 |
|
 |
|
|
|
This page contains some examples of interesting polycyclic and / or heterocyclic molecules used as pharmaceuticals. Look at the JSMOL images to see the types and shapes of the ring systems that are present.
| RANITIDINE : C13H22N4O3S,
mol. wt. = 314.41 g/mol Physical properties: Solid, mp = 69-70oC. US patent is held by Allen and Hanburys. The hydrochloride of Ranitidine is called Zantac, one of the most prescribed drugs in the western world. Zantac is an off white solid, mp = 133-134 oC. It is soluble in acetic acid, water and methanol, sparingly soluble in ethanol, insoluble in chloroform. Ranitidine is a histamine H2-receptor antagonist which inhibits gastric acid secretion. Therapeutically it is used as an antiulcerative. |
|
| PRONTOSIL : C12H13N5O2S,
mol. wt. = 291.33 g/mol The hydrochloride salt is an orange-red cyrstaline material, mp : 248-250 oC, solubility: 1g in 400 ml water, much more soluble in hot water, soluble in alcohol, acetone, fats and oils. Prontosil was original prepared as an "azo-dye" and used for dyeing wool fibres. However, it was part of an in vivo study for antibacterial activity (found to be active against Gram-positive infections) and became a prototype compound that led to the development of the important sulphonamide antibacterials. Prontosil was first drug introduced to treat bacterial infections. Therapeutically it is used as an antibacterial, but it is also used as a specific stain for carbonic anhydrase in polyacrylamide gels. |
|
| PROMAZINE : C17H20N2S, mol.
wt. = 284.43 g/mol Physical properties: an oily liquid, having an "amine" odour. bp(0.3) : 203-210 oC. Prepared by heating a xylene solution of phenothiazine and 3-dimethylamino-1-chloro-propane in the presence of sodamide. US patent for Promazine is held by Rhone-Poulenc. The hydrochloride salt, Prazine (also known as Talofen or Sparine) is a white/yellow crystalline material that oxidises in air. One gram is soluble in 3 ml of water. it is also soluble in alcohols and chloroform, insoluble in diethyl ether and benzene. Aqueous solutions are slightly acidic to litmus. Therapeutically it is used as an antipsychotic and an antihistamine in man and as a tranquilizer for animals. |
|
| NOVOCAIN : C13H20N2O2.HCl,
mol. wt. = 273.07 g/mol Novocain is the hydrochloride salt of another pharmaceutical, Procaine. Novocain is a crystaline material:mp = 153-156 oC. Numbing taste. Air stable. Solubility: 1g dissolvesin 1ml water and 30ml of alcohol, slightly soluble in chloroform, virtuallyinsoluble in diethyl ether. pH of 0.1M solution is 6.0. Aqueous solutionscan be sterilised by boiling. LD50 (mice mg/kg) = 660. Novocain was synthesised to replace cocaine due to the abuse of cocaine.It was designed to have the same pain-killing properties but not the psychologicalside effects. Therapeutically used as a local anesthetic for humans and animals. |
|
| LIDOCAINE : C14H22N2O, mol.
wt. = 234.34 g/mol Physical properties: crystaline needles (from benzene or alcohol) mp = 68-69oC, bpt (4mm) = 180-182oC. Soluble in chloroform, benzene, ether and alcohol. Insoluble in water. Lidocaine was developed from Procaine (ie Novocain), the structure of which is shown above. Compare the two structures. Due to the presence of a labile ester bond, Procaine has only a short lifetime/duration of action. Changing this to a more stable amide linkage as in Lidocaine provides a material with a longer lifetime and therefore duration. The US patent is held by Astra. Also known as Lignocaine and Xylocaine amongst many other names. Therapeutically it is used as a local anesthetic and a class IB antiarrhythmic. |
|
| DIAZEPAM : C16H13ClN2O, mol.
wt. = 284.74 g/mol Physical properties: crystaline plates (from acetone and petroleum ether) mp = 125-126oC. pKa = 3.4. Soluble in chloroform, dimethyl formamide, benzene, acetone and alcohol. Slightly soluble in water. LD50 (orally for rats) = 710mg/kg This is a controlled substance in US code of Federal Regulations. US patent is held by Hoffmann-La Roche. Also known as Valium, Novazam amongst many other names. Therapeutically it is a anxiolytic, a skeletal muscle relaxant. |
|
| NORETHINDRONE : C20H26O2, mol.
wt. = 298.43 g/mol Physical properties: crystaline (from ethyl acetate) mp = 203-204oC. Specific rotation = -31.7 in chloroform. Prepared from 19-nor-4-androstene-3,17-dione. US patent is held by Syntex. Also known as Coniudag, Menzol, Micronor, Micronovum, Mini-Pe, Norcuolut, Noriday, Norluten, Norlutin, Nor-Qd, Primolut N, and, Utovlan. Norethindrone is a synthetic steroid and was developed since it was known that natural steroids have potent physiological effects. Therapeutically it is a progestogen. Norethindorne and its acetate with estrogen is used as an oral contraceptive. The enanthate is an injectable contraceptive. |
|
| MIFEPRISTONE : C29H35NO2, mol.
wt. = 429.60 g/mol Physical properties: mp = 150oC. Specific rotation = +138.5o (c = 0.5 in chloroform). Mifepristone is a progesterone receptor antagonist with partial agonist activity. When used with prostaglandins, Mifepristone terminates pregnancy within the first 9 weeks of gestation. Structurally it is very similar to Norethindrone. The US patent is held by Rousell-UCLAF. Also known as RU-486 and Mifegyne. Therapeutically it is used as an abortifacient. |
|
Information source: The Merck Index. 12th edition
 |
 |
|
© Dr. Ian Hunt, Department of Chemistry |  |