Green and Practical Synthesis of Carbamates from Ureas and Organic Carbonates

A practical method for the synthesis of carbamates from ureas and organic carbonates was developed with 100% atom economy using La₂O₃/SiO₂ as catalyst without any additional solvent. The scope of the protocol is demonstrated in the synthesis of 14 carbamates with various functional groups in excellent yields (76–95%).

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.

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.

Solvent-Free Amination of Secondary Benzylic Alcohols with N-Nucleophiles Catalyzed by FeCl3

A general, simple, and environmentally friendly method for the direct amination of secondary benzyl alcohols with amides or 4-nitroaniline is described. This method has been applied to a variety of substrates, and the reaction proceeded smoothly at room temperature under solvent-free conditions. CbzNH₂ was proved to be very useful in the direct preparation of the benzylic amines from corresponding alcohols.

Three-Component,One-Pot Synthesis of 2,4,5-Trisubstituted Imidazoles Catalyzed by TiCl4-SiO2 Under Conventional Heating Conditions or Microwave Irradiation

In this study, silica-supported titanium tetrachloride was prepared and used as a novel catalyst for rapid and efficient synthesis of 2,4,5-trisubstituted imidazoles by a three-component, one-pot condensation of 1,2-diketones and aryl aldehydes in excellent yield under solvent-free conditions using conventional heating or microwave irradiation.

Stereoselective Synthesis of Dialkyl 2-(Arylsulfonylamino)-3-(dialkoxyphosphoryl) Succinates by Reaction of Trialkyl(aryl) Phosphites,Dialkyl Acetylenedicarboxylates,and Arylsulfonamides

A three-component reaction of trialkyl(aryl) phosphites, dialkyl acetylenedicarboxylates, and arylsulfonamides is described as a simple and efficient route for the synthesis of dialkyl 2-(arylsulfonylamino)-3-(dialkoxyphosphoryl)-succinates in good yields.

Kaolin/KOH Is an Efficient Heterogeneous Catalyst for the Synthesis of 3-Hydroxy-3-indolyl Oxindoles

3-Hydroxy-3-indolyl oxindoles were synthesized from isatins and indoles in good to excellent yields by using heterogeneous catalyst kaolin preloaded with KOH.

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.

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.

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.

Reductive Studies on 3-Oxidopyrylium-alkene [5 + 2] Cycloadducts: Access to Some Hydroxy Cycloheptenoids

The scope of nickel boride as a versatile reducing reagent is extended to the 3-oxidopyrylium-alkene [5 + 2] cycloadducts. In this report, we demonstrate that nickel boride is capable of one-pot 1,2- and 1,4-reduction of enones present in the cycloadducts in good yields. Subsequent elaboration of the cycloadducts towards synthesis of functionalized cycloheptenoid derivatives devoid of the oxa-bridge is also explored.

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.

Facile and Efficient Method for the Synthesis of 14-Substituted-14-H-dibenzo[a,j]xanthenes Catalyzed by Ruthenium Chloride Hydrate as a Homogeneous Catalyst

Synthesis of dibenzoxanthenes through condensation of β-naphthol with various aromatic and aliphatic aldehydes in ethanol as an ecofriendly solvent using Ru^III as catalyst is reported.

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).

Iodine- and Indium(III) Chloride–Catalyzed Facile Syntheses of 1,5- and 1,8-Naphthyridines

Iodine- and InCl₃-catalyzed facile syntheses of 1,5- and 1,8-naphthyridines from 3-aminopyridine and 2-aminopyridines are described. The catalyst InCl₃ could be recovered and reused up to five times efficiently.

Improved Synthesis of 1H-Pyrazole-4-carbaldehyde

A simple and convenient two-step method for the synthesis of the title compound 1 was developed using N-protected 4-pyrazolilmagnesium bromide 9 as a key intermediate. Laborious procedures for purification or isolation of target compound are not required, therefore, up to 20 g of 1 could be obtained in a single run.

Ionic Liquid Oxidant for Efficient and Selective Oxidation of Benzylic Alcohols

Hexamethylenebis (N-methylimidazolium) dichlorochromate was easily prepared by addition of N-methylimidazole to 1,6-dibromohexane to form the corresponding dibromide salt and subsequent treatment with CrO₃ in 6 N HCl solution. It is a low-melting orange salt that selectively oxidized benzylic alcohols.

Novel Asymmetric Synthesis of (S)-Esmolol Using Hydrolytic Kinetic Resolution

An efficient asymmetric synthesis of (S)-methyl 3-[4-[2-hydroxy-3-(isopropyl amino) propoxy] phenyl] propanoate is described. The key intermediate (S)-methyl 3-[4-(oxiran-2-ylmethoxy) phenyl] propanoate was obtained by hydrolytic kinetic resolution method using Jacobsen 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.

Studies Towards the Synthesis of ATP Analogs as Potential Glutamine Synthetase Inhibitors

In research directed at the development of adenine triphosphate (ATP) analogs as potential glutamine synthetase (GS) inhibitors, adenine and allopurinol derivatives have been synthesized either as novel ATP analogs or as scaffolds for the construction of such analogs.