Alicyclic rings

Derivatives analogous to benzoselenazole but possessing an alicyclic ring, such as 2-amino-4,5.6.7 tetrahydrobenzoselenazole (Scheme 8) are obtained from a-chlorocyclohexanone and seienourea (18. 201. 

As noted above, the formation of an alicyclic ring from an acyclic compound makes relatively little difference to the properties of the compound. The same principle applies... 

Fluonnation and skeletal transformation of fluorinated cycloalkanes occurs in the reaction with antimony pentafluoride at high temperature [777] In the case of perfluorinated benzocyclobutanes, an unexpected alicyclic ring cleavage has been observed Perfluorinated alkyl benzocyclobutanes, when treated with antimony pentafluoride, ean be converted to perfluorinated styrenes and then transformed to perfluorinated indans [77S, 779]... 

Substitution of an alicyclic ring for one of the aromatic rings in the amino alcohols such as 32 or 39 produces a series of useful antispasmodic agents that have found some use in the treatment of the symptoms of Parkinson s disease. Mannich reaction of acetophenone with formaldehyde and piperidine affords the amino-ketone, 44a. Reaction of the ketone with cyclohexylmagnesium... 

Replacement of the alicyclic ring of morphine in addition to omission of the furan ring leads to a thoroughly investigated series of analgesic compounds known as the... 

Changing the functionality on the alicyclic ring from an amine to a carboxylic acid leads to a compound that shows antiallergic activity, acting possibly by means of inhibition of the release of allergic mediators. Thus, condensation of acylated indole with cyclohexanone carboxylic acid affords directly oxarbazole (29). ... 

Benzocyclopropene is an intriguing example in which the electronic structure of benzene is greatly perturbed by the fusion of the smallest alicyclic ring, cyclopropene, to the aromatic system. Benzocyclopropene thus arouses theoretical interest and the high strain energy (approximately 68 kcal./mole)3 associated with the compound suggests unusual chemical reactivity. A review article has recently appeared.4... 

Optical Activity Caused by Restricted Rotation of Other Types. Substituted paracyclophanes may be optically active and 25, for example, has been resolved. In this case, chirality results because the benzene ring cannot rotate in such a way that the carboxyl group goes through the alicyclic ring. Many chiral layered cyclophanes (e.g., 26) have been prepared. ... 

Hernaez MJ, E Andujar, JJ Rios, SR Kaschabek, W Reineke, E Santero (2000) Identification of a serine hydrolase which cleaves the alicyclic ring of tetralin. / Bacfeno/ 182 5488-5453. 

Trudgill PW (1984) Microbial degradation of the alicyclic ring structural relationships and metabolic pathways. In Microbial Degradation of Organic Compounds (Ed DT Gibson), pp. 131-180. Marcel Dekker Inc, New York. 

FIGURE 6.13 a-Tocopherol-type benzofurans and benzopyrans having different strains in the alicyclic ring (15a-i) and nonanullated a-tocopherol-type hydroquinones (16a-b). 

When CH2F is a substituent on most alicyclic rings, such as a cyclohexane ring, the 19F chemical shift of this group is not significantly altered from that of an acyclic system (Scheme 3.2). On the other hand, when it is attached to a cyclopropane ring, a unique deshielding influence is observed. 

Various Dewar benzenes of type 27 are forma depending upon the size of the alicyclic ring. 

Ashton, J.G., Szasz, G.J., Fink, H.L. (1943b) The heat capacity, heats of transition, fusion and vaporization and the vapor pressures of cyclohexane. The vibrational frequencies of alicyclic ring systems. J. Am. Chem. Soc. 65, 1135-1139. 

Class 2.1 Saturated alicyclic rings attached to aliphatic chains. 

Class 2.2 Unsaturated alicyclic rings attached aliphatic chains... 

Class 3.3 Alicyclic rings attached to phenyl groups. 

Miyamoto and Yamazaki elaborated a general synthetic method to spiro-substituted [l,2,4]triazolo[l,5-c]pyrimi-dines bearing alicyclic rings of different sizes and bearing different (amino and sulfano) substituents in position 5 <1997JHC871>. 13C NMR chemical shifts of the ring carbon atoms of some selected derivatives are compiled in Table 4. 

Nature of Ring. So far we have studied the stability of saturated alicyclic rings, but interesting results, though not systematic and uniform have been obtained by introducing heteroatoms, phenyl rings or unsaturation in such compounds. Some of the compounds thus synthesized are ... 

In semicydic allenic hydrocarbons, one of the terminal allene carbon atoms is part of an alicyclic ring system, as illustrated by the general structure 37 in Scheme 5.3. Numerous hydrocarbons of this type are known, some of them carrying more than one allene group, such as in the case of the conjugated bisallenes 127 and 129 (see Scheme 5.17), and many of them are described in the review literature [2] and will not be repeated here. However, since Chapter 6 on cycloallenes does not treat these derivatives, some new developments in this area will be briefly presented, limited to the two cases in which cydopropane rings form the end groups of the allene moiety, i.e. 246 and 249. 

The same methodology can be applied to the synthesis of pharmaceutically relevant quinazolines and quinazolinones containing a fused alicyclic ring [45,46]. 

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