The 1,2-Didehydronaphthalene to 1H-Indenylidenecarbene Rearrangement: Formation of 7-Methyl-1H-Indenylideneethenone and Its Rearrangement to Acenaphthylen-4-Ol in a Flash Vacuum Pyrolytic Reaction

1987 ◽  
Vol 40 (10) ◽  
pp. 1687 ◽  
Author(s):  
RFC Brown ◽  
KJ Coulston ◽  
BJ Dobney ◽  
FW Eastwood ◽  
GD Fallon
Keyword(s):  
Crystal Structure ◽  
Trifluoroacetic Anhydride ◽  
X Ray ◽  
Flash Vacuum Pyrolysis ◽  
Ethanoic Acid ◽  
Vacuum Pyrolysis ◽  
Pyrolytic Reaction ◽  
E And Z Isomers

7-Methyl-1 H- indenone was trapped as the cyclopentadiene adduct endo* 8-methyl-1,4,4a,9a tetrahydro-1,4-methano-9H-fluoren-9-one (11) which was converted into the E- and Z-isomers (15) and (16) of endo (8'-methyl-l',4',4a',9a'-tetrahydro-1',4'-methano-9'H-fluoren-9'-ylidene) ethanoic acid by addition of methoxyethyne, rearrangement and hydrolysis. Both acids yielded the anhydride (17) of the E-acid on treatment with trifluoroacetic anhydride. Flash vacuum pyrolysis of this anhydride at 650� gave acenaphthylen-4-ol. 7-Methyl-1 H- indenylideneethenone (7) is proposed as an intermediate in this reaction and the results are discussed in relation to the rearrangement described in the title. The X-ray crystal structure of methyl endo (E)-(8'-methyl-l',4',4a',9a'-tetrahydro-l',4'-methano-9'H-fluoren-9'-ylidene) ethanoate (13) is reported.

Unexpected Pyrolytic Behaviour of Substituted Benzo[c]thiopyran and Thieno[2,3-c]thiopyran S,S-dioxides

2014 ◽  
Vol 67 (9) ◽  
pp. 1288 ◽  
Author(s):  
R. Alan Aitken ◽  
Clémence Hauduc ◽  
M. Selim Hossain ◽  
Emily McHale ◽  
Adrian L. Schwan ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Ring Expansion ◽  
Hydrogen Atom Transfer ◽  
Membered Ring ◽  
X Ray ◽  
Flash Vacuum Pyrolysis ◽  
Vacuum Pyrolysis ◽  
Higher Temperature ◽  
Intramolecular Hydrogen ◽  
Carbonyl Products

Flash vacuum pyrolysis (FVP) of benzo[c]thiopyran S,S-dioxide (1) results in formation of indene and 2-vinylbenzaldehyde as previously described. A range of eight analogues with various substitution patterns are found to behave differently. In general, there is no extrusion of SO2 to give products analogous to indene, but unsaturated carbonyl products analogous to 2-vinylbenzaldehyde are formed in most cases by way of ring expansion to a 7-membered ring sultine, extrusion of SO, and intramolecular hydrogen atom transfer. Other processes observed include formation of anthracene via an isomeric 7-membered sultine with loss of SO, CO and methane or butane, and formation of 4-ethylidene-4,5-dihydrocyclobuta[b]thiophenes by way of SO loss, a radical rearrangement, and extrusion of acetone. The analogues with a halogen substituent at position 8 on the benzene ring require a higher temperature to react and give naphthalene resulting from net elimination of HX and SO2. The X-ray crystal structure of 1 is also reported.

