One-pot Synthetic Approaches for the Construction of Isochroman-4-ones and Benzoxazin-3-ones Using O,P-Acetals

Synthesis ◽  
2021 ◽  
Author(s):  
Akira Nakamura ◽  
Kouhei Yamamoto ◽  
Ryo Murakami ◽  
Norihito Kawashita ◽  
Kouichi Matsumoto ◽  
...  
Keyword(s):  
Carbon Atom ◽  
Intramolecular Cyclization ◽  
Heterocyclic Compounds ◽  
Functional Group ◽  
Methylene Carbon ◽  
One Pot ◽  
Methylene Carbon Atom ◽  
Synthetic Approaches ◽  
Sequential Reactions

A method for synthesizing six-membered heterocyclic compounds was developed based on the features of O,P-acetals. Sequential reactions of intramolecular cyclization between the methylene carbon atom of O,P-acetal and its electrophilic functional group (ester or protected carbamate) was followed by Horner-Wadsworth-Emmons (HWE) olefination with various aldehydes. The developed one-pot method yielded isochroman-4-one and benzoxazin-3-one derivatives with an alkylidene moiety.

The Synthesis of 5,7-Dichlorocoumaran-3-one and Related Problems

1960 ◽  
Vol 13 (1) ◽  
pp. 95 ◽  
Author(s):  
WLF Armarego
Keyword(s):  
Acetic Acid ◽  
Carbon Atom ◽  
Intramolecular Cyclization ◽  
Phosphorus Pentoxide ◽  
Dichlorophenoxyacetic Acid ◽  
Methylene Carbon ◽  
Methylene Carbon Atom ◽  
Stage Synthesis ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
Dichlorophenoxy Acetic Acid

5,7-Dichlorocoumaran-3-one has been prepared from methyl 2-hydroxy-3,5-dichlorobenzoate by a three stage synthesis. It could not be prepared by (i) intramolecular cyclization of 2,4-dichlorophenoxy- acetic acid or 2,4-dichlorophenoxyacetyl chloride or (ii) by the reaction of ω-bromo-2-hydroxy-3,5-dichloroacetophenone with bases. The reaction of 2,4-dichlorophenoxyacetic acid with phosphorus pentoxide in benzene gave 2,4-dichlorophenol, 2',4'-dichlorophenyl 2,4-dichlorophenoxyacetate, and diphenylmethane. By the use of 14C-labelled acids the methylene carbon atom of the diphenylmethane was shown to be derived from the methylene carbon atom of 2,4-dichlorophenoxyacetic acid. A possible mechanism is proposed for this reaction.

scholarly journals The effect of adenosine triphosphate on porphyrin excretion and on glycine metabolism in Rhodopseudomonas spheroides

1968 ◽  
Vol 106 (1) ◽  
pp. 185-192 ◽  
Author(s):  
A. Gajdos ◽  
M. Gajdos-Török ◽  
A. Gorchein ◽  
A. Neuberger ◽  
G. H. Tait
Keyword(s):  
Carbon Dioxide ◽  
Fatty Acid ◽  
Carbon Atom ◽  
Marked Effect ◽  
Methylene Carbon ◽  
Methylene Carbon Atom ◽  
Glycine Metabolism ◽  
Porphyrin Synthesis ◽  
Rhodopseudomonas Spheroides ◽  
Carboxyl Carbon

1. ATP, GTP, CTP and UTP at concentrations of 1mm markedly decrease the amount of coproporphyrin excreted by Rhodopseudomonas spheroides illuminated in a medium containing glycine, succinate and fumarate. 2. The effect of ATP is decreased if ethionine is also added to the medium. 3. Evidence is presented showing that ATP is taken up by the organisms from the medium. 4. ATP is shown to have a marked effect on the utilization of glycine. In the presence of ATP the incorporation of the methylene carbon atom of glycine into the fatty acid moieties of the phospholipids is greatly increased, and more of the carboxyl carbon atom is lost, probably as carbon dioxide. 5. ATP has little effect on the utilization of succinate or fumarate. 6. The possible significance of these results with regard to the control by ATP of porphyrin synthesis and excretion and glycine metabolism is discussed.

The stereochemistry of β -diketo complexes with trimethylplatinum iv. III. The crystal structure of trimethyl (acetylacetonyl-) 2:2'-bipyridyl platinum

1962 ◽  
Vol 266 (1327) ◽  
pp. 527-546 ◽  
Keyword(s):  
Crystal Structure ◽  
Carbon Atom ◽  
Three Dimensional ◽  
Crystal Structure Analysis ◽  
Method Of Least Squares ◽  
Methylene Carbon ◽  
X Ray ◽  
Methylene Carbon Atom ◽  
Active Methylene ◽  
Oxygen Atoms

