Unexpected regiospecific Michael addition product: synthesis of 5,6-dihydrobenzo[1,7]phenanthrolines

RSC Advances ◽  
2015 ◽  
Vol 5 (48) ◽  
pp. 38640-38645 ◽  
Author(s):  
Selvaraj Mohana Roopan ◽  
Annadurai Bharathi ◽  
Jeyakannu Palaniraja ◽  
K. Anand ◽  
R. M. Gengan
Keyword(s):  
Michael Addition ◽  
Addition Product ◽  
Unexpected Formation ◽  
First Time

The unexpected formation of 5,6-dihydrobenzo[1,7]phenanthroline instead of 5,6-dihydrobenzo[1,7]phenanthroline-3-carbonitrile in acridine molecules using Michael addition has been observed for the first time.

Catalyst-Free One-Pot Synthesis of Novel Heteroarylamine Substituted Furo[3,2-c]coumarins

Synlett ◽  
2018 ◽  
Vol 29 (12) ◽  
pp. 1589-1592 ◽  
Author(s):  
Abolfazl Olyaei ◽  
Mahnaz Saraei ◽  
Reyhaneh Khoeiniha
Keyword(s):  
Michael Addition ◽  
Aldol Condensation ◽  
Ring Closure ◽  
Dehydration Reaction ◽  
One Pot ◽  
Catalyst Free ◽  
One Pot Synthesis ◽  
Tandem Process ◽  
First Time

A high-yielding cyclocondensation of 4-hydroxycoumarin, phenylglyoxal monohydrate, and heteroarylamines proceeds without catalysis, which gives novel functionalized furo[3,2-c]coumarins and heteroarylamino alkylation of coumarin products in acetonitrile under reflux, is reported for the first time. This tandem process involves sequentially an aldol condensation, Michael addition, a ring closure, and dehydration reaction.

A concentration dependent auto-relay-recognition by the same analyte: a dual fluorescence switch-on by hydrogen sulfide via Michael addition followed by reduction and staining for bio-activity

2016 ◽  
Vol 14 (2) ◽  
pp. 570-576 ◽  
Author(s):  
Avijit Kumar Das ◽  
Shyamaprosad Goswami ◽  
Gorachand Dutta ◽  
Sibaprasad Maity ◽  
Tarun kanti Mandal ◽  
...  
Keyword(s):  
Hydrogen Sulfide ◽  
Michael Addition ◽  
Dual Role ◽  
Dual Fluorescence ◽  
Fluorescence Switch ◽  
First Time

H2S is shown, for the first time, to play an extraordinary dual role due to its nucleophilicity and reducing property with a single chemosensor.

Syntheses of C-nucleosides. IX. Reactions of D,L-3,4-di-O-isopropylidene-2,5-anhydroallose with Wittig reagents. Syntheses of bis-homo anhydro-C-nucleosides.

1976 ◽  
Vol 54 (18) ◽  
pp. 2940-2947 ◽  
Author(s):  
George Just ◽  
Mohabir Ramjeesingh ◽  
Teng Jiam Liak
Keyword(s):  
Michael Addition ◽  
Nmr Spectra ◽  
Addition Product

The nmr spectra of the two anomers of 1-O-acetyl-3,4-di-O-isopropylidene-2,5-anhydro-D,L-allose (2a, 2b) are discussed. The reactions of D,L-3,4-di-O-isopropylidene-2,5-anhydroallose (1) with carbethoxymethylenetriphenylphosphorane, bromocarbethoxymethylenetriphenylphosphorane and ethyl triphenylphosphoranylidene pyruvate to give respectively the olefin derivatives 7, 9, and 10 and an internal Michael addition product 11 are described. From 11, two bis-homo anhydro-C-nucleosides having 6-azauracil (15) and 4-hydroxy-5-carbox-amidopyrazole (19) bases were synthesized.

scholarly journals Synthesis of interesting β-nitrohydrazides through a thiourea organocatalysed aza-Michael addition

RSC Advances ◽  
2014 ◽  
Vol 4 (19) ◽  
pp. 9856-9865 ◽  
Author(s):  
Ana Alcaine ◽  
Eugenia Marqués-López ◽  
Raquel P. Herrera
Keyword(s):  
Michael Addition ◽  
Target Product ◽  
First Time

The synthesis of interesting β-nitrohydrazides, as the target product of our reaction, is reached for the first time under organocatalytic enantioselective conditions.

scholarly journals Comment on “An unexpected formation of the novel 7-oxa-2-azabicyclo[2.2.1]hept-5-ene skeleton during the reaction of furfurylamine with maleimides and their bioprospection using a zebrafish embryo model” by C. E. Puerto Galvis and V. V. Kouznetsov, Org. Biomol. Chem., 2013, 11, 407

2017 ◽  
Vol 15 (30) ◽  
pp. 6447-6450 ◽  
Author(s):  
F. I. Zubkov ◽  
E. A. Kvyatkovskaya ◽  
E. V. Nikitina ◽  
P. N.-A. Amoyaw ◽  
V. V. Kouznetsov ◽  
...  
Keyword(s):  
Michael Addition ◽  
Zebrafish Embryo ◽  
The Novel ◽  
Unexpected Formation

It has been proved that the reaction between furfuryl amines and N-R-maleimides leads to the formation of aza-Michael addition products – 3-(furylmethylamino)-N-R-pyrrolidine-2,5-diones, instead of 7-oxa-2-azabicyclo[2.2.1]hept-5-enes, as this journal reported previously.

