Enzymic aromatization of deuterium labelled testosterone and androst-4-ene-3,17-dione

1981 ◽  
Vol 59 (19) ◽  
pp. 2809-2819 ◽  
Author(s):  
Herbert L. Holland ◽  
Gregg J. Taylor
Keyword(s):  
Double Bond ◽  
Isotope Effect ◽  
Nmr Spectra ◽  
Deuterium Nmr ◽  
Secondary Effects ◽  
Deuterium Isotope Effect ◽  
Oxidative Removal ◽  
Primary And Secondary Effects ◽  
Rate Limiting

The preparation and aromatization by human placental microsomes of androst-4-ene-3-ones labelled with deuterium at C-4, C-6α, C-6β, C-16, and C-19 is described. Deuterium nmr spectra are reported for these compounds and for a sample of a 1,2-dideuterated androst-4-ene-3-one; the latter is formed nonstereospecifically by reduction of the C-1(2) double bond of a Δ1,4-diene-3-one. Aromatization by placental microsomes occurs with retention of deuterium at C-4 and C-6, but with some loss from C-16. The aromatization of 19-d1 and 19,19,19-d3 steroids in the presence of 16,16-d2 steroids has been carried out to determine the deuterium isotope effect for the oxidative removal of C-19. The values obtained (kH/kD for 19-d1 = 2.3, kH/kD for 19,19, 19-d3 = 3.2) are a combination of primary and secondary effects, but suggest that oxidation at C-19 is a rate-limiting reaction of the biosynthetic sequence.The fungus Pellicularia filamentosa NRRL 2727, reported to hydroxylate androst-4-ene-3,17-dione at C-19, gave only the products of hydroxylation at C-11α, C-11β, and C-14.

Three types of stereospecificity and the kinetic deuterium isotope effect in the oxidative deamination of dopamine as catalyzed by different amine oxidases

1988 ◽  
Vol 66 (8) ◽  
pp. 853-861 ◽  
Author(s):  
Peter H. Yu
Keyword(s):  
Isotope Effect ◽  
Amine Oxidase ◽  
Deuterium Atom ◽  
Amine Oxidases ◽  
Deuterium Isotope Effect ◽  
Plasma Amine Oxidase ◽  
Benzylamine Oxidase ◽  
Rate Limiting ◽  
Hog Kidney ◽  
Pea Seedling

When the stereospecifically deuterated dopamine enantiomers, (R)- and (S)-[α-2H1]dopamine, are incubated with amine oxidases, the deuterium atom may be either retained to form monodeuterated 3,4-dihydroxyphenylacetaldehyde, or eliminated to produce the nondeuterated or protio-aldehyde product. These two aldehydes can be separated from one another and identified by high-performance liquid chromatography with electrochemical detection. Three types of stereospecific abstraction of a hydrogen from the α-carbon of dopamine during deamination have been observed. In the first type, the pro-R hydrogen is removed from the α-carbon. Enzymes in this category are mitochondrial monoamine oxidases A and B, as isolated from different tissues and species. The second type of deamination involves the abstraction of pro-S hydrogen from the α-carbon of dopamine. Soluble enzymes, such as rat aorta benzylamine oxidase or diamine oxidase from hog kidney and pea seedling, have been found to belong to this group. Bovine plasma amine oxidase exhibits the third type of deamination where no absolute stereospecificity is required. This enzyme catalyzes the oxidation of either (S)- or (R)-[α-2H1]dopamine, preferably breaking the C—H bond rather than the C—2H bond in both cases. The kinetic deuterium isotope effect during the deamination of dopamine catalyzed by the different amine oxidases varies greatly; VH/VD ranges from 1.5 to 5.5. The high magnitude of the isotope effect suggests that hydrogen abstraction may be the rate-limiting step (i.e., in reactions catalyzed by benzylamine oxidase and monoamine oxidase). When the isotope effect is low (i.e., for diamine oxidases from hog kidney or pea seedling), it is uncertain if the breaking of the bond is rate limiting.

Deuterium isotope effect on 13C NMR spectra of ortho Mannich bases

1995 ◽  
Vol 67 ◽  
pp. 63-69 ◽  
Author(s):  
Maria Rospenk ◽  
Aleksander Koll ◽  
Lucjan Sobczyk
Keyword(s):  
Isotope Effect ◽  
13C Nmr ◽  
Nmr Spectra ◽  
Mannich Bases ◽  
13C Nmr Spectra ◽  
Deuterium Isotope Effect

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.

15N, 13C, and 1H NMR Spectra of Azo and Hydrazo Compounds Derived from 1,3,3-Trimethyl-2-methylidene-2,3-dihydroindole (Fischer Base)

1998 ◽  
Vol 63 (7) ◽  
pp. 1012-1020 ◽  
Author(s):  
Antonín Lyčka ◽  
Josef Jirman ◽  
Alois Koloničný
Keyword(s):  
Double Bond ◽  
Hydrochloric Acid ◽  
Nmr Spectra ◽  
Coupling Constants ◽  
Azo Compounds ◽  
Passive Component ◽  
Geometric Isomers ◽  
H Nmr ◽  
Fischer Base ◽  
Hydrazone Form

The 15N, 13C, and 1H NMR spectra were measured for azo and hydrazo compounds derived from 1,3,3-trimethyl-2-methylidene-2,3-dihydroindole (Fischer base), which is a passive component with a terminal methylidene group. Products prepared by coupling in hydrochloric acid exist in the corresponding hydrazone form as the E-isomers. Neutralization gives a mixture of two isomeric azo compounds which differ in the arrangement at the C(2)=C(10) double bond. This mixture was alkylated with methyl iodide to obtain the =N-N(CH3)- hydrazone derivatives. The geometric isomers were resolved based on the NOESY approach and the stereospecific behaviour of the 2J(15N,13C) coupling constants was studied for the 15N-labelled compounds.

Sign in / Sign up

Export Citation Format

Share Document