Synthesis and antitumor activity of puupehedione and related compounds

The first enantiospecific synthesis of bioactive marine puupehedione (2) and related compounds from (−)-sclareol (11) is reported. The antitumor activity of these compounds was assayed and compared with that of the natural products.     

Synthesis of aminothiazole derived morphinans

Two aminothiazole derived morphinans 9 and 11 were prepared for our ongoing opioid ligands study. The synthesis was initiated from levorphanol 1, which was first triflated, and then subjected to Pd-catalyzed reduction followed by nitration. The resulting two nitrated isomers were characterized by analogy to known compounds. The formation of the aminothiazole ring occurred highly selectively to yield only one product from each of the anilines 6 and 7.     

Carbofunctional sulfur-containing organosilicon compounds: Synthesis and application fields

Recently published data concerning the preparation and valuable properties of organosilicon compounds of silatrane structure with carbofunctional sulfur-containing substituents (thiol, sulfide, disulfide, polysulfide) and heteroatomic sulfur-containing groups (thiourea, thiourea dioxide, dithiocarbamate, thiuram disulfide) are summarized and analyzed.     

Synthesis and biological activity of sulfur-containing aryl-aldehyde Schiff bases

A series of chemically modified aryl-aldehyde Schiff bases has been synthesized and tested for their antioxidant activity and radiation protection. We observed that disulfide-containing aryl-aldehyde Schiff base 6c exhibited potent free radical scavenging, antioxidation, and radioprotection activities.     

Functional sulfur-containing compounds

The Thorpe-Ziegler intramolecular cyclization of 2-RCH₂S-, 2-RCH₂S(O)-, and 2-RCH₂SO₂-substituted nicotinic acid esters and nitriles (R is alkyl, aryl, and 2-thienyl) upon the action of potassium tert-butoxide has been studied. The reaction results in the formation of the corresponding 2-R-substituted 3-aminothieno[2,3-b]pyridines, 3-aminothieno[2,3-b]pyridine 1-oxides, and 3-aminothieno[2,3-b]pyridine 1,1-dioxides with the reaction taking place only in the case if R is aryl or 2-thienyl. Methyl esters of 2-RCH₂S-, 2-RCH₂S(O)-, and 2-RCH₂SO₂-substituted nicotinic acids also undergo the intramolecular cyclization of the Dieckmann type to form the corresponding 2-R-substituted 3-hydroxythieno[2,3-b]pyridines, thieno[2,3-b]pyridin-3(2H)-one 1-oxides, and thieno[2,3-b]pyridin-3(2H)-one 1,1-dioxides. Such a reaction takes place for all the R groups except when R = AlkCH₂S and AlkCH₂S(O).     

Organofluorine sulfur-containing compounds

Polyfluorinated aryldifluoromethyl sulfides have been obtained by treatment of polyfluorinated 4-X-substituted thiophenols with chlorodifluoromethane in an alkaline medium. Reactions of difluoromethylpentafluorophenyl sulfide with H₂O₂, KMnO₄, and HNO₃, giving the corresponding sulfoxide and sulfone, were studied.     

Synthesis,structure and antioxidant activity of sulfur-containing tetrakisphenol

3-[2-(3,5-Di-tert-butyl-4-hydroxyphenylsulfanyl)acetoxy]2,2-bis[2-(3,5-di-tert-butyl-4-hydroxyphenylsulfanyl) acetoxymethyl]propyl 3,5-di-tert-butyl-4-hydroxyphenylsulfanylacetate was synthesized. Its structure was determined by means of ¹H and ¹³C NMR spectroscopy and X-ray-diffraction analysis. This compound was found to possess high antioxidant activity in the conditions of auto-oxidation of low-pressure polyethylene.     

Synthesis of dl-guinesines and related compounds

Guinesines A, B and C were synthesized starting from 1,3-bis(benzylthio)-2-propanone and N-methyl-2,2-diethoxypyrrolidine.     

Functionally substituted sulfur-containing compounds

Reactions of 2-[(organylthio)methyl]oxiranes with aliphatic alcohols in the presence of catalytic amounts of BF₃·Et₂O are accompanied by 1,2-migration of the organylthio group to give mixtures of 2-alkoxy-3-(organylthio)propan-1-ols and 3-alkoxy-2-(organylthio)propan-1-ols. The ratio of these isomers is significantly influenced by the structure of the alcohol and the nature of the organylthio group. The proposed reaction mechanism includes the formation of a thiiranium intermediate and its subsequent transformations. For Part 11, see Ref. 1. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 881–887, May, 2000.     

Synthesis of santonin related compounds

(±)-1-Nordesmotroposantonin ( 2 ), a thermolysis product of santonin, and its isomer, α-(1,2,3,4-tetrahydro-1,7-dihydroxy-α,6-dimethyl-2-naphthalene)acetic acid γ-lactone ( 3 ) were synthesized from 4-(4-methoxy-3-ethylphenyl)butanoic acid.     

Synthesis and cytotoxic activity of a series of diacetylenic compounds related to falcarindiol

The synthesis of a series of diacetylenic compounds related to the natural product falcarindiol has been carried out. Unsymmetrical diacetylenes were prepared by a modification of the Cadiot-Chodkiewicz coupling reaction, while a Glaser coupling was used to prepare symmetrical diacetylenes. These compounds have been tested for in vitro cytotoxic activity against Hep-G2, and H-4-II-E cell lines. Diacetylenes with additional unsaturation at C-1, 2, appended with hydroxyl groups at C-3 and C-8, or with long hydrophobic chains, exhibited IC50 values in the micromolar range.     

Streptonigrin and related compounds III. Synthesis and microbiological activity of destrioxyphenylstreptonigrin and analogues

Synthesis of three tricyclic analogues of streptonigrin, based on the 2-(2′-pyridyl)quinoline-5,8-dione system and with the characteristic substitution pattern of rings A and C of streptonigrin is described. The C-ring precursor, in the form of a substituted 2-acetylpyridine was condensed with either 3-hydroxy-5-methoxy-2-nitrobenzaldehyde or 3-hydroxy-4-methoxy-2-nitrobenzaldehyde, followed by reductive cyclization and oxidation to the corresponding quinones 12 and 29 . The 7-amino substitution was introduced in 12 via bromination and azidation. The 6-amino substitution was introduced through direct reaction of 29 with sodium azide. Destrioxyphenylstreptonigrin 2 was twice as active and the 6-amino-7-inethoxy analogue 4 was as active as streptonigrin in a microbiological assay. A 4′-bromo analogue of 2 was 60% as active as streptonigrin.