Ozonolysis of Derivatives of Labda-8(17),14-dien-13-ol (Manool) and Their Conversion Into Large Ring Unsaturated Lactones

1988 ◽  
Vol 41 (5) ◽  
pp. 711 ◽  
Author(s):  
PK Grant ◽  
KL Chee ◽  
JS Prasad ◽  
MY Tho
Keyword(s):  
Double Bond ◽  
Good Yield ◽  
Spatial Relationship ◽  
Hydroxyl Group ◽  
Exocyclic Double Bond ◽  
Large Ring ◽  
Unsaturated Lactones ◽  
Derivatives Of

Dehydration of the unstable hydroperoxy ethers (4) and (6) formed on ozonolysis of the manool derivatives (2) and (5) resulted in the formation of the ten- membered unsaturated lactones (11) and (12) in good yield. The results of an investigation into the nature of the hydroxyl group and its spatial relationship to the exocyclic double bond in lactone formation are reported for other manool derivatives.

scholarly journals Oxepinamide F biosynthesis involves enzymatic d-aminoacyl epimerization, 3H-oxepin formation, and hydroxylation induced double bond migration

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Liujuan Zheng ◽  
Haowen Wang ◽  
Aili Fan ◽  
Shu-Ming Li
Keyword(s):  
Cytochrome P450 ◽  
Double Bond ◽  
Biosynthetic Pathway ◽  
Hydroxyl Group ◽  
Cytochrome P450 Enzyme ◽  
Double Bond Migration ◽  
Feeding Experiments ◽  
Aspergillus Ustus ◽  
P450 Enzyme ◽  
Derivatives Of

Abstract Oxepinamides are derivatives of anthranilyl-containing tripeptides and share an oxepin ring and a fused pyrimidinone moiety. To the best of our knowledge, no studies have been reported on the elucidation of an oxepinamide biosynthetic pathway and conversion of a quinazolinone to a pyrimidinone-fused 1H-oxepin framework by a cytochrome P450 enzyme in fungal natural product biosynthesis. Here we report the isolation of oxepinamide F from Aspergillus ustus and identification of its biosynthetic pathway by gene deletion, heterologous expression, feeding experiments, and enzyme assays. The nonribosomal peptide synthase (NRPS) OpaA assembles the quinazolinone core with d-Phe incorporation. The cytochrome P450 enzyme OpaB catalyzes alone the oxepin ring formation. The flavoenzyme OpaC installs subsequently one hydroxyl group at the oxepin ring, accompanied by double bond migration. The epimerase OpaE changes the d-Phe residue back to l-form, which is essential for the final methylation by OpaF.

BEZIEHUNGEN ZWISCHEN SUBSTITUTION IM RING A UND ABBAU IM STOFFWECHSEL BEI VERWANDTEN DES TESTOSTERONS

1962 ◽  
Vol 41 (4) ◽  
pp. 494-506 ◽  
Author(s):  
H. Langecker
Keyword(s):  
Double Bond ◽  
Ring System ◽  
Keto Group ◽  
Hydroxyl Group ◽  
Methyl Group ◽  
Structural Peculiarities ◽  
Metabolic Degradation ◽  
The Difference ◽  
Testosterone Metabolites ◽  
Derivatives Of

ABSTRACT Judging from the metabolites found in the urine, 1-methyl-androst-1-en-17β-ol-3-one (methenolone) and testosterone are metabolized in a different manner. For further clarification, other derivatives of testosterone with modifications in Ring A were investigated with regard to the oxidation of the 17-hydroxyl group. The production of urinary 17-ketosteroids decreased in the following sequence: testosterone; 1α-methyltestosterone and androstan-17β-ol-3-one; 1β-methyl-androstan-17β-ol-3-one; 2α-methyl-androstan-17β-ol-3-one and androst-1-en-17β-ol-3-one; 1α-methyl-androstan-17β-ol-3-one; 1-methyl-androsta-1,4-dien-17β-ol-3-one; 1,17α-dimethyl-androst-1-en-17β-ol-3-one and 1 -methyl-androst-1 -en-17β-ol-3-one (methenolone). The difference in metabolic degradation is also demonstrated in the fractionation of the urinary ketones. While after the administration of testosterone practically only hydrogenated 17-ketones are observed in the urine, the unchanged compound is still traceable in remarkable quantities after the administration of methenolone, along with minor quantities of the corresponding diketone. Testosterone-metabolites here are absent, whereas they represent the major substances present after the administration of androst-1-en-17β-ol-3-on. Following the administration of 1α-methyltestosterone only hydrogenated 17-ketones are detected which are still partly methylated. The 1-methyl-group and the Δ 1-double-bond seem to be responsible for the inhibition of the oxidation of methenolone in the 17-position. In addition, the hydrogenation of the double-bond and the reduction of the 3-keto-group are inhibited, obviously on account of the same structural peculiarities. The demethylation of methenolone is also inhibited. Any change in the steroid ring system forms a new substrate, thus producing new conditions for the enzymatic attack in the metabolic degradation.

