scholarly journals Oxidative side-chain and ring fission of pregnanes by Arthrobacter simplex

1988 ◽  
Vol 255 (3) ◽  
pp. 769-774 ◽  
Author(s):  
S B Mahato ◽  
S Banerjee ◽  
S Podder
Keyword(s):  
Methoxy Group ◽  
Ring Cleavage ◽  
Side Chain ◽  
Reaction Sequence ◽  
Arthrobacter Simplex ◽  
Ring Fission ◽  
Multistep Process ◽  
Microbial Preparation ◽  
17 Hydroxyprogesterone ◽  
Steroid Skeleton

Metabolic processes involving side-chain and ring cleavage of progesterone, 17-hydroxyprogesterone, 11-deoxycortisol and 16-dehydropregnenolone by Arthrobacter simplex were studied. The formation of the metabolites from progesterone indicates a pathway somewhat different from normal in the enzymic reaction sequence, and the 17-hydroxyprogesterone metabolites reveal a non-enzymic rearrangement step. The presence of a hydroxy group at C-21, as in 11-deoxycortisol, induces reduction of the C-20 carbonyl group. The microbial preparation of a novel androstane analogue, 17 beta-hydroxy-16 alpha-methoxyandrosta-1,4-dien-3-one, by incubation of 16-dehydropregnenolone with the bacterial strain was achieved. The formation of this metabolite is a multistep process involving a novel microbial generation of a methoxy group from a double-bond transformation in a steroid skeleton.

scholarly journals Comparative analysis of bile-salt degradation in Sphingobium sp. strain Chol11 and P. stutzeri Chol1 reveals functional diversity of β-proteobacterial steroid degradation enzymes and suggests a novel reaction sequence for side-chain degradation involving a hydroxylation step

2021 ◽  
Author(s):  
Franziska Maria Feller ◽  
Phil Richtsmeier ◽  
Maximilian Wege ◽  
Bodo Philipp
Keyword(s):  
Comparative Analysis ◽  
Bile Salt ◽  
Functional Diversity ◽  
Bile Salts ◽  
Deletion Mutant ◽  
Pseudomonas Stutzeri ◽  
Degradation Pathway ◽  
Ring Cleavage ◽  
Side Chain ◽  
Reaction Sequence

The reaction sequence for aerobic degradation of bile salts by environmental bacteria resembles degradation of other steroid compounds. Recent findings show that bacteria belonging to the Sphingomonadaceae use a pathway variant for bile-salt degradation. This study addresses this so-called Δ4,6 -variant by comparative analysis of unknown degradation steps in Sphingobium sp. strain Chol11 with known reactions found in Pseudomonas stutzeri Chol1. Investigations with strain Chol11 revealed an essential function of the acyl-CoA dehydrogenase Scd4AB for growth with bile salts. Growth of the scd4AB deletion mutant was restored with a metabolite containing a double bond within the side chain which was produced by the Δ22-acyl-CoA dehydrogenase Scd1AB from P. stutzeri Chol1. Expression of scd1AB in the scd4AB deletion mutant fully restored growth with bile salts while expression of scd4AB only enabled constricted growth in P. stutzeri Chol1 scd1A or scd1B deletion mutants. Strain Chol11 Δscd4A accumulated hydroxylated steroid metabolites which were degraded and activated with coenzyme A by the wild type. Activities of five Rieske type monooxygenases of strain Chol11 were screened by heterologous expression and compared to the B-ring cleaving KshABChol1 from P. stutzeri Chol1. Three of the Chol11 enzymes catalyzed B-ring cleavage of only Δ4,6 -steroids while KshABChol1 was more versatile. Expression of a fourth KshA homolog, Nov2c228 led to production of metabolites with hydroxylations at an unknown position. These results indicate functional diversity of β-proteobacterial enzymes for bile-salt degradation and suggest a novel side-chain degradation pathway involving an essential ACAD reaction and a steroid hydroxylation step.

