silyl enol ether. ^ Hackhs Chemical Dictionary,1969, page 30, ^ Hackhs Chemical Dictionary,1969, page 95
4.
Antibiotic
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Antibiotics, also called antibacterials, are a type of antimicrobial drug used in the treatment and prevention of bacterial infections. They may either kill or inhibit the growth of bacteria, a limited number of antibiotics also possess antiprotozoal activity. Antibiotics are not effective against viruses such as the cold or influenza. Drugs which inhibit viruses are termed antiviral drugs or antivirals rather than antibiotics, sometimes the term antibiotic is used to refer to any substance used against microbes, synonymous with antimicrobial. Some sources distinguish between antibacterial and antibiotic, antibacterials are used in soaps and disinfectants, while antibiotics are used as medicine, Antibiotics revolutionized medicine in the 20th century, and have together with vaccination led to the near eradication of diseases such as tuberculosis in the developed world. However, their effectiveness and easy access led to overuse, especially in raising, prompting bacteria to develop resistance. All classes of antibiotics in use today were first discovered prior to the mid 1980s, substances with antibiotic properties had been used for various purposes since ancient times. Before the early 20th century, treatments for infections were based primarily on medicinal folklore, mixtures with antimicrobial properties that were used in treatments of infections were described over 2000 years ago. Many ancient cultures, including the ancient Egyptians and ancient Greeks, used specially selected mold and plant materials, more recent observations made in the laboratory of antibiosis between microorganisms led to the discovery of natural antibacterials produced by microorganisms. Louis Pasteur observed, if we could intervene in the antagonism observed between some bacteria, it would offer perhaps the greatest hopes for therapeutics. In 1874, physician Sir William Roberts noted that cultures of the mold Penicillium glaucum that is used in the making of types of blue cheese did not display bacterial contamination. In 1876, physicist John Tyndall also contributed to this field, Louis Pasteur conducted research showing that Bacillus anthracis would not grow in the presence of the related mold Penicillium notatum. In his thesis, Duchesne proposed that bacteria and molds engage in a battle for survival. Duchesne observed that E. coli was eliminated by the fungus Penicillium glaucum when they were grown in the same culture. He also observed that when he inoculated animals with lethal doses of typhoid bacilli together with Penicillium glaucum. Unfortunately Duchesnes army service after getting his degree prevented him from doing any further research, Duchesne died of tuberculosis, a disease now treated by antibiotics. In 1928, Sir Alexander Fleming identified penicillin, a molecule produced by molds that kills or stops the growth of certain kinds of bacteria. Fleming was working on a culture of disease-causing bacteria when he noticed the spores of a mold, Penicillium chrysogenum
5.
Penicillin
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Penicillin is a group of antibiotics which include penicillin G, penicillin V, procaine penicillin, and benzathine penicillin. Penicillin antibiotics were among the first medications to be effective against many bacterial infections caused by staphylococci and streptococci, penicillins are still widely used today, though many types of bacteria have developed resistance following extensive use. About 10% of people report that they are allergic to penicillin, however, serious allergies only occur in about 0. 03%. Penicillin was discovered in 1928 by Scottish scientist Alexander Fleming, people began using it to treat infections in 1942. There are several enhanced penicillin families which are effective against additional bacteria, these include the penicillins, aminopenicillins. They are derived from Penicillium fungi, the term penicillin is often used generically to refer to benzylpenicillin, procaine benzylpenicillin, benzathine benzylpenicillin, and phenoxymethylpenicillin. Procaine penicillin and benzathine penicillin have the same activity as benzylpenicillin. Phenoxymethylpenicillin is less active against gram-negative bacteria than benzylpenicillin, infrequent adverse effects include fever, vomiting, erythema, dermatitis, angioedema, seizures, and pseudomembranous colitis. About 10% of people report that they are allergic to penicillin, however, serious allergies only occur in about 0. 03%. Penicillin can also induce serum sickness or a serum sickness-like reaction in some individuals, serum sickness is a type III hypersensitivity reaction that occurs one to three weeks after exposure to drugs including penicillin. It is not a drug allergy, because allergies are type I hypersensitivity reactions. Pain and inflammation at the site is also common for parenterally administered benzathine benzylpenicillin, benzylpenicillin. Significantly, there is a reaction to Streptolysin S, a toxin released by certain killed bacteria and associated with Penicillin injection. Allergic reactions to any β-lactam antibiotic may occur in up to 1% of patients receiving that agent, the allergic reaction is a Type I hypersensitivity reaction. Anaphylaxis will occur in approximately 0. 01% of patients and it has previously been accepted that there was up to a 10% cross-sensitivity between penicillin-derivatives, cephalosporins, and carbapenems, due to the sharing of the β-lactam ring. Assessments in 2006 found no risk for cross-allergy for second-generation or later cephalosporins than the first generation. However, as a risk, research shows that all beta lactams have the intrinsic hazard of very serious hazardous reactions in susceptible patients. Only the frequency of these reactions vary, based on the structure, bacteria constantly remodel their peptidoglycan cell walls, simultaneously building and breaking down portions of the cell wall as they grow and divide
6.