scholarly journals C-Lactam Derivatives of Oleanolic Acid. The Synthesis of C-lactam by Beckmann Rearrangement of C-oxime

2011 ◽  
Vol 6 (12) ◽  
pp. 1934578X1100601
Author(s):  
Barbara Bednarczyk – Cwynar
Keyword(s):  
Double Bond ◽  
Nitrogen Atom ◽  
Oleanolic Acid ◽  
Structure Elucidation ◽  
Beckmann Rearrangement ◽  
Hydroxyl Group ◽  
Chemical Transformations ◽  
Group A ◽  
Derivatives Of ◽  
Carbonyl Function

Oleanolic acid, one of the most known triterpenes, was subjected to different chemical transformations within C-3 β-hydroxyl group, a double bond between C-12 and C-13, and a carboxyl function at C-17 in order to obtain new derivatives. The key compound consists of four six-membered rings (A, B, D, E) and one enlarged ring (C ring) containing a nitrogen atom and a carbonyl function – lactam. This type of derivative can be obtained by Beckmann rearrangement of the appropriate oxime. The lactam can be transformed into thiolactam with the use of Lavesson's reagent. The method is also presented for new derivatives synthesis, as well as their structure elucidation by spectroscopic means.

scholarly journals Refractive dispersion of organic compounds. V-Oxygenated derivatives of cyclohexane the inadequacy of the Ketteler-Helmholtz equation

1934 ◽  
Vol 146 (857) ◽  
pp. 300-312 ◽  
Keyword(s):  
Double Bond ◽  
Preceding Paper ◽  
Hydroxyl Group ◽  
Double Bonds ◽  
Ring Compounds ◽  
Wide Range ◽  
Olefinic Double Bond ◽  
The One ◽  
Conjugated Compounds ◽  
Derivatives Of

In the preceding paper of this series, refractive indices and molecular extinction coefficients over a wide range of wave-lengths were recorded for the two cyclic hydrocarbons cyclohexene and 1:3- cyclohexadiene . These observations completed a study of the refractive dispersions of the series of 6-ring compounds C 6 H 12 , C 6 H 10 , C 6 H 8 , C 6 H 6 ; they also provided a basis for the study of the phenomenon of "optical exaltation," which is exhibited by compounds containing conjugated double bonds, since the last two members of the series belong to this type. Conjugation, however, may be effected, not only between two olefinic double bonds, but also between an olefinic double bond and an oxygenated radical, such as the carboxyl, carbonyl, or hydroxyl group. The present paper, therefore, records the absorption spectra and refractive dispersions of three oxygenated derivated of cyclohexane, namely, cyclohexanol , cyclohexanone , and ethyl hexahydrobenzoate , in the molecules of which each of the preceding groups is exemplified. Dispersion curves are thus now available for typical compounds of the cyclohexane series containing "unsaturated" radicals of all the principal types which are used in constructing conjugated systems, and the way has been prepared for a detailed study of conjugation, as exemplified on the one hand by cyclo hexadiene, and similar compounds containing two olefinic radicals, and on the other hand by a variety of compounds containing a double bond in addition to a hydroxyl, carbonyl, or carboxyl group. It is anticipated that, with the help of the date set out in the preceding and present papers, it will be possible in a later communication to demonstrate in what respect the behaviour of conjugated compounds differs from that which might be anticipated from a merely additive behaviour of the chromophoric radicals, and thus to determine the nature, and if possible to discover the origin, of the phenomenon of optical exaltation.

ChemInform Abstract: SYNTHESIS OF DERIVATIVES OF TRICYCLO(2.1.0.02,5)PENTANE WITH AN EXOCYCLIC DOUBLE BOND

1977 ◽  
Vol 8 (32) ◽  
pp. no-no
Author(s):  
N. S. ZEFIROV ◽  
N. V. AVERINA ◽  
A. M. BOGANOV ◽  
T. S. KUZNETSOVA ◽  
S. S. YAROVOI
Keyword(s):  
Double Bond ◽  
Exocyclic Double Bond ◽  
Derivatives Of

Theoretical Investigations on the Role of Steroid-Skeleton C4 = C5 Unsaturation in Competitive Aromatase Inhibition

1989 ◽  
Vol 44 (3-4) ◽  
pp. 217-225 ◽  
Author(s):  
Martin Bohl ◽  
Zeno Simon ◽  
Jens Reiner Lochmann
Keyword(s):  
Double Bond ◽  
Competitive Inhibition ◽  
Quantitative Structure Activity Relationship ◽  
Hydroxyl Group ◽  
Theoretical Investigations ◽  
Derivatives Of ◽  
Ring Position ◽  
Steroid Skeleton ◽  
Good Agreement

