Том 55, № 8 (2019)

The reactions of 1,3-benzothiazole-2-thiol and di(1,3-benzothiazol-2-yl) disulfide with (iodomethyl)silanes containing exocyclic and endocyclic silicon atoms occurs in the presence of elemental iodine to afford organosilicon benzothiazolium and disulfonium iodides and polyiodides.

A previously unknown isonitroso diketone containing a naphthalen-1-yl substituent was synthesized. Its condensation with hydrazine hydrate resulted in the isolation for the first time of 3-(memoxymemyl)-5-(naphthalen-1-yl)-4-nitroso-1H-pyrazole. The cycloaromatization reaction of isonitroso β-diketones containing naphthalen-1-yl, phenyl, and methoxymethyl substituents with alkyl hydrazines was studied. The structure of the novel 4-methoxy-1-(naphthalen-1-yl)butan-1,2,3-trione 2-oxime, its condensation product with hydrazine hydrate, as well as N-alkyl-substituted 4-nitroso-1H-pyrazoles was confirmed by ¹H and ¹³C NMR, IR, and UV spectroscopy and mass spectrometry.

The addition of lithium enolates and TMS ethers of cyclohexanone and cyclododecanone to levoglucosenone in the presence of Lewis acids was studied. It was established that the optimal way to obtain of Michael adducts involves the reaction levoglucosenone at −78°C with lithium enolates of cyclohexanone and cyclododecanone in the presence of ZnCl₂. Additional amounts of Michael adducts can be obtained by treatment of 1,2-adducts with lithium diisopropylamine. 1,2-Adducts are best prepared by the reaction of the corresponding lithium enolates with levoglucosenone in the presence of Ti(Oi-Pr)₄.

8,17-Disubstituted 8,9,15c,15d,17,18-hexahydro-6b,8,9a,15b,17,18a-hexaazaheptalenobis[1,10-ab]-phenalenes were synthesized for the first time by the reaction of 2,2′,3,3′-tetrahydro-1H,1′H-2,2′-biperimidine with 1,3,5-tricycloalkyl-1,3,5-triazinanes in the presence of NiCl₂·6H₂O as a catalyst.

(R)-2,3-O-Cyclohexylideneglyceraldehyde was involved in the Barbier allylation reaction with such 2-substituted functionalized allyl bromide as methyl 3-(bromomethyl)but-3-enoate under the action of various metals or metal salts. The best diastereoselectivity was observed with Zn and DMF or THF plus saturated aqueous ammonium chloride as solvents. The feasibility of the resulting homoallyl alcohol, specifically methyl 3-{(2S)-2-[(2R)-1,4-dioxaspiro[4.5]dec-2-yl]-2-hydroxyethyl}but-3-enoate, as a building block for the macrocyclic anticancer agents, such as laulimalides and their synthetic analogs.

Methyl (Z)-3-[(2R,3R,4S,5S)-5-(2-methoxy-2-oxoethyl)-3,4-(isopropylidenedioxy)tetrahydrofuran-2-yl]-prop-2-enoate was synthesized, and its intramolecular carbocyclization was studied. This reaction proceeds smoothly and quickly under the action of t-BuOK in THF, leading to three cycles with the methoxy and methoxycarbonylmethyl side substituents trans to each other. A stepwise route for the formation of methyl (1R,2R,6S,7R,8R,9R)-9-(2-methoxy-2-oxoethyl)-4,4-dimethyl-3,5,10-trioxatricyclo[5,2,1,0^2,6]decane-8-carboxylate and methyl (1R,2R,6S,7R,8S,9S)-9-(2-methoxy-2-oxoethyl)-4,4-dimethyl-3.5,10-trioxatricyclo-[5,2,1,0^2,6]decane-8-carboxylate with the trans orientation of the side substituents is proposed. The observed stereochemical result of the reaction is interpreted in terms of epimerization in the C¹ and C⁴ centers of methyl (Z)-3-[(2R,3R,4S,5S)-5-(2-methoxy-2-oxoethyl)-3,4-(isopropylidenedioxy)-tetrahydrofuran-2-yl]prop-2-enoate, which ultimately leads to the cyclized β,β’-cis diastereomer of methyl (Z)-3-[(2R,3R,4S,5S)-5-(2-methoxy-2-oxoethyl)-3,4-(isopropylidenedioxy)-tetrahydrofuran-2-yl]prop-2-enoate and the corresponding α,α’-cis diastereomer, a precursor of methyl (1R,2R,6S,7R,8S,9S)-9-(2-methoxy-2-oxoethyl)-4,4-dimethyl-3,5,10-trioxatricyclo[5,2,1,0^2,6]decane-8-carboxylate.

