Cyclohepten

Cyclic alkenes give different regioisomers depending on the reaction conditions owing to double bond isomerization caused by syii elimination of Pd—H species and its readdition. The following three reaction conditions were tested for the reaction of cycloheptene (35)[18,38] ... 

Cycloalkenes that have trans double bonds m rings smaller than 12 mem bers are less stable than their cis stereoisomers trans Cyclooctene can be isolated and stored at room temperature but trans cycloheptene is not stable above -30°C... 

PEROXIDES AND PEROXIDE COMPOUNDS - ORGANIC PEROXIDES] (Vol 18) 4-(5H-Dibenzo[a,d]cyclohepten-5-ylidenemethyl)benzenamine [119344- 18-2]... 

Alkenes exhibit large strain energy when molecular geometry does not permit all the bonds to the two sp -hybridized carbons to be coplanar. An example that illustrates this point is -cycloheptene ... 

E-Cyclooctene is also significantly straine4 but less so than -cycloheptene. As the ring size is increased, the amount of strain decreases. The. E-isomers of both cyclononene and cyclodecene are less stable than the corresponding Z-isomers, but for cycloundecene and cyclododecene, the E-isomers are the more stable. Table 3.10 gives data concerning the relative stability of the C7 through C12 cycloalkenes. 

Allylic conjugation stabilizes carbanions, and pAT values of 43 (in cyclohexylamine) and 47—48 (in THF-HMPA) have been determined for propene. On the basis of exchange rates with cesium cyclohexylamide, cyclohexene and cycloheptene have been found to have pAT values of about 45 in cyclohexylamine. The hydrogens on the sjp-... 

The course of alkylation is also influenced by the steric arrangement of the enamine. 1-Pyrrolidino-l-cycloheptene gave approximately equal quantities of the C- and N-alkylated products in dioxane, while 1-pyrroli-dino-l-cyclooctene, and 1-pyrrolidino-l-cyclononene afforded N-alkylated products exclusively under similar eonditions (29). The reason for N alkylation in the eight- and nine-membered ring compounds is to be found in the conformation of these rings, which prevents full interaction of the unshared electrons on nitrogen with the n eleetrons of the double bond. 

On the other hand there have been isolated salts of either the acyclic amino ketone form or the cyclic enamine form, namely 6-methylamino-l-a-naphthyl-l-hexanone (95, = 5) and 12-methylamino-l-a-naphthyl-l-dodecanone (95, n=ll), or l-methyl-2-a-naphthyl-l-aza-2-cycloheptene... 

HOMO of trawi-cycloheptene reveals distortion of the molecule s 7C system. 

Calculate energy differences between cis and trans-cycloheptene and cis and trans-cyclooctene. Which is the more stable isomer for each compound Is there a significant (>.008 au or 5 kcal/mol) increase in the energy difference between cis and trans isomers in going from the seven to eight-membered cycloalkene Are your results consistent with the fact that trans-cyclooctene is an isolable, stable compound while trans-cycloheptene is not ... 

Compare geometries of the cis and trans cycloalkenes. Are the double bonds incorporated into the trans compounds significantly more distorted than those incorporated into the analogous cis cycloalkenes Consider carbon-carbon bond lengths and the twisting and/ or puckering of the double bond. Are any distortions greater in trans-cycloheptene than in trans-cyclooctene ... 

Another measure of distortion is the shape of the highest-occupied molecular orbital (HOMO). This corresponds to the 7t bond. Is the orbital relatively undistorted in the cis compounds (as in cis-2-butene)l Is it more distorted in trans-cycloheptene than in trans-cyclooctene Explain why distortion in the HOMO is likely to be energetically unfavorable. 

Oxime 26 was prepared from 5,ll-dihydro-dibenzo[a,d]cyclohepten-10-one. The Hoch-Campbell reaction of 26 with 3-dimethylaminopropylmagnesium bromide produced aziridine 27 in 46% yield after acidic workup. Extension of the Hoch-Campbell reaction to steroids has also been reported. Thus, treatment of 3(3-hydroxy-5-pregnen-20-one oxime (28) with methylmagnesium iodide furnished a mixture of diastereomers, 20ot/20P,21-imino-20-methyl-5-pregnen-3P-ol (29) in a 50% combined yield and a 3 1 ratio. On the other hand, homo-adamantan-4-one oxime (30) was transformed to homo-adamantano[4,5-b]-2 -ethylaziridine (31) in 76% yield upon the action of... 

