Reaction of 1,4-dibromohexafluoro-2-butene with O- and N-nucleophiles

1988 ◽  
Vol 53 (3) ◽  
pp. 619-625 ◽  
Author(s):  
Ivan Hemer ◽  
Věra Moravcová ◽  
Václav Dědek
Keyword(s):  
Kinetic Study ◽  
Sodium Methoxide ◽  
Allylic Rearrangement ◽  
Rearrangement Product

Reaction of 1,4-dibromohexafluoro-2-butene (I) with sodium methoxide, ethoxide or isopropoxide in the corresponding alcohols proceeds with allylic rearrangement under formation of 3-alkoxy-4-bromohexafluoro-1-butenes II-IV. A kinetic study has proven the SN2’ mechanism for reaction of I with potassium phenoxide leading to 4-bromo-3-phenoxyhexafluoro-1-butene (V). Also the reaction of I with ammonia, affording 3-amino-4-bromo-2,4,4-trifluoro-2-butenenitrile (IX), is compatible with the allylic rearrangement by SN2’ mechanism. On the contrary, reaction of I with diethylamine gave no rearrangement product and, after hydrolysis, afforded N,N-diethyl-4-bromo-2,3,3,4,4-pentafluorobutanamide (XVI) and N,N-diethyl-4-bromo-2,3,4,4-tetrafluoro-2-butenamide (XVII) in the ratio 85:15.

Juvabione and its analogues. II. Isolation, identification, and occurrence of juvabiol and its epimer isojuvabiol from the whole wood of Abies balsamea

1976 ◽  
Vol 54 (15) ◽  
pp. 2365-2371 ◽  
Author(s):  
John Fieve Manville
Keyword(s):  
Petroleum Ether ◽  
Juvenile Hormone ◽  
Abies Balsamea ◽  
Ethanol Extract ◽  
Allylic Rearrangement ◽  
Rearrangement Product ◽  
Widespread Occurrence ◽  
Selective Action ◽  
Juvenile Hormone Analogues ◽  
Wood Extract

Epimeric mixtures of juvabiol (3a) and isojuvabiol (4a) have been detected in six North American Abies balsamea (L.) Mill. trees and isolated from the whole-wood extract of three. These juvabione related alcohols are insect juvenile hormone analogues with selective action typical of juvabione (1) and Δ4′-dehydrojuvabione (2). The widespread occurrence of these alcohols indicates that the original 'paper factor' was not due to 1 alone, nor was it due to a mixture of 1 and 2. In addition a fifth IJHA with selective action, Δ3′-dehydrojuvabi-5′-ol (5), was detected in the hot ethanol extract of four trees and isolated from one tree. It is shown that 5 is an allylic rearrangement product of the Δ4′-dehydrojuvabiols 6a and 7a. Mixtures of campesterol and sitosterol are the major crystalline components present in all the petroleum ether soluble extracts.

Reaction of N-methyl-N-(2,4-dinitrophenyl)glycine methylamide with methoxide

1989 ◽  
Vol 54 (2) ◽  
pp. 430-439 ◽  
Author(s):  
Vladimír Macháček ◽  
Miloslav Sebránek ◽  
Vojeslav Štěrba
Keyword(s):  
Equilibrium Constant ◽  
Half Life ◽  
Sodium Methoxide ◽  
Side Reactions ◽  
Subsequent Reduction ◽  
Rearrangement Product ◽  
Smiles Rearrangement ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Rate Limiting

The side reactions of N-methyl-N-(2,4-dinitrophenyl)glycine methylamide with methanolic sodium methoxide reversibly give the spiro adduct (spiro[(1,3-dimethyl-5-imidazolidone)-2,1'-(2',4'-dinitrobenzenide)]) and irreversibly produce N-methyl-2-nitroso-4-nitroaniline which undergoes subsequent reduction. The diazolidine ring of the spiro adduct is opened by action of methanolic hydrogen chloride, whereby the Smiles rearrangement is completed. The rearrangement product-2-methylamino-N-methyl-N-(2,4-dinitrophenyl)acetamide hydrochloride-is present in the form of a mixture of Z and E isomers (ratio 1.9). The equilibrium constant of formation of the spiro adduct from 2-methylamino-N-methyl-N-(2,4-dinitrophenyl)acetamide hydrochloride is by 9 orders of magnitude lower than that found for the analogous trinitrophenylderivative. The rate-limiting step of the transformation of the Z-isomer into the spiro adduct consists in the isomerization Z ⇄ E. The E-isomer is cyclized with a half-life shorter than 1 ms.

