The Chemistry of Laurenene. XII. The Structure of a Minor Product From the Formic Acid Induced Rearrangement of Lauren-1-ene

1990 ◽  
Vol 43 (6) ◽  
pp. 1061 ◽  
Author(s):  
AR Hayman ◽  
NB Perry ◽  
RT Weavers
Keyword(s):  
Formic Acid ◽  
Membered Ring ◽  
Carbon Skeleton ◽  
A Minor

Rearrangement of lauren-1-ene (1) with formic acid gives a trisubstituted alkene (4) in addition to the previously characterized tetrasubstituted alkene (3). The structure was determined by n.m.r . Studies on (4) and the derived diol (5). Alkene (4) contains a new tetracyclic carbon skeleton which comprises one six- membered ring and three five- membered rings.

Gastradefurphenol, a minor 9,9′-neolignan with a new carbon skeleton substituted by two p -hydroxybenzyls from an aqueous extract of “tian ma”

2017 ◽  
Vol 28 (6) ◽  
pp. 1185-1189 ◽  
Author(s):  
Xue Zhou ◽  
Qing-Lan Guo ◽  
Cheng-Gen Zhu ◽  
Cheng-Bo Xu ◽  
Ya-Nan Wang ◽  
...  
Keyword(s):  
Aqueous Extract ◽  
Carbon Skeleton ◽  
A Minor

The Chemistry of Laurenene. X. A New Carbon Skeleton by Rearrangement of Laurenan-2-β-ol

1990 ◽  
Vol 43 (1) ◽  
pp. 141 ◽  
Author(s):  
PJ Eaton ◽  
AR Hayman ◽  
RT Weavers
Keyword(s):  
Trifluoroacetic Acid ◽  
Major Product ◽  
Ring System ◽  
Membered Ring ◽  
Carbon Skeleton ◽  
Deuterium Labelling ◽  
Carbon Ring ◽  
Starting Point ◽  
Remote Part

Treatment of laurenan-2β-ol (2) with trifluoroacetic acid in dichloromethane at 0° gives as the major product the rearranged alkene (4). This compound has a new carbon-ring system containing three five-membered rings and one six- membered ring. The structure of (4) has been determined by a range of n.m.r. techniques applied to (4) and selected derivatives. Deuterium- labelling experiments have established that the rearrangement proceeds to a remote part of the molecule and then returns to its starting point.

Proton and carbon-13 nuclear magnetic resonance studies of the conformational properties of seven-membered heterocycles. 2,4-Benzodithiepin and its derivatives

1979 ◽  
Vol 57 (24) ◽  
pp. 3221-3229 ◽  
Author(s):  
F. Sauriol-Lord ◽  
M. St-Jacques
Keyword(s):  
Membered Ring ◽  
Steric Effects ◽  
Axial Position ◽  
Minor Amount ◽  
Equatorial Position ◽  
Stable Conformation ◽  
Magnetic Resonance Studies ◽  
Conformational Effect ◽  
Conformational Properties ◽  
A Minor

The conformational properties of 1,3-dithia-5,6-benzocycloheptene (7) (2,4-benzodithiepin), three 2,2-dialkyl derivatives, and two monosubstituted derivatives (2-CH3 and 2-OCH3) have been investigated by 1H and 13C dnmr methods. It is reported that the most stable conformation of the seven-membered ring is a chair on which, in the case of the monosubstituted compounds, the 2-CH3 group adopts an equatorial position while the 2-OCH3 group takes the axial position. Only for the 2,2-pentamethylene derivative (10) was a minor amount (13%) of TB form detected. These results are markedly different from those found previously for the oxygen analogs and the conformational effect of the cyclic heteroatoms will be discussed in terms of the anomeric and steric effects.

scholarly journals Crystal structure of (1R,3S,8R,11R)-11-acetyl-3,7,7-trimethyl-10-oxatricyclo[6.4.0.01,3]dodecan-9-one

2015 ◽  
Vol 71 (12) ◽  
pp. o1013-o1014
Author(s):  
Abdoullah Bismoussa ◽  
My Youssef Ait Itto ◽  
Jean-Claude Daran ◽  
Abdelwahed Auhmani ◽  
Aziz Auhmani
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Title Compound ◽  
Chair Conformation ◽  
Membered Ring ◽  
Boat Conformation ◽  
Two Dimensional ◽  
Compound C ◽  
Dimensional Network ◽  
A Minor

The title compound, C16H24O3, is built up from three fused rings, a six-membered, a seven-membered and a three-membered ring. The absolute configuration of the title compound was determined as (1R,3S,8R,11R) based on the synthetic pathway. The six-membered ring has an half-chair conformation whereas the seven-membered ring displays a boat conformation. In the cyrstal, C—H...O hydrogen bonds build up a two-dimensional network parallel to (0 0 1). The crystal studied was an inversion twin with a minor twin component of 34%.

