Protecting groups for the pyrrole nitrogen atom. The 2-chloroethyl, 2-phenylsulfonylethyl, and related moieties

1983 ◽  
Vol 61 (8) ◽  
pp. 1697-1702 ◽  
Author(s):  
Carlos Gonzalez ◽  
Robert Greenhouse ◽  
Ramon Tallabs ◽  
Joseph M. Muchowski
Keyword(s):  
Nitrogen Atom ◽  
Michael Reaction ◽  
Phase Transfer ◽  
Homogeneous Solution ◽  
Sodium Hydride ◽  
Protecting Groups ◽  
Protecting Group ◽  
One Pot ◽  
Subsequent Degradation ◽  
Pyrrole Nitrogen

The 2-chloroethyl and 2-phenylsulfonylethyl moieties are versatile protecting groups for the pyrrole nitrogen atom. The 2-chloroethyl group is easily attached under phase transfer conditions using 1,2-dichloroethane. The 2-phenylsulfonylethyl moiety is readily appended under both phase transfer and homogeneous solution conditions using 2-phenylsulfonylcthyl chloride 5. Deprotection of the N-(2-chloroethyl)pyrroles is accomplished by means of efficient three-step, one-pot sequences via the N-vinyl compounds 3 and subsequent degradation of the N-(1-hydroxyethyl) compounds 4 or the acctoxymercuration derivatives 5 obtained therefrom. The 2-phenylsulfonylethyl group is excised by a reverse Michael reaction using sodium hydride or DBN as the base.The utility of the 2-chloroethyl protecting group is exemplified in a synthesis of benzyl cyclopenta[b] |pyrrole-5-carboxylate 13 from 1-(2-chloroethyl)-4-oxotetrahydroindolc 2d.

Verbesserte präparative Darstellung von Polyisopropyl- und Poly-tert-butylcyclopentadienen / Improved Preparation of Polyisopropyl- and -tert-butylcyclopentadienes

1993 ◽  
Vol 48 (4) ◽  
pp. 457-460 ◽  
Author(s):  
Eckehard V. Dehmlow ◽  
Christof Bollmann
Keyword(s):  
Potassium Hydroxide ◽  
Phase Transfer ◽  
Sodium Hydride ◽  
Aliquat 336 ◽  
Pt Catalysts ◽  
One Pot

Phase transfer catalytic isopropylation or tert-butylation of cyclopentadiene yields 1-6 in efficient one-pot procedures. Powdered potassium hydroxide or solid sodium hydride are the prefered bases, Aliquat 336 or dibenzo-18-crown-6 are the PT catalysts.

A Study on the Rearrangement of Dialkyl 1-Aryl-1-hydroxymethylphosphonates to Benzyl Phosphates

2020 ◽  
Vol 24 (4) ◽  
pp. 465-471 ◽  
Author(s):  
Zita Rádai ◽  
Réka Szabó ◽  
Áron Szigetvári ◽  
Nóra Zsuzsa Kiss ◽  
Zoltán Mucsi ◽  
...  
Keyword(s):  
Quantum Chemical ◽  
Room Temperature ◽  
Phase Transfer ◽  
One Pot ◽  
Substrate Dependence ◽  
Triethylbenzylammonium Chloride ◽  
One Step ◽  
The Pudovik Reaction ◽  
The One ◽  
Solid Liquid

The phospha-Brook rearrangement of dialkyl 1-aryl-1-hydroxymethylphosphonates (HPs) to the corresponding benzyl phosphates (BPs) has been elaborated under solid-liquid phase transfer catalytic conditions. The best procedure involved the use of triethylbenzylammonium chloride as the catalyst and Cs2CO3 as the base in acetonitrile as the solvent at room temperature. The substrate dependence of the rearrangement has been studied, and the mechanism of the transformation under discussion was explored by quantum chemical calculations. The key intermediate is an oxaphosphirane. The one-pot version starting with the Pudovik reaction has also been developed. The conditions of this tandem transformation were the same, as those for the one-step HP→BP conversion.

scholarly journals A One-Pot Approach to Novel Pyridazine C-Nucleosides

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2341
Author(s):  
Flavio Cermola ◽  
Serena Vella ◽  
Marina DellaGreca ◽  
Angela Tuzi ◽  
Maria Rosaria Iesce
Keyword(s):  
Organic Chemistry ◽  
Research Field ◽  
Modified Nucleosides ◽  
Protecting Groups ◽  
Coupling Reactions ◽  
One Pot ◽  
Pharmacological Interest ◽  
Classical Methodology ◽  
Glycosyl Donor ◽  
Neutral Conditions

