3,3'-Dipyrrolyl sulfides, useful building blocks for the syntheses of macrocycles containing dipyrromethene units

2003 ◽  
Vol 81 (9) ◽  
pp. 988-991 ◽  
Author(s):  
Qingqi Chen ◽  
David Dolphin
Keyword(s):  
Key Words ◽  
Building Blocks ◽  
Acidic Conditions ◽  
High Yields

5,5'-Dicarboxy-3,3'-dipyrrolyl sulfide was condensed with 5,5'-diformyl-3,3'-dipyrrolyl sulfide or 5,5'-diformyldipyrromethane under acidic conditions to produce, in high yields, macrocycles containing four dipyrromethene units. Key words: 3,3-dipyrrolyl sulfide, cyclopolypyrrole, dipyrromethene, macrocycle.

Stereospecific, Palladium-catalyzed C(sp3)–H Alkenylation and Alkynylation of a Proline Derivative Enabled by 8-Aminoquinoline as a Directing Group

2020 ◽  
Author(s):  
Aleksandra Balliu ◽  
Aaltje Roelofje Femmigje Strijker ◽  
Michael Oschmann ◽  
Monireh Pourghasemi Lati ◽  
Oscar Verho
Keyword(s):  
Carboxylic Acid ◽  
Building Blocks ◽  
Wide Range ◽  
Palladium Catalyzed ◽  
Directing Group ◽  
High Yields ◽  
Vinyl Iodides ◽  
Initial Results

<p>In this preprint, we present our initial results concerning a stereospecific Pd-catalyzed protocol for the C3 alkenylation and alkynylation of a proline derivative carrying the well utilized 8‑aminoquinoline directing group. Efficient C–H alkenylation was achieved with a wide range of vinyl iodides bearing different aliphatic, aromatic and heteroaromatic substituents, to furnish the corresponding C3 alkenylated products in good to high yields. In addition, we were able show that this protocol can also be used to install an alkynyl group into the pyrrolidine scaffold, when a TIPS-protected alkynyl bromide was used as the reaction partner. Furthermore, two different methods for the removal of the 8-aminoquinoline auxiliary are reported, which can enable access to both <i>cis</i>- and <i>trans</i>-configured carboxylic acid building blocks from the C–H alkenylation products.</p>

scholarly journals Synthesis of 4-Substituted-1,2-Dihydroquinolines by Means of Gold-Catalyzed Intramolecular Hydroarylation Reaction of N-Ethoxycarbonyl-N-Propargylanilines

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3366
Author(s):  
Antonio Arcadi ◽  
Andrea Calcaterra ◽  
Giancarlo Fabrizi ◽  
Andrea Fochetti ◽  
Antonella Goggiamani ◽  
...  
Keyword(s):  
Building Blocks ◽  
Fine Tuning ◽  
Para Position ◽  
Cyclization Product ◽  
Synthetic Route ◽  
Substituted Anilines ◽  
Novel Approach ◽  
High Yields

An alternative Au(I)-catalyzed synthetic route to functionalized 1,2-dihydroquinolines is reported. This novel approach is based on the use of N-ethoxycarbonyl protected-N-propargylanilines as building blocks that rapidly undergo the IMHA reaction affording the 6-endo cyclization product in good to high yields. In the presence of N-ethoxycarbonyl-N-propargyl-meta-substituted anilines, the regiodivergent cyclization at the ortho-/para-position is achieved by the means of catalyst fine tuning.

scholarly journals Synthesis and Antiproliferative Activity of Phosphorus Substituted 4-Cyanooxazolines, 2-Aminocyanooxazolines, 2-Iminocyanooxazolidines and 2-Aminocyanothiazolines by Rearrangement of Cyanoaziridines

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4265
Author(s):  
Victor Carramiñana ◽  
Ana M. Ochoa de Ochoa de Retana ◽  
Francisco Palacios ◽  
Jesús M. de los de los Santos
Keyword(s):  
Ring Opening ◽  
Human Lung ◽  
Ring Expansion ◽  
Moderate Activity ◽  
A549 Cell Line ◽  
One Pot ◽  
Acidic Conditions ◽  
Lung Adenocarcinoma A549 ◽  
High Yields

