Showing papers on "Bicyclic molecule published in 1976"

Orbital interaction in three systems

Abstract: The three-system interaction theory previously developed for giving an orbital interaction rationale for the role of the catalysts is shown to cover various organic chemical reactions of both ground- and excited-state molecules. The mechanisms of thermal and photochemical multicycloadditions of layered compounds with olefins and the effects of protic acids and of sub- stituents on symmetry-disfavored reactions are clarified, especially in connection with orbital phase relation. Bicyclic com- pounds with w bonds on each bridge are classified into three groups, i.e., electron-delocalizing, semielectron-delocalizing, and electron-localizing systems. The bridge flipping in such bicyclic compounds is also discussed.

cis- and trans-Azetidin-2-ones from nitrones and copper acetylide

Abstract: The reaction between nitrones and copper acetylides in pyridine yields cis- and trans-azetidinones Deuteriation and isomerisation studies indicate that the trans-compound is produced from the initially formed cis-isomer and that the amount of cis-product may be increased by using non-basic solvents Lactams with aromatic, aliphatic, and ethoxycarbonyl substituents may be obtained from appropriately substituted acetylenes, and the use of cyclic nitrones leads to bicyclic compounds

Syntheses of heterocylic fused thiazole acetic acids. 2.

Abstract: A number of tricyclic and bicyclic fused thiazole-2-acetic acid derivatives were prepared and the chemistry and biological properties of these compounds are discussed. Many of the esters exhibited antitubercular activity. The bicyclic thiazole-2-acetic acids had antidepressant activity. Interesting antimetastatic activity against Lewis lung tumor in mice was found with several compounds, in particular, the thiazolo[3,2-a]benzimidazole-2-acetic acid derivative XI.

13C N.M.R. spectra of pyrrolidines and piperidines. Structure of the Perhydroisoindol-5-ones and 3-Azabicyclo[3,3,1]nonan-6-imines formed by the cyanoisopropyl radical induced cyclization of N-Methyl-N,N-bis(2-alkylallyl)amines

Abstract: The 13C N.M.R. chemical shifts of a series of substituted pyrrolidines and piperidines are documented and substituent parameters determined. These data have been used to assign structures to the polymers and bicyclic products formed in the cyanoisopropyl radical induced cyclizations of a series of N-methyl-N,N-bis(2-a1kylallyl)amines. The formation of perhydroisoindol-5-one and/or 3-azabi- cyclo[3,3,1]nonan-6-imine depends upon the bulk of the 2-alkyl substituent and correlates with the presence of pyrrolidine and/or piperidine units in the polymer structure.

Carbon-13 chemical shifts of bicyclo[3.2.1]octane and bicyclo[2.2.1]heptane derivatives

Abstract: 13C chemical shifts of more than fifty bicyclo[3.2.1]octane and bicyclo[2.2.1]heptane derivatives (hydrocarbons, alcohols, ketones and esters) have been determined. The usefulness of ethyl derivatives for the assignment of close 13C chemical shifts in bicyclic methyl derivatives is shown both for the bicyclo[3.2.1]octane and bicyclo[2.2.1]heptane series. Comparison of substituent effects on α-, β-, γ- and δ-carbons in both series of compounds shows remarkable differences in steric interactions. In contrast to the rigid bicyclo[2.2.1]heptane system, both chair and boat conformations can be predominant in the bicyclo[3.2.1]octane series with the conformationally flexible 6-membered ring.

The electronic structure of the quinonoid bicyclic heterocycles isoindole, benzo[c]furan, benzo[c]thiophen, and 2H-indene

Abstract: Non-empirical calculations for the electronic ground and lowest triplet excited states for isoindole, benzo[c]furan, benzo[c]thiophen, and N-methylisoindole show that some resonance energy (RE) is present in these systems, and that their instability can be attributed to a combination of a low RE and a low-lying excited state. The photoelectron spectra are reported for the last three compounds, and the ionisation potentials are assigned in the light of the calculations. Detailed analysis of the 1H n.m.r. spectra of these compounds supports the conclusions of low aromatic character.