Transformation of Alachlor by Microbial Communities

Weed Science ◽  
1990 ◽  
Vol 38 (4-5) ◽  
pp. 416-420 ◽  
Author(s):  
Hone L. Sun ◽  
Thomas J. Sheets ◽  
Frederick T. Corbin
Keyword(s):  
Carbon Source ◽  
Growth Medium ◽  
Basal Medium ◽  
Sole Source ◽  
Ring Cleavage ◽  
Side Chain ◽  
Microbial Culture ◽  
Mixed Microbial Culture ◽  
Alternative Carbon Source ◽  
Thin Layer Chromatographic Analysis

A mixed microbial culture able to transform alachlor at a concentration of 50 μg ml-1was obtained from alachlor-treated soil after an enrichment period of 84 days. The microbial community was composed of seven strains of bacteria. No single isolate was able to utilize alachlor as a sole source of carbon. There was no alachlor left in the enriched culture after a 14-day incubation, but only 12% of the14C-ring-labeled alachlor was converted to14CO2through ring cleavage during 14 days in the basal medium amended with alachlor as a sole carbon source. The presence of sucrose as an alternative carbon source decreased the mineralization potential of the enriched culture, but sucrose increased the mineralizing ability of a three-member mixed culture. Thin-layer chromatographic analysis showed that there were four unidentified metabolites of alachlor produced by the enriched culture. Sucrose decreased the amount of two of the four metabolites. The absence of a noticeable decline in radioactivity beyond the initial 12% suggested that the side chain of alachlor was utilized as carbon source by the enriched culture. Little difference in radioactivity between growth medium and cell-free supernatant of the growth medium suggested that the carbon in the ring was not incorporated into the cells of the degrading microorganisms.

scholarly journals Photolysis of carboxymethylflavin in aqueous and organic solvent: a kinetic study

RSC Advances ◽  
2019 ◽  
Vol 9 (46) ◽  
pp. 26559-26571 ◽  
Author(s):  
Iqbal Ahmad ◽  
Tania Mirza ◽  
Syed Ghulam Musharraf ◽  
Zubair Anwar ◽  
Muhammad Ali Sheraz ◽  
...  
Keyword(s):  
Acid Solution ◽  
Organic Solvent ◽  
Kinetic Study ◽  
Alkaline Solution ◽  
Ring Cleavage ◽  
Side Chain ◽  
Keto Acid ◽  
Side Chain Cleavage ◽  
Chain Cleavage

Carboxymethylflavin (CMF) undergoes photolysis in acid solution to form lumichrome (LC) and in alkaline solution, LC and lumiflavin (LF) by side-chain cleavage and β-keto acid and a dioxoquinoxalaine (DQ) compound by isoalloxazine ring cleavage.

Synopses from the poster exhibition organized by R. H. Pain 1. New very efficient antibiotics in the field of cephalosporin derivatives

1980 ◽  
Vol 289 (1036) ◽  
pp. 361-376 ◽  
Keyword(s):  
Antimicrobial Activity ◽  
Structural Features ◽  
Side Chain ◽  
Unexpected Result ◽  
Reaction Sequence ◽  
General Reaction ◽  
Gram Negative ◽  
High Level ◽  
Very High

The semi-synthetic cephalosporin derivatives containing a 2-(2-amino-4-thiazolyl)-2- syn -oxyiminoacetyl side chain are obtained according to the general reaction sequence outlined in figure 1. They are characterized by a very high level of antimicrobial activity, especially against Gram-negative species. This unexpected result is due to the conjunction of two structural features: the aminothiazolyl moiety and the syn -oxyimino substituent.