The results of an X -ray crystal structure analysis of the crystalline complex, (CH 3 ) 3 Pt(CH 3 . CO . CH . CO . CH 3 )C 10 H 8 N 2 , formed by trimethylplatinum with acetylacetone and 2:2'-bipyridyl are presented. There are four monomeric molecules in a monoclinic unit cell having a = 14.863, b = 8.480, c = 13.749 Å, β = 99° 24' at 110±10 °K and space group P 2 1 / c . The atomic positions have been determined by three-dimensional analysis from observations collected at 100 to 120 °K. Refinement, including allowance for anisotropic thermal motion, was carried out by the method of least squares until the value of the residual R was 0.084. The platinum atom is octahedrally co-ordinated to three methyl groups in the cis configuration (Pt—C = 2.05 Å), to the two nitrogen atoms of the bipyridyl (Pt—N = 2.15 Å) and to the central or ‘active methylene’ carbon atom of acetylacetone (Pt—C = 2.36 Å). The oxygen atoms of the acetylacetone take no part in the co-ordination; this is the first example of a β -diketone acting as an unidentate ligand solely through a carbon atom. Comparison of the bond lengths in this and in the dimeric trimethyl 4:6-dioxononyl platinum suggests that in both compounds the β -diketone is in the keto and not the enol form; in the present compound the oxygen atoms are not chelated and the C=0 bonds are not parallel.

The Effect of Chemical Changes in the Rubber Hydrocarbon on Its Oxidizability

1951 ◽  
Vol 24 (2) ◽  
pp. 229-231
Author(s):  
Jean Le Bras ◽  
Jacqueline de Merlier
Keyword(s):  
Double Bond ◽  
Carbon Atom ◽  
Maleic Anhydride ◽  
Type Ii ◽  
Methylene Carbon ◽  
Chemical Changes ◽  
Isoprene Unit ◽  
Methylene Carbon Atom ◽  
Substitutive Addition ◽  
Related Compounds

Abstract The hydrocarbon of rubber, which contains one ethylene linkage or double bond per isoprene unit, has such a structure that it is very sensitive to the action of oxygen, and the investigations of Farmer have shown clearly the part played by the α-methylene carbon atom in the process of oxidation. Since the rubber hydrocarbon can be made to react with compounds which unite directly with it, an attempt was made to find out what influence any changes of this kind might have on the oxidiazbility of rubber. The reagents chosen were saligenol and maleic anhydride. According to Cunneen, Farmer, and Koch, saligenol attaches itself to double bonds, with formation of a chromanic nucleus (I), the nature of which the present authors have examined and confirmed by ultraviolet spectrography of the compounds prepared. In the case of maleic anhydride, Delalande has shown that this compound and also related compounds, such as maleic imide, can combine according to the substitutive addition mechanism described by Alder, with the formation of a molecule of type (II). The reactions were carried out with exclusion of air, in accordance with the technique of Moureu and Dufraisse on benzene solutions of purified crepe rubber, and in the absence of a catalyst.

scholarly journals PEG-SO3H promoted one pot grinding method for the synthesis of 2-amino-4H-chromene-3-carboxylates

2020 ◽  
Vol 11 (4) ◽  
pp. 5321-5327
Author(s):  
Mahesh S ◽  
Balaji G L
Keyword(s):  
Heterocyclic Compounds ◽  
Catalytic Amount ◽  
One Pot ◽  
Simple Method ◽  
Grinding Method ◽  
Medical Need ◽  
Three Component Reaction ◽  
Wide Range ◽  
Synthetic Approaches ◽  
Short Time

There is a crucial medical need for the synthesis of 4H-chromene compounds via simple efficient methods. 4H-chromene compounds are stated to have a wide range of medicinal applications such as anti-bacterial, anti-cancer (EPC2407 and MX58151), antimalarial, antifungal, anti-rheumatic and anti-viral properties depending up on the substituents which is present on the heterocyclic compounds. Nowadays multi component protocols shows a better advantages such as better yield, less reaction time and no usage of different solvents for synthesis of biological important heterocyclic compounds over other synthetic approaches. The operational simplicity and applicability of this protocol to various analogues make it an alternative to previous reported methods.Therefore, this work was to prepare a series of 4H-chromene analogues via simple method with short time. Here, we reported the synthesis of 2-amino-4H-chromene-3-carboxylates using green solvent(water) under grinding method by one pot three component reaction of substituted aldehydes, dimedone and cyano acetates. This reaction was catalysed by catalytic amount of PEG-SO3H at room temperature. This catalyst proved the efficient for synthesis of many heterocyclic compounds. This reaction proceeds with very short time i.e. 5 mins. The 2-amino-4H-chromene derivatives (4a-i) was obtained with excellent yields(85-94%).

scholarly journals Advances in Green Catalysis for the Synthesis of Medicinally Relevant N-Heterocycles

Catalysts ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1108
Author(s):  
A. Sofia Santos ◽  
Daniel Raydan ◽  
José C. Cunha ◽  
Nuno Viduedo ◽  
Artur M. S. Silva ◽  
...  
Keyword(s):  
Heterocyclic Compounds ◽  
Heterogeneous Catalysts ◽  
Catalytic Synthesis ◽  
Biologically Active ◽  
Synthetic Methods ◽  
One Pot ◽  
Metal Catalyzed ◽  
The Individual ◽  
Green Catalysis ◽  
Synthetic Approaches

