Hydroxyphosphorane intermediates in substitution reactions at phosphorus in acyclic phosphonofluoridates: evidence from nuclear magnetic resonance

1980 ◽  
Vol 102 (13) ◽  
pp. 4523-4525 ◽  
Author(s):  
Itshak Granoth ◽  
Yoffi Segall ◽  
Daniel Waysbort ◽  
Ezra Shirin ◽  
Haim Leader
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Substitution Reactions ◽  
Nuclear Magnetic

Nuclear magnetic resonance investigation of intermediates formed by the action of nucleophiles on substituted stilbenes

1969 ◽  
Vol 47 (13) ◽  
pp. 2331-2342 ◽  
Author(s):  
C. A. Fyfe
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Negative Charge ◽  
Trans Isomers ◽  
Substitution Reactions ◽  
Resonance Investigation ◽  
Nuclear Magnetic Resonance Spectra ◽  
Nuclear Magnetic Resonance Investigation ◽  
Magnetic Resonance Investigation ◽  
Nuclear Magnetic

A nuclear magnetic resonance investigation of the colored species formed by the action of bases on a series of α-cyano-4-nitro-4′-X-stilbenes characterizes these as the intermediate carbanions formed by the addition of base to the β-carbon atom of the double bond. The nuclear magnetic resonance spectra reveal that, whereas there is free rotation about the β-phenyl—Cβ and Cβ—Cα bonds in these adducts, there is restricted rotation around the α-phenyl—Cα bond due to very substantial delocalization of the negative charge into this ring. It has been verified that the same intermediates are formed by the action of bases on either the cis or trans isomers of α-cyano-4-nitrostilbene. The relation of these observations to the theory of alkene nucleophilic substitution reactions is discussed.

Pyrazolo[3,4-b]pyridines: Syntheses, reactions, and nuclear magnetic resonance spectra

1988 ◽  
Vol 66 (3) ◽  
pp. 420-428 ◽  
Author(s):  
Brian Maurice Lynch ◽  
Misbahul Ain Khan ◽  
Huk Chia Teo ◽  
Francisco Pedrotti
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Pyrazole Ring ◽  
Substitution Reactions ◽  
Nuclear Magnetic Resonance Spectra ◽  
Substituted Pyridines ◽  
Substituted Pyrazoles ◽  
Homolytic Substitution ◽  
Magnetic Resonance Spectra ◽  
Nuclear Magnetic

Efficient syntheses of approximately 70 simple substituted representatives of pyrazolo[3,4-b]pyridine 1 are reported from the following: (a) suitably substituted pyridines onto which a pyrazole ring is annelated, and (b) appropriately substituted pyrazoles onto which a pyridine ring is annelated. Selected examples of electrophilic, nucleophilic, and homolytic substitution reactions and group transformations are described, providing regiosynthetic paths to useful intermediate species. Some systematic aspects of substituent chemical shift influences in the 1H and 13C nuclear magnetic resonance spectra, aiding in structural assignments, are illustrated.

A study of Br/NO2 substitution reactions and nuclear magnetic resonance of 2,2-diaryl-1-picrylhydrazines

1983 ◽  
Vol 61 (8) ◽  
pp. 1760-1765 ◽  
Author(s):  
Patricia F. Currie ◽  
J. Wilson Quail ◽  
Ann C. M. Rusk ◽  
John A. Weil
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Substitution Reactions ◽  
Paramagnetic Resonance ◽  
Electron Paramagnetic ◽  
Layer Chromatography ◽  
Resonance Electron ◽  
C Nmr ◽  
Nuclear Magnetic

A series of compounds of type 2-Ma-2-Mb-1-pierylhydrazine with Ma, Mb = phenyl, p-bromophenyl, and p-nitrophenyl has been investigated. Conversion of p-bromophenyl into p-nitrophenyl caused by reaction with NO2 has been observed in compounds of the above series. Parameters of the 1H and 13C nmr spectra for the members of the series are reported. The new compound 2-(p-bromophenyl)-2-(p-nitrophenyl)-1-pierylhydrazine has been prepared and characterized using mass spectrometry, nuclear magnetic resonance, electron paramagnetic resonance, thin-layer chromatography, and elemental analysis.

