Synthetic drugs structures

Methadone is a synthetic drug structurally and pharmacologically similar to morphine it acts mainly at the p-receptor. Methadone is largely metabolised to products that are excreted in the urine (t) 8 h). The principal feature of methadone is its duration of action. Analgesia may last for as long as 24 h. If used for chronic pain in palliative care (12-hourly) an opioid of short t) should be provided for breakthrough pain rather than an extra dose of methadone. 

Chemotherapy is the control and treatment of disease by synthetic drugs. Most of these are organic compounds, often of remarkably simple structure. Sulfanilamide is one example of an organic compound synthesized by chemists for the treatment of bacterial infections. 

Special mention must be accorded to iatrogenic effects, where the usefulness of novel synthetic drugs is impaired by untoward side effects of obscure etiology. In some, if not many of them, these side effects may find their explanation in the inhibitory action of the drug upon a vitamin, as in the case of primidone vs. folic acid (B3a). These relationships appear to be fortuitous until the structural chemical kinship of drug and vitamin is recognized. 

Levothyroxine is used to treat hypothyroidism (an underactive thyroid gland). Thyroid hormone can be made from beef and pork thyroid, but this lacks standardization and it is difficult to control dosage. The synthetic drug is more desirable. Levothyroxine is one of two important thyroid hormones. It is converted into the second important hormone, liothyronine, in the body. The key step in the synthesis of structures such as levothyroxine is the substitution of an iodonium salt by an iodinated phenol. Siql-like reactions on an aromatic ring are not common, but an iodonium salt provides a good leaving group. 

Where more than one chiral centre is present in a molecule there is the possibility of diastereoisomers, e.g. captopril. Another example of a synthetic drug with two chiral centres is labetalol. The number of diastereoisomers arising from n chiral centres is 2"i.e. 2 in the case of labetalol. In the structure shown in Figure 2.5 chiral centres 1 and 2 in structure A have the configurations R and S respectively the enantiomer of this structure (B) has the S and R configurations in centres 1 and 2. In addition there is a pair of enantiomers C and D that are diastereoisomers of the structures A and B, which have the configurations R2R and 16 25 . 

Whether a drug is isolated from nature or synthesized in the laboratory makes no difference as to how good it may be for you. There are a multitude of natural products diat are downright harmful, just as there are many synthetic drugs that are also harmful. The effectiveness of a drug depends on its chemical structure, not the source of this chemical structure. 

Quinuclidine (l-azabicyclo[2.2.2]octane) is a heterocyclic system which is part of the structure of a number of natural physiologically active compounds and synthetic drugs.1 Among the natural alkaloids, the following quinoline and indole derivatives contain the quinuclidine ring cinchonine, cinchonamine (alkaloids of Cinchona species),8-12... 

Description and Characterization. This section should provide a clear description of the physical and chemical properties of the synthetic drug substance, including the chemical structure, primary and subunit structure, molecu-... 

STP is a synthetic drug closely resembling mescaline in its chemical structure. It produces a twelve-hour intoxication with strong stimulation and may be less euphoric than mescaline. In the late 1960s, it was blamed for an epidemic of bad trips lasting many hours. The problem was overdose some hlack-markct tablets contained twenty times the recommended amount. This episode left STP with such a bad reputation that few people seek it out. 

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