Convenient method for preparation of esters of N-carbonyl-α-amino acids

Conclusions A convenient method was proposed for obtaining the esters of N-carbonyl--amino acids, which is based on the reaction of the esters of N-trimethylsilyl--amino acids with phosgene in the presence of a tertiary amine.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1682–1684, July, 1977.     

A novel method for preparation of 2-(methyl- or phehnylthio)alkanoic esters

Ethyl 2-acetylalkanoate gave ethyl 2-(methyl- or phenylthio)alkanoate in high yield on treatment wiht CH₃SSO₂CH₃, PhSSO₂Ph, or PhSSPh in the presence of small excess of EtONa in EtOH. Application of the present method to synthesis of pellitorine and the queen substance is also described.     

A new method for the preparation of diphenylmethyl esters by using tri-diphenylmethyl phosphate as alkylating agent

The diphenylmethyl group is introduced for the protection of the hydroxyl group of α-hydroxy acids.     

A practical method for preparation of phenols from arylboronic acids catalyzed by iodopovidone in aqueous medium

A novel and efficient strategy for the ipso-hydroxylation of arylboronic acids to phenols has been developed using inexpensive, readily available, air-stable water-soluble povidone iodine as catalyst and aqueous hydrogen peroxide as oxidizing agent. The reactions were performed at room temperature under metal-, ligand- and base-free condition in a short reaction time. The corresponding substituted phenols were obtained in moderate to good yields by oxidative hydroxylation of arylboronic acids in aqueous medium.     

A selective method for the preparation of aliphatic methyl esters in the presence of aromatic carboxylic acids

2,2-Dimethoxypropane, methanol and a catalytic amount of HCl selectively esterify aliphatic carboxylic acids, in the presence of aromatic carboxylic acids, at room temperature and in high yields.     

Carbonylation in benzyl alcohol. A new and easy method for the preparation of aromatic benzyl esters

The carbonylation of the iodides 2a-c and 12a-b in benzyl alcohol with carbon monoxide affords the corresponding benzyl esters 3a-c and 13a-b in good yields. It is shown that 3a can be easily and selectively cleaved to the acid 4a by catalytic hydrogenation. The acid is converted to an ester, 7a, and an amide, 6a.     

A general method for the preparation of 4- and 6-azaindoles

Nitropyridines reacted with an excess of vinyl Grignard reagent to produce 4- or 6-azaindoles. Improved yields were obtained when a halogen atom was present at the position alpha to the nitrogen atom in the pyridine ring.     

A method for preparation of C-diformylmethylnitropyrazoles

Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 230–231, January, 1993.     

Simple method for the preparation of esters from Grignard reagents and alkyl 1-imidazolecarboxylates

The reaction of Grignard reagents with alkyl imidazolecarboxylates, which were prepared from alcohols with carbonyl diimidazole, gave the corresponding esters in good to excellent yields. This method conveniently provides esters from alkyl halides and alcohols by C1-carbon chain extension.     

A general method for the preparation of 3-acyl-4-cyano-5-amino-pyrazoles

This letter describes a general synthesis for N1-substituted 3-acyl-4-cyano-5-amino-pyrazoles.     

A practical approach for the preparation of monofunctional azulenyl squaraine dye

The synthesis of monofunctional azulenyl squaraine dye NIRQ₇₀₀ is described. The essential azulene intermediate 3, 1-(methoxycarbonyl)-2-methylazulene, was achieved via [8+2] cycloaddition between lactone 2, 2H-3-methoxycarbonyl-cyclohepta[b]furan-2-one, and the in situ generated vinyl ethers under high temperature and pressure conditions. Methylation on the cycloheptatriene ring of 2-methyl azulene 6 via Meisenheimer-type intermediate following Schrott's method formed the carboxylic acid intermediate 9, 3-(2-methyl-azulen-4-yl)-propionic acid. Condensation of 9 with squaric acid provided the title compound NIRQ₇₀₀ at moderate yields. The non-fluorescent squaraine dye NIRQ₇₀₀ absorbed in a 600-700 nm range and potentially can be used to quench a number of available NIR fluorochromes in order to extend the spectrum of biological quenching assays.