Showing papers on "Bicyclic molecule published in 1981"
169 citations
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TL;DR: In this article, linear, cyclic, and bicyclic ground-state structures for C4 were considered, and at the highest levels of theory, MP4SDQ/6-31∗/HF/6 -31∆, 3 with two π electrons was found to be the most stable.
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TL;DR: The use of acylnitroso compounds of the general formula RCONO as enophiles in the formation of carbon-nitrogen bonds is described in this paper, where both inter- and intramolecular ene reactions have been studied.
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TL;DR: In this paper, the electron-rich (4n + 2)π systems of planar tetrasulfur tetranitride with 12π electrons have been considered and rationalized.
Abstract: The molecular structures of monocyclic sulfur-nitrogen ring systems, such as S2N2, S3N, S4N and S5N, can be considered as examples of electron rich (4n + 2)π systems. The structures of S4N4, S4N, P4S4, As4S4 and the bicyclic structures S4N, S4N as well as S5N6 can be rationalized on the basis of a planar tetrasulfur tetranitride with 12π electrons.
53 citations
Patent•
21 Oct 1981TL;DR: New bicyclic compounds, including salts thereof, of the formula: as discussed by the authors have inhibitory activities of angiotensin converting enzyme and bradykinin decomposing enzyme, and are useful as antihypertensive agents.
Abstract: New bicyclic compounds, inclusive of salts thereof, of the formula:
wherein R 1 and R 2 , which may be the same or different, each represent hydrogen, halogen, lower alkyl, hydroxyl, lower alkyloxy or aralkyloxy, or R' and R 2 jointly represent lower alkylenedioxy: R 3 and R 4 each represent hydrogen or lower alkyl; R 3 represents hydrogen,lower alkyl or -CH 2 SR 7 (R 7 represents hydrogen or acyl): R 6 represents hydrogen or acyl, or R 6 and R 7 jointly represent a single bond; X represents -CH 2 -, -O- orN-R 5 (R 8 represents hydrogen, acyl or lower alkyl); I and n represents 2, 3 or 4, have inhibitory activities of angiotensin converting enzyme and bradykinin decomposing enzyme, and are useful as antihypertensive agents.
TL;DR: A preliminary study of the properties of nine cyanoaryl esters of various 40-alkylbicyclo [2.2] octane-carboxylic acids has been conducted in this paper.
Abstract: A preliminary study of the properties of nine cyanoaryl esters of various 40-alkylbicyclo [2.2.2] octane-carboxylic acids has been extended and results are now presented for a wider range of 4-cyanophenyl, 2-cyano-6-naphthyl, and 4-cyano-4-biphenyl 4-alkylbicyclo [2.2.2]octane-1-carboxylates.
TL;DR: The bicyclic system of bicyclomycin has been constructed by oxidative cyclization of 6 using phenylselenyl chloride as discussed by the authors, which is the same method as the one described in this paper.
TL;DR: In this paper, the dilithio derivative of 3-methoxybenzanilide with the bicyclic ketoaldehyde 12 leads to a convergent and 100% regiospecific synthesis of (±)-decarbomethoxyaklavinone.
TL;DR: In this paper, a new method for the synthesis of some fused bicyclic β-lactams based on the completion of the molecular backbone by a free-radical CC bond forming reaction is described.
TL;DR: In this paper, the assignment of the configuration of 7-Aminobicyclo[410]heptane derivatives with a morpholino-, a pyrrolidino-or a piperidinomoiety in 7-position was investigated.
Abstract: In Bicyclo[410]heptanderivaten 1a–c mit einem Morpholino-, Pyrrolidino- oder Piperidinorest in 7-Position last sich 1H-NMR-spektroskopisch die exo-endo-Konfiguration zuordnen Die Verbindungen 1a–c sind auf einfache Weise aus Enaminosulfonium-Salzen 9 zuganglich Dabei werden endo-Amino-Derivate 3a–c erhalten Der sterische Verlauf der Substitution an Bicyclo[410]heptan-7-on-aminalen wird untersucht
The Assignment of the Configuration of 7-Aminobicyclo[410]heptanes1)
In bicyclo[410]heptane derivatives 1a–c with a morpholino-, a pyrrolidino-or a piperidinomoiety in 7-position the assignment to exo- endo-configuration is possible by 1H-NMR spectroscopy The compounds 1a–c are easily obtained from enaminosulfonium salts 9 In this case endo-amino derivatives 3a–c are formed The steric course of the substitution on bycyclo[410]heptan-7-one aminals is investigated
TL;DR: In this paper, the bicyclic amidines and amidinium salts are partially hydrolyzed by KOH/H2O to lactames, and two possible isomeric lactames are discussed.
Abstract: Amidines as Intermediates in Transamidation Reactions
By loss of water in the presence of p-toluenesulfonic acid/xylole N-aminoalkyllactames form bicyclic amidines. The corresponding N-alkylaminoalkyl-lactames' react to bicyclic amidinium salts or to transamidated products, ring-enlarged by the N-alkylamino residue, respectively (s. Scheme 1).