Several phosphorus-substituted N-acylated cyanoaziridines 2 and N-carbamoylated cyanoziridines 5 were prepared in good to high yields. N-Acylated cyanoaziridines 2 were used, after ring expansion, in an efficient synthesis of oxazoline derivative 3a and in a completely regio-controlled reaction in the presence of NaI. Conversely, N-carbamoyl cyanoaziridines 5 reacted with NaI to obtain a regioisomeric mixture of 2-aminocyanooxazolines 7. Mild acidic conditions can be used for the isomerization of N-thiocarbamoyl cyanoaziridine 6a into a 2-aminocyanothiazoline derivative 8a by using BF3·OEt2 as a Lewis acid. Likewise, a one pot reaction of NH-cyanoaziridines 1 with isocyanates obtained 2-iminocyanooxazolidines 9 regioselectively. This synthetic methodology involves the addition of isocyanates to starting cyanoaziridines to obtain N-carbamoyl cyanoaziridines 5, which after the ring opening, reacts with a second equivalent of isocyanate to give the final 2-imino cyanooxazolidines 9. In addition, the cytotoxic effect on the cell lines derived from human lung adenocarcinoma (A549) was also screened. 2-Iminooxazolidines 9 exhibited moderate activity against the A549 cell line in vitro. Furthermore, a selectivity towards cancer cells (A549) over non-malignant cells (MCR-5) was detected.

Nucleic acid related compounds. 63. Synthesis of 5′-deoxy-5′-methyleneadenosine and related Wittig-extended nucleosides

1991 ◽  
Vol 69 (2) ◽  
pp. 334-338 ◽  
Author(s):  
Stanislaw F. Wnuk ◽  
Morris J. Robins
Keyword(s):  
Nucleic Acid ◽  
Key Words ◽  
Organic Bases ◽  
Key Words Adenosine ◽  
Tosyl Group ◽  
High Yields ◽  
Related Compounds

Treatment of the purified 5′-aldehyde (2a) (derived from 6-N-benzoyl-2′,3′-O-isopropylideneadenosine (1a)) with methylenetriphenylphosphorane and successive deprotection with ammonia and acid gave 9-(5,6-dideoxy-β-D-ribo-hex-5-enofuranosyl)adenine (5′-deoxy-5′-methyleneadenosine) (4). Oxidation of 1a or 2′,3′-O-isopropylideneadenosine (1b) and treatment of the crude 5′-aldehydes (2a or 2b) with (p-toluenesulfonylmethylene)triphenylphosphorane gave high yields of the 5′-deoxy-5′-tosylmethylene derivatives (5a or 5b). Removal of the tosyl group from 5b to give 3b was effected with tributylstannyllithium, but sulfone cleavage by the usual reductive methods failed. Reduction and deprotection of 5a or 5b gave 9-[5,6-dideoxy-6-(p-toluenesulfonyl)-β-D-ribo-hexofuranosyl]adenine (6b). Isomerization of the vinyl tosyl (5b) to a 4′,5′-unsaturated allylic tosyl derivative (7) occurred under cleavage conditions and in solutions of aqueous or organic bases. Key words: adenosine, 5′-deoxyadenosine, 5′-methylene-5′-deoxyadenosine, nucleosides.

scholarly journals Bifurcated synthesis of methylene-lactone- and methylene-lactam-fused spirolactams via electrophilic amide allylation of γ-phenylthio-functionalized γ-lactams

2020 ◽  
Vol 16 ◽  
pp. 2769-2775
Author(s):  
Tetsuya Sengoku ◽  
Koki Makino ◽  
Ayumi Iijima ◽  
Toshiyasu Inuzuka ◽  
Hidemi Yoda
Keyword(s):  
Hydroxy Group ◽  
The Other ◽  
Synthetic Methods ◽  
Other Hand ◽  
Acidic Conditions ◽  
High Yields

New synthetic methods for spirolactams bearing an α-methylene-γ-butyrolactone or its analogous methylene-lactam have been developed. The allylation of γ-phenylthio-functionalized γ-lactams with 2-(acetoxy)methyl acrylamides was accomplished by using 2.5 equivalents of NaH to give the corresponding adducts in excellent yields. The remaining phenylthio group was substituted with a hydroxy group by treatment with CuBr, and the resulting γ-hydroxyamides were cyclized under acidic conditions to afford the corresponding methylene-lactam-fused spirolactams in high yields. On the other hand, methylene-lactone-fused spirolactams could be delivered from the allyl adducts in high yields through a sequential N-Boc protection/desulfinative lactonization.

