A new and convenient method for the synthesis of strong non-ionic bases

Various strong non-ionic phosphazene bases were obtained by a new, efficient and very simple method involving the lithium phosphonium azayldiide Ph3P=NLi as a precursor.     

A convenient method for the synthesis of roflumilast

A convenient synthetic method has been developed for the synthesis of roflumilast from 4-difluoromethoxy-3-hydroxybenzaldehyde and bromomethyl cyclopropane via O-alkylation, oxidation and N-acylation. With sodium hydroxide as alkali in the last step, the total yield of roflumilast can be up to 68.3 % and the purity of the target product reached 99.2 %. It was obvious that sodium hydroxide showed more economic advantage for scale-up production than sodium hydride or potassium tert-butoxide.     

A convenient method for 3-pyrroline synthesis

[reaction: see text]. The synthesis of a range of 3-pyrrolines has been achieved from primary amine starting materials using a two-step alkylation/alkylidene carbene CH-insertion reaction sequence. We have shown that insertion into a range of CH-bond types is possible, and the formation of nitrogen-bearing quaternary stereocenters is a relatively facile process. The insertion reaction occurs with >95% retention of stereochemistry, but the presence of protecting groups on nitrogen is generally deleterious to the cyclization process.     

A convenient method for the synthesis of substituted thioureas

A convenient method for the synthesis of substituted thioureas by the reaction of primary amines with molybdenum dialkyl dithiocarbamates has been developed. Primary amines on reaction with 0.5 equiv of molybdenum xanthate produce the corresponding thioureas in moderate to good yields in short times. Similar reactions with propargylamine or 2-aminoethanol produce cyclic thiaoxazolidine and oxazolidine derivatives, respectively.     

A convenient method for the synthesis of electron-rich phosphonates

Very electron-rich benzylic-type phosphonates can be prepared by treating the corresponding alcohols in triethyl phosphite with one equivalent of iodine at an appropriate temperature in a general one-pot process.     

A convenient method for the synthesis of N-hydroxyureas

Treatment of amines with 1-(4-nitrophenol)-N-(O-benzylhydroxy)carbamate yields the O-benzyl protected N-hydroxyureas. Hydrogenation of the O-benzyl protected N-hydroxyureas over 5% Pd/BaSO₄ cleanly gives the N-hydroxyureas in good yield. In addition to primary and secondary aliphatic and aromatic amines, this method converts amino sugars to the corresponding N-hydroxyureas without extensive protecting group chemistry.     

A convenient method for the synthesis of polyfluorinated β-diimines

The higher internal perfluoroak-2-enes react with ammonium hydroxide at atmospheric pressure to give the corresponding iminoenamines, whose further transformations yield heptafluoroacetylacetone analogs. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1710–1712, September, 1999.     

A convenient method for the synthesis of α-silylacetic acids

A method is described for the preparation of α-silylacetic acids of the type R₃SiCH₂CO₂H by treating trimethylsilyl acetate with LDA followed by quenching with chlorosilanes.     

A convenient method for the synthesis of six-membered heterocyclic enaminones

Enaminones are widely employed in the synthesis of heterocycles, however heterocyclic enaminones and their use in the synthesis of more complex systems have been less studied. The reaction between 4-chloroacetylacetate and aliphatic or aromatic 1,2-aminoalcohols, 1,2-aminothiols or 1,2-diamines, yields in one pot a six-membered 1,4-heterocyclic system containing the enaminone moiety.     

A convenient method for the synthesis of chlorocymantrene and bromocymantrene

Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2046–2047, November, 1994.     

A convenient general method for the synthesis of hydroxy diacids

Olefinic aldehydes and epoxides with terminal double bonds react with Grignard reagents, and the acetates made from the resulting alcohols undergo double bond cleavage on treatment with RuCl₃·xH₂O in the presence of NaIO₄ to give acetoxy diacids. Hydrolysis with LiOH then affords hydroxy diacids.     

A new crown ether as vesicular carrier for 5-fluoruracil: synthesis, characterization and drug delivery evaluation

Niosomes have shown promise as cheap and chemically stable drug delivery systems. In this paper a novel crown ether amphiphile, 1,16-hexadecanoyl-bis-(2-aminomethyl)-18-crown-6 (Bola A-16), has been synthesized with the aim of developing a long time stable controlled release system. Niosomes have been prepared with different molar ratios of amphiphile and cholesterol and their morphological properties have been determined by quasi-elastic light scattering and transmission electron microscopy. The composition of niosomes affects the entrapment efficiency and the release rate of 5-fluorouracil, a well-known antineoplastic molecule. In addition, other two known azacrown ether amphiphiles (4,7,10,13-pentaoxa-16-aza-cyclooctadecane)-hexadecanedioc acid diamide (Bola D-16) and ,ω-(4,7,10,13-pentaoxa-16-aza-cyclooctadecane)-hexadecane (Bola C-16), have been synthesized and the obtained vesicles have been characterized for comparison. Furthermore, the release profile of 5-fluorouracil in vitro, from these niosomes, has been studied over a period of 6 h in order to simulate a hematic adsorption.     

A new convenient synthesis of γ-keto-sulfoxide

γ-Keto-sulfoxides have been very conveniently synthesized through a series of reactions from commercially available acrolein. They were obtained as crystals and shown to be effective as the vinyl ketone equivalents.     

A convenient new synthesis of homoserine lactone

N-trityl L-homoserine lactone is synthesised in three steps from L-aspartic acid.     

A convenient method for the synthesis of 2,3-dioxo-1,2,3,4-tetrahydroquinoxalines

A method for the synthesis of substituted 2,3-dioxo-1,2,3,4-tetrahydroquinoxalines by the reduction of substituted (o-nitrophenyl)glycines with subsequent oxidation of the 2-oxo-1,2,3,4-tetrahydroquinoxaline products has been developed. When tin(II) chloride was used as the reducing agent a chlorine atom was introduced ortho to the NHC(O) fragment of the heterocycle. __________ Translated from Khimiya Geterotsikicheskikh Soedinenii, No. 8, 1206–1210, August, 2006.     

A novel and convenient method for the synthesis of substituted naphthostyrils

3-Pyrrolyl-6-fluoro-naphthostyril 13 was synthesized via a base-catalyzed intramolecular cyclization of oxindole precursor 2 (Y=H). Derivatization of 2 (Y=I) through a one-pot reaction give 5-substituted naphthostyrils. This method allows convenient access to 3,5,6-trisubstituted naphthostyrils which may serve as a new template for CDK2 inhibition.     

A convenient method for the synthesis of α-Ketoesters from aldehydes

An efficient two step, two carbon homologation of aldehydes to α-ketoesters is described.