Showing papers on "Bicyclic molecule published in 1973"

Isobenzofulvenes. I. The in situ preparation of 8,8-Dimethyl- and 8,8-Diphenylbenzo[b]fulveues and their pericyclic reactions with 2π-Cycloaddends

Abstract: A new route to the generation of the previously undescribed 8,8- dimethyl- and 8,8-diphenyl-benzo[b]fulvene (isobenzofulvenes)? is reported. This method involved the mild thermal fragmentation of 3,6- di(2?-pyridyl)-15-(α,α-disubstituted methylene)-4,5- diazatetracyclo[6,6,1,02,7,09,14]pentadeca-3,5,9,11,13-pentaene (39), which was prepared from the benzyne adduct of the 7-(α,α-disubstituted methylene)bicyclo[2,2,1]-hepta-2,5-diene (36) and 3,6-di(2?-pyridyl)-s- tetrazine (37). This retroversion reaction is one of order [8π+6π] and, based on the limited evidence available, appears to be a non-concerted process. The isobenzofulvenes were readily isolated, in quantitative yield, as [8π+2π] cycloadducts with a variety of electron deficient olefins (tetraenophiles). Mixtures of exo- and endo-adducts were often obtained and their ratios explained in terms of a combination of dipole-dipole, steric, and orbital interactions operative in the respective transition states. Ozonolysis of these adducts yielded products formally derived from cycloadditions to isoindenone, and this represents an excellent route to these compounds. No spectral evidence for the existence of the monomeric isobenzofulvenes could be obtained, although acid-catalysed decomposition of the dimethyl precursor yielded significant proportions of 2-isopropenylindene, which is logically derived from 8,8-dimethylbenzo[b]fulvene. P.m.r. and mass spectral data are reported for all new compounds and briefly discussed where relevant.

Synthesis of novel bicyclic prostaglandins by photochemical cycloaddition reactions

Abstract: Light-induced addition reactions of cyclopentenone derivatives with ethylene, followed by elaboration of the alkyl chains at positions 8 and 12, give bicyclic prostanoic acid analogues belonging to the prostaglandin E2 and F2α series. Cycloaddition of ethylene to prostaglandin A2 methyl ester yields simultaneously the α- and β-cyclo-adducts. Photochemical addition of allene to prostaglandin A2 derivatives affords mixtures of photoadducts which vary with the nature of the functional group at position 15, thus illustrating the versatility of these photocondensation reactions.

N-Aryl-N'-(phenyl-or phenoxy-alkyl)-piperazines and salts thereof

Abstract: Compounds of the formula ##EQU1## wherein R is phenyl; phenyl having one or more substituents attached thereto, said substituents being selected from the group consisting of alkyl of 1 to 4 carbon atoms, alkoxy of 1 to 4 carbon atoms, alkylthio of 1 to 4 carbon atoms, halogen and trifluoromethyl; a bicyclic aromatic or cycloaliphatic-aromatic ring, especially naphthyl, tetrahydronaphthyl or indanyl; or a mono- or bicyclic heterocyclic ring, especially pyridyl, pyrimidyl, isoquinolyl or thiazolyl; R 1 is ##EQU2## where B is ##EQU3## n is 2, 3 or 4, R 3 is hydrogen, alkyl of 1 to 4 carbon atoms or alkanoyl of 1 to 4 carbon atoms, R 4 and R 5 , which may be identical to or different from each other, are each hydrogen or alkyl of 1 to 4 carbon atoms, p is 0 or 1, and Q is oxygen or two hydrogens, R 2 is hydrogen, alkyl of 1 to 4 carbon atoms, alkoxy of 1 to 4 carbon atoms or halogen, A is a single carbon-to-carbon bond or --OCH 2 --, R 6 is hydrogen, hydroxyl, alkoxy of 1 to 4 carbon atoms or alkanoyloxy of 1 to 4 carbon atoms, and m is 0, 1, 2, 3, 4 or 5, but other than 0 when R 6 is hydroxyl, And non-toxic, pharmacologically acceptable acid addition salts thereof; the compounds as well as their salts are useful as CNS-depressants, adrenolytics, antiphologistics, analgesics, antihistamines and anticholesterols.