Highly Selective One-Pot Synthesis of Polysubstituted Isoflavanes using Styryl Ethers and Electron-Withdrawing ortho-Quinone Methides Generated In Situ

Synlett ◽  
2018 ◽  
Vol 30 (02) ◽  
pp. 189-192 ◽  
Author(s):  
Yujiro Hoshino ◽  
Kiyoshi Honda ◽  
Kenta Tanaka ◽  
Mami Kishimoto ◽  
Naoya Ohtsuka ◽  
...  
Keyword(s):  
Biologically Active ◽  
Quinone Methides ◽  
One Pot ◽  
One Pot Synthesis ◽  
Reaction Proceeds ◽  
Acidic Conditions ◽  
High Yields

A highly selective one-pot synthesis of polysubstituted isoflavanes has been developed. The reaction proceeds through the cycloaddition of methyl styryl ethers, derived from phenylacetaldehyde dimethyl acetals under acidic conditions, with electron-withdrawing ortho-quinone methides generated in situ. When phenylacetaldehyde dimethyl acetals were reacted with salicylaldehydes, the reaction proceeded smoothly to afford the corresponding isoflavanes stereoselectively in high yields and with excellent regioselectivities. The present reaction provides versatile access to functionalized isoflavanes, and constitutes a useful tool for the synthesis of biologically active molecules.

Synthesis of a hexasaccharide fragment of the capsular polysaccharide of Streptococcus pneumoniae type 3

2002 ◽  
Vol 80 (1) ◽  
pp. 76-81 ◽  
Author(s):  
Dirk J Lefeber ◽  
Eneko Aldaba Arévalo ◽  
Johannis P Kamerling ◽  
Johannes FG Vliegenthart
Keyword(s):  
Streptococcus Pneumoniae ◽  
Key Words ◽  
Selective Oxidation ◽  
Capsular Polysaccharide ◽  
Building Blocks ◽  
Oligosaccharide Synthesis ◽  
Tempo Oxidation ◽  
Carboxylic Groups ◽  
New Generation ◽  
Type 3

In the framework of the development of a new generation of neoglycoconjugate vaccines against Streptococcus pneumoniae, the synthesis is described of a spacer-containing hexasaccharide fragment related to the capsular polysaccharide of S. pneumoniae type 3. Hexasaccharide β-D-GlcpA-(1[Formula: see text]4)-β-D-Glcp-(1[Formula: see text]3)-β-D-GlcpA-(1[Formula: see text]4)-β-D- Glcp-(1[Formula: see text]3)-β-D-GlcpA-(1[Formula: see text]4)-β-D-Glcp-(1[Formula: see text]O-(CH2)3NH2) (1), comprised of three repeating units, was synthesized via a blockwise strategy employing suitably protected disaccharide building blocks. Carboxylic groups were introduced by selective oxidation with TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxy) in the last reaction steps. Deprotection afforded target hexasaccharide 1.Key words: oligosaccharide synthesis, Streptococcus pneumoniae type 3, TEMPO oxidation.

A facile method to fabricate hydrogels from DMSO polymer gels via solvent exchange

2017 ◽  
Vol 41 (12) ◽  
pp. 4793-4796 ◽  
Author(s):  
Heekyoung Choi ◽  
Misun Go ◽  
Yubin Cha ◽  
Yeonweon Choi ◽  
Ki-Young Kwon ◽  
...  
Keyword(s):  
Polymer Gels ◽  
Building Blocks ◽  
Solvent Exchange ◽  
Acidic Conditions

A mixture of the bipyridine, phenyl and/or cyclohexanediamine-based building blocks 1, 2, and/or 3, having hydrazide, aldehyde or amine moieties, respectively, formed DMSO polymer gels by the hydrazone reaction under acidic conditions.

Iridium-catalyzed acid-assisted asymmetric hydrogenation of oximes to hydroxylamines

Science ◽  
2020 ◽  
Vol 368 (6495) ◽  
pp. 1098-1102 ◽  
Author(s):  
Josep Mas-Roselló ◽  
Tomas Smejkal ◽  
Nicolai Cramer
Keyword(s):  
Room Temperature ◽  
Asymmetric Hydrogenation ◽  
Selective Reduction ◽  
Building Blocks ◽  
Efficient Catalyst ◽  
Cyclopentadienyl Ligand ◽  
Acidic Conditions ◽  
Asymmetric Hydrogenations ◽  
Metal Catalyzed ◽  
Oxygen Bond

Asymmetric hydrogenations are among the most practical methods for the synthesis of chiral building blocks at industrial scale. The selective reduction of an oxime to the corresponding chiral hydroxylamine derivative remains a challenging variant because of undesired cleavage of the weak nitrogen-oxygen bond. We report a robust cyclometalated iridium(III) complex bearing a chiral cyclopentadienyl ligand as an efficient catalyst for this reaction operating under highly acidic conditions. Valuable N-alkoxy amines can be accessed at room temperature with nondetected overreduction of the N‒O bond. Catalyst turnover numbers up to 4000 and enantiomeric ratios up to 98:2 are observed. The findings serve as a blueprint for the development of metal-catalyzed enantioselective hydrogenations of challenging substrates.

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