Polyoxamacrobicyclic diamines. Structure of 4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane and of its bisborohydride, C18H36N2O6·2BH3

Abstract: The crystal structures of C18H36N2O6·2BH3(I) and C18H36N2O6(II) have been determined from diffractometer data by direct methods and refined by least-squares to R 0.054 [(I), 877 independent observed reflections] and 0.054 [(II), 1 774 independent observed reflections] respectively. (I) Exists in the exo-exo-conformation, while (II), which forms remarkably stable complexes with various metal cations, possesses the endo-endo conformation (i.e., the lone pairs of the nitrogen atoms are both inside the molecular cavity). The values of the nonbonding N ⋯ N distance in both (I) and (II) are very close [6.76 (I), and 6.87 A(II)]. The conformations of (I) and (II) can be related to those of bicyclic [8.8.8]hexacosanes corresponding to paths on the diamond lattice. Crystals of both compounds are monoclinic: (I), space group C2/c with a= 18.849(6), b= 9.610(4). c= 13.291(5)A, β= 102.25(6)°. Z= 4; (II), space group P21/c, a= 16.832(7), b= 7.450(3), c= 16.921 (8)A, β= 95.77(5)°, Z= 4.

1,3-Dimethyl-2,9-dioxabicyclo[3.3.1]nonane; A host-specific substance in Norway spruce under attack by Trypodendron lineatum Oliv.

Abstract: The isolation and identification of the title compound was carried out in the following manner: Twenty kilograms of the bark from T. lineatum-infested Norway spruce were collected and put directly into pentane after the entrance holes of boring beetles were thoroughly cut out. After standing for 72 h at room temperature the solvent was removed through a 1-m Vigreux column and the residue was distilled under N z at 15Torr. All volatiles up to 100 ~ were collected, yielding 5.2 g of mainly monoterpene hydrocarbons, oxidized monoterpenes, and sesquiterpene hydrocarbons. GLC analysis was carried out on a Carto-Erba 2100, using a 50-m stainless steel capillary column with Marlophen 87 under program from 50 to I40 ~ at a rate of 3 ~ mass spectra were obtained from a Varian MAT 111 GCMS coupling system. A trace substance (0.2Zo) eluting between 7-terpinene and terpinolene furnished a mass spectrum which strongly resembled the known 1-methyl-6,8dioxabicyclo[3.3.1]octanes [1, 2]: 43 (100), 54 (11), 55 (12), 58 (22), 67 (11), 68 (16), 71 (26), 81 (12), 87 (40), 114 (28), 156 (6, P). Preparative GLC on a Carlo-Erba 2400 with a stainless steel column (8 m, 8 mm i.D., 10% PPG on Chromosorb G AW-DMCS 60-80 mesh) yielded 0.2 mg of the substance, the IH-NMR spectrum (Bruker WH 270, 15,000 scans) of which showed two characteristic signals at b 4.09 (1 H) and 4.21 (1 H), suggesting a bicyclic ketal structure together with the molecular formula C9H1602, obtained by high-resolution mass spectrometry (Varian MAT SM 1). None of the probable 6,8-dioxabicyclo[3.2.1]octane structures which were prepared for comparison were completely in accord with all data of the natural compound. But 1,3-dimethyl-2,9-dioxabicyclo[3.3.1]nouane, a ketal belonging to a bicyclic system recently found in tobacco flavor [3], was identical in all respects with the natural compound. The substance was prepared in low yield by Diels-Alder reaction of 3-buten-2-one and 4-penten-2-ol followed by cyclization. Results of our investigations concerning the exact stereochemistry will be reported later. As the new compound is permanently and exclusively present in Norway spruce attacked by I". lineatum it is now l~ioassayed to clarify whether it serves as a primary attractant beside other chemical messengers such as 3hydroxy-3-methylbutanone [4, 5] and c~-pinene/ethanol [6].