Studies of Substitution Reactions in Chromium(VI)–Fluorine Species

1971 ◽  
Vol 49 (9) ◽  
pp. 1505-1509 ◽  
Author(s):  
A. M. Arena ◽  
D. S. Brown ◽  
D. G. Tuck
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Oxygen Exchange ◽  
Substitution Reactions ◽  
Chromyl Chloride ◽  
Chromium Vi ◽  
Pure Compounds ◽  
Nuclear Magnetic

Nuclear magnetic resonance (n.m.r.) studies show that the exchange between fluorochromate(VI) and fluoride in dimethylsulfoxide is slow, in agreement with previous work on oxygen exchange between water and chromates(VI). No substitution was detected in the system CrO3F−/Cl− in acetonitrile. Mixtures of chromyl fluoride and chromyl chloride show rapid fluorine exchange, both as the pure compounds, and in solution in trichlorofluoromethane. Possible mechanistic implications of these results are discussed.

High Resolution Nuclear Magnetic Resonance Investigation of the Structure of the Adducts Formed by the Interaction of Benzylidenemalononitriles with Trialkylphosphines

1972 ◽  
Vol 50 (11) ◽  
pp. 1713-1718 ◽  
Author(s):  
C. A. Fyfe ◽  
M. Zbozny
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
High Resolution ◽  
Carbon Atom ◽  
Substitution Reactions ◽  
Resonance Investigation ◽  
Nuclear Magnetic Resonance Investigation ◽  
Magnetic Resonance Investigation ◽  
Nuclear Magnetic

High resolution n.m.r. has been used to determine unambiguously the structure of the adducts formed by the action of trialkylphosphines on para-substituted benzylidenemalononitriles2 as a zwitterionic species formed by attack of the phosphine on the α-carbon atom of the alkene. The relation of this result to possible mechanisms of nucleophilic alkene substitution reactions is discussed.

The four trans chlorohydrins of 3-methoxycyclohexene

1967 ◽  
Vol 45 (17) ◽  
pp. 1906-1920 ◽  
Author(s):  
E. J. Langstaff ◽  
E. Hamanaka ◽  
G. A. Neville ◽  
R. Y. Moir
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Hydrogen Chloride ◽  
Substitution Reactions ◽  
Chemical Methods ◽  
Oxide Ring ◽  
Nuclear Magnetic Resonance Spectra ◽  
Close Parallel ◽  
Magnetic Resonance Spectra ◽  
Nuclear Magnetic

trans-3-Methoxycyclohexene oxide (II), when treated with ethereal hydrogen chloride, gives the chlorohydrin dl-1α-chloro-2β-hydroxy-3α-methoxycyclohexane (IVa), and the cis oxide III gives dl-1β-chloro-2α-hydroxy-3α-methoxycyclohexane (Va). The point of scission of the oxide ring (remote from the methoxyl) is therefore the same as in other reactions observed by ourselves and others. The reaction of 3-methoxycyclohexene (I) with N-chlorosuccinimide and water at 100° gives three chlorohydrins: dl-1β-chloro-2α-hydroxy-3α-methoxycyclohexane (VI), dl-2β-chloro-1α-hydroxy-3α-methoxycyclohexane (VIa), and dl-2α-chloro-1β-hydroxy-3α-methoxycyclohexene (VIIa) (approximately in the ratio 10:38:50, respectively). Two of the chlorohydrins were solids, and the homogeneity of the liquid isomers was demonstrated in several ways. The structures were proven by the nuclear magnetic resonance spectra of the p-nitrobenzoates, and by chemical methods. The results are of considerable interest with regard to the theory of addition and substitution reactions. There is a close parallel with the results in the bromohydrin series.

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