Carbapenem
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Carbapenems are antibiotics used for the treatment of infections known or suspected to be caused by multidrug-resistant bacteria. Their use is primarily in people who are hospitalized, like the penicillins and cephalosporins, they are members of the beta lactam class of antibiotics, which kill bacteria by binding to penicillin-binding proteins and inhibiting cell wall synthesis. They exhibit a spectrum of activity compared to cephalosporins and penicillins. Their effectiveness is less affected by many mechanisms of antibiotic resistance than other beta lactams. Carbapenem antibiotics were developed at Merck & Co. from the carbapenem thienamycin. Concern has arisen in recent years over increasing rates of resistance to carbapenems, agents with anti-pseudomonal activity, including doripenem, imipenem, and meropenem are not recommended in this population. Doripenem, imipenem, and meropenem are recommended for high-risk community-acquired abdominal infections, combination therapy, typically with an aminoglycoside, is recommended for Pseudomonas infections to avoid resistance development during treatment. Imipenem and meropenem are useful in cases in which P. aeruginosa is a suspected pathogen, in 2015, the National Institute for Health and Care Excellence recommended piperacillin-tazobactam as first line therapy for the treatment of bloodstream infections in neutropenic cancer patients. For bloodstream infections known to be due to extended spectrum beta-lactamase producing Enterobacteriaceace, carbapenems exhibit broad spectrum activity against gram-negative bacteria and somewhat narrower activity against gram-positive bacteria. For empiric therapy they are combined with a second drug having broader spectrum gram-positive activity. Activity is maintained against most strains of E. coli and K. pneumoniae that are resistant to cephalosporins due to the production of extended spectrum beta-lactamases, imipenem, doripenem, and meropenem also exhibit good activity against most strains of Pseudomonas aeruginosa and Acinetobacter species. The observed activity against these pathogens is especially valued as they are resistant to many other antibiotic classes. The spectrum of activity of the carbapenems against gram-positive bacteria is fairly broad, good activity is seen against methicillin-sensitive strains of Staphylococcus species, but many other antibiotics provide coverage for such infections. Good activity is observed for most Streptococcus species, including penicillin-resistant strains. Carbapenems generally exhibit good activity against anaerobes such as Bacteriodes fragilis, like other beta lactam antibiotics, they lack activity against atypical bacteria, which do not have a cell wall and are thus not affected by cell wall synthesis inhibitors. Carbapenems are contraindicated in patients with allergic reactions to beta lactam antibiotics. Serious and occasionally fatal allergic reactions can occur in people treated with carbapenems, seizures are a dose-limiting toxicity for both imipenem and meropenem. Clostridium difficile-related diarrhea may occur in people treated with carbapenems or other broad spectrum antibiotics, imipenem, the first clinically used carbapenem, was developed at Merck and Co
7.
Monobactam
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Monobactams are β-lactam compounds wherein the β-lactam ring is alone and not fused to another ring, in contrast to most other β-lactams. They are effective only against aerobic Gram-negative bacteria, currently the only commercially available monobactam antibiotic is aztreonam. Other examples of monobactams are tigemonam, nocardicin A, and tabtoxin, adverse effects to monobactams can include skin rash and occasional abnormal liver functions. They have no cross-hypersensitivity reactions with penicillin but like penicillins can trigger seizures in patients with history of seizures, monobactams at the US National Library of Medicine Medical Subject Headings
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