scholarly journals Addition of some 6-amino-4-aryl-2(1H)-pyridones to phenylisocyanate and related reactions

2019 ◽  
Vol 74 (2) ◽  
pp. 191-195
Author(s):  
Lyubomir Dimitrov Raev ◽  
Ivo Christov Ivanov ◽  
Silviya Georgieva Agontseva
Keyword(s):  
Michael Addition ◽  
Acetyl Derivative ◽  
Phenyl Isocyanate ◽  
Crystallographic Analysis ◽  
Molar Ratio ◽  
X Ray ◽  
The Michael Addition

AbstractThe Michael addition of enaminoesters to coumarins leads to the formation of the rearranged adduct 1 whose structure has been previously elucidated by X-ray crystallographic analysis. Now, N- and/or O-carbamoylation of the 6-amino-2-pyridone 1 by treatment with phenyl isocyanate in a molar ratio of 1:1 and 1:2 gave N-mono- (2a) or N,O-bis-(phenylcarbamoyl) (3) derivatives, respectively. Further transformations of the corresponding new 2-pyridone derivative 2a into the O-acetyl derivative 2b and the chromeno[3,4-c]pyridine 4 are reported as well.

A Base-Promoted One-Pot Asymmetric Friedel–Crafts Alkylation/Michael Addition of 4-Substituted Indoles

Synthesis ◽  
2019 ◽  
Vol 52 (08) ◽  
pp. 1215-1222
Author(s):  
Robert Connon ◽  
Laura Carroll ◽  
Patrick J. Guiry
Keyword(s):  
Michael Addition ◽  
Crystallographic Analysis ◽  
Indole Derivatives ◽  
One Pot ◽  
X Ray ◽  
Excellent Yield ◽  
Tricyclic Core ◽  
Cyclobutane Derivative

Herein, we report a base-promoted Zn(II)–bis(oxazoline)-catalyzed one-pot Friedel–Crafts alkylation/Michael addition of 3-(indol-4-yl)acrylonitrile derivatives with trans-β-nitrostyrenes to yield the tricyclic core of the ergoline skeleton in up to 71% yield and 85% ee. During the purification of 3-(indol-4-yl)acrylonitrile, the key substrate for catalytic studies, a novel trans-cis-trans-cyclobutane derivative, thought to be formed via a [2+2] light-promoted cycloaddition, was identified by X-ray crystallographic analysis. Finally, a novel class of 4-substituted bis(indole)methane derivatives were serendipitously prepared in excellent yield by reacting 4-substituted indole derivatives with 4-nitrobenzaldehyde. One bis(indole)methane was characterized by X-ray crystallographic analysis.

Base mediated dimerization of 2-tetradecynoic acid

1983 ◽  
Vol 61 (11) ◽  
pp. 2449-2454 ◽  
Author(s):  
Suzanne R. Abrams ◽  
J. Wilson Quail ◽  
Louis T. J. Delbaere
Keyword(s):  
Sodium Salt ◽  
Michael Addition ◽  
Dimethyl Ester ◽  
Crystallographic Analysis ◽  
Strong Base ◽  
X Ray ◽  
Crude Product ◽  
Monomethyl Ester

Under the influence of the very strong base, the sodium salt of 1,2-diaminoethane in 1,2-diaminoethane, 2-tetradecynoic acid is converted to 3-tetradecynoic acid (35%) and a novel dimer 3. Compound 3 ((Z)-2-(1-dodecynyl)-3-undecyl-pent-2-en-1,5-dioic diacid) is isolated as the monomethyl ester 1 after treatment of the crude product with methanolic HCl. The structures of 1 and 3 are deduced from an X-ray crystallographic analysis of the dimethyl ester 2 obtained by reaction of 1 with diazomethane. The dimer 3 is thought to arise from Michael addition of the dianion 4 of 3-tetradecynoic acid with the sodium salt of 2-tetradecynoic acid.

On the Stereoselectivity of the (-)-Dimenthyl Malonate Addition to α,β-Unsaturated Ketones

1996 ◽  
Vol 61 (12) ◽  
pp. 1805-1814 ◽  
Author(s):  
Ľubomír Šebo ◽  
Juraj Alföldi ◽  
Grety Rihs ◽  
Štefan Toma
Keyword(s):  
Michael Addition ◽  
Pure State ◽  
Nmr Spectra ◽  
Reaction Products ◽  
X Ray ◽  
Unsaturated Ketones ◽  
H Nmr ◽  
The Michael Addition

The Michael addition of (-)-dimenthyl malonate to eight α,β-unsaturated ketones has been studied. The ratio of diastereomers was calculated on the basis of the 1H NMR spectra of the crude reaction products. The diastereomer excess varied from 10 to 50%, depending on the structure of the starting enone. The pure diastereomer produced by addition of (-)-dimenthyl malonate to 2-benzylidene-1,4-indandione was isolated by repeated crystallization. X-ray analysis has shown that the isomer is (-)-dimenthyl (R)-2-[1-(1,3-dioxoindan-2-yl)-1-phenylmethyl]malonate (5a). The predominating diastereomers of (-)-dimenthyl(3-ferrocenyl-3-oxophenylpropyl)malonate (1a) and (-)-dimenthyl-2-(1-(1,3-dioxo[3]ferrocenophan-2-yl)-1-phenyl malonate (6a) were also isolated in pure state by careful crystallization.