Observation of 13C rearrangement in [13C2]biphenylene formed from benzyne on pyrolysis of [1,6-13C2]phthalic anhydride and [2a,3-13C2]benzocyclobutenedione

1984 ◽  
Vol 37 (8) ◽  
pp. 1643 ◽  
Author(s):  
M Barry ◽  
RFC Brown ◽  
FW Eastwood ◽  
DA Gunawardana ◽  
C Vogel
Keyword(s):  
Mass Spectrometry ◽  
Sulfur Dioxide ◽  
Isotopic Composition ◽  
Gas Phase ◽  
Phthalic Anhydride ◽  
Carbon Skeleton ◽  
Hydrogen Shift ◽  
Thermal Elimination ◽  
A Minor

Examination of [13C2]biphenylene formed by gas phase pyrolysis of doubly labelled benzyne precursors shows that the principal pyrolytic process leads to overall 1,2→1,3 rearrangement of the C6H4 carbon skeleton either in an intermediate C7H4O before decarbonylation or in benzyne itself. A minor process involves an apparent 1,3-hydrogen shift. [1,2-13C2]Ethyne-1,2-diylbistrimethylsilane was acylated with 3-(2,5-dihydro-1,1-dioxothien- 2-yl)propanoyl chloride and the resulting ketone was desilylated to yield 5-(2,5-dihydro-1,l-dioxo-thien-2-yl)[1,2-13C2]pent-1-yn-3-one. Thermal elimination of sulfur dioxide and cyclization followed by dehydrogenation yielded [7,7a-13C2]-2,3-dihydro-1H-inden-1-one which was oxidized and dehydrated to give [3a,4-13C2]isobenzofuran-1,3-dione. This doubly labelled phthalic anhydride was diluted to approximately 5% 13C2 and the resulting material was converted via benzenediazonium- 2-carboxylate into biphenylene at 84�, and pyrolysed at 830� to yield biphenylene, and a sample diluted to 7.5% was converted into [2a,3-13C2]benzocyclobutenedione which was pyrolysed at 650�, 750� and 830� to yield further samples of biphenylene. The biphenylene samples were examined by mass spectrometry at 20 eV to determine their isotopic composition and by 13C n.m.r. spectroscopy to determine the distribution of labelling.

Synthesis and conformations of α-aminoadipyl- and glycyl-α-aminoadipylthiazepine sulfoxides

1981 ◽  
Vol 59 (2) ◽  
pp. 406-421 ◽  
Author(s):  
Saul Wolfe ◽  
Raymond John Bowers ◽  
Syed Khaqan Hasan ◽  
Peter Michael Kazmaier
Keyword(s):  
Hydrogen Bond ◽  
Carbon Atom ◽  
Formic Acid ◽  
Chair Conformation ◽  
Membered Ring ◽  
Amide Proton ◽  
Penicillin Biosynthesis ◽  
Boat Conformation ◽  
Internal Hydrogen Bond ◽  
Twist Boat

The title compounds, having the R-absolute configurations at sulfur, and labelled with 14C at carbons 5, 6, and 7 of the seven-membered ring, have been synthesized by condensation of isotopically labelled 3D-benzhydryloxycarbonyl-6L-amino-2,2-dimethyl-5-oxoperhydro-1,4-thiazepine with N-Boc- and α-benzhydryl-protected L-α-aminoadipic acid and glycyl-L-α-aminoadipic acid, followed by oxidation with m-chloroperoxybenzoic acid and complete deprotection with formic acid. The conformations of the sulfoxides, and related thiazepines and thiazepine sulfoxides, have been examined by 1Hmr spectroscopy. All thiazepines, and the two title sulfoxides, appear to exist in a twist boat conformation. Most other sulfoxides exist in a chair conformation, which is stabilized by an internal hydrogen bond between the sulfinyl oxygen and the amide proton at C6; when this hydrogen bond is not present, both chair and twist boat conformations may be observable. The title compounds are of interest as possible intermediates in penicillin biosynthesis from glycyl-δ-(L-α-aminoadipyl)-L-cysteinyl-D-valine (GACV) or ACV, according to a new theory, which deals, in particular, with the stereochemical course of the biosynthesis at the beta (β) carbon atom of valine.