The Pyrolytic Rearrangement of 1-Alkynoyl-3-methylpyrazoles: Synthesis of Pyrazolo[1,5-a]pyridin-5-ols and Related Compounds

1994 ◽  
Vol 47 (6) ◽  
pp. 991 ◽  
Author(s):  
RFC Brown ◽  
FW Eastwood ◽  
GD Fallon ◽  
SC Lee ◽  
RP Mcgeary
Keyword(s):  
Carbon Chain ◽  
Ring Structure ◽  
High Yield ◽  
Methyl Group ◽  
X Ray ◽  
X Ray Crystallography ◽  
Flash Vacuum Pyrolysis ◽  
Vacuum Pyrolysis ◽  
Fused Ring ◽  
Related Compounds

Flash vacuum pyrolysis of 1-(alkyn-2′-oyl)-3-methylpyrazoles at 650°/0.03 mm forms pyrazolo[1,5-a]pyridin-5-ols, often in high yield, which may bear substituents at C2, C3 or C7. In the absence of a 3-methyl group in the precursor, N-ethynylpyrazoles are formed in low yield. The formation of both types of product is interpreted as involving 3-(N-pyrazolyl)propadienones formed by N1 → N2 migration of the N-alkynoyl group with inversion of the three-carbon chain. The fused-ring structure of 2-methylpyrazolo[1,5-a]pyridin-5-ol (25) was established by X-ray crystallography of the O-benzoyl derivative (27).

scholarly journals Synthesis, Structure, and Cyclocondensation of the 4,4,4-Trifluoro-3,3-dihydroxy-2-methyl-1-(thien-2-yl)-1-butanone with Hydroxylamine and Hydrazine

2018 ◽  
Vol 2018 ◽  
pp. 1-8
Author(s):  
Alex F. C. Flores ◽  
Bruna P. Kuhn ◽  
Darlene C. Flores ◽  
Mariano A. Pereira ◽  
Tatiane L. Balliano ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Structural Analysis ◽  
Torsion Angle ◽  
Trifluoroacetic Anhydride ◽  
X Ray ◽  
Disorder Effect

The synthesis of 4,4,4-trifluoro-3,3-dihydroxy-2-methyl-1-(thien-2-yl)butan-1-one (3) through acylation of 1,1-dimethoxy-1-(thien-2-yl)propane (1) with trifluoroacetic anhydride and its reactions with hydroxylamine and hydrazine was investigated. X-ray structural analysis of new trifluoromethyl-substituted dielectrophile 3 revealed that this hydrate exists as a racemate with inter- and intramolecular O-H·O bonds. The crystal structure shows alignment along axis b of pair molecules with the same configuration of the O2-H·O1 bond. For 5(3)-trifluoromethyl-4-methyl-3(5)-(thien-2-yl)-1H-pyrazole (4), obtained via cyclocondensation of precursor 2 and hydrazine hydrochloride, X-ray structural analysis indicated that its rings are almost planar (torsion angle N2-C5-C6-C7–5.4°) and that S1 at the thienyl moiety is anti-periplanar to N2 (torsion angle N2-C5-C6-S1 176.01); no disorder effect was observed for the thienyl ring.

The geometry of 4-(1-ethoxyethylidene)-5-oxazolones and thiazolones: 1H and 13C studies and the crystal structure of 4-[(Z)-1-ethoxyethylidene]-2-phenyl-5-oxazolone

1985 ◽  
Vol 63 (12) ◽  
pp. 3618-3630 ◽  
Author(s):  
R. A. Bell ◽  
R. Faggiani ◽  
C. J. L. Lock ◽  
R. A. McLeod
Keyword(s):  
Crystal Structure ◽  
Chemical Shifts ◽  
Substituent Effects ◽  
Side Chain ◽  
Oxazole Ring ◽  
X Ray ◽  
X Ray Crystallography ◽  
Cell Dimensions ◽  
Ring Nitrogen ◽  
E And Z Isomers