[LM(CO)3,4X] complexes of manganese(I) and rhenium(I) with phosphino- and thiophosphinatopyrazole ligands

Abstract: A series of complexes [LM(CO)3X] R2pz = pyrazolyl, or 3,5-dimethylpyrazolyl, x = 0–2; M = Mn, X = Cl; M = Re, X = Br) and were prepared by the reaction of the appropriate ligand with [M(CO)5X] or [M(CO)4X]2, and were characterized by elemental analysis, solution molecular weight, and infrared, mass, and nmr spectroscopic data. The products are formed via tetracarbonyl intermediates, of which the phosphorus bonded derivative was isolated and characterized. The tricarbonyl complexes [LM(CO)3X] and adopt a cis-octahedral configuration, in which the ligands form four-, five-, or six-membered chelate structures, via (i) the P atom and the 2-N site of the pyrazolyl moiety, with , (ii) the sulphur and 2-N atoms, with , (iii) the 2-N atoms of two pyrazolyl rings, with and (iv) the 2-N atoms of three pyrazolyl rings, resulting in a bicyclic system, with P(R2pz)3.The reactions of [CH3Re(CO)5] with require forcing conditions, resulting in the simultaneous elimination of carbon monoxide and methane, and yielding a va...

Synthesis and central nervous system depressant activity of some bicyclic amides.

Abstract: A series of aryl bicyclic analogs of succinimide and glutarimide was prepared and evaluated for CNS depressant activity. The 8a-aryl-3,4,6,7,8,8a-hexahydro-2H-pyrrolo[2,1-beta][1,3]oxazin-6-ones possessed the best overall spectrum of activity relative to the standard agents glutethimide and phenobarbital.

Über cyclische und bicyclische Hydrazinbis (phosphine)

Abstract: Durch nucleophile Substitutionsreaktionen an 3,6-Dichlor-1,2,4,5-tetramethyl-perhydro-1,2,4,5,3,6-tetrazadiphosphorin (1) wurden neue 3,6-Derivate dargestellt und der PIII-Phosphor mit Schwefel und Selen zu Pv oxidiert. AlCl3 reagiert mit 1 zu einem „Addukt”, das als Tetrachloroaluminat eines neuen cyclischen Kations mit P der Koordinationszahl 2 aufgefast werden kann. Reaktionen von 1 mit Heptamethyldisilazan, Hexamethyldisilthian oder H2O fuhren zu den bicyclischen Verbindungen 24–26, wahrend Hydrazin und Methylhydrazin die Hydrazinophosphine 20 und 18 mit Bicyclo [2,2,2]octan-Struktur liefern. Die spektroskopischen Daten der neuen Verbindungen werden diskutiert. New Cyclic and Bicyclic Hydrazinebis(phosphines) Nucleophilic substitutions at 3,6-dichloro-1,2,4,5-tetramethyl-perhydro- 1,2,4,5,3,6-tetrazadiphosphorine (1) led to new 3,6-derivatives. The III phosphorus was oxidized to Pv by sulfur and selenium. AlCl3 reacts with 1 to yield an „adduct” which can be regarded as a tetrachloroaluminate of a new cyclic cation with dicoordinate phosphorus. Reactions of 1 with heptamethyldisilazane, hexamethyldisilthiane or H2O lead to the bicyclic compounds 24–26 while hydrazine and methylhydrazine yield the hydrazinophosphines 20 and 18 with bicyclo[2,2,2]octane structure The spectroscopic data of the new compounds are discussed.

Eine Synthese von Bicyclo[10.3.0]pentadec‐1(12)‐en‐13‐on und seinem 14‐Methylderivat

Abstract: A Synthesis of Bicyclo[10.3.0]pentadec-1(12)-en-13-one and its 14-Methyl Derivative. A new route to bicyclo[10.3.0]pentadec-1(12)-en-13-one (2) and its 14-methyl derivative 3 – useful intermediates in the synthesis of cyclopentadecanone (4 = exaltone®) and rac-muscone (5) – is described.