The Interaction of Walsh-Orbitols in Diademane and Related Hydrocarbons

Abstract: To obtain further information concerning the interaction between Walsh-orbitols of ‘conjugated’ cyclopropane rings, the photoelectron spectra of the following compounds have been recorded: bicyclo[4.1.0]heptane 1, cis- and trans-tricyclo[5.1.03, 5]octane 2, 3, diademane 4, trans-pentacyclo[3.3.2.02, 9.04, 10, 06, 8]decan 5 and bicyclo[4.1.0]heptene-2 6. The first bands in the PE.-spectra of these compounds have been assigned on the basis of a ZDO HMO-approximation. For 2 and 4 the value for resonance integral between linked 2p atomic orbitals of two adjacent eclipsed cyclopropane rings is found to be −1.73 eV.

Pyrazine chemistry. Part V. Diels-Alder reactions of some 2,5-dihydroxypyrazines

Abstract: Certain 2,5-dihydroxypyrazines and related systems undergo 1,4-cycloaddition reactions. Dimethyl acetylenedicarboxylate reacts to give bicyclic adducts which readily undergo a retro-Diels-Alder reaction with elimination of cyanic acid and formation of substituted pyridones. 5-Ethoxy-1,3-dimethylpyrazin-2-one (16) has been synthesised and shown to undergo ready cycloaddition reactions even with non-activated double bonds. The implications of these reactions relative to the biosynthesis of the mould metabolite brevianamide A and related compounds are discussed.

Aromaticity and tautomerism. Part II. The 4-pyridone, 2-quinolone, and 1-isoquinolone series

Abstract: Aromatic resonance energies for 4-pyridone and its analogues are similar to those for the 2-pyridone series. For the bicyclic compounds, the differences in aromaticity between the quinolinoid and the quinolonoid forms are significantly less than for the monocyclic derivatives. A new acidity function H–(q) is derived for the deprotonation of methyl quaternary salts to netural heterocyclic methide and imine bases. Quantitative tautomeric ratios are reported for the thioamide–thioimidate equilibrium in an Appendix.

Macrocyclic compounds and complexes thereof

Abstract: Novel macrocyclic (monocyclic and bicyclic) compounds having nitrogen bridgehead atoms and having in the hydrocarbon bridging chains at least two additional hetero atoms selected from the group consisting of sulfur, oxygen, and nitrogen, when admixed with a compatible cation-donor compound form stable cationcontaining macrocyclic complexes which, in turn, can be conveniently dissociated by addition of acid or a quaternizing agent. The novel macrocyclics are valuable for use in the same way and for the same purposes as chelating agents. The macrocyclic compounds are prepared by condensation reactions carried out via high dilution techniques, e.g. by condensing a substituted hydrocarbon di-carbonyl halide with a substituted hydrocarbon having terminal primary or secondary amino groups followed by reduction of the resulting lactam or, alternatively, by condensing a substituted hydrocarbon having terminal secondary or tertiary amino groups which have at least one hydrogenolyzable group with a substituted hydrocarbon di-halide (or di-sulfonate) followed by hydrogenolyzation of the macrocyclic compound thereby formed.

Synthesis of Bridged Bicyclic Molecules using Halocarbenes. Derivatives of bicyclo[4.2.1]nonane

Abstract: The addition of dichlorocarbene (generated by the interaction of sodium methoxide and ethyl trichloroacetate) to bicyclo[3.2.1]oct-2-ene, its 3-chloro and exo-3,4-dichloro derivatives gives the exo 1 : 1 adducts in yields of 94, 89 and 48%. By suitable chemical reactions of these adducts, convenient syntheses of bicyclo[4.2.1]nona-2,4-diene and bicyclo[4.2.1]non-3-ene, together with their monochloro, dichloro and trichloro derivatives are obtained. Bicyclo[4.2.1]-nonan-3-one is also obtained from bicyclo[4.2.1]non-3-ene in a synthesis starting from the readily available 5-hydroxymethylnorborn-2-ene in an overall yield of 20%.

