One-pot synthesis of polyfunctionalized cyclic urea derivatives

[reaction: see text] Unexpectedly, imidazolidin-2-ones are easily obtained from beta-keto esters upon treatment with tert-butyl nosyloxycarbamate and calcium oxide under mild conditions. The structure of the product was established by X-ray crystallography.     

One-pot transformation of trichloroacetamide into readily deprotectable carbamates

[Structure: see text] A trichloroacetamide group was converted to an isocyanate, which was in situ captured by a variety of alcohols in the presence of CuCl and n-BuN4Cl to afford the corresponding carbamates. The scope and limitation of this transformation are also described.     

One-pot synthesis of cyclic triamides with a triangular cavity from trans-stilbene and diphenylacetylene monomers

Base-promoted self-condensation reactions of trans-stilbene and diphenylacetylene monomers bearing 4-alkylamino and 4'-methoxycarbonyl groups were investigated. Reactions of N-propyl monomers under pseudohigh-dilution conditions (a THF solution of monomer was added dropwise to a THF solution of LiHMDS) afforded the corresponding cyclic triamides in good yields. X-ray crystallographic analysis showed that these cyclic triamides possessed an almost equilateral triangle structure with a cavity surrounded by tilted benzene rings.     

One-pot synthesis of homotryptamines from indoles

A method is presented for the one-pot synthesis of homotryptamines by the MacMillan reaction of indoles with acrolein followed by reductive amination.     

Practical synthesis of unsymmetrical ureas from isopropenyl carbamates

A very convenient method for the synthesis of unsymmetrical ureas is described, based on isopropenyl carbamates. The synthetic efficiency of traditional methods for urea formation, such as use of phosgene or alkyl and aryl carbamates, is limited by the formation of symmetrical urea side products or reaction reversibility. Isopropenyl carbamates react with amines cleanly and irreversibly and give unsymmetrical ureas in high yield and purity. This method is ideal for the rapid synthesis of compound libraries.     

One-pot synthesis of azanucleosides from proline derivatives

Common cyclic amino acids, derived from proline and hydroxyproline, can be readily transformed into azanucleosides. The mildness of the reaction conditions, and the good yields obtained, make this procedure an interesting alternative to the conventional processes.     

One-pot synthesis of conjugated alkynenitriles from aldehydes

A method of preparing conjugated alkynenitriles was developed from various aldehydes with CCl₃CN and PPh₃ in the presence of ^tBuLi. The reaction proceeded via α-chlorovinyl nitrile as an intermediate without any side reactions such as chlorination of starting aldehydes.     

One-pot synthesis of N-substituted (3-oxobutanyl)carbamates from primary amines using modified zeolite Hβ at room temperature

The one-pot synthesis of N-substituted (3-oxobutanyl)carbamates via the tandem condensation of primary amines with methyl chloroformate, followed by the conjugate addition of the resulting carbamate with methyl vinyl ketone in the presence of Sn⁴⁺ modified zeolite Hβ (Hβ-SnA) at room temperature is described.     

Stereospecific synthesis of urea-tethered neoglycoconjugates starting from glucopyranosyl carbamates

Silyl-assisted elimination reaction of glucopyranosyl carbamates has been established for the synthesis of α- and β-d-glucopyranosyl isocyanates and ureas. This method proved to be useful for the synthesis of urea-tethered neoglycoconjugates.     

An efficient synthesis of vinylogous carbamates from alkyl azides

An efficient one-pot synthesis of vinylogous carbamates is reported starting from alkyl azides by using NH₄Cl/Zn dust.     

One-pot synthesis of carbohydrate thionolactones from 1-thiosugars

A general and efficient one-pot method for the synthesis of carbohydrate thionolactones from the corresponding 1-thiosugar is described involving the formation of an intermediate glycosyl S-tert-butyl thiosulfinate in situ by treatment of a thiol with commercially available tert-butylsulfinyl chloride in toluene at room temperature, followed by thermolysis. The method can also be used to generate reactive thioaldehydes and thioketones directly from thiols, which can be trapped in situ with a suitable diene.     

One-pot electrochemical synthesis of acid anhydrides from alcohols

Russian Journal of General Chemistry - One-pot indirect electrochemical oxidation of alcohols in the methylene chloride–aqueous solution of sodium hydrocarbonate two-phase system in the...     

One-pot synthesis of diarylimidazolium salts from 1H-imidazole

Diarylimidazolium salts(3) were directly synthesized starting from 1H-imidazole(1) by a one-pot strategy using diaryliodonium salts as the arylating reagents.1H-Benzimidazole and 1H-1,2,4-triazole are suitable substrates as well to form the corresponding diarylazolium salts.     

One-pot synthesis of unsymmetrical triarylamines from aniline precursors

The "one-pot" synthesis of triarylamines from an aniline and two different aryl halides is described. A catalytic system composed of Pd2(dba)3/P(t-Bu)2-o-biphenyl (1) is used to prepare a variety of triarylamines in a single flask by the coupling of an aniline with an aryl bromide and aryl chloride. The synthesis of triarylamines containing a heterocyclic aryl group is also described by employing a one-flask, two-step method. These methods can be used to synthesize both discrete triarylamines and a triarylamine library.     

One-pot synthesis of 2-aminoquinoline-based alkaloids from acetonitrile

α-Diaminoboryl carbanions, readily prepared from acetonitrile, stereoselectively convert 2-nitrobenzaldehydes into nitrophenyl (Z)-acrylonitriles. Subsequent reductive cyclization leads to a series of 2-aminoquinoline derivatives. The entire procedure is practically operated in a single flask.     

One-pot synthesis of trichloromethyl carbinols from primary alcohols

Versatile trichloromethyl carbinols can be prepared in one pot from primary alcohols by treatment with Dess-Martin periodinane (DMP) in CHCl(3) followed by introduction of commercially available 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD). A modification of the method was used to convert chiral primary alcohol (R)-(-)-2,2-dimethyl-1,3-dioxolane-4-methanol to the corresponding trichloromethyl carbinol with complete stereochemical fidelity, despite the reactant proceeding through a base-sensitive aldehyde intermediate.     

Strategies for the synthesis of 2-substituted indoles and indolines starting from acyclic alpha-phosphoryloxy enecarbamates

Strategies have been developed for the synthesis of 2-substituted indoles and indolines starting from acyclic alpha-phosphoryloxy enecarbamates. A highly chemoselective cross-coupling of N-(o-bromophenyl)-alpha-phosphoryloxyenecarbamates with boron nucleophiles enabled the efficient preparation of various N-(o-bromophenyl)enecarbamates, which served as useful precursors for subsequent Heck-type cyclization or 5-endo-trig aryl radical cyclization to furnish 2-substituted indoles or indolines, respectively.     

One-pot synthesis of N-substituted pantolactams from pantolactone

Rac-N-substituted pantolactams (5) are readily obtained in medium to good yields by reaction of rac-pantolactone (1) with primary amines under acid catalysis, whether at 250°C in a pressure reactor or under microwave irradiation. It appears that the amine can react with pantolactone at the carbonyl carbon atom to give a hydroxyamide (3) in a reversible way and at the methylene carbon atom to give a γ-amino acid (4). The last one on dehydration would give the corresponding pantolactam (5).