Vier- und fünfgliedrige Phosphorheterocyclen, XIII. Trigonal-bipyramidaler Phosphor als Bicyclo[3.2.0]heptan-Brückenkopf in [1,3,2λ5]Diazaphospheto[2,1-b][1,3,4,2λ5]oxadiazaphosphol-6(5H)-onen

Abstract: Trichlordimethylphosphoran (1) reagiert mit 1-Acetylsemicarbaziden 6 zu den im Titel genannten Bicyclophosphoranen 7, in denen der Phosphor trigonal-bipyramidal umgeben ist und einen jeweils axial-aquatorial angeordneten Vier- und Funfring mit gemeinsamer aquatorialer Bindung zusammenschliest (meridionale Anordnung A). Die Spannung im Diazaphosphetidinon-Ring fuhrt zu einer starken Verzerrung der Idealgeometrie entgegen dem sonst oft beobachteten Ubergang zur quadratischen Pyramide. 7a (R = CH3) kristallisiert monoklin in der Raumgruppe P21. Die Struktur wurde aus 1797 unabhangigen Diffraktometerdaten bestimmt und zu R = 0.040 verfeinert. Four- and Five-membered Phosphorus Heterocycles, Trigonal-Bipyramidal Phosphorus as Bicyclo[3.2.0]heptan-Bridge-head in [1,3,2λ5]Diazaphospheto[2,1-b][1,3,4,2λ5]oxadiazaphosphol-6(5H)-ones Trichlorodimethylphosphorane (1) reacts with the 1-acetylsemicarbazides 6 to give the title bicyclophosphoranes 7. Both the four- and five-membered rings span axial-equatorial sites at the trigonal-bipyramidally coordinated phosphorus, with the bond common to both rings taking up an equatorial position (meridional arrangement A). The strain in the diazaphosphetidinone ring gives rise to a considerable distortion of the ideal geometry opposite in direction to the frequently observed distortion towards a square pyramid. Crystals of 7a (R = CH3) are monoclinic, space group P21. the structure was elucidated from 1797 independent diffractometer data and refined to R = 0.040.

Reductive cyclization of nonconjugated acetylenic ketones to 2- methylenecyclopenanols

Abstract: Electroreduction of series of γ-ethynl ketones in dimethylformamide gave the cyclization products, 2-methylenecyclopentanols, as the sole product in excellent yeilds. furthermore, this electrochemical techniqe was applied to a new synthesis of bicyclic alcohols with an exocyclic double bond adjacent to a bridgehed hydroxy group.

A distorted trigonal-bipyramidal phosphorane with a diequatorial four-membered ring; X-ray crystal structure of 4-p-bromophenyl-2′,2′,3′,4′,4′-pentamethyl-3,3,6,6-tetrakistrifluoromethyl-2,7-dioxa-1-phospha(V)bicyclo[3,2,0]hept-4-ene-1-spiro-1′-phosph(V)etan

Abstract: hexafluoroacetone and 1-phenylethynylphosphetan gave a 2 : 1 adduct shown by X-ray structure analysis to be a five-co-ordinate phosphorane having distorted trigonal bipyramidal geometry with a diequatorial phosphetan ring.

Photochemische Reaktionen. 83. Mitteilung. Verbindungen der 3,4‐Dihydrojonon‐Reihe als Modelle zur Photochemie γ, δ‐ bzw. δ, ϵ‐ungesättigter Ketone und Aldehyde

Abstract: Compounds of the 3,4-dihydro-ionone series as models for the photochemistry of γ, δ- and δ,ϵ- unsaturated ketones and aldehydes. The photochemistry of γ, δ- and δ,ϵ-unsaturated carbonyl compounds of the dihydro-ionone series has been studied, with special attention to the investigation of oxetane formation versus hydrogen abstraction. UV.-irradiation of the dihydro-β-ionone compounds with structure A (1, 7, 14, 18, 24, 29) led to isomeric ethers with structures B (2, 8, 15, 19, 25, 30), C (3, 9, 16, 20, 26, 31) and D (4, 21, 27), isomeric bicyclic alcohols with structure E (5, 10, 17, 22, 28), and photoreduction products with structure F (6, 11, 12, 13). Photolysis of dihydro-γ-ionone (32) gave a complex mixture containing fragmentation product 35, hydrocarbon 36, β-ambrinol (34), oxetane 33, as well as dihydro-β-ionone (1) and three of its photoproducts (2, 3, 5). The dihydro-α-ionone compounds 37 and 40 gave mixtures of fragmentation products and the oxetanes 38 and 41. Irradiation of the side-chain homologues 42 and 45 yielded 43, which photo-cyclizes to 44. In contrast, 3, 4-dihydro-3′,4′-dehydro-β-ionone (46) gave merely the isomeric open-chain triene-ketone 47. The structures assigned to the ethers 2, 3, 33, 38 and to the alcohols 5, 10, 13 could be confirmed by chemical reactions and mutual interconversions. The structure of the ether 21 had to be established by X-ray analysis, details of which are described. A novel intramolecular hydrogen transfer is involved in formation of ethers B. The photocyclization A D probably proceeds by addition of the carbonyl-C atom to the double bond (A h), followed by methyl (1 2)-shift (h i). Process A h may also be involved in formation of compounds of type C and E.