Reductive cleavage of 2-alkoxy- and 2-aryloxy-tetrahydropyrans with LiAlH4–AlCl3

1967 ◽  
Vol 45 (21) ◽  
pp. 2547-2558 ◽  
Author(s):  
U. E. Diner ◽  
R. K. Brown
Keyword(s):  
Ring Cleavage ◽  
Side Chain ◽  
Resonance Spectroscopy ◽  
Trans Isomers ◽  
Aryl Group ◽  
Side Chain Cleavage ◽  
Chain Cleavage ◽  
Cis And Trans Isomers ◽  
Steric Factors ◽  
Cis And Trans

A series of 2-alkoxy- and 2-aryloxy-tetrahydropyrans has been hydrogenolyzed in ether by LiAlH4–AlCl3. As the alkyl group attached to the exo oxygen atom is changed from primary to tertiary, the proportion of ring cleavage to side-chain cleavage increases. Only side-chain cleavage occurs with the 2-aryloxytetrahydropyrans. The results are explained in terms of the polar properties of the alkyl or aryl group attached to the ring oxygen or the side-chain oxygen. Any control by steric factors is considered to be submerged by the polar effects, but does have a clearly apparent directive effect when the polar factors are equal for the two routes of cleavage. The results of the hydrogenolysis of 6-substituted 2-alkoxytetrahydropyrans could be explained on the same basis.The configurations of the cis and trans isomers of the disubstituted tetrahydropyrans were determined by nuclear magnetic resonance spectroscopy. Their conformational preference is discussed.

scholarly journals Microbiological degradation of bile acids. The preparation of some hypothetical metabolites involved in cholic acid degradation

1976 ◽  
Vol 154 (3) ◽  
pp. 577-587 ◽  
Author(s):  
S Hayakawa ◽  
Y Kanematsu ◽  
T Fujiwara ◽  
H Kako
Keyword(s):  
Fatty Acid ◽  
Carboxylic Acid ◽  
Bile Acids ◽  
Cholic Acid ◽  
Valeric Acid ◽  
Side Chain ◽  
Partial Synthesis ◽  
Arthrobacter Simplex ◽  
Acid Degradation ◽  
Oxidation Mechanisms

1. To identify the intermediates involved in the degradation of cholic acid, the further degradation of (4R)-4-[4a-(2-carboxyethyl)-3aa-hexahydro-7ab-methyl-5-oxoindan-1β-yl]valeric acid (IVa) by Arthrobacter simplex was attempted. The organism could not utilize this acid but some hypothetical intermediate metabolities of compound (IVa) were prepared for later use as reference compounds. 2. The nor homologue (IIIa) and the dinor homologue (IIIb) of compound (IVa) were prepared by exposure of 3-oxo-24-nor-5β-cholan-23-oic acid (I) and (20S)-3b-hydroxy-5-pregnene-20-carboxylic acid (II) to A. simplex respectively. These compounds correspond to the respective metabolites produced by the shortening of the valeric acid side chain of compound (IVa) in a manner analogous to the conventional fatty acid a- and b-oxidation mechanisms. Their structures were confirmed by partial synthesis. 3. The following authentic samples of reduction products of the oxodicarboxylic acids (IIIa), (IIIb) and (IVa) were also synthesized as hypothetical metabolities: (4R)-4-[3aa-hexahydro-5a-hydroxy-4a-(3-hydroxypropyl)-7ab-methylindan-1b-yl]valeric acid (Vb) and its nor homologue (VIIa) and dinor homologue (IXa);(4R)-4-[3Aaa-hexahydro-5a-hydroxy-4a-(3-hydroxypropyl)-7ab-methylindan-1b-yl]-pentan-1-ol (Vc); and their respective 5β epimers (Ve), (VIIc), (IXc) and (Vf). 4. In connexion with the non-utilization of compound (IVa) by A. simplex, the possibility that not all the metabolites formed from cholic acid by a certain micro-organism can be utilized by the same organism is considered.

