Heterocyclic compounds are organic compounds containing at least one atom of carbon, and at least one element other than carbon, such as sulfur, oxygen or nitrogen within a ring structure. These structures may comprise either simple aromatic rings or non-aromatic rings. Some examples are pyridine (C5H5N), pyrimidine (C4H4N2) and dioxane (C4H8O2).
Note that compounds such as cyclopropane, an anaesthetic with explosive properties, and cyclohexane, a solvent, are not heterocyclic; they are merely cycloalkanes. The prefix 'cyclic' implies a ring structure, whereas 'hetero' refers to an atom other than carbon, as above. Many heterocyclic compounds, including some amines, are carcinogenic.
Heterocyclic chemistry is the chemistry branch dealing exclusively with synthesis, properties, and applications of heterocycles.
Heterocycles with three atoms in the ring are more reactive because of ring strain. Those containing one heteroatom are, in general, stable. Those with two heteroatoms are more likely to occur as reactive intermediates. Common 3-membered heterocycles are:
|Oxygen||Ethylene oxide (epoxides, oxiranes)||Oxirene|
|Nitrogen||Tetrahydropyrrole (azolidine, pyrrolidine)||Dihydropyrrole (pyrroline), Pyrrole|
|Oxygen||Tetrahydrofuran (oxolane)||Dihydrofuran, Furan|
|Sulfur||Tetrahydrothiophene (thiolane)||Dihydrothiophene, Thiophene|
Six membered rings with a single heteroatom:
With two heteroatoms:
|Nitrogen / oxygen||Oxazine|
|Nitrogen / sulfur||Thiazine|
Some heterocyclic amines (HCAs) found in cooked meat are known carcinogens. Research has shown that cooking certain meats at high temperatures creates chemicals that are not present in uncooked meats. For example, heterocyclic amines are the carcinogenic chemicals formed from the cooking of muscle meats such as beef, pork, fowl, and fish. HCAs form when amino acids and creatine (a chemical found in muscles) react at high cooking temperatures. Researchers have identified 17 different HCAs resulting from the cooking of muscle meats that may pose human cancer risk. NCI's Division of Cancer Epidemiology and Genetics found a link between individuals with stomach cancer and the consumption of cooked meat, and other studies for colorectal, pancreatic, and breast cancer is associated with high intakes of well-done, fried, or barbecued meats. Other sources of protein (milk, eggs, tofu, and organ meats such as liver) have very little or no HCA content naturally or when cooked.
Patent Issued for Nitrogenous Heterocyclic Compounds and Process for Making Nitrogenous Heterocyclic Compounds and Intermediates
Oct 02, 2013; Millennium Pharmaceuticals, Inc. (Cambridge, MA) has been issued patent number 8536184, according to news reporting originating...
US Patent Issued to Millennium Pharmaceuticals on Jan. 10 for "Nitrogenous Heterocyclic Compounds and Process for Making Nitrogenous Heterocyclic Compounds and Intermediates Thereof" (California Inventors)
Jan 14, 2012; ALEXANDRIA, Va., Jan. 14 -- United States Patent no. RE43,098, issued on Jan. 10, was assigned to Millennium Pharmaceuticals Inc....
US Patent Issued to Millennium Pharmaceuticals on Sept. 17 for "Nitrogenous Heterocyclic Compounds and Process for Making Nitrogenous Heterocyclic Compounds and Intermediates Thereof" (California Inventors)
Sep 17, 2013; ALEXANDRIA, Va., Sept. 17 -- United States Patent no. 8,536,184, issued on Sept. 17, was assigned to Millennium Pharmaceuticals...
Wipo Publishes Patent of Basf Schweiz and Basf for "Pesticidal Methods Using Heterocyclic Compounds and Derivatives for Combating Animal Pests" (German, American Inventors)
Oct 04, 2013; GENEVA, Oct. 4 -- Publication No. WO/2013/144228 was published on Oct. 3.Title of the invention: "PESTICIDAL METHODS USING...