spiro compounds การใช้

• Assignment of absolute configuration of spiro compounds has been challenging, but a number of each type have been unequivocally assigned.
• "' Fluorescamine "'is a spiro compound that is not fluorescent itself, but reacts with primary amines to form highly fluorescent products.
• Spiro compounds are present throughout the natural world, some cases of which have been exploited to provide tool compounds for biomedical study and to serve as scaffolds for the design of therapeutic agents with novel shapes.
• A further example of an acetal formed from a cyclic ketone, except with a dithiol, is the spiro compound spirapril, which has a five-membered ring formed from 1, 2-ethanedithiol.
• The simplest spiro compounds are bicyclic ( having just two rings ), or have a bicyclic portion as part of the larger ring system, in either case with the two rings connected through the defining single common atom.
• The presence of the bridge connecting the bridgehead atoms, which are most often two non-adjacent atoms, distinguishes bridged compounds from " fused ring compounds " that have two rings linked by two adjacent atoms, and from spiro compounds that have two rings linked by a single atom.
• A common case is the presence of two atoms that are not carbon in one of the rings, with those two rings both attached to the spiro atom; indeed, often the earliest exposure of a chemist in training to a spiro compound is to a heterocyclic form, the protection of ketones by diols and dithiols.
• Hence, in the third case, the lack of planarity described above gives rise to what is termed axial chirality in otherwise identical isomeric pair of spiro compounds, because they differ only in the right-" versus " left-handed " twist " of structurally identical rings ( as seen in allenes, sterically hindered biaryls, and alkylidenecycloalkanes as well ).
• The one common atom connecting the participating rings distinguishes spiro compounds from other bicyclics : from " isolated ring compounds " like biphenyl that have no connecting atoms, from " fused ring compounds " like decalin having two rings linked by two adjacent atoms, and from " bridged ring compounds " like norbornane with two rings linked by two non-adjacent atoms.
• "' Spirolactones "', also known as "'steroid-17?-spirolactones "', "'17?-spirolactosteroids "', or simply "'17?-spirolactones "', are a group of steroids which are both spiro compounds and lactones and which feature these two structural properties combined in the form of a spirolactone antagonists of the mineralocorticoid receptor ( which is activated predominantly by the mineralocorticoid steroid hormone aldosterone ), and have been employed clinically as potassium-sparing diuretics.
• First, while nevertheless appearing to be twisted, they yet may have a chiral center making them analogous to any simple chiral compound, and second, while again appearing twisted, the specific location of substiuents, as with alkylidenecycloalkanes, may make a spiro compound display " central chirality " ( rather than axial chirality resulting from the twist ); third, the substiuents of the rings of the spiro compound may be such that the only reason they are chiral arises solely from the twist of their rings, e . g ., in the simplest bicyclic case, where two structurally identical rings are attached via their spiro atom, resulting in a twisted presentation of the two rings.
• First, while nevertheless appearing to be twisted, they yet may have a chiral center making them analogous to any simple chiral compound, and second, while again appearing twisted, the specific location of substiuents, as with alkylidenecycloalkanes, may make a spiro compound display " central chirality " ( rather than axial chirality resulting from the twist ); third, the substiuents of the rings of the spiro compound may be such that the only reason they are chiral arises solely from the twist of their rings, e . g ., in the simplest bicyclic case, where two structurally identical rings are attached via their spiro atom, resulting in a twisted presentation of the two rings.