A series of E and Z isomers of substituted 4-(1-ethoxyethylidene)-5-oxazolones and thiazolones have been prepared and their 1H and 13C spectra recorded. The vinylic methyl 1H chemical shifts showed minimal differences between E and Z isomers whereas the vinylic OCH21H signals differed by 0.15–0.43 ppm, with the Z isomer being consistently the more deshielded. Both vinylic methyl and OCH2 groups showed different 13C resonances for each isomer, with the Z isomers being the more deshielded. The Z geometry was conclusively defined for one isomer of 4-(1-ethoxyethylidene)-2-phenyl-5-oxazolone, 5, by X-ray crystallography and this was sufficient to assign the geometry of the remaining pairs of E and Z isomers. Oxazolone 5 has the space group P21/n and cell dimensions a = 9.219(3), b = 19.899(5), c = 7.459(1) Å, β = 118.01(2)°, and has four formula units in the unit cell. Intensities were measured with use of MoKα radiation and a Nicolet P3 diffractometer. The crystal structure was determined by standard methods and refined to R1 = 0.0709, R2 = 0.0696 based on 1419 independent reflections. The molecule is essentially planar and most bond lengths and angles are normal. Exceptions are the very short C(olefin)—O(ether) bond (1.339(4) Å) and the large ether C—O—C angle (122.1(3)°) caused by extreme delocalization in the O(ether)CCCO(carbonyl) system. The planarity causes a number of strong intramolecular repulsive interactions, causing an exceptionally small external olefin angle, O(ether)CC(methyl), of 108.1(4)°. The ethoxyl side chain of 5 adopts a conformation in the solid state which places the methylene of the OCH2 group adjacent to the oxazole ring nitrogen. This conformation is proposed to persist in solution phases and is consistent with the observed 13C chemical shifts and known γ and δ substituent effects.

Synthesis of 1,8,8-Trimethyl-6,10-dioxaspiro[4.5]dec-2-ene-1-ethanol; X-Ray Crystallography of (1RS,2SR)-1,8,8-Trimethyl-1-(prop-2'-enyl)-6,10-dioxaspiro[4.5]dec-2-yl Benzoate

1994 ◽  
Vol 47 (4) ◽  
pp. 739 ◽  
Author(s):  
DJ Collins ◽  
GD Fallon ◽  
RP Mcgeary
Keyword(s):  
Oxidative Cleavage ◽  
Quantitative Yield ◽  
Borohydride Reduction ◽  
X Ray ◽  
X Ray Crystallography ◽  
Flash Vacuum Pyrolysis ◽  
Hydride Reduction ◽  
Tetrabutylammonium Fluoride ◽  
Vacuum Pyrolysis ◽  
Relative Stereochemistry

Reaction of 2-methyl-2-(prop-2′-enyl)cyclopentane-1,3-dione (2) with 2,2-dimethylpropane-1,3-diol gave 1,8,8-trimethyl-1-(prop-2′-enyl)-6,10-dioxaspiro[4.5]decan-2-one (3), hydride reduction of which afforded a 1:1 epimeric mixture of the corresponding alcohols (4a) and (4b). They were separated, and the derived benzoates (5a) and (5b) were each subjected to a three-step sequence of oxidative cleavage, borohydride reduction and silylation to give the pure epimers (8a) and (8b) of 1,8,8-trimethyl-1-(2′-t-butyldimethylsilyloxyethyl)-6,10-dioxaspiro[4.5]dec-2-yl benzoate. Flash vacuum pyrolysis of a mixture of these epimeric benzoates (8a,b) gave an almost quantitative yield of 1,8,8-trimethyl-1-(2′-t-butyldimethylsilyloxyethyl)-6,10-dioxaspiro[4.5]dec-2-ene (9a), treatment of which with tetrabutylammonium fluoride afforded the corresponding alcohol (9b). The relative stereochemistry of (1RS,2SR)-1,8,8-trimethyl-1-(prop-2′-enyl)-6,10-dioxaspiro [4.5]dec-2-yl benzoate (5b) was established by X-ray crystallography.

