Chemical conversion of cyclic alpha-amino acids to cyclic alpha-aminophosphonic acids

The oxidative decarboxylation of cyclic alpha-amino acids having urethane-type N-protecting groups with lead tetraacetate [Pb(OAc)4] gave 2-hydroxy derivatives, which were transformed into the corresponding alpha-aminophosphonic acid esters by treatment of trialkyl phosphites in the presence of Lewis acids. Deprotection and ester cleavage of the products in the usual manner afforded cyclic alpha-aminophosphonic acids. The convenient chemical conversion of five- and six-membered cyclic alpha-amino acids to the corresponding cyclic alpha-aminophosphonic acids has been accomplished.     

An efficient direct amination of cyclic amides and cyclic ureas

[reaction: see text] An efficient one-step amination of cyclic amides and ureas has been developed. Treatment of cyclic amides and cyclic ureas with BOP in the presence of DBU in various solvents led to the formation of cyclic amidines and cyclic guanidines in good to excellent yields. Concise syntheses of biologically intriguing kinetin and potent kinase inhibitor olomoucin were thus achieved in just one and two steps, respectively.     

On the base-induced isomerization of cyclic propargylamides to cyclic allenamides

The reaction of lactams 4 (n = 1-5) with propargyl bromide affords propargylamides or allenylamides depending on the ring-size. Theoretical calculations support the dependence of the extension of the isomerization on the ring-size.     

Synthesis of cyclic oxoenaminoesters

Ammonia and primary amines react with dimethyl 3-oxo-1,ω-alkanedioates to give cyclic,N-acylated enaminoesters.     

Synthesis of cyclic sulfides

2,8-Dimethyl-1-thiahydrindan and 9-methyl-1-thiadecalin, respectively, were obtained by the reaction of 1-methyl-1-cyclohexene episulfide with allylmagnesium bromide and subsequent intramolecular cyclization of the resulting 1-methyl-2-allylcyclohexane-1-thiol by the action of sulfuric acid or UV irradiation. The cyclization proceeds stereospecifically.See [1] for communication V.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1186–1188, September, 1972.     

Stereochemistry of cyclic compounds

Conclusions The stereochemistry of the bromination of 3-methyl-4-cyclohexene-cis-1,2-dicarboxylic acid and its anhydride was studied, and the configurations of the products were proved. The observed features of the bromination were explained on the basis of the ionic mechanism of these reactions.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 127–132, January, 1967.     

Synthesis of cyclic sulfides

Two isomers of 2,3-dimethyl-1-thiahydrindane and two isomers of 4-methyl-1-thiadecali were obtained by the reaction of cyclohexene episulfide with crotylmagnesium bromide and subsequent cyclization of the resulting 2-(-methyl--propenyl)-1-cyclohexanethiol by the action of 75% sulfuric acid and UV irradiation.See [3] for communication IV.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 622–625, May, 1972.     

Synthesis of cyclic acylsilanes

An improved route to dydlic acyclic acylsilanes, involving the synthesis of intermediate disubitituted spirodithianes and their hydrolysis, is described.     

Rotaxanes of cyclic peptides

The synthesis of rotaxanes derived from the synthetic peptide macrocycles cyclo(l-ProGly)4 and cyclo(l-ProGly)5 and diammonium threads is described. [2]Rotaxanes are formed in good yields (56-63%), despite the disruption of internal amide-amide hydrogen bonding in the macrocycles.     

Synthesis of cyclic sulfides

A general scheme is proposed for the synthesis of 4-alkylthiacyclohexanes by reaction of 1-alken-3-ylmagnesium halides with ethylene episulfide and subsequent cyclization of the resulting 3-alkylpent-4-ene-1-thiols under the in-fluence of UV irradiation. 4-Amyl- and 4-octylthiacyclohexanes, together with 2-methyl-3-octylthiacyclopentane, were obtained, respectively, from 1-octen-3-ylmagnesium bromide, 1-undecen-3-ylmagnesium chloride, and ethylene episulfide.See [1] for communication. VII.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1622–1624, December, 1977.     

Stereochemistry of cyclic compounds

Russian Chemical Bulletin -     

Synthesis of cyclic sulfides

3-Phenylthiacyclohexane and 2-methyl-4-phenylthiacyclopentane were synthesized by reaction of styrene episulfide with allylmagnesium bromide and subsequent photochemical cyclization of the resulting 2-phenyl-4-pentene-1-thiol.     

Synthesis of cyclic sulfides

2-n-Amyl-5-methylthiacyclopentane and 2-n-amylthiacyclohexane, respectively, were synthesized by the reaction of 1-heptene episulfide with allylmagnesium bromide with subsequent cyclization of the resulting 1-decene-5-thiol by the action of 75% sulfuric acid and UV irradiation.See [3] for communication III.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1337–1338, October, 1971.