Sterically Crowded Heterocycles. VII. Reduction of Some (Z)-1,3-Diphenyl-3-(2-phenylimidazo[1,2-a]pyridin-3-yl)prop-2-en-1-ones as Their Axial Chirality Probe

1996 ◽  
Vol 61 (7) ◽  
pp. 1018-1026 ◽  
Author(s):  
Richard Kubík ◽  
Stanislav Böhm ◽  
Josef Kuthan
Keyword(s):  
Hydroxy Derivative ◽  
Borohydride Reduction ◽  
Axial Chirality ◽  
Pm3 Calculations

Borohydride reduction of titled ketones 1a-1g gave diastereoisomeric mixtures of (Z)-1,3-diphenyl-3-(2-phenylimidazo[1,2-a]pyridin-3-yl)prop-2-en-1-ols 2a-2g and 3a-3g in which the former ones prevailed. Only individual racemic products were obtained after borohydride reduction of (E)-1,3-diphenyl-3-(2-phenylimidazo[1,2-a]pyridin-3-yl)-prop-2-en-1-one 4 to corresponding 1-hydroxy derivative 5 and by conversion of (Z)-1-oxo derivative 1a to 1,3-diphenyl-3-(2-phenylimidazo[1,2-a]pyridin-3-yl)propan-1-one (6) with sodium hydrogenselenide. Diastereoselectivity of the borohydride reduction is discussed using the PM3 calculations of the molecules 1a, 2a, 2b, 3a, 3b, 4, 5, and 6.

Synthesis of (15E)-17β-hydroxy-5α-androstane-3,15-dione 15-[O-(Carboxymethyl)]oxime, New Hapten for Dihydrotestosterone (17β-hydroxy-5α-androstan-3-one)

1997 ◽  
Vol 62 (10) ◽  
pp. 1642-1649 ◽  
Author(s):  
Ivan Černý ◽  
Tereza Slavíková ◽  
Vladimír Pouzar
Keyword(s):  
Hydroxy Group ◽  
Carboxy Group ◽  
Title Compound ◽  
Oxidative Cleavage ◽  
Hydroxy Derivative ◽  
Borohydride Reduction ◽  
Protecting Group ◽  
Free Hydroxy Group

Addition of 4-methoxybenzyl alcohol to 3β-hydroxy-5α-androst-15-en-17-one gave the mixture of isomeric 15-(4-methoxyphenyl)methoxy derivatives from which, after acetylation and chromatography, the major 15β isomer was separated. Borohydride reduction gave 17β-hydroxy derivative which was protected as methoxymethyl ether. Oxidative cleavage of protecting group at position 15 and the subsequent Jones oxidation afforded corresponding 15-ketone. Its oximation with O-(carboxymethyl)hydroxylamine, deacetylation and methylation with diazomethane gave protected O-(carboxymethyl)oxime derivative with free hydroxy group at position 3. Its oxidation afforded dihydrotestosterone derivative and successive deprotection of position 17 and of carboxy group led to final (15E)-17β-hydroxy-5α-androstane-3,15-dione 15-[O-(carboxymethyl)]oxime. The title compound was designed as dihydrotestosterone hapten for heterologous radioimmunoassays.

Alumina-K3PO4 Solid Supported Microwave Synthesis of 1, 3-diaryl-2- propene-1-one Derivatives as a Prominent Antioxidant Scavenger

2020 ◽  
Vol 7 (2) ◽  
pp. 145-156
Author(s):  
Pravinkumar Patil ◽  
Gangadhar Bhopalkar ◽  
Sainath Zangade
Keyword(s):  
Antioxidant Activity ◽  
Reaction Time ◽  
Microwave Irradiation ◽  
Spectral Studies ◽  
Hydroxy Derivative ◽  
Scavenging Activity ◽  
Short Reaction Time ◽  
Basic Alumina ◽  
Ic50 Value ◽  
Nitric Oxide Radical