The Allylic Rearrangement. V.1Reaction of 4-Haloisophorone with Sodium Methoxide in Methanol

1987 ◽  
Vol 17 (7) ◽  
pp. 773-780 ◽  
Author(s):  
Sadao Tsuboi ◽  
Yoichi Kurihara ◽  
Takayuki Watanabe ◽  
Akira Takeda
Keyword(s):  
Sodium Methoxide ◽  
Allylic Rearrangement

CHASMANINE AND ITS STRUCTURE

1965 ◽  
Vol 43 (4) ◽  
pp. 825-839 ◽  
Author(s):  
O. Achmatowicz Jr. ◽  
Y. Tsuda ◽  
Léo Marion ◽  
T. Okamoto ◽  
Mitsutaka Natsume ◽  
...  
Keyword(s):  
Cyclic Ether ◽  
Membered Ring ◽  
Hydroxyl Groups ◽  
Lithium Aluminium Hydride ◽  
Allylic Rearrangement ◽  
Rearrangement Product ◽  
Lithium Aluminium ◽  
Pyrolytic Reaction ◽  
Acid Catalyzed ◽  
Tertiary Hydroxyl

The alkaloid chasmanine, C25H41O6N, isolated from A. chasmanthum contains four methoxyl and two hydroxyl groups as well as an imino-ethyl. It undergoes the usual pyrolytic reaction and the unsaturated product, pyrochasmanine, C25H39O5N, gives rise to an acid-catalyzed allylic rearrangement product, isopyrochasmanine. Pyrochasmanine, on treatment with lithium aluminium hydride, is demethoxylated. It can be concluded that the base, like bikhaconine, contains the sequence [Formula: see text]. Chasmanine can be oxidized to a compound containing a cyclopentanone ring so that its second hydroxyl must be secondary and located on a five-membered ring. It is possible to benzoylate the secondary hydroxyl and acetylate the tertiary hydroxyl. The n.m.r. characteristics of the resulting double ester determine the location of these two groups and their stereochemistry. The relative position of two of the remaining methoxyl groups is established via a demethylation reaction resulting in the formation of a cyclic ether. All the chemical reactions studied are in agreement with structure IV (R = R′ = H) for chasmanine. There is, however, no positive proof for the location of the fourth methoxyl and it has been placed in ring A by analogy. An attempted correlation with bikhaconine is described.

Immunocytochemical localization of desmin and vimentin in chick embryonic myocardial cells

1990 ◽  
Vol 48 (3) ◽  
pp. 448-449
Author(s):  
Yukiko Sugi
Keyword(s):  
Sodium Methoxide ◽  
Intermediate Filament Protein ◽  
Chick Embryos ◽  
Immunocytochemical Localization ◽  
Myocardial Cells ◽  
Immunofluorescence Study ◽  
Immunofluorescent Localization ◽  
Rabbit Igg ◽  
Semithin Sections ◽  
Filament Protein

In cultured skeletal muscle cells of chick, one intermediate filament protein, vimentin, is primarily formed and then synthesis of desmin follows. Coexistence of vimentin and desmin has been immunocytochemically confirmed in chick embryonic skeletal musclecells. Immunofluorescent localization of vimentin and desmin has been described in developing myocardial cells of hamster. However, initial localization of desmin and vimentin in early embryonic heart has not been reported in detail. By quick-freeze deep-etch method a loose network of intermediate filaments was revealed to exist surrounding myofibrils. In this report, immunocytochemical localization of desmin and vimentin is visualized in early stages of chick embryonic my ocardium.Chick embryos, Hamburger-Hamilton (H-H) stage 8 to hatch, and 1 day old postnatal chicks were used in this study. For immunofluorescence study, each embryo was fixed with 4% paraformaldehyde and embedded in Epon 812. De-epoxinized with sodium methoxide, semithin sections were stained with primary antibodies (rabbit anti-desmin antibody and anti-vimentin antibody)and secondary antibody (RITC conjugated goat-anti rabbit IgG).

A kinetic study of controlling nitrogen in process for boron steel by using30N2isotope gas

2008 ◽  
Vol 105 (12) ◽  
pp. 601-608
Author(s):  
Seung Min Han ◽  
Dong Joon Min ◽  
Joo Hyun Park ◽  
Jung Ho Park ◽  
Jong Min Park
Keyword(s):  
Kinetic Study ◽  
Boron Steel

Kinetic Study of the Effect of Heparin on the Amidase Activity of Trypsin, Plasmin and Urokinase

1983 ◽  
Vol 49 (03) ◽  
pp. 199-203 ◽  
Author(s):  
V M Yomtova ◽  
N A Stambolieva ◽  
B M Blagoev
Keyword(s):  
Kinetic Study ◽  
Active Center ◽  
Simultaneous Presence ◽  
Amidase Activity ◽  
Competitive Inhibitors ◽  
Uncompetitive Inhibitor

SummaryIt was found that the effect of heparin on the amidase activity of urokinase (E C 3.4.21.31), plasmin (E C 3.4.21.7) and trypsin (E C 3.4.21.4) depended on the substrate used. No effect of heparin on the amidase activity of urokinase and trypsin was observed when Pyro Glu-Gly-Arg-p-nitroanilide (S-2444) and α-N-acetyl-L-lysine-p-nitroanilide (ALNA) were used as substrates. Heparin acted as a uncompetitive inhibitor of trypsin (Ki = 1.2×10-6 M), plasmin (Ki = 4.9×10-6 M) and urokinase (Ki = l.0×10-7 M) when Bz-Phe-Val-Arg-p-nitroanilide (S-2160), H-D-Val-Leu-Lys-p-nitroanilide (S-2251) and plasminogen, respectively, were used as substrates. These results, as well as the data obtained by studying the effect of the simultaneous presence of heparin and competitive inhibitors suggest that although heparin is not bound at the active center of these enzymes, it may influence the effectivity of catalysis.

Sign in / Sign up

Export Citation Format

Share Document