Synthese von Spiro‐Verbindungen, IV: Totalsynthese von racem. Acorenon‐B und racem. 4‐Epiacorenon

Abstract: Schlusselreaktion der Synthese von 1b und c ist die saurekatalysierte Cyclisierung (HCO2H oder HCO2H/(CH2),CL2) geeignet substituierter Cyclopentanol-Derivate (5 bzw. 6), die bevorzugt unter Spiroanellierung erfolgt. 5 lieferte als Hauptprodukt das rel. -(4S,5R)-konfigurierte Spiroformiat 7 neben einer geringen Menge des bicyclischen Isomeren 11. Esterverseifung und Oxidation ergaben die Ketone 15 und 17, die uber ihre (2,2-Dimethyltrimethylen)acetale getrennt wurden. Durch katalytische Hydrierung von 15 wurden die epimeren Spiroketone 19a (1,4-cis; Hauptprodukt) und 19b (1,4-trans) erhalten. Aus 19a wurde Acorenon-B (1b) dargestellt. — Ausgehend vom Cyclopentanol-Derivat 6 wurde das Spiroformiat 9 mit bereits vollstandigem Substitutionsmuster erhalten. Die Folgereaktionen (91023a, b21a, b) ergaben Acorenon-B (1b) und 4-Epiacorenon (1c), die getrennt wurden. — 1c wurde auserdem aus 1d uber das α, β-Epoxyketon 26 durch Wharton-Reaktion dargestellt (Konfigurationsinversion am Spirochiralitatszentrum). Synthesis of Spiro Compounds, IV1) Total Synthesis of rac. Acorenone B and rac. 4-Epiacorenone Acid catalyzed cyclization (HCO2H or HCO2H/(CH2) 2CL2 of suitably substituted cyclopentanol derivatives (5 and 6) proceeds predominantly by spiroanellation and is the key step in the synthesis of 1b and c·5 affords the spiro formate 7 with rel.-(4S,5R) configuration as main product and the bicyclic isomer 11 as minor product. Ester cleavage and oxidation yield the ketone 15 and 17 which were separated as 2,2-dimethyltrimethylene acetals. The epimers 19a (1,4-cis; main product) and 19b (1,4-trans) were obtained by catalytic hydrogenation of 15a. Acorenone B(1b) was then prepared from 19a. —Starting from the cyclopentanol derivative 6 the spiro formate 9 was obtained; 9 has already the complete substitution pattern. The subsequent reactions (91023a, b21a,b) afford acorenone B (1b) and 4-epiacorenone (1c) which were separated. — 1c was also obtained from 1dvia the α,β-epoxyketone 26 and Wharton reaction (inversion of configuration at the spiro chirality center).

Certain 7-oxo-4-thio-2,6-diazabicyclo-3,2,0-hept-2-ene compounds

Abstract: An intermediate represented by following formula for synthesizing 3-hydroxy-3-cephem compounds. ##STR1## wherein A and B each is a hydrogen or amino substituent; R is a hydrogen or thiol substituent; Hal is a halogen; X is a hydroxy or carboxy protecting group; the broken line between A and R shows that when R and B are hydrogens, and A is a carboxylic acyl, the substituents can be combined to form an azetidinothiazoline bicyclic ring; and the enamine derivatives thereof.