Background: The various industrial processes have a diverse effect on the environment through pollution. In view of these observations, some environmentally benign synthetically protocols have developed under green chemistry. For rapid and sustainable synthesis, the microwave irradiation (MI) has gained popularity as a powerful tool compared to conventional synthesis. The present study describes the synthesis of novel substituted 1, 3-diaryl-2-propene-1-one derivative using alumina supported K3PO4-MWI combination. Objective: Chalcones are important compounds which are widely spread in nature like in fruits, vegetables, tea, spices, etc. The 2’-hydroxy derivative of chalcones plays an important role in the synthesis of bioactive compounds. The present communication deals with a convenient and rapid synthesis of 1, 3-diaryl-2-propene-1-one under the support of alumina-tripotassium phosphate and microwave irradiation. Our efforts are focused on the introduction of typical and easier route for the synthesis of title compounds using a microwave. All synthesized chalcones have been screened and evaluated for the antioxidant activity by DPPH and nitric oxide radical scavenging. Some of these compounds are found to be more potent scavengers and may lead to the development of a new class of antioxidants. Methods: The α, β-unsaturated carbonyl functionality contains two electrophilic centers allowing them to undergo addition and cyclization reactions with different nucleophiles. In the literature survey, we found that Chalcones were synthesized using tripotassium phosphate catalyst under refluxing by a conventional method. A novel method for the synthesis of 1, 3-diaryl-2-propene-1-one via Claisen Schmidt has been introduced by reacting substituted 2’- hydroxyl acetonaphthones with substituted aromatic aldehydes under the support of basic alumina –tripotassium phosphate via microwave radiations. Formation of corresponding Chalcones was confirmed by spectral studies followed by their screening for antioxidant activity. The scavenging activity is expressed in terms of % inhibition and IC50 value (μg/ml). Results: The structures of newly synthesized Chalcones were confirmed and in good agreement with obtained spectral analysis such as IR, NMR, Mass and elemental analysis. Commercially available basic alumina and tripotassium phosphate in combination of microwave were utilized and found to be effective, convenient route for the synthesis of 1, 3-diaryl-2-propene-1-one derivatives with desirable yields in short reaction time (5-12 min). The results of antioxidant activity revealed that the IC50 value for compounds 3a, 3d, 3e, 3f, 3g, 3h, 3j, 3l and 3n are lower than that of standard ascorbic acid to scavenge DPPH radical. This indicates that these compounds are more significant scavengers in comparison with standard drug. On the other hand, compounds 3a, 3b, 3c, 3d, 3g, 3l and 3n are more potent scavengers for NO free radical. Conclusion: We have introduced an efficient, ecofriendly, simple and fast microwave assisted method using basic alumina-tripotassium phosphate for the synthesis of 1, 3-diaryl-2-propene-1- one derivatives. Microwave irradiation provides an effective way for the preparation of Chalcones in terms of several advantages as a simple procedure, short reaction time, milder reaction condition, cleaner reaction and excellent yield. The scavenging activity of chalcones against DPPH and NO free radicals showed excellent properties of antioxidants.

N‐Heterocyclic Carbene‐Catalyzed Atroposelective Annulation for Access to Thiazine Derivatives with C−N Axial Chirality

2021 ◽  
Vol 60 (17) ◽  
pp. 9362-9367
Author(s):  
Tingting Li ◽  
Chengli Mou ◽  
Puying Qi ◽  
Xiaolin Peng ◽  
Shichun Jiang ◽  
...  
Keyword(s):  
Axial Chirality

scholarly journals Asymmetric Alkenyl Catellani Reaction for the Construction of C–N Axial Chirality

2021 ◽  
Author(s):  
Qianghui Zhou ◽  
Chenggui Wu ◽  
Yong Shang ◽  
Chang Liu ◽  
Ze-Shui Liu ◽  
...  
Keyword(s):  
Axial Chirality

ChemInform Abstract: PYRIDAZINES. LXXXIV. STUDIES ON BOROHYDRIDE REDUCTION OF PYRIDAZINE COMPOUNDS

1976 ◽  
Vol 7 (52) ◽  
pp. no-no
Author(s):  
P. K. KADABA ◽  
B. STANOVNIK ◽  
M. TISLER
Keyword(s):  
Borohydride Reduction

Effect of metabolites on ε-N-hydroxylysine formation in cell-free extracts of Aerobacter aerogenes 62-1

1977 ◽  
Vol 55 (6) ◽  
pp. 625-629 ◽  
Author(s):  
G. J. Murray ◽  
G. E. D. Clark ◽  
M. A. Parniak ◽  
T. Viswanatha
Keyword(s):  
Enzymatic Activity ◽  
Hydroxy Derivative ◽  
Differential Centrifugation ◽  
Hydroxylase Activity ◽  
Aerobacter Aerogenes ◽  
Lactate And Pyruvate ◽  
First Time

The conversion of L-lysine to its corresponding ε-N-hydroxy derivative has been achieved for the first time by cell-free extracts of Aerobacter aerogenes 62-1. Partial fractionation by differential centrifugation (at 12 000 × g) revealed that both supernatant and pellet are essential for maximum enzymatic activity. The ω-N-hydroxylase (EC 1.14.99) was found to function optimally at pH 7–7.5 and exhibited an apparent Km of about 75 μM for L-lysine. L(+)-Lactate or DL-lactate and pyruvate greatly stimulate the ω-N-hydroxylase activity. The system is strongly inhibited by arsenite and sulfite.

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