4-(4-Acetylphenyl)-3-hydroxy-2H-chromen-2-one has been prepared by the reaction of (4-acetylbenzene)diazonium chloride with 3-hydroxy-2H-chromen-2-one under Meerwein reaction conditions. The reactions of 4-(4-bromoacetylphenyl)-3-hydroxy-2H-chromen-2-one with pyridine, 4-methylpyridine, quinolone, and benzo[f]quinoline gave quaternary salts, and the reactions of the same bromo derivative with thioacetamide, thiourea, pyridine-2-amine, pyrimidin-2-amine, and thiazol-2-amine provided corresponding thiazole, imidazo[1,2-a]pyridine, imidazo[1,2-a]pyrimidine, and imidazo[2,1-b]thiazole derivatives. The reactions of 4-(4-bromoacetylphenyl)-3-hydroxy-2H-chromen-2-one with thiosemicarbazide and aromatic aldehydes involve thiazole ring formation, leading finally to corresponding hydrazones. It was established that 4-(4-acetylphenyl)- and 4-[4-(2-bromoacetyl)phenyl]-3-hydroxy-2H-chromen-2-ones can be used in three-component reactions to form a thiazole ring.

2,2′-(Disulfanediyl)- and 2,2′-[alkanediylbis(sulfanyl)]-bisbenzimidazoles react with aliphatic, aromatic, and heterocyclic α-iodoketones in the presence of elemental iodine without solvents, basic media, and catalysts to afford polyiodides of the N- and S-S-acetonyl derivatives. The selectivity of the alkylation reaction depends on the structure of the starting substrates. In the case of the disulfide, the reaction involves the sulfur atoms to give hitherto unknown disulfanium derivatives. The introduction of an organic bridge between the sulfur atoms leads to the formation of polyiodides of 2,2′-[alkanediylbis(sulfanyl)]bisbenzimidazole N-acetonyl derivatives.

A Stork reaction — intramolecular transamination — alkylation tandem protocol was used to synthesize functionalized partially hydrogenated quinolines. The molecular and crystal structures of 5-(4-methoxyphenyl)-8,8-dimethyl-6-oxo-2,5,6,7,8,9-hexahydro-1H-thiazolo[3,2-a]quinoline-4-carbonitrile, 9-allyl-3-amino-7,7-dimethyl-5-oxo-4-phenyl-4,5,6,7,8,9-hexahydrothieno[2,3-b]quinoline-2-carbonitrile, and 3-amino-4-(2,5-dimethoxyphenyl)-N-phenyl-5,6,7,8-tetrahydrothieno[2,3-b]quinoline-2-carboxamide were studied by X-ray diffraction analysis.

The exocyclic C=C double bond in phenacylideneoxindole and 2-oxoacenaphthen-1-ylidene ketone derivatives has been selectively reduced in good yields with a combination of the Hantzsch ester and zinc chloride in acetonitrile at ambient temperature.

An easy, efficient and improved synthetic route has been developed for the synthesis of Sertaconazole (1-{2-[(7-chlorobenzo[b]thiophen-3-yl)methoxy]-2-(2,4-dichlorophenyl)ethyl}-1H-imidazole) employing multiple chemical transformation.

3-(Piperidin-4-yl)-6,7-dihydro-5H-pyrrolo[2,1-c][1,2,4]triazole was synthesized through a four-step process including etherification, hydrazonation, cyclization, and reduction with an overall yield of 39%. The final product was characterized by ¹H NMR and ESI-MS/MS. The molecular structures of benzyl (Z)-4-(2-(pyrrolidin-2-ylidene)hydrazine-1-carbonyl)piperidine-1-carboxylate and related compounds were analyzed using DFT calculations at the B3LYP/6-311+G(d,p) level of theory. The results indicated a higher stability of the hydrazone tautomers.

The reactions of 4-[(1-oxo-3,4-dihydro-2H-naphmalen-2-ylidene)methyl]benzoic acid with 3-(1,3-dioxobutane-1-yl)-2H-chromen-2-one in the presence of nitrogenous bases (piperidine, triethylamine or pyridine) were used to synthesize for the first time hybrid systems containing the pharmacophoric fragments of the reagents. The reaction scheme involves formation of a condensed dihydropyran structure and its subsequent aromatization into a benzodihydrochromenilium salt under the action of HCl. The process may be accompanied by the competing addition of an azanucleophile by the double bond of the chalcone.

A method of synthesis of 1,1′-(alkanediyl)bis{3-cyano-4-[4,5,5-trimethyl-2-oxo-5H-furan-3-yl]-pyridin-2(1H)-ones} from the corresponding lactones is developed. The synthesized compounds undergo intramolecular cyclization to form symmetrical 7,7′-(alkanediyl)bis{5-amino-3,3-dimethylfuro[3,4-f]isoquinoline-1,6(3H,7H)-diones}.

The reaction of 3-(3-arylpropenoyl)-2H-chromen-2-ones with methyl 1-bromocyclopentane-1-carboxylate and zinc resulted in the isolation, after hydrolysis of the reaction mixture, adducts of the Reformatsky reagent across the double bond of the heterocyclic fragment. The synthesized compounds exist in the enolic form.