scholarly journals A novel and practical synthesis of iclaprim

2020 ◽  
Author(s):  
Weiyuan Liu ◽  
Liang Chen ◽  
Jing Pan ◽  
Ting Zhou ◽  
Kuaile Lin ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Acetic Anhydride ◽  
Michael Addition ◽  
Knoevenagel Condensation ◽  
Total Yield ◽  
Buffer System ◽  
Facile Synthesis ◽  
Practical Synthesis ◽  
First Time ◽  
Amino Protection

A novel and facile synthesis of iclaprim was reported. Started from Trimethoprim (TMP), the amino-protection and Friedel-Crafts acetylation with acetic anhydride were simultaneously completed in CH2Cl2 with SnCl4 as catalyst. The Knoevenagel condensation of 2,4-diamino-5-(2-acetyl-3-hydroxy-4,5-dimethoxybenzyl)pyrimidine with cyclopropyl carboxaldehyde followed by the intramolecular Michael addition in the buffer system (pyrrolidine and acetic acid) installed the key framework (chromanone 13). The dehydration was catalyzed by H2SO4 so that the formation of 5-cyclopropyl-2,3-dimethoxy-4,5,6,6a,7,12-hexahydronaphtho[1,8-bc]pyrimido[5,4-f]azepin-9-amine, an impurity of iclaprim reported at the first time, could be minimized. In the end, iclaprim was obtained in a total yield of 21%.

The Thomson Synthesis of (–)-GB17

2015 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Michael Addition ◽  
Physiological Activity ◽  
Addition Product ◽  
Systematic Investigation ◽  
Unsaturated Ester ◽  
Wide Range ◽  
Stereogenic Centers ◽  
Northwestern University ◽  
Convergent Assembly ◽  
Stereogenic Center

(–)-GB17 3 is one of the Galbulimima alkaloids, a family that shows a wide range of interesting physiological activity. Regan J. Thomson of Northwestern University devised (Angew. Chem. Int. Ed. 2012, 51, 2481) a convergent assembly of 3, a key step of which was the intramolecular Michael cyclization of 1 to 2. The hydroxy aldehyde 6 was prepared by alkylation of the dithiane 4 with 5, followed by hydrolysis. The preparation of 9, by condensation of 8 with 7 followed by hydrogenation and protection, had been reported by Lhommet. Condensation of 9 with the linchpin reagent 10 gave an intermediate keto phosphonate, which was combined with 6 to give, after oxidation, the aldehyde 1. Two new stereogenic centers are created in the course of the cyclization of 1. The authors found that the TFA salt 11 of the Hayashi catalyst delivered 2 with high diastereocontrol. Control experiments showed that the buttressing effect of the dithiane was required for the cyclization. The authors then explored the next intramolecular Michael cyclization of 13 to 14. In this cyclization, the stereogenic center at 6 is in jeopardy by elimination and readdition. Cyclization of the trans unsaturated ester led to the wrong diastereomer of 14, but cyclization of the cis ester 13, prepared by the Still-Gennari protocol, cleanly gave the desired diastereomer. The reaction worked best with the free amine. Under the conditions of the reaction the Michael addition product spontaneously cyclized to the lactam 14. The ketone of 14 was selectively enolized, then converted to its enol triflate, which under Pd-mediated reduction gave the alkene 15. Alkylation of 15 with 16 predominantly gave the diene 18. Hydrolysis of the dithiane to the ketone followed by reduction gave mainly the desired equatorial alcohol, which was cleaved oxidatively to (–)-GB17 3. Although there have been many isolated reports of the utility of intramolecular Michael addition as a synthetic method, there has been little systematic investigation. The optimization studies that are the heart of this work are a welcome addition.

Direct organocatalytic asymmetric Michael reaction of fluorine hemiaminal-type nucleophile to 4-nitro-5-styrylisoxazoles

2020 ◽  
Vol 7 (11) ◽  
pp. 1343-1348
Author(s):  
Luyao Li ◽  
Bo Zhu ◽  
Huihui Fan ◽  
Zhiyong Jiang ◽  
Junbiao Chang
Keyword(s):  
Michael Addition ◽  
Michael Reaction ◽  
Addition Reaction ◽  
Michael Addition Reaction ◽  
Asymmetric Michael Addition ◽  
Asymmetric Michael Reaction ◽  
First Time

Herein, we report a chiral bifunctional thiourea catalyzed asymmetric Michael addition reaction between 2-(trifluoromethyl)oxazol-5(2H)-one as a direct C-2-position nucleophile to 4-nitro-5-styrylisoxazoles for the first time.

Origin of stereoselectivity in an isothiourea catalyzed Michael addition reaction of aryl ester with vinyl disulfone

2020 ◽  
Vol 44 (41) ◽  
pp. 17906-17911
Author(s):  
Congcong Wang ◽  
Shi-Jun Li ◽  
Min Zhang ◽  
Donghui Wei ◽  
Lina Ding
Keyword(s):  
Michael Addition ◽  
Addition Reaction ◽  
Michael Addition Reaction ◽  
First Time ◽  
Aryl Ester

The origin of stereoselectivity in an isothiourea-catalyzed addition reaction of aryl ester with vinyl disulfone was explored for the first time.

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