Ammonium Chloride–Catalyzed One-Pot Synthesis of Tetrahydrobenzo[α]xanthen-11-one Derivatives Under Solvent-Free Conditions

A one-pot, multicomponent reaction of aldehydes, dimedone, and β-naphthols is described for the preparation of 12-aryl- or 12-alkyl-8,9,10,12-tetrahydrobenzo[α]xanthen-11-one derivatives using ammonium chloride as a mild, inexpensive, and environmentally benign catalyst under solvent-free conditions. Different types of aldehyde and β-naphthol derivatives are used in the reaction, and in all cases the products were synthesized successfully.

Amberlyst-15–Catalyzed Facile Synthesis of α-Amino Phosphonates

A simple and efficient method has been developed for the synthesis of sulfonamide phosphonates from N-tosyl aldimines and dimethyl trimethylsilyl phosphite at 0 °C in the presence of Amberlyst-15 as a heterogeneous catalyst.

Simple Strategy for Sulfonyl Ethynylogs of Coumarins

Synthesis of 3-(2-(phenylsulfonyl) ethynyl)-2H-chromen-2-one is described. Reaction of β-ketosulfones with semicarbazide hydrochloride in ethanol at reflux temperature gave the corresponding semicarbazones, which on oxidative cyclization with selenium dioxide resulted in the formation of the corresponding 1,2,3-selenodiazole derivatives. These on pyrolysis gave the titled compounds.

Recyclable Siloxy Serine Organocatalyst for the Direct Asymmetric Mannich Reactions in Ionic Liquids

A recyclable siloxy-L-serine organocatalyst has been developed to catalyze the asymmetric direct three-component Mannich reactions in ionic liquid hmim[PF₆], furnishing the β-amino carbonyl scaffold in high enantio- and diastereoselectivities. The direct Mannich reaction between a selection of aromatic aldehydes and ketones resulted in good yields and high enantioselectivities.

Preparation of Substituted Dihydrofluorenones by Photoisomerization of Benzotropolone Derivatives

The photoisomerization of the Diels–Alder adduct formed between tetramethylpurpurogallin and maleic anhydride is described. The process is highly stereoselective, involves the β,γ-unsaturated ketone chromophore present in the adduct, proceeds through the formation of allyl and aroyl radical intermediates, and leads to a novel substituted dihydrofluorenone in good yields.

Synthesis of 4-Methylene-1,3-naphthoxazines by the Reaction of Imines with Triphosgene

Reaction of 2-acetyl-1-naphthol with aliphatic amines under microwave irradiation gave the corresponding imines (Schiff bases), which were treated with triphosgene to give 4-methylene-1,3-naphthoxazines in good yields.

Natural α-Amino Acid L-Lysine–Catalyzed Knoevenagel Condensations of α,β-Unsaturated Aldehydes and 1,3-Dicarbonyl Compounds

Knoevenagel condensations of α,β-unsaturated aldehydes and 1,3-dicarbonyl compounds were catalyzed by primary natural amino acid L-lysine. The reactions were carried out at room temperature in dimethylsulfoxide. It provides a facile entry to a wide variety of α,β,γ,δ-unsaturated dicarbonyl compounds.

Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file.

Simple and Efficient One-Pot Synthesis of Nitriles from Amides and Oximes Using in Situ–Generated Burgess-Type Reagent

The dehydration of aldoximes and amides, and oxidation of benzoin are accomplished in one-pot using in situ–generated Burgess-type reagent.

Highly Efficient One-Pot Synthesis of 2-Aminobenzoxazoles Using Triflic Acid as a Cyclodesulfurizing Reagent

An efficient one-pot synthetic strategy for 2-aminobenzoxazoles was developed from isothiocyanates and 2-aminophenol using triflic acid as a cyclodesulfurizing reagent.

Synthesis of Bis(phosphonatomethyl)-, Bis(phosphinatomethyl)-, and Bis(phosphinoxidomethyl)amines,as Well as Related Ring Bis(phosphine) Platinum Complexes

The double Kabachnik–Fields condensation of primary amines with 2 equivalents of the other reagents (formaldehyde and a >P(O)H species, such as dialkyl phosphites, diphenylphosphine oxide, as well as the related dioxaphosphorine and oxaphosphorine derivatives) carried out under microwave conditions afforded the title products in 79–94% yields. The bis(phosphinoxidomethyl)amines were converted, after double deoxygenation, to the corresponding ring platinum complexes.