Abstract A quantitative structure-activity relationship (QSAR ) approach by use of the minimal topological difference (MTD) method including 46 derivatives of 4-androstene-3,17-dione and 5a-androstane- 3,17-dione is applied to give indications about the role of the C 4 = C5 double bond in competitive inhibition of human placental aromatase and about sterical requirements in steroidaromatase interactions. The inhibitory activity is found to correlate with the sterical MTD variable, hydrophobicity, and π-system conjugation in the A,B-ring region. A comparison of the MTD results reveals a good agreement with interpretations based on freeenergy data derived from inhibition constants. By means of MM2 molecular mechanics and PCILO quantum-chemical calculations, the 4-ene structure is shown to significantly influence conformational features of C19 substituents which are important in enzym atic transformations. While 19-hydroxy-5a-androstane-3,17-dione favour a conformation having the hydroxyl group in the enzyme-directed out-of-ring position, the C 4 = C5 double bond energetically enables the steroid to adopt a conformation which can be hydroxylated without internal rotations. According to present theoretical findings, the 4-ene unsaturation thus exerts an indirect conformational influence by hydroxyl positioning appropriate to aromatase interactions and a direct electronic influence by π conjugation.

Biochemically important reactions of 2-furylethylenes. Reactions with low-molecular thiols

1982 ◽  
Vol 47 (5) ◽  
pp. 1523-1529 ◽  
Author(s):  
Ernest Šturdík ◽  
Tibor Liptaj ◽  
Štefan Baláž ◽  
Ľudovít Drobnica
Keyword(s):  
Biological Activity ◽  
Double Bond ◽  
Aqueous Medium ◽  
Exocyclic Double Bond ◽  
Nmr Analysis ◽  
Sh Groups ◽  
Derivatives Of

As evidenced by spectrophotometry and radiochromatography, derivatives of 2-furylethylene are able to react with thiols in an aqueous medium. The NMR analysis of reaction mixture showed that the site attacked by the thiol is the more electrophilic C(1) atom of the exocyclic double bond of the 2-furylethylenes under study. The ability to react with SH groups is of extraordinary importance particularly in connection with the study of mechanism of biological activity of 2-furylethylenes.

Chemistry of meso-Dimethylaminopropenyl- porphyrins and -bisporphyrins: the Synthesis of Australochlorin, a Benzochlorin Isomer.

1997 ◽  
Vol 50 (5) ◽  
pp. 487 ◽  
Author(s):  
Dmitry V. Yashunsky ◽  
Gelii V. Ponomarev ◽  
A. S. Moskovkin ◽  
Dennis P. Arnold
Keyword(s):  
Acetic Acid ◽  
Double Bond ◽  
Trifluoroacetic Acid ◽  
Membered Ring ◽  
Macrocyclic Complexes ◽  
Exocyclic Double Bond ◽  
Derivatives Of

The nickel(II) complex of meso-dimethylaminoprop-1-enyloctaethylporphyrin (2c) was converted by quaternization and thermolysis into a pair of novel isomeric macrocyclic complexes (3) and (4). These have a fused six-membered ring, and an exocyclic double bond on the neighbouring β-position, and have been named ‘australochlorins’. Heating these compounds in acetic acid leads to the known nickel(II) octaethylbenzochlorin (1) and a novel β-(1-acetoxyethyl)benzochlorin (5). Trifluoroacetic acid promotes the regioselective formation of benzochlorin/porphyrin species from the mononickel(II) complexes of the acrolein derivatives of bis(octaethylporphyrinyl)ethane and trans-ethene.

scholarly journals Synthesis of novel spiro-isoxazoline and spiro-isoxazolidine derivatives of tomentosin

RSC Advances ◽  
2017 ◽  
Vol 7 (11) ◽  
pp. 6523-6529 ◽  
Author(s):  
Mohamed Zaki ◽  
Abdelouahd Oukhrib ◽  
Mohamed Akssira ◽  
Sabine Berteina-Raboin
Keyword(s):  
Double Bond ◽  
Dipolar Cycloaddition ◽  
Exocyclic Double Bond ◽  
Enantiomerically Pure ◽  
Nitrile Oxides ◽  
Dittrichia Viscosa ◽  
Derivatives Of

A series of novel enantiomerically pure spiro-(isoxazolidines/isoxazolines) were synthesized regioselectively by 1,3-dipolar cycloaddition using nitrones and nitrile oxides, on the exocyclic double bond of tomentosin extracted from Dittrichia viscosa.

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