Synthesen und Kristallstrukturen von PPh4[RuCl4(NO)(NSCl)] und (PPh4)2[RuCl4(NS)]2·4C H2Cl2 / Syntheses and Crystal Structures of PPh4[RuCl4(NO)(NSCl)] and (PPh4)2[RuCl4(NS)]2·4C H2Cl2

1986 ◽  
Vol 41 (5) ◽  
pp. 560-566 ◽  
Author(s):  
Wolfgang Willing ◽  
Ulrich Müller ◽  
Udo Demant ◽  
Kurt Dehnicke
Keyword(s):  
Crystal Structure ◽  
Ir Spectra ◽  
Crystal Structures ◽  
Crystal Data ◽  
Acceptor Interaction ◽  
X Ray ◽  
Bond Lengths ◽  
Vacuum Pyrolysis ◽  
Structure Determinations ◽  
Donor Acceptor

Abstract By reaction of trithiazylchloride, (NSCl)3, with PPh4[RuCl4(NO)]2 in dichloromethane the thiazylchloridenitrosyl complex PPh4[RuCl4(NO)(NSCl)] is obtained; its vacuum pyrolysis at 200-220 °C yields the thionitrosyl com plex (PPh4)2[RuCl4(NS)]2 which crystallizes from CH2Cl2 solution with four molecules of CH2Cl2. Both com pounds were charaterized by their IR spectra and by X-ray crystal structure determinations. Crystal data: PPh4[RuCl4(NO)(NSCl)], mono­clinic, space group P 21/n, Z = 4, a = 982.6, b = 1700.0, c = 1772.3 pm , β = 104.79° (2548 observed reflexions, R = 0.046); (PPh4)2[RuCl4(NS)]2·4CH2Cl2, triclinic, P1̄ , Z = 1, a = 952.9, b = 1380.0, c = 1458.5 pm , α = 112.91, β = 106.67, γ = 92.61° (3760 observed reflexions, R = 0.053). In the [RuCl4(NO)(NSCl)]⊖ ion the nitrosyl and thiazyl chloride ligands occupy ex ­ positions; bond lengths indicate double bonds in the linear Ru=N=O group, while the NSCl molecule is attached by a donor-acceptor interaction Ru-N≡S̲-Cl , although with a rather short Ru-N bond of 198 pm (N≡S 144 pm, S-Cl 213 pm). The centrosymmetric [RuCl4(NS)]22⊖ ions have chloro bridges and NS ligands in axial positions; the nearly linear Ru=N=S group has bond lengths Ru=N 175 pm and N=S 147 pm.

Synthesis of 4-Aminocoumarin Derivatives with N-Substitutents Containing Hydroxy or Amino Groups

2013 ◽  
Vol 68 (9) ◽  
pp. 1031-1040 ◽  
Author(s):  
Ivo C. Ivanov ◽  
Violina T. Angelova ◽  
Nikolay Vassilev ◽  
Ioannis Tiritiris ◽  
Boyan Iliev
Keyword(s):  
Crystal Structure ◽  
Structure Analysis ◽  
Nmr Spectra ◽  
Amino Alcohols ◽  
Crystal Structure Analysis ◽  
Amino Groups ◽  
X Ray ◽  
Elemental Analyses ◽  
E And Z Isomers ◽  
Novel Products

Reactions of 4-hydroxycoumarin (1a) and 4-chlorocoumarin-3-carbaldehyde (1b) with amino alcohols or alkylene diamines led to the formation of the corresponding N-substituted 4-aminocoumarins 3, 5 and 6. However, 4-hydroxycoumarin-3-carbaldehyde (8) reacted with 2-aminoethanol and ethylenediamine to give N-substituted 3-(aminomethylene)-chromane-2,4-diones 9a, b. The structure and the E-configuration of compound 6 were proven by X-ray crystal structure analysis. Products 9a, b displayed signals of both E- and Z-isomers in their NMR spectra. All novel products have been characterized by means of spectral (IR, NMR, MS) data and elemental analyses

scholarly journals Synthesis, structure, and first reactions of a new class of thiacyclophanes