The bicyclic amidines and amidinium salts are partially hydrolyzed by KOH/H2O to lactames (s. Scheme 2). Which of the two possible isomeric lactames are formed is discussed.
TL;DR: In the presence of acid, 2-alkyl-2-vinylcyclobutanones rearrange mainly by a 1,2-acyl migration to give cyclopentenones while 2vinyl cyclobutanone lacking 2-kyl substituents undergo a 1 3-acyls migration to produce cyclohexenones; the former rearrangement can be used to produce angularly substituted fused bicyclic systems.
TL;DR: For the SH2 process R·+ PhSeSePh → PhSeR + PhSe·, k=ca. 5 × 107 mol 1 s−1 at 80 °C in benzene when R is primary alkyl.
Abstract: For the SH2 process R·+ PhSeSePh → PhSeR + PhSe·, k=ca. 5 × 107 mol–1 s–1 at 80 °C in benzene when R is primary alkyl; with 1-adamantyl radicals this SH2 displacement affords a route to 1-adamantyl phenyl selenide which, on oxidation and pyrolysis of the resultant selenoxide, gives adamantan-1-ol; in contrast the selenoxide from bicyclo[3.3.1]nonan-1-yl phenyl selenide decomposes via bicyclo[3.3.1]non-l-ene.
TL;DR: In this article, enyes are co-cycled with alkynes and stoicheiometric amounts of dicarbonyl(cyclopentadienyl) cobalt to furnish bicyclic-diene cobalt complexes and their free ligands regiospecifically, the former being convertible into the latter by oxidative demetallation.
Abstract: α,ω-Enynes are co-cyclised with alkynes and stoicheiometric amounts of dicarbonyl(cyclopentadienyl) cobalt to furnish bicyclic-diene cobalt complexes and their free ligands regiospecifically, the former being convertible into the latter by oxidative demetallation.
TL;DR: In this paper, a reaction mechanism which involves formation of an oxetan ring was proposed for 1-methylurea and 1-dimethylurea reactions with diacetyl to form 4,4′-methylenebis.
Abstract: Urea and 1-methylurea react with both aromatic and aliphatic acyloins to form 4-imidazolin-2-ones but, under the same reaction conditions, 1,3-dimethylurea does not react. However, 1,3-dimethylurea does react with diacetyl to form 4,4′-methylenebis-(1,3,5-trimethyl-4-imidazolin-2-one)(4a). The carbon atom lost in the formation of (4a) is eliminated as formaldehyde. We propose a reaction mechanism which involves formation of an oxetan ring. With 1-methylurea and urea the main products of reaction with diacetyl are the bicyclic compounds (6a–c). However, it is possible that reactions analogous to that leading to the formation of (4a) also occur and that the carbonium ion (5c) is the coloured species formed in the well known colorimetric procedure for the determination of urea concentrations in biological liquids.
TL;DR: In this article, the tributyltin hydride-azobisisobisobutyronitrile induced cyclization of N-choloromethyl-, N-phenylselenomethsyl-, and Nphenylthiomethymyl-4-allyloxy-2-azetidinones to 9-oxo-6-oxa-1-azabicyclo[5.2]nonane is described.
TL;DR: In this paper, it was shown that ammonium ylides (22) and dihydrothiopyridinium (29) undergo a thermal [3,2] rearrangement, but not a [1,2]-pathway, leading to a single diastereoisomer.
Abstract: The allylic ammonium ylides (22) and (47) and sulphonium ylide (53) are isolable, usually as crystalline solids, because their [3,2] sigmatropic rearrangements are inhibited by the strain associated with the bicyclic transition state of a concerted reaction mechanism. The tetrahydropyridinium (22) and dihydrothiopyranium (29) ylides undergo a thermal [3,2] rearrangement, but, the pyrrolinium ylide (47) rearranges by a [1,2], rather than a [3,2], sigmatropic pathway. The dihydrothiophenium ylide (53) does not undergo either a [1,2] or [3,2] sigmatropic rearrangement but instead reacts in a bimolecular fashion to give eventually buta-1,3-diene, 2,5-dihydrothiophen, and the heterocycle (55). The [3,2] rearrangements of the ylides (22) and (29) follow predominantly an endo-pathway leading to a single diastereoisomer of the products (23) and (31); this strong endo preference is not shown by analogous acyclic ammonium ylides.
TL;DR: In this paper, a Mannich-directed 2-azonia-[3,3]-sigmatropic rearrangement was used for the preparation of 9a-aryl hydrolilolidines.
TL;DR: Vinylmercurials react with Li2PdCl4 and monocyclic olefins to produce π-allylpalladium compounds or 1,4-dienes if triethylamine is added as discussed by the authors.