Thermal Isomerization at a C=N Double Bond: How Does the Mechanism Vary with the Substituent?

2005 ◽  
Vol 78 (10) ◽  
pp. 1851-1855 ◽  
Author(s):  
Hiroshi Yamataka ◽  
Salai Cheettu Ammal ◽  
Tsutomu Asano ◽  
Yasushi Ohga
Keyword(s):  
Double Bond ◽  
Thermal Isomerization

Isomérisation thermique de vinyl-2 aziridines N-substituées

1976 ◽  
Vol 54 (10) ◽  
pp. 1590-1598 ◽  
Author(s):  
Daniel Borel ◽  
Yvonne Gelas-Mialhe ◽  
Roger Vessière
Keyword(s):  
Double Bond ◽  
Thermal Isomerization ◽  
Experimental Results ◽  
Phenyl Substituent ◽  
Ethylene Imine ◽  
Ring Carbon ◽  
Reaction Proceeds

The thermal isomerization of 2-vinylaziridines, variously substituted on the ring and the double bond, has been studied. The nature of the products formed depends on the nature of the substituents in positions 1 and 3. If the ring carbon-3 carries a phenyl substituent, the thermolysis yields, in most cases, a Δ-2-pyrroline. With unsubstituted or 3-alkylaziridines the reaction proceeds, depending on the nature of the substituent on the nitrogen, either to an ethylene imine or to a mixture of Δ-2- and Δ-3-pyrrolines. Mechanisms to interpret the experimental results are proposed. [Journal translation]

Deactivation of Rhodopsin in the Transition from the Signaling State Meta II to Meta III Involves a Thermal Isomerization of the Retinal Chromophore CN Double Bond†

Biochemistry ◽  
2003 ◽  
Vol 42 (33) ◽  
pp. 9863-9874 ◽  
Author(s):  
Reiner Vogel ◽  
Friedrich Siebert ◽  
Gerald Mathias ◽  
Paul Tavan ◽  
Guibao Fan ◽  
...  
Keyword(s):  
Double Bond ◽  
Thermal Isomerization ◽  
Retinal Chromophore

THE THYMOLYTIC ACTIVITY OF 6- AND 9-HALOCORTICOIDS AND RELATED STEROIDS

1965 ◽  
Vol 49 (2) ◽  
pp. 262-270 ◽  
Author(s):  
Ralph I. Dorfman ◽  
P. G. Holton ◽  
Fred A. Kind
Keyword(s):  
Double Bond ◽  
Subcutaneous Injection ◽  
Fluocinolone Acetonide ◽  
Relative Potency ◽  
Subcutaneous Route ◽  
Adrenalectomized Rats

ABSTRACT Adrenalectomized rats were used for the determination of the relative potency of various 6- and 9-halo substituted corticoids administered subcutaneously or by gavage using thymus weightas the endpoint. By subcutaneous injection, fluocinolone acetonide was the most active corticoid at 700 times that of cortisol. This compound was also the most active corticoid by the gavage route and was judged to be 570 times as active as the standard cortisol. The introduction of the 16,17-acetonide and 16,17-acetone 21-acetate groups into 17α,21-dihydroxy-9α,11β-dichloropregna-1,4-diene-3,20-dione increased the activity by a factor of 42 and 100, respectively. The introduction of the δ1 double bond into 6α-fluoroprogesterone 16,17-acetonide caused an increase of 10-fold in thymolytic activity assessed by the subcutaneous route

TRIGLYCERIDE COMPOSITION OF SIXTEEN STRAINS OF MARINE DIATOM

2013 ◽  
Vol 5 (1) ◽  
Author(s):  
Lily M.G. Panggabean ◽  
Abdullah Rasyid ◽  
Zarrah Duniani ◽  
Yana Meliana ◽  
Indah Kurniasih
Keyword(s):  
Mass Spectrometry ◽  
Fatty Acid ◽  
Double Bond ◽  
Unsaturated Fatty Acid ◽  
Ion Trap ◽  
Carbon Chain ◽  
Highly Unsaturated Fatty Acid ◽  
Marine Diatom ◽  
Ion Trap Mass Spectrometry ◽  
Spectra Analysis

Trigliceride or triacylglicerol (TAG) composition in crude oil of sixteen strain of marine diatom has been detected by spectra analyses on an Electrospray - Ion Trap – Mass Spectrometry (ESI-IT-MS) HCT Bruker-Daltonic GmbH instrument with AgNO3 used as coordination ionization agent. Biomass samples of each microalga strain were taken from early and late stationary cultures in f/2 enriched seawater and algal oils were extracted according to Bligh and Dyer. Results from spectra analysis showed that P-Pt-P (C16:0-C16:1-C16:0) were distinguished in TAG from diatom strains Chaetoceros sp.1, Chaetoceros sp.2, Thalasiossira sp.1, Thalasiossira sp.2, Thalasiossira sp.3, Navicula sp. 1, Navicula sp. 2, Navicula sp. 3, Navicula sp. 4, Nitzschia sp. 2 and Amphora sp. In contrast, TAGs in Melosira sp. included P-P-P (C16:0-C16:0-C16:0) and P-P-O (C16:0-C16:0-C18:1) were identified. TAGs from Chaetoceros sp. were the most varies among samples, i.e. P-Pt-P (C16:0-C16:1-C16:0), A-P-M (C20:4-C16:0-C14:0), P-Pt-Lt (C16:0-C16:1-C18:3), P-Pt-A (C16:0-C16:1-C20:4), D-P-P (C22:6-C16:0-C16:0), A-Ln-P (C20:4-C18:2-C16:0). Various TAGs were also detected in Nitzschia sp.2, i.e. P-Pt-M (C16:0-C16:1-C14:0), P-Pt-P (C16:0-C16:1-C16:0), P-Pt-S (C16:0-C16:1-C18:0), P-Pt-A (C16:0-C16:1-C20:4). TAGs composition in Skeletonema strains that similar to those in Nitzschia sp.1 has longer carbon, i.e. P-P-O (C16:0-C16:0-C18:1), P-O-O (C16:0-C18:1-C18:1) and O-O-O (C18:1-C18:1-C18:1). TAGs with longer carbon chain and more double bond including highly unsaturated fatty acid C20:4 were increased with culture age in diatoms Chaetoceros sp.1, Chaetoceros sp.2, Thalasiossira sp.2, Navicula sp.1 and Nitzschia sp. 2.Keywords: diatom, TAG, ESI-IT-MS, f/2, early and late stationary

Some Considerations Regarding the 1H and 13C Spectra of 4-(1-azulenyl)-2,6-bis(2-heteroaryl-vinyl)- pyrylium and Pyridinium and their Corresponding Pyridines

2018 ◽  
Vol 69 (1) ◽  
pp. 64-69
Author(s):  
Liviu Birzan ◽  
Mihaela Cristea ◽  
Constantin C. Draghici ◽  
Alexandru C. Razus
Keyword(s):  
Double Bond ◽  
13C Nmr ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Pyridinium Salts ◽  
13C Nmr Spectra ◽  
1H And 13C Nmr ◽  
Pyrylium Salts

The 1H and 13C NMR spectra of several 2,6-diheteroarylvinyl heterocycles containing 4-azulenyl moiety were recorded and their proton and carbon chemical shifts were compared with those of the compounds without double bond between the heterocycles. The influence of the nature of central and side heterocycles, molecule polarization and anisotropic effects were revealed. The highest chemical shifts were recorded for the pyrylium salts and the lowest at pyridines, but in the case of the pyridinium salts, the protons chemical shifts at the central heterocycle are more shielded due to a peculiar anisotropy of the attached vinyl groups.

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