Stereoselectivity of Michael Addition to 3-Phenyl-1-(η6-o-tolyltricarbonylchromium)propenone

1994 ◽  
Vol 59 (12) ◽  
pp. 2621-2631 ◽  
Author(s):  
Ľubomír Šebo ◽  
Ján Šraga ◽  
Grety Rihs ◽  
Štefan Toma
Keyword(s):  
Michael Addition ◽  
Dimethyl Malonate ◽  
X Ray ◽  
The Michael Addition

The stereoselectivity of the Michael addition of several C-nucleophiles to 3-phenyl-1-(η6-o-tolyltricarbonylchromium)propenone has been studied. The ratio of diastereoisomers formed varied from 65 : 35 (malonodinitrile), 72 : 28 (methyl cyanoacetate) and 78 : 22 (nitromethane) and to 90 : 10 (dimethyl malonate). The ratio of diastereoisomers 63 : 37 was found even when addition of dimethyl malonate was carried out at 75 °C in methanol using piperidine as the catalyst. The (S,R) or (R,S) configuration of the main pair of isomers was proved by the X-ray analysis of the dimethyl malonate adduct.

Absolute Konfiguration von (+)-1,2,3,4,6,7,8,8a-Octahydro-6-isochinolon- 8a-carbonsäuremethylester und die Stereochemie einer Kupfer-katalysierten asymmetrischen Michael-Reaktion / Absolute Configuration of Methyl (+)-1,2,3,4,6,7,8,8a-Octahydro-6-isoquinolone-8a-carboxylate and Stereochemistry of a Copper-Catalyzed Asymmetric Michael Reaction

2004 ◽  
Vol 59 (4) ◽  
pp. 375-379 ◽  
Author(s):  
Jens Christoffers ◽  
Wolfgang Frey ◽  
Heiko Scharl ◽  
Angelika Baro
Keyword(s):  
Absolute Configuration ◽  
Michael Addition ◽  
Michael Reaction ◽  
Addition Product ◽  
Crystallographic Analysis ◽  
Subsequent Reaction ◽  
X Ray ◽  
Quaternary Stereocenter ◽  
Asymmetric Michael Reaction

AbstractEnantiopure Boc-protected piperidine derivative (+)-5c, with a quaternary stereocenter, was obtained by copper-catalyzed, L-valine diethylamide-mediated Michael reaction. For determination of the absolute configuration, 5c was derivatized by cyclization with pyrrolidine/AcOH to give compound 6 with bicyclo[4.4.0]-constitution, deprotection of the amino function with TFA and subsequent reaction with 2-iodobenzoic acid to yield the crystalline bicyclic amide 7. X-ray crystallographic analysis confirmed the constitution of compounds 5c and 6 and established the (R) configuration of 7. Thus, starting Michael addition product (+)-5c has to be (S) configured, because an epimerization at the quaternary stereocenter is excluded. This result is in accordance with our working model of the Cu-catalyzed, auxiliary-assisted Michael reaction.

scholarly journals Concise Diastereoselective Total Synthesis of (±)-Parvistemonine A

Synlett ◽  
2020 ◽  
Vol 31 (18) ◽  
pp. 1800-1804
Author(s):  
Kazuyuki Sugita ◽  
Rintaro Matsuo ◽  
Ayumu Miyashita ◽  
Motoi Kuwabara ◽  
Shinya Adachi ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Michael Addition ◽  
Wittig Reaction ◽  
Crystallographic Analysis ◽  
Mitsunobu Reaction ◽  
X Ray ◽  
Linear Sequence ◽  
Relative Stereochemistry ◽  
Key Steps ◽  
First Time

AbstractWe have developed a concise diastereoselective total synthesis of (±)-parvistemonine A. By using a Mukaiyama–Michael addition, an aza-Wittig reaction, a Paal–Knorr pyrrole synthesis, an acid-mediated annulation, and a Mitsunobu reaction as key steps, we achieved a total synthesis in which the longest linear sequence was ten steps and the overall yield was 19.6%. Additionally, the relative stereochemistry of parvistemonine A was confirmed by X-ray crystallographic analysis for the first time.

