Cyclohepta-1,3-dienes

When treated with fuming sulfuric acid and then with water, decafluoro-cyclohepta-1,4-diene gives hexafluoro-l,5-dihydroxy-8-oxabicyclo(3 2 l)octan-3-one rather than octafluorocyclohepta-2,6-dienone, which is a probable intermediate [28] (equation 31)... 

Chemical Name 3-(3 -Dimethylaminopropylidene)dibenzo [a,d] cyclohepta-1,4-diene N-oxide... 

A mixture of 114.5 g of 5-(3-chloropropylidene)dlbenzo[a i] cyclohepta[1,4] diene, 75 ml of benzene, and about 400 ml of methylamine is heated in an autoclave at 120°Cfor six hours. The excess methylamine is distilled from the reaction mixture under vacuum and the residue is stirred with 300 ml of water. Acidification of the mixture with hydrochloric acid causes the separation of the hydrochloride of 5-(3-methylaminopropylidene)dlbenzo[a,dlcyclo-hepta[ 1,4] diene. The product is collected by filtration and is purified by recrystallizatlon from a mixture of absolute ethanol and ethyl acetate. MP 210°C to 212 C. 

Cyclohexa-1,3-diene is readily hydrogenated to cyclohexene, but cycloheptatriene is hydrogenated more slowly to give a mixture of cycloheptene and cyclohepta-1,3-and 1,4-diene. Further hydrogenation of the conjugated diene is extremely slow. Cyclohepta-1,4-diene and cyclo-octatetraene are not hydrogenated. 

A quantum-chemical study has been undertaken on the isomerization of ctx-1-vinyl-, -1-formyl-, -1-thioformyl-, and -l-iminomethyl-2-vinylcyclopropane to cyclohepta-1,4-diene, 2,5-dihydrooxepine, 2,5-dihydrothiepine, and 2,5-dihydroaze-pine, respectively. Reaction pathways for circumambulatory rearrangements of main group migrants (NO, PO, NCS, SCN, NCO, OCN, SR, Cl, Br, and XX where X... 

The a bonding orbital may also be raised by incorporation into a 3- or 4-membered ring. The divinylcyclopropane to cyclohepta-1,4-diene (Figure 12.6c) is an example, as is the rapid degenerate rearrangement of bullvalene (Figure 12.6d) and related compounds. 

Reaction with cyclopentadienones or their acetals also occurs readily hydrolysis of the acetals and decarbonylation also leads to cycloheptatrienes, while hydrogenation prior to the elimination produces cyclohepta-1,4-dienes 221 222) ... 

DPH600 CAS 4985-15-3 HR 3 5-DIMETHYLAMINOETHYLOXYIMINO-5H-DIBENZO(a,d)CYCLOHEPTA-1,4-DIENE HYDROCHLORIDE... 

Northriptyline Hydrochloride is prepared by the reaction of 5-oxodibenzo [a,dl cyclohepta-1,4-diene with the sodium derivate of N-methylpropargylamine, followed by hydrogenation and then dehydration8. A general scheme follows ... 

Compounds containing a benzo[l,2]cyclohepta-1,4-diene, or -cyclohexa-1,4-diene moiety undergo di-7r-methane rearrangement, both on direct and on sensitized irradiation, to afford fused cyclopropanes. In contrast to benzocycloheptadienes 34 where the primary bonding step invariably occurs between C2 and C4, preferential product formation from benzocyclo-hexadienes 36 can be controlled by the appropriate choice of substituents on either the aromatic ring or the cycloalkene moiety. 

The reaction of cyclohepta-1,4-diene and cycloocta-1,4-diene with electrophiles (bromine, iodine) results in transannular 7t-cyclization. Thus, reaction of cyclohepta-1,4-diene with silver(I) perchlorate and iodine in methanol gave /ranj-2,5-dimethoxybicyclo[4.1.0]heptane (26, n = 1) in 56% yield. Cycloocta-1,4-diene reacted similarly. ... 

Cyclohepta-1,4-diene reacts analogously (see Section 4.4.2.), but reactions of cyclohexa-1,4-diene and cyclonona-1,4-diene with bromine in carbon tetrachloride are consistent with 1,2-addition and showed no signs of cyclopropane formation. ... 

Cyclohepta-1,4-diene (3) has been prepared by the thermolysis of pyrazolines 1, which were obtained by 1,3-dipolar cycloaddition of l-diazoprop-2-ene to butadiene. The yields differ from those obtained under photochemical conditions (see Section 2.4.5.1.2.). 

The bis-alkylation of the dilithio derivative of allyl phenyl sulfone with ( )- ,4-dichlorobut-2-ene (7) affords the cw-cyclopropane 8 which rearranges in refluxing xylenes into the cyclohepta-1,4-diene system 9 in 65% overall yield. 

Conjugate addition of vinylcyclopropylcuprate reagents to j8-iodo enones, e.g. to 42 and 46, provides a convenient means of synthesis of cyclic ketones annulated with the cyclohepta-1,4-diene moiety. Where permitted, the initially formed product, e.g. 44, isomerizes into conjugation under the reaction conditions. Thus, enone 45 (n = 1,2) is the only product from the isomerization of fran.9-vinylcyclopropyl enones 43 (R = H). 

Cyclohepta-1,4-diene (3) has been obtained from the low-temperature photolysis of pyrazolines 1 and the intermediate cis- and rran5-l,2-divinylcyclopropanes (2). c -l,2-Divinylcyclopropane has been prepared by this method and shown to be stable below 0 C. ... 

In contrast to acyclic 1,4-dienes, which rearrange to vinylcyclopropanes from the excited singlet state vide supra), cyclic 1,4-dienes usually undergo the di-7i-methane rearrangement from the triplet state.24 Bicyclo[3.1.0]hex-2-enes (2, n = 1) and bicyclo[4.1.0]hept-2-enes (2, n = 2) are thus obtained from cyclohexa-1,4-dienes and cyclohepta-1,4-dienes, respectively. 

CCRIS 2780 Dibenzo(a,d)cycloheptadien-5-one Di-benzo(a,d)cyclohepta(1,4)dien-5-one 5H-Dibenzo-(a,d)cyolohepten-5-one, 10,11-dihydro- Dibenzo-(b,f)cycloheptan-1-one Dibenzocycloheptenone Di-benzosuberan-5-one Dibenzosuberone 2,3 6,7-Di-benzosuberone Dibenzsuberone 10,11-Dihydro-5H-dibenzo(a,d)cyclohepten-5-one 10,11 -Dihydrodibenzo-... 

Bandoli, G. and Nicolini, M. (1983) Crystal structure of the antidepressant noxiptyline hydrochloride (5-dimethylaminoethyloximino-5H-dibenzo[a,d]-cyclohepta-1,4-diene hydrochloride). J. Crystallogr. Spectrosc. Res. 13 191-199. 

Dibenzo[adl cyclohepta-1,4-diene-5-one 3-Dlmethylamlnopropanol Magnesium Chloride Hydrogen Peroxide... 

---