THE REACTION OF CHLORAL WITH HALOBENZENES AND WITH 2,4-DICHLOROPHENOL: SYNTHESIS OF HALOGENATED ETHYLBENZENES AND OF α-METHOXYPHENYLACETIC ACIDS

1966 ◽  
Vol 44 (5) ◽  
pp. 575-582 ◽  
Author(s):  
Wilkins Reeve ◽  
John P. Mutchler ◽  
Charles L. Liotta
Keyword(s):  
Carbon Disulfide ◽  
Potassium Hydroxide ◽  
Methoxy Group ◽  
Methylene Chloride ◽  
Aluminium Chloride ◽  
Molar Ratio ◽  
Side Chain ◽  
New Compounds ◽  
Hydroxy Groups

The Friedel–Crafts reaction of chloral with aromatic compounds to form aryltrichloromethylcarbinols is reviewed. The molar ratio of aluminium chloride to chloral is critical and varies from 0.15 to 2.0 depending on the solvent, steric considerations, and the reactivity of the aromatic ring. The reaction has been used to prepare several new compounds with carbon disulfide or excess aromatic compound as the solvent. From 2,4-dichlorophenol, an o-hydroxy-α-trichloromethylbenzyl alcohol is obtained. Both the phenolic and side-chain hydroxy groups of this alcohol are methylated with equal ease by dimethyl sulfate.It has now been found that changing the solvent from carbon disulfide to methylene chloride results in the hydroxy group of the initial carbinol also being replaced by chlorine. This role of the solvent in controlling the course of the reaction has not been observed previously.The trichloromethylcarbinols are converted into α-methoxy acids by treatment with methanolic potassium hydroxide. Sodium in liquid ammonia removes the α-methoxy group, as well as the halogens, from 3,5-dichloro-α,2-dimethoxyphenylacetic acid.

Glucosylation of 5-androsten-3β-ol derivatives containing butenolide, furan or unsaturated ester moieties in the side chain

1984 ◽  
Vol 49 (4) ◽  
pp. 881-891 ◽  
Author(s):  
Ivan Černý ◽  
Vladimír Pouzar ◽  
Pavel Drašar ◽  
Miloš Buděšínský ◽  
Miroslav Havel
Keyword(s):  
Sodium Borohydride ◽  
Lactone Ring ◽  
Acetyl Derivative ◽  
Side Chain ◽  
Unsaturated Ester ◽  
Reaction Sequence ◽  
Silver Silicate

3-O-(Tetra-O-acetyl-β-D-glucopyranosyl) derivatives II, V, XV and XX were prepared from 5-androstene-3β,17β-diol 17-benzoate (I), (20R)-3β-hydroxy-21-nor-5,22-choladien-(24 -20)-olide (IV), 17β-(2-furyl)-5-androsten-3β-ol (XIV) and methyl (20E)-3β-hydroxy-5,20-pregnadiene-21-carboxylate (XIX), respectively, using tetra-O-acetyl-α-D-glucopyranosyl bromide and silver silicate. The furyl derivative XIV was obtained from methyl 3β-methoxymethyletienate VIII by reaction sequence in which the key reactions were alkylation of the keto sulfoxide IX with bromoacetate, cyclization of the obtained product with sodium borohydride and reduction of the mixture of lactones XI and XII with diisobutylaluminium hydride. The unsaturated ester XIX was prepared from 3β-acetoxy-5-androstene-17β-carbaldehyde (XVII) by treatment with diethyl methoxycarbonylmethylphosphonate and deacetylation of the formed acetyl derivative XVIII. Deacetylation of the acetyl derivatives II, XV and XX afforded the glucosides III,XVI and XXI, respectively; the deacetylation of V was accompanied by opening of the lactone ring under formation of the methyl 21-nor-20-oxo-5-cholen-24-oate derivative VI.

scholarly journals The biosynthesis of patulin: The mechanism of oxidative aromatic ring cleavage and loss of side chain protons from aromatic intermediates.

1983 ◽  
Vol 31 (1) ◽  
pp. 362-365 ◽  
Author(s):  
Hiroshi Iijima ◽  
Hiroshi Noguchi ◽  
Yutaka Ebizuka ◽  
Ushio Sankawa ◽  
Haruo Seto
Keyword(s):  
Aromatic Ring ◽  
Ring Cleavage ◽  
Side Chain ◽  
Aromatic Ring Cleavage
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