13C–H Coupling Constants in Cyclic Systems; a Probe for Hyperconjugation and Homoconjugation?

Abstract: 13C–H coupling constants have been determined for bicyclic and tricyclic carbonyl compounds. In comparison to acyclic and monocyclic ketones these systems show an increase in the coupling constant at the bridgehead alpha to the carbonyl group.

Photo-additions of Naphthalene Derivatives with Substituted Ethylenes: Influence of Methoxy- and Cyano-substituents on the Products

Abstract: Irradiation of 2-methoxynaphthalene and acrylonitrile in ethanol affords exo- and endo-7-cyano-6-methoxy-2,3-benzobicyclo[4.2.0]octa-2,4-diene, in the ratio 30:70. The structures are assigned from the n.m.r. spectra. The endo compound is the more stable, and on base equilibration predominates (90%). These adducts eliminate a methoxy-group on treatment with tert-butoxide at 80°, to afford 2,3-naphtho-cyclobutene carboxamide. Irradiation of 2-cyanonaphthalene and methyl vinyl ether in ethanol gives a complicated mixture of adducts which includes the cyclobutane 7-methoxy-6-cyano-2,3-benzobicyclo-[4.2.0]octa-2,4-diene as a major product (35%). Also formed are 7-methoxy-2,3(8-cyanobenzo)bicyclo-[3.3.0]octa-2,7-diene (8%), 8-methoxy-10-cyano-1,2-benzocycloocta-1,3,5-triene (18%), and a dimer of the latter (7%), and 8-methylene-5-methoxy-2,3(10-cyanobenzo)bicyclo[2.2.1]heptene (35%). The structures of the latter adducts are assigned from spectroscopic data, including nuclear Overhauser effects. Possible mechani...

Nitrones and oxaziridines. X. Photorearrangement of some bicyclic oxaziridines

Abstract: Photochemical irradiation of cis-5-t-butyl-2,2-dimethyl-3-phenyl-6-oxa- 1-aza-bicyclo[3,1,0]hexane (4) afforded 5,5-dimethyl-4- phenylpyrrolidin-2-one (7) and 2,2-di-methyl-3-phenyl-1- pivaloylazetidine (8), which was further hydrolysed by acid to 2-t- butyl-6,6-dimethyl-5-phenyl-5,6-dihydro-4H-1,3-oxazine (9). Photochemical irradiation of 2,2,4,4-tetramethyl-6-oxa-1- azabicyclo[3,1,0]hexane (5) gave only 2,2,4,4-tetramethyl-azetidine-1- carbaldehyde (12).

Bicyclic compounds and processes for making and using same

Abstract: Bicyclic compounds containing four to six alkyl groups and having the formula: WHEREIN THE DASHED LINE IS A SINGLE OR DOUBLE CARBON-TO-CARBON BOND; X is a carbonyl oxygen or two hydrogen atoms; Y is -CHR9or -CHR10-CHR11-; R1, R2, R3 and R4 are the same or different alkyl; R7, R8, R9, R10 and R11 are hydrogen or the same or different alkyl, R7 or R8 being alkyl when R9 is alkyl; R5 is not present and R6 is hydrogen when the dashed line is a double bond; and R5 and R6 are hydrogen, or taken together, form an oxirane ring when the dashed line is a single bond, together with methods of preparation for such bicyclic compounds, perfume compositions containing the compounds, and methods for altering aromas utilizing such compounds.

Synthesis and crystal structure of bicyclo[1,1,0]butan-1-yl-lithium- tetramethylethylenediamine

Abstract: The crystal structure of bicyclo[1,1,0] butan-1-yl-lithium-tetramethylethylenediamine(TMEDA) was determined and found to consist of dimeric units consisting of two lithium atoms bridged by two bicyclobutyl groups and a TMEDA molecule co-ordinated to each lithium atom.