1192-86-5

Upstream product

• 126-99-8 chloroprene 
• 36398-96-6 7-methylenebicyclo<4.1.0>hept-2-ene 
• 4096-95-1 bicyclo<3.2.1>octa-2,6-diene 
• 76507-89-6 Natriumsalz von Bicyclo<4.1.1>oct-2-en-7-on-4-methylphenylsulfonylhydrazon 
• 85633-68-7 3-Vinyl-1,4-cyclohexadien 
• 765-72-0 tetracyclo<3.3.0.0^2,8.0^4,6>octane 
• 29185-91-9 tetracyclo<3.3.0^2,4.0^3,6>octane 
• 106362-91-8 6,7-diaza-2-methylenebicyclol<3.2.2>nona-3,6-diene 
• 76507-93-2 3-methylenehepta-1,4,6-triene 
• 66633-24-7 cis-1-cycloocten-3-yne 
• 1211-27-4 5,6-Diacetoxy-cycloocten 
• 1210-54-4 2,3-Diacetoxy-bicyclo-<3,3,0>-octan 

Downstream Products

• 64-18-6 formic acid 
• 74-11-3 para-chlorobenzoic acid 

Relevant academic research and scientific papers

THE GENERATION AND E.S.R. OBSERVATION OF A DERIVATIVE OF VINYL-TMM (2-METHYLENECYCLOHEPT-3-EN-1,5-DYIL)

Photolysis of 6,7-diaza-2-methylenebicyclonona-3,6-diene in a glassy matrix at 77K gives the triplet biradical, 2-methylenecyclohept-3-en-1,5-diyl, which shows D/hc0.019 and E/hc0.006 cm-1.

Synthesis and reactivity of trans-tricyclo[4.2.0.0]oct-4-ene

The first synthesis of trans-tricyclo[4.2.0.0]oct-4-ene (1), an ethenyl bridged spirohexane, was accomplished in four steps starting from Carpino et al. gem-dichloro ketone 6. An X-ray crystal structure of 1 with one substituent was obtained to provide geometry data on this novel ring system and to confirm the stereochemical assignment of the penultimate synthetic intermediate. Tricyclo[4.2.0.0]oct-4-ene is surprisingly stable. It reacts with glacial acetic acid but only slowly at 145 °C; the products were isolated and identified. A unimolecular rearrangement takes place at elevated temperatures (165 °C and higher), presumably, via a biradical intermediate to afford tricyclo[4.2.0.0]oct-3-ene (23). The structure of this 1,5-bridged bicyclo[2.1.0]pentane derivative was established by NMR and an X-ray crystal structure of its Diels-Alder adduct with isobenzofuran. Tricyclo[4.2.0.0]oct- 4-ene equilibrates with 23, so equilibrium constants and reaction rates were measured over a 20 °C temperature range from 180 °C to 200 °C. The difference in the heats of formation (ΔΔH°(f) (23 - 1)) is -2.1 kcal/mol, which is in good agreement with ab initio (HF and MP2) calculations using the 6-31G(d) basis set (-1.9 (HF) and -1.4 (MP2) kcal/mol). Computations on trans-tricyclo[4.2.0.0]octane and spirohexane also were carried out, and the structures and energies were compared.

Making a Vinyl-Trimethylenemethane Precursor through the Addition of Diethyl Azodicarboxylate to Tropone

Diethyl 2-oxo-6,7-diazabicyclonona-3,8-diene-6,7-dicarboxylate (11) has been prepared by the addition of diethyl azodicarboxylate to tropone.The 3,4-double bond was protected by reaction with triethyl orthoformate-ethanol-tosic acid (toluene-p-sulphonic acid), the 8,9-double bond reduced, and the enone unit deprotected with water-dioxane-tosic acid.The resultant enone was converted into the conjugated diene by reaction with methyl-lithium and dehydration.Hydrolysis ot the carbamate groups (KOH-MeOH) and oxidation (HgO) gave 2-methylene-6,7-diazabicyclonona-3,6-diene (9).UV irradiation of a glassy solution of this diaz ene at 77 K gave the first observable triplet ESR spectrum of a vinyl-trimethylenemethane biradical, 2-methylenecyclohept-3-ene-1,5-diyl (10).Despite the fact that this non-Kekule polyene has a triplet ground state, the singlet biradical reacts as such to give a mixture of 7-methylenebicyclohept-2-ene (28), 2-methylenebicyclohept-3-ene (29), and 3-methylenehepta-1,4,6-triene (30) faster than it undergoes intersystem crossing.Several interesting contrasts exist between the chemistry of the bridged vinyl-TMM precursor (9) and the equivalent bridged TMM precursor, 7-isopropylidene-2,3-diazabicyclohept-2-ene (4).In the former case, pyrolysis proceeds via the singlet biradical to give mainly monomeric products.There is no CIDNP effect and trapping with alkenes gives low yields of cycloadducts (Scheme 1).In the latter case, pyrolysis gives dimeric products via the triplet biradical.There is a strong CIDNP effect and in the presence of alkenes high yields of cycloadducts are obtained (Scheme 2).

An Experimental Approach to the C8H10 Hypersurface. Kinetic and Thermochemical Investigations on a Formally Forbidden Ground-state <2? + 2?) Cycloaddition

The C8H10 hydrocarbons 1, 3, 4, and 6 have been thermolyzed in a static system and the Arrhenius parameters have been obtained.Calorimetric measurements have been carried out to determine the heats of formation.From these data an experimental energy hypersurface is constructed which shows the following remarkable features: 1) The ground-state energy of endo-1 is higher than that of exo-4 by 8 kcal/mol. 2) The predominant reaction pathway of endo-1 is the formally forbidden 6 and 4->3 are the same, the reaction yielding 6 is faster due to a sizeably higher A factor. 4) The tetracycle 3 chooses the microscopic reverse pathway, i.e. its thermolysis proceeds via exo-4 to give the diene 6.

STRAINED CYCLOALKENYNES

Presently known strained cycloalkynes with one, two or three additional cis- or trans-configurated double bonds are summarized in Table 3.The main topics of the article are the geometrical ring strain, the preparation or in situ generation of these compounds by fragmentation of the corresponding 1,2,3-selendiazoles, and the thermal isomerisation processes performed at room temperature or in flash pyrolysis experiments at 440-640 deg C.

Carbene Rearrangements, XI. Bicyclooct-2-en-7-ylidene

Three reactions are operative in bicyclooct-2-en-7-ylidene (6) generated by flash pyrolysis of the dry sodium salt of the corresponding tosylhydrazone.Cyclobutylidene-methylenecyclopropane rearrangement leads to bicycloocta-1,3-diene (18).A

MECHANISM OF THE THERMAL CONVERSION OF TETRACYCLO(3.3.0.02,4.03.6)OCT-7-ENE INTO DIHYDROPENTALENES

One of a number of possible mechanisms has been established for the title reaction.