Chemical Name 7-1(10,11-Dihydro-5H-dibenzo[a,d]cyclohepten-5-yl-amino] heptanoic acid hydrochloride... 

Chloro-10,11 -dihydro-6H-dibenzo(a/d)cycloheptene Ethyl 7-aminoheptanoate... 

Chemical Name 3-( 10,11-dihydro-5H-dibenzo[a,d] -cyclohepten-5-ylidene)-N,N-dimethyl-1-propaneamine hydrochloride... 

Phthalic anhydride is reacted with phenylacetic acid to form 3-benzylidenephthalide which is then hydrogenated to 2-phenethylbenzoic acid. Conversion to the acid chloride followed by intramolecular dehydrochlorination yields the ketone, 5H-dibenzo[a,d] cyclohepten-5-one. The ketone undergoes a Grignard reaction with 3-(dimethylamino)propyl chloride to give 5-(7-dimethylaminopropylidene)-5H-dibenzo[a,d] cycloheptene. 

N-Methyl-4-chloropiperidine Polyphosphoric Acid 4-Aza-10,11 -dihydro-5-H-dibenzo-[a,d] -cycloheptene-5 one... 

Preparation of 4-aza-S-(N-methyl-4-piperidyll-10,11-dihydro-SH-dibenzo[a,d]cycloheptene-S-ol Add 17.4 g of N-methyl-4-chloropiperidine to a stirred mixture containing 3.2 g of magnesium, 20 ml of anhydrous tetrahydrofuran, 1 ml of ethyl bromide and a crystal of iodine. Reflux for two hours, cool to 30°-35°C and add a solution of 13 g of 4-aza-10,11 -dihydro-5H-dibenzo[a,d] cycloheptene-5-one in 25 ml of tetrahydrofuran. Stir for five hours, remove the solvent by distillation in vacuo and add 250 ml of ether. Add 100 ml of 10% ammonium chloride solution and extract the mixture with chloroform. Concentrate the chloroform solution to a residue and recrystallize from isopropyl ether obtaining 20 g of the carbinol,... 

Preparation of 4-aza-S-(N-methyi-4-piperidyiidene)-10,11-dihydro-SH-dibenzo[a,d]cyciohep-tene dimaieate To a solution containing 4.3 g of 4-aza-(N-methyl-4-piperldylidene)-10,11-dihydro-5H-dibenzo[a,d] cycioheptene in 55 ml of ethyl acetate, add a solution of 3.45 g of maleic acid dissolved in ethyl acetate. Filter the resulting precipitate and recrystallize the desired product from an ethyl acetate-methanol mixture to yield 4-aza-5-(N-methyl-4-pi-perldylidene)-10,11 -dihydro-5H-dibenzo[a/d] cycloheptene dimaieate, MP 152°-154°C. 

Chemical Name ( )-10,11 -dihydro-N,N,/3-trimethyl-5H-dibenzo[a,d] cycloheptene-5-propan-amine... 

In an initial step, dibenzo[a,d] cyclohepten-5-one is reacted with the Grignard reagent of 3-di-methylaminopropyl chloride and hydrolyzed to give 5-(3-dimethylaminopropyl)-dibenzo[a,d] -[1,4] cycloheptatriene-5-ol. Then 13 g of that material, 40 ml of hydrochloric acid, and 135 ml of glacial acetic acid is refluxed for 314 hours. The solution is then evaporated to dryness in vacuo and added to ice water which is then rendered basic by addition of ammonium hydroxide solution. Extraction of the basic solution with chloroform and removal of the solvent from the dried chloroform extracts yields the crude product which when distilled in vacuo yields essentially pure 5-(3-dimethylaminopropylidene)-dibenzo[a/f ] [ 1,4] cycloheptatriene, BP 173°C to 177°C at 1.0 mm. 

Chemical Name 5H-Dibenzo[a,d] cyclohepten-5-oneO-[2-(methylamino)ethyl] oxime Common Name —... 

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