Zinc-Mediated Tandem-One-Pot Facile Synthesis of 1-(Arylsulfonyl) Aryl/Heteryl Methanes: A Case of C‒S Bond Formation

Reaction of arylmethyl/heteryl methyl zinc chloride (generated in situ from aryl methyl and heteryl methyl chloride and zinc metal) with aryl sulfonyl chlorides in tetrahydrofuran (THF) under mild conditions (i.e., at room temperature) furnishes the corresponding 1-(aryl sulfonyl)aryl/heteryl methanes in good yields.

Microwave-Accelerated Ruthenium-Catalyzed [2π + 2π] Cycloadditions of Dimethylacetylene Dicarboxylate with Norbornenes

An efficient and convenient procedure has been developed for the ruthenium-catalyzed [2π + 2π] cycloadditions of dimethylacetylene dicarboxylate with norbornenes. Reaction is significantly accelerated in microwave conditions, while the commonly used benzene solvent was replaced by environmentally benign tetrahydrofuran.

Deoxygenation of Aromatic Ketones Using Transfer Hydrogenolysis with Raney Nickel in 2-Propanol

Aryl ketones are readily deoxygenated to their corresponding aryl alkanes upon treatment with Raney nickel catalyst in boiling 2-propanol.

Improved Synthesis of Monoprotected 5- and 6-Amino-2-azanorbornanes

An improved synthesis of Boc-monoprotected 5- and 6-amino-2-azanorbornanes is reported. The synthetic scheme consists of five steps and allows multigram quantities of the title compounds to be obtained. The regio- and stereochemistries of the products are established by two-dimensional NMR experiments.

Use of Magnesium (Turnings) as a Powerful Catalyst for the O-Acylative Cleavage of Tetrahydrofuran

In a short reaction time, acyl chlorides and dry tetrahydrofuran react in the presence of a catalytic amount of magnesium turnings (Mg) at 25 °C to give 4-chlorobutyl esters in excellent yields.

Novel Synthetic Routes of 3-Methoxypropanal from Glycerol

A new synthesis of 3-methoxypropanal from glycerol was presented. With this new approach, the conversion of glycerol to 3-methoxypropanal can be effected in moderate yield using catalysts of copper sulfate and polyethylene glycol (PEG).

Tartaric Acid–Catalyzed Synthesis of α-Aminophosphonates Under Solvent-Free Conditions

A facile procedure is developed for the synthesis of α-aminophosphonates, using tartaric acid as a stable, environmentally benign, low cost, and easily available organocatalyst. In the presence of tartaric acid (10 mol%), triethyl phosphite reacts with imines (generated in situ from an aldehyde and an amine) to yield the corresponding α-aminophosphonates. The organocatalyst tartaric acid is more stable during reaction. The catalyst provides easier workup, affords better yields, and takes less reaction time in comparison to generally used Lewis acid catalysts.

Novel One-Pot Synthesis for 2,5-Diaryl and 5-Aryl-pyridazin-3(2H)-ones

A novel method for the synthesis of 2-phenyl-5-(o-hydroxyphenyl)-pyridazin-3(2H)-ones and 5-(o-hydroxyphenyl)-pyridazin-3(2H)-ones has been found during the reaction of 4-bromomethylcoumarins with phenylhydrazine and hydrazinehydrate, respectively, under controlled alkaline conditions.

Model Route to 5-Bromo-3,4-dihydro-4-hydroxy-7,9,10-trimethoxy-1,3-dimethyl-1H-naphtho[2,3-c]pyran: A Potential Precursor to Extended Quinones

A protocol has been developed for the synthesis of the linear naphthopyran 16, by the TiCl₄-catalyzed isomerization of 2,5-dimethyl dioxolane 1, having a methoxy group at position 1′ and a bromine atom at position 4′ of the naphthyl precursor to favor isomerization at position 2′.

Synthesis of Novel Cryptates Based on Triazole Motif: A Regioselective Approach

Regioselective syntheses of cryptands were achieved via two different approaches, first by protection–deprotection and second by cyclization reactions between 1,ω-dihaloalkanes and the lariat amino triazolophanes. The syntheses of all triazolophanes and cryptands were carried out regioselectively, and the compounds were obtained in good yields. All compounds were studied and confirmed with different spectroscopic tools.