2017 ◽  
Vol 95 (3) ◽  
pp. 278-285 ◽  
Author(s):  
Arunachalam Kannan ◽  
Henning Hopf ◽  
Ina Dix ◽  
Peter G. Jones ◽  
Ludger Ernst
Keyword(s):  
Spectroscopic Data ◽  
Phase Transfer Catalysis ◽  
Phase Transfer ◽  
X Ray ◽  
Flash Vacuum Pyrolysis ◽  
New Class ◽  
Product Mixture ◽  
Vacuum Pyrolysis ◽  
Molecular Bridge ◽  
Meta Isomer

In our effort to prepare [m.n]cyclophanes carrying functional groups in their molecular bridges, the thiacyclophanes 14, 19, 20, and 21 have been prepared by simple routes from the pseudo-gem dibromide 10a and the corresponding bis-thiol 10b. The triply-bridged bis-thia-cyclophanes 14, and 19-21 were characterized by their spectroscopic data as well as by X-ray structural analyses. The meta-isomer 20 was oxidized to the bis-sulfone 23, which on flash vacuum pyrolysis (FVP) yielded a product mixture presumably containing the hydrocarbon 26 with a cleaved molecular bridge. Subjecting 23 to Ramberg-Bäcklund conditions (CCl4, NaOH, phase transfer catalysis) provided the chloride 24 in poor yield (9%), a [2.2]paracyclophane in which the new molecular bridge is fully conjugated.

Experiments Directed Towards the Synthesis of Anthracyclinones. XXXVI Asymmetric Dihydroxylations of Alkylidene Anthracyclinones

1999 ◽  
Vol 52 (8) ◽  
pp. 781 ◽  
Author(s):  
Richard C. Cambie ◽  
Russell B. Clark ◽  
Peter S. Rutledge ◽  
J. J. Rustenhoven
Keyword(s):  
Crystal Structure ◽  
Molecular Modelling ◽  
X Ray ◽  
E And Z Isomers

The methylidene tetracycle (2) has been synthesized in 11 steps from quinizarin (5) in an overall yield of 38% by using a highly ecient selective dihydroxylation step and an intramolecular ene cyclization. Also prepared with the selective dihydroxylation methodology were the silyloxy alkene (3) and the 6-demethoxy alkene (4). A mixture (1 : 2) of the (E)- and (Z)-isomers of the ethylidene compound (6) has been prepared by similar methods. The products resulting from the reactions of AD-mix-α and AD-mix-β on the alkenes (1)–(3) and (6) have been investigated and their stereochemistries assigned by using 1 H n.m.r. and NOESY experiments, and molecular modelling of acetonide derivatives. An X-ray crystal structure of the acetate (64) has confirmed the relative stereochemical assignments.

The Pyrolysis of Butatrienone Precursors: 3,4-Diazatricyclo[5.2.1.02,6]deca-3,8-diene-endo-cis-2,6-dicarboxylic anhydride and Its 5,5-Diphenyl Derivative

1990 ◽  
Vol 43 (3) ◽  
pp. 549 ◽  
Author(s):  
MR Anderson ◽  
RFC Brown ◽  
NR Browne ◽  
FW Eastwood ◽  
GD Fallon ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Infrared Spectroscopy ◽  
Matrix Isolation ◽  
Argon Matrix ◽  
Flash Vacuum Pyrolysis ◽  
Vacuum Pyrolysis

Flash vacuum pyrolysis of the title anhydride (4) gave a poor yield of butatrienone , detected by argon matrix isolation infrared spectroscopy. Similar pyrolysis of the 5,5-diphenyl derivative (8) failed to give diphenylbutatrienone ; the red product (16) is considered to have been formed by dimerization of an intermediate 2H-indenylidenemethanone (15). The crystal structure of (16) has been determined.

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