Diterpene Imines. The Preparation of 2-Azalauren-1-ene and the Facile Autoxidation of 6-Azadihydrorimuene

1990 ◽  
Vol 43 (4) ◽  
pp. 719 ◽  
Author(s):  
AR Hayman ◽  
LR Hanton ◽  
RT Weavers
Keyword(s):  
Formic Acid ◽  
Membered Ring ◽  
Keto Acid ◽  
X Ray ◽  
Model Studies ◽  
Crystallographic Study

2-Azalauren-1-ene (2) has been synthesized from keto acid (5), but attempts to generate its C15 epimer (19) have produced only (2). Model studies of imine production by treatment of a rimuene -derived keto acid (3) with iodosylbenzene /formic acid have produced a hydroxy imine (11), a conjugated imine (13), and a keto lactam (12) which has a ten-membered ring. An X-ray crystallographic study which proves the structure of (12) is described. Data in support of the intermediacy of imine (7) (6-azadihydrorimuene) in the production of (11), (12) and (13) have been obtained.

scholarly journals Crystal structures of 3,6-diallyltetracyclo[6.3.0.04,11.05,9]undeca-2,7-dione and 1,7-diallylpentacyclo[5.4.0.02,6. 03,10.05,9]undecane-8,11-dione: allylated caged compounds

2014 ◽  
Vol 70 (11) ◽  
pp. 410-414 ◽  
Author(s):  
Sambasivarao Kotha ◽  
Vital Seema ◽  
Deepak Deodhar ◽  
Mobin Shaikh
Keyword(s):  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Membered Ring ◽  
Carbon Skeleton ◽  
Ring Closing Metathesis ◽  
Methylene Bridge ◽  
Caged Compounds

The title compounds, C17H20O2(1) and C17H18O2(2), are allylated caged compounds. In (1), the carbon atoms bearing the allyl groups are far apart [2.9417 (17) Å], hence the expected ring-closing metathesis (RCM) protocol failed to give a ring-closing product. When these carbon atoms are connected by a C—C bond as in (2), the distance between them is much smaller [1.611 (3) Å] and consequently the RCM process was successful. The caged carbon skeleton of (1) can be described as a fusion of four five-membered rings and one six-membered ring. All four five-membered rings exhibit envelope conformations. The structure of compound (2) consists of four five-membered rings, of which two are cyclopentanone rings bonded at the 2, 4 and 5 positions and linked at the 3-carbons by a methylene bridge. It also consists of one four-membered and two six-membered rings. All four five-membered rings adopt envelope conformations. In the crystal of (1), molecules are linkedviaC—H...O hydrogen bonds, forming sheets lying parallel to (010). In the crystal of (2), molecules are linkedviaC—H...O hydrogen bonds forming chains along [100].

THE FATE OF CARBON-19 IN THE COURSE OF OESTROGEN BIOSYNTHESIS FROM TESTOSTERONE-19-14C

1965 ◽  
Vol 48 (3) ◽  
pp. 383-391 ◽  
Author(s):  
Leonard R. Axelrod ◽  
Charles Mattijssen ◽  
P. Narasimha Rao ◽  
Joseph W. Goldzieher
Keyword(s):  
Chemical Analysis ◽  
Formic Acid ◽  
Major Product ◽  
Complete Inhibition ◽  
Acid Cycle ◽  
Tetrahydrofolic Acid ◽  
A Minor

ABSTRACT Testosterone-19-14C was incubated with various fractions obtained from placental homogenates. Radioactive formic acid was the major product, and under certain conditions radioactive formaldehyde was also formed. Chemical analysis of formic acid and formaldehyde did not correspond quantitatively with the amount of these radioactive compounds formed. Magnesium and tetrahydrofolic acid were found to inhibit the reaction partially and cyanide produced virtually complete inhibition. Radioactive CO2 was found to be a minor product of the overall reaction. Analysis of methionine, serine and various intermediates of the tetrahydrofolic acid cycle showed that this pathway is not involved in the immediate removal of carbon-19.

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