A One-Pot Intramolecular Tandem Michael–Aldol Annulation Reaction for the Synthesis of Chiral Pentacyclic Terpenes

Synthesis ◽  
2019 ◽  
Vol 51 (21) ◽  
pp. 3964-3972
Author(s):  
Jianyu Lu ◽  
Serkan Koldas ◽  
Huafang Fan ◽  
John Desper ◽  
Victor W. Day ◽  
...  
Keyword(s):  
Michael Addition ◽  
Aldol Condensation ◽  
Crystallographic Analysis ◽  
Side Chain ◽  
One Pot ◽  
X Ray ◽  
Double Ring ◽  
Stereogenic Centers

A chiral tricyclic terpene possessing a 6,6,6-tricyclic framework and a 3,3-dimethyl-7-oxooctylidenyl side chain undergoes a double ring-closing reaction to give two chiral pentacyclic terpenes in a ratio of 4:3 via an intramolecular Michael addition followed by aldol condensation under basic conditions. Three new stereogenic centers are introduced in the initial Michael annulation reaction. Stereoselective installation of an ethoxycarbonyl group at C17 of the two pentacyclic terpenes separately gives the corresponding highly functionalized pentacyclic terpenoids with seven stereogenic centers. The structures and stereochemistry of key intermediates and products are established through X-ray crystallographic analysis. A mechanism is proposed for explaining the stereochemistry in the Michael annulation reaction.

Synthesis of steroidal [4,6-b,c]-benzothiazepines, a new class of aromatase inhibitor

1995 ◽  
Vol 73 (12) ◽  
pp. 2185-2189 ◽  
Author(s):  
Herbert L. Holland ◽  
Sudalaiyandi Kumaresan ◽  
Gingipalli Lakshmaiah
Keyword(s):  
Aromatase Inhibitor ◽  
Michael Addition ◽  
Competitive Inhibitor ◽  
Crystallographic Analysis ◽  
X Ray ◽  
New Class ◽  
Acidic Conditions

Several steroidal [4,6-b,c]benzothiazepines have been prepared via base-catalyzed Michael addition of 2-aminothiophenol to 3β,17β-diacetoxyandrost-4-en-6-one. The product of this reaction has the 4β,5α stereochemistry, but cyclizes to a benzothiazepine with the steroidal 4β,5β configuration, confirmed by X-ray crystallographic analysis. 2-Aminothiophenol reacts with 3β,17β-diacetoxyandrost-4-en-6-one under acidic conditions to give a steroidal 6-spiro-benzothiazole. An androst-4-ene-3,17-dione-based [4,6]benzothiazepine has been shown to be a moderate competitive inhibitor of the human placental aromatase enzyme with IC50 = 42.3 µM. Keywords: steroid, aromatase, benzothiazepine.

scholarly journals Synthesis of 2H-Chromene-4-Carbonitriles Via Trimethylsilyl Cyanide

2018 ◽  
Vol 42 (6) ◽  
pp. 297-299 ◽  
Author(s):  
Demin Ren ◽  
Hexiu Liu ◽  
Yulin Huang ◽  
Xinliang Fu ◽  
Xiaofang Li
Keyword(s):  
Michael Addition ◽  
Crystallographic Analysis ◽  
X Ray ◽  
Trimethylsilyl Cyanide ◽  
Tetrabutylammonium Fluoride ◽  
Elimination Pathway

A number of 2-aryl-2 H-chromene-4-carbonitriles were synthesised by cyanation of 2-aryl-3-nitro-2 H-chromenes using trimethylsilyl cyanide (TMSCN) in the presence of tetrabutylammonium fluoride (TBAF) in moderate yields via a Michael addition/elimination pathway. The structures of all the products were characterised thoroughly by NMR, IR and HRMS spectroscopy and X-ray crystallographic analysis.

scholarly journals Synthesis of 2-(1-Oxo-2,3-Dihydro-1H-Pyrrolizin-2-yl)-2-(Aryl)Acetonitrile Derivatives Via Michael Addition of Trimethylsilyl Cyanide

2018 ◽  
Vol 42 (9) ◽  
pp. 467-470 ◽  
Author(s):  
Demin Ren ◽  
Jiaying Lei ◽  
Xianyong Yu ◽  
Yulin Huang ◽  
Xiaofang Li
Keyword(s):  
Mass Spectrometry ◽  
High Resolution ◽  
Michael Addition ◽  
High Resolution Mass Spectrometry ◽  
Crystallographic Analysis ◽  
X Ray ◽  
Trimethylsilyl Cyanide ◽  
Tetrabutylammonium Fluoride ◽  
High Resolution Mass ◽  
Resolution Mass

Several 2-aryl-2-(1-oxo-2,3-dihydro-1 H-pyrrolizin-2-yl)acetonitrile derivatives were synthesised by Michael addition of ( E)-2-arylidene-2,3-dihydro-1 H-pyrrolizin-1-ones with trimethylsilyl cyanide in the presence of tetrabutylammonium fluoride in moderate yields. The structures of all of the products were fully characterised by NMR, IR and high-resolution mass spectrometry, together with X-ray crystallographic analysis.

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