Benzobicyclo octene

In the endo- and exo-benzobicyclo[3.2.1]octen-3-yl chlorides PET bond cleavage produced an inverted reactivity pattern with the C—Cl bond now in the y-position. The e/wfo-isomer was observed to undergo C—Cl photocleavage 10X faster than the exo-isomer. The variation in reactivity pattern was attributed to the favorable arylchlorine relationship in the endo-isomer which compensates for the ii creased aryl-y carbon separation [81]. 

Examination of these points suggested skeletons 15 and 16 of Table V. Since the benzobicyclo[2.2.1]-heptene analogs (skeleton 15) are considerably more strained than the benzobicyclo[2.2.2]octene (skeleton... 

Evaluation of Some Bicyclic Systems as Conformationally-Defined Phenylethylamines. X-Ray Crystallography. Perhaps the ultimate test of the suitability of a chemical structure for preparing conformationally-defined analogs would be their ability to produce biological effects identical to those of the parent compound. Since this ideal is rarely achieved, and since a "wrong" conformer should be inactive, it is useful to have other criteria with which to evaluate these systems. The bicyclic molecules to be examined in the present study are compounds I-VIII (Figure 7), benzobicyclo[2.2.2]octenes, benzobicyclo [2.2.1]heptenes, and 1,2,3,4-tetrahydro-l,4-epoxynaphthalenes. A number of structural parameters... 

The x-ray structure determinations of exo- and endo-2-methylamino-1,2,3,4-tetrahydro-l,4-ethanonaph-thalene hydrochlorides (145) served as the basis for calculations of the benzobicyclo[2.2.2]octene compounds (NM-X and NM-N). 

Building the C-2 oxygen atom into the bicyclo-[2.2.1] ring system seriously distorts x, the O-C-C-N dihedral angle. As shown in Figure 10, rhe benzobicyclo [2. 2. 2 ] octenes provide excellent values for (endo, 59° exo, 56°), but VII forms an 83° angle. 

The observed interatomic distance from the center of the aromatic ring to the C2-oxygen atom (CR to C2-0 ranges from 3.53 to 3.76 ii, with a mean value of 3.68 A, The benzobicyclo[2.2.2]octene system gives a reasonably good CR to C2-0 distance (3.78 A). As might be expected, compounds VII and VIII, in which the oxygen atom is built into a somewhat strained structure, provide a much less accurate CR to C2-0 distance,... 

CNDO/2 Calculations on Bicyclic Systems. Calculation of the energy differences between the exo-and endo-isomers in either the benzobicyclo[2.2.2]octene or benzobicyclo[2.2.l]heptene system (e.g., I, II,... 

Synthesis. The synthesis of the amphetamine and methamphetamine derivatives in the benzobicyclo[2.2.2]-octene system has been described elsewhere (141 and references cited therein). To be able to study certain of the pharmacological aspects of these compounds, 3H-derivatives were prepared of NM-X and NM-N by reducing the N-formyl derivatives of the amphetamine analogs NH-X and NH-N with lithium aluminum tritiide (142). 

These results show the advantages of the benzobicyclo[2,2,2]octadiene and the -octene series in studying solvolysis reactions over the norbomane derivatives. When these models are used the exo and endo isomers yield different reaction mixtures which precludes the intermediate formation of a classical cation with the same skeleton. If this is formed at the stage of reaction proceeding along the k, route it results in products with a skeleton other than that of the compounds formed in the k processes. 

CycUztUion of bicyclic alcohols to tricyclic hydrocarbons. TFA has been found to be excellent for the acid-catalyzed cyclization of the alcohol (1) to the benzobicyclo[3.2.1]octene (2) and of the alcohol (3) to the benzobicyclo[3.3.1]-nonene-2 (4). Sulfuric acid is less satisfactory. 

Solvolyses of 8-X-3,4-tetrafluorobenzobicyclo[3,2,l]-octadienes and -octenes (X = leaving group) have been reported the syn-epimers react with retention of the skeleton and stereochemistry at C-8 by way of the non-classical carbonium ion intermediate, whereas the anti-compounds yield products with the benzobicyclo-[3,3,0]octane structure, presumably by a classical ion pathway. Although the epimeric tosylates (124) and (125) are solvolysed at different states and show different sensitivities to solvent variation, they produce the same product mixture, comprising... 

A class of benzobicyclo [2.2.2] octene derivatives is known to possess a variety of biological activities (Figure 8.4). For example, benzobicyclo[2.2.2]octenols 20 act as calcium channel blockers and amino-substituted benzobicyclo[2.2.2]octenes 21 work as y-secretase inhibitors. Benzobicyclo[2.2.2]octenone 23 serves as the... 

---