N-heterocycles, both saturated and unsaturated, are ubiquitous biologically active molecules that are extremely appealing scaffolds in drug discovery programs. Although classical synthetic methods have been developed to access many relevant N-heterocyclic scaffolds, representing well-established and reliable routes, some do not meet the needs of sustainability. In this context, several advances have been made towards the sustainable synthesis of N-heterocycles. This review focuses on the most recent examples from the last five years of catalytic synthesis of several heterocyclic compounds of medicinal relevance. Thus, the synthesis of isoindoloquinazolines, quinazolines and azaindoles, among others, are covered. The synthetic methods selected include the use of homogeneous and heterogeneous catalysts and the use of alternative and sustainable methods such as, for example, metal-catalyzed acceptorless coupling and one-pot reactions. The green aspects of the individual synthetic approaches are highlighted, and the scope of each methodology is described.

scholarly journals Crystal structure of 1-butyl-3-{2-[(indan-5-yl)amino]-2-oxoethyl}-1H-imidazol-3-ium chloride

2018 ◽  
Vol 74 (11) ◽  
pp. 1665-1668
Author(s):  
Vidya Zende ◽  
Tejpalsingh Ramsingh Girase ◽  
Nicolas Chrysochos ◽  
Anant Ramakant Kapdi ◽  
Carola Schulzke
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Carbon Atom ◽  
Aromatic Ring ◽  
Methylene Carbon ◽  
Hydrogen Bonding Interactions ◽  
Methylene Carbon Atom ◽  
Molecular Salt

In the cation of the title molecular salt, C18H24N3O+·Cl−, an intramolecular C—H...O hydrogen bond stabilizes the almost coplanar orientation of the aromatic ring of the indane unit and the amide plane. In the crystal, the packing is dominated by intermolecular C—H...Cl hydrogen-bonding interactions that result in the formation of slab-like structures propagating along [010]. The slabs are linked by weak C—H...O interactions, forming layers lying parallel to (100). The methylene carbon atom of the indanyl substituent is disordered over two positions with a refined occupancy ratio of 0.84 (2):0.16 (2). The crystal studied was refined as a twin with matrix [1 0 0.9, 0 \overline{1} 0, 0 0 \overline{1}]; the resulting BASF value is 0.30.

One-pot access to 2-oxazolines via a Castro-Stephens coupling and intramolecular cyclization

2021 ◽  
Vol 08 ◽  
Author(s):  
Dnyaneshwar Nighot ◽  
Arvind Kumar Jain ◽  
Imran Ali ◽  
Varun Rawat
Keyword(s):  
Organic Chemistry ◽  
Biological Activity ◽  
Intramolecular Cyclization ◽  
Heterocyclic Compounds ◽  
Cross Coupling ◽  
One Pot ◽  
Alcohol Group ◽  
Xrd Studies ◽  
Oxazoline Derivatives

Aim: Here, we have reported easy one-pot access to a series of oxazolines using a modified Castro-Stephens coupling protocol. Background: 2-oxazolines have been shown to have significant biological activity and wide-ranging applications in organic chemistry. These properties make oxazolines as heterocyclic compounds of immense importance. Objective: The objective of this study is to synthesize oxazoline derivatives via an economical and one-pot protocol. Method: 2-oxazoline has been synthesized through Cu-powder mediated Castro-Stephens coupling and intramolecular cyclization route. The mechanism involves a rearrangement in which one of the oxygen from the N-acylamino alcohol group is liberated as water and then transferred to alkyne functionality to form 2-oxazoline derivatives. The oxazolines were characterized by NMR, mass, and XRD studies. Result: The protocol is economically viable and uses readily available Cu-powder along with DMF for cross-coupling and cyclization steps.

Metal-Free Photoinduced Hydroalkylation Cascade Enabled by an Electron-Donor-Acceptor Complex

2020 ◽  
Author(s):  
José Tiago Menezes Correia ◽  
Gustavo Piva da Silva ◽  
Camila Menezes Kisukuri ◽  
Elias André ◽  
Bruno Pires ◽  
...  
Keyword(s):  
Electron Donor ◽  
Functional Group ◽  
Photoexcited Electron ◽  
One Pot ◽  
Quaternary Centers ◽  
Metal Free ◽  
Acceptor Complex ◽  
Catalyst Free ◽  
Donor Acceptor ◽  
Radical Cascade

A metal- and catalyst-free photoinduced radical cascade hydroalkylation of 1,7-enynes has been disclosed. The process is triggered by a SET event involving a photoexcited electron-donor-aceptor complex between NHPI ester and Hantzsch ester, which decomposes to afford a tertiary radical that is readily trapped by the enyne. <a>The method provides an operationally simple, robust and step-economical approach to the construction of diversely functionalized dihydroquinolinones bearing quaternary-centers. A sequential one-pot hydroalkylation-isomerization approach is also allowed giving access to a family of quinolinones. A wide substrate scope and high functional group tolerance was observed in both approaches</a>.

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