Synthesis of pyrylium salts and heterocyclic nitrogen bases from cycloalkenylacetic acid esters

2-Alkyl-6-methoxy-3,4-tetramethylene- and 3,4-pentamethylenepyrylium perchlorates were obtained by acylation of cycloalkenylacetic acid esters with aliphatic acid anhydrides. 2-Methyl-6-methoxy[2,3-c]cholestanopyrylium perchlorate was similarly synthesized. 2-Alkyl-3,4-tetramethylene-6-pyridones were isolated by treatment of 2-alkyl-6-methoxy-3,4-tetramethylene-pyrylium perchlorates with excess concentrated ammonium hydroxide. 2-Methyl-3,4-pentamethylene-6-aminopyridine was obtained by the action of excess concentrated ammonium hydroxide on 2-methyl-6-methoxy-3,4-pentamethylenepyrylium perchlorate.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1323–1326, October, 1976.     

Amino esters of heterocyclic dicarboxylic acids

The corresponding amino esters and their complexes with 7,7,8,8-tetracyanoquinodimethane were obtained by the condensation of the acid dichlorides of furan-2,5-dicarboxylic acid and tetrahydrothiophene-2,5-dicarboxylic acid with 8-hydroxy- and 5,7-dibromo-8-hydroxyquinolines. Almost all of the compounds obtained have antimicrobial activity.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 538–540, April, 1972.     

Amino esters of heterocyclic dicarboxylic acids

The corresponding amino esters and their hydrochlorides and quaternary salts were obtained by the condensation of 2,5-furan- and 2,5-tetrahydrothiophenedicarboxylic acid chlorides with 1-methyl-, 1-ethyl-, or 1-butyl-3-hydroxypiperidines.deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 515–518, April, 1971.     

Reaction of heterocyclic betaines. Synthesis of a new heterocyclic system

A new condensed heterocyclic system, viz., 1,3,7,9-tetra-oxo-2,8-diphenyl-6-formylpyrimido [3,4-a]pyrimido[4,5-dloxazine, was synthesized, and its electronic and PMR spectra were recorded. Factors that affect the orientation of nucleophilic substitution in betaines of the pyrimidine series with aliphatic amines are discussed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 993–995, July, 1980.     

C-aminoimidoylation and C-thiocarbamoylation of esters, sulfones, and ketones

Esters, sulfones, and ketones were C-aminoimidoylated and C-thiocarbamoylated by benzotriazole-1-carboxamidines 8a-g and 1-(alkyl-or-arylthiocarbamoyl)benzotriazoles 9a-i, respectively. The present work represents the first systematic approach to these compound classes, the few previously known examples of which were obtained by diverse approaches.     

Synthesis and spectral data of some heterocyclic compounds. The reaction of arylpropiolic esters with tetralones and acetylcyclopropane

Reaction of phenylpropiolic ester (I) with α- and β-tetralones in the presence of sodium ethoxide yielded 5,6-dihydro-7,8-benzflavones and ethyl β-(2-tetralon-1-yl)cinnamates, as a result of Claisen and Michael reactions, respectively. The reaction of I with 3-ethoxy-2-cyclohexen-l-one and acetylcyclopropane in the presence of sodium ethoxide yielded acetylenic β-diketones and 2-aryl-6-cyclopropylpyran-4-ones, respectively. These products were identified on the basis of spectral and analytical data.     

Hydrozirconation of stannylacetylenes. Synthesis and reactions of ketene Stannyl(Telluro) acetals

Stannylacetylenes 7a-e react with Cp(2)Zr(H)Cl in THF at room temperature to give the alpha-zirconated vinylstannane intermediates 8a-e, which subsequently react with butyltellurenyl bromide (2.0 equiv) to give exclusively ketene stannyl(telluro) acetals 6a-e of E configuration. Similar reactions were performed using phenylselenenyl bromide (2.0 equiv) as the electrophile, but a mixture of products was formed including the expected ketene stannyl(seleno) acetals 12. Otherwise, the use of 1.4 equiv of Cp(2)Zr(H)Cl and 1.0 equiv of PhSeBr results in the exclusive formation of 12, in good yields. Treatment of ketene stannyl(telluro) acetals with iodine or NBS followed by reductive dehalogenation results in the formation of 1-iodo-1-telluroalkenes 4a-e and 1-bromo-1-telluroalkenes 5a-e, respectively, with total retention of the configuration.     

Synthesis of phosphonato esters involving heterocyclic biological bases in a highly diastereoselective and chemoselective route

Abstract  

Synthesis of five phosphonato esters has been accomplished via reaction between dimethyl acetylenedicarboxylate and triphenyl phosphite in the presence of biological compounds such as theophylline, 4-hydroxypyrimidine, 2H-3,1-benzoxazine-2,4(1H)-dione, 2-chloroaniline, or 3-nitroaniline at ambient temperature. The configuration of the compounds was determined on the basis of coupling constants emerging from the Karplus equation.     

Synthesis of heterocyclic homotriptycenes

A series of novel heterocyclic homotriptycenes bearing furan, thiophene, and pyridine rings, 7a-f, were synthesized by intramolecular dehydration reactions of 10,10-dihetarylmethyl-9,10-dihydroanthracen-9-ols 6a-f. In the presence of acids, the secondary alcohols 6a-f show different reactions which depend on the electron densities of the attached heterocyclic rings. The initially formed carbenium ions react in an electrophilic substitution with electron-rich heterocycles. The formation of a transannular bridge (1,7-elimination) leads to homotriptycenes in high yields. When the heterocyclic ring has a moderate electron density, two competitive reactions exist, which afford 9-monosubstituted anthracenes by 1,4-elimination or 9,10-disubstituted anthracenes by a rearrangement, respectively. Electron-deficient heterocycles undergo a disproportionation to give hydrocarbons and ketones.     

Synthesis of heterocyclic sulfonylureas

We examined the scope of the previously reported one-pot synthesis [1] of chromone-3-sulfonylureas. Different anilines and heterocyclic amines were thereby reacted with chlorosulfonyl isocyanate-derived chlorosulfonylureas. These were treated with different enaminones and enamines to provide the title compounds.     

Synthesis of heterocyclic thiosulfonates

[formula: see text] A simple synthesis of heterocyclic thiosulfonates containing indole, indoline, benzoimidazole, and quinoxaline rings is described. The synthesis of these thiosulfonates involves the preparation of the appropriately substituted thiols followed by sulfonylation to give thiosulfonates. The corresponding thiols were prepared in a simple and efficient manner by using a thiocyanation reaction either prior to heterocycle ring formation or after heterocycle ring formation. These thiosulfonates were coupled successfully to the 5,6-dihydropyran-2-one ring to give products that showed excellent HIV protease activity.