The synthesis of glycosides and modified nucleosides represents a wide research field in organic chemistry. The classical methodology is based on coupling reactions between a glycosyl donor and an acceptor. An alternative strategy for new C-nucleosides is used in this approach, which consists of modifying a pre-existent furyl aglycone. This approach is applied to obtain novel pyridazine C-nucleosides starting with 2- and 3-(ribofuranosyl)furans. It is based on singlet oxygen [4+2] cycloaddition followed by reduction and hydrazine cyclization under neutral conditions. The mild three-step one-pot procedure leads stereoselectively to novel pyridazine C-nucleosides of pharmacological interest. The use of acetyls as protecting groups provides an elegant direct route to a deprotected new pyridazine C-nucleoside.

Short protecting-group-free synthesis of 5-acetylsulfanyl-histidines in water: novel precursors of 5-sulfanyl-histidine and its analogues

2016 ◽  
Vol 14 (44) ◽  
pp. 10473-10480 ◽  
Author(s):  
Sylvain Daunay ◽  
Remi Lebel ◽  
Laurence Farescour ◽  
Jean-Claude Yadan ◽  
Irene Erdelmeier
Keyword(s):  
Amino Acids ◽  
Protecting Group ◽  
One Pot ◽  
Step Procedure ◽  
Sulfur Containing

Natural and novel sulfur-containing amino acids are preparedviaa new regioselective one-pot two-step procedure.

ChemInform Abstract: Enantioselective Phase-Transfer-Catalyzed Intramolecular Aza-Michael Reaction: Effective Route to Pyrazino-Indole Compounds.

ChemInform ◽  
2008 ◽  
Vol 39 (34) ◽  
Author(s):  
Marco Bandini ◽  
Astrid Eichholzer ◽  
Michele Tragni ◽  
Achille Umani-Ronchi
Keyword(s):  
Michael Reaction ◽  
Phase Transfer ◽  
Indole Compounds

ChemInform Abstract: One-Pot Etherification of Ketones and Aldehydes with Organic Halides Using Sodium Hydride as a Reductant

ChemInform ◽  
2009 ◽  
Vol 40 (42) ◽  
Author(s):  
Qingwei Meng ◽  
Bin Gong ◽  
Chuang Hui ◽  
Zhanxian Gao
Keyword(s):  
Sodium Hydride ◽  
One Pot ◽  
Organic Halides

scholarly journals One-pot synthesis of (1RS,21SR)-diethyl 2-[23-amino-22-ethoxycarbonyl-8,11,14-trioxa-25-azatetracyclo[19.3.1.02,7.015,20]pentacosa-2,4,6,15(20),16,18,22-heptaen-25-yl]but-2-endioate

2018 ◽  
Vol 74 (9) ◽  
pp. 1281-1284
Author(s):  
Thi Thanh Van Tran ◽  
Tuan Anh Le ◽  
Hong Hieu Truong ◽  
Thi Nhung Dao ◽  
Anatoly T. Soldatenkov ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Molecular Conformation ◽  
Michael Reaction ◽  
Biological Activities ◽  
Boat Conformation ◽  
One Pot ◽  
Computer Prediction ◽  
Compound C ◽  
Intramolecular Hydrogen ◽  
The Michael Reaction

The title compound, C30H34N2O9 (4), is a product of the Michael reaction of azacrown ether with dimethyl acetylenedicarboxylate modified by an addition of NH3 (aq.) at 298 K. The aza-14-crown-4-ether ring adopts a bowl conformation. The dihedral angle between the planes of the benzene rings fused to the aza-14-crown-4-ether moiety is 8.65 (5)°. The tetrahydropyridine ring has a boat conformation. The molecular conformation is supported by one N—H...O and two C—H...O intramolecular hydrogen bonds. Both heterocyclic and amino N atoms have essentially planar configurations (sums of the bond angles are 359.35 and 358.00°). Compound 4 crystallizes as a racemate consisting of enantiomeric pairs of the 1R,21S diastereomer. In the crystal, molecules of 4 are connected by N—H...O hydrogen bonds, forming chains along [100]. According to the PASS program (computer prediction of biological activities), compound 4 may exhibit antiallergic (72% probability) and antiasthmatic (67%) activity, as well as be a membrane permeability inhibitor (65%).

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