Synthesis of New 1,3-Thiazolecarbaldehydes

H-Lithiation and Br-lithiation reactions of 1,3-thiazole were studied in order to obtain new thiazole derivatives. Four isomeric chloromethyl derivatives of 1,3-thiazole containing a protected aldehyde group like 2-(1,3-dioxolan-2-yl)-5-(chloromethyl)-1,3-thiazole, 5-(1,3-dioxolan-2-yl)-2-(chloromethyl)-1,3-thiazole, 4-(1,3-dioxolan-2-yl)-2-(chloromethyl)-1,3-thiazole, and 2-(1,3-dioxolan-2-yl)-4-(chloromethyl)-1,3-thiazole were synthesized. Their nucleophilic substitution reactions with dimethylamine and sodium methylthiolate were studied. New aldehydes of 1,3-thiazole series of low-molecular weight were obtained.     

Synthesis of 4-aminocycloheptimidazoles

2-Methyl- 1a , 2-phenyl- 1b , and 2-amino-4-(2-methyl-1,3-dioxolan-2-yl)cycloheptimidazole ( 1c ) were treated with hydrazoic acid to give the corresponding 4-aminocycloheptimidazoles, respectively. However, the reaction of 4-(2-methyl-1,3-dioxolan-2-yl)cycloheptimidazole gave complex material. Some approaches to the synthesis of 4-aminonocycloheptimidazole itself are also described.     

Synthesis of (R)-(+)-tanikolide through stereospecific C-H insertion reaction of dichlorocarbene with optically active secondary alcohol derivatives

Stereospecific alpha C-H insertion reaction of protected chiral 1,2-glycols, (S)-1,2-isopropylidenedioxytridecane (3) and ethyl (S)-4,5-isopropylidenedioxy-pentanoate (4), prepared from (R)-glyceraldehyde acetonide (2), with dichlorocarbene generated from CHCl(3)/50% NaOH/cetyltrimethylammonium chloride (as ptc.) took place with complete retention of configuration to provide (S)-4-dichloromethyl-2,2-dimethyl-4-undecyl-1,3-dioxolane (5) and ethyl (S)-3-(4-dichloromethyl-2,2-dimethyl-1,3-dioxolan-4-yl)-propanoate (8), respectively. The ester (8) was transformed to 5 by elongation of the side chain. The glycol derivative (5) was converted into O-TBDPS-protected (S)-2-hydroxymethyl-2-undecyloxirane (16). Reaction of 16 with a cuprate reagent containing homoallylic carbon chain followed by oxidative manipulation of the terminal olefin afforded (R)-(+)-tanikolide (1).     

Reduction of n-(1,3-dioxolan-2-yl)-1-methylpyridinium ions: Molecular structure of the 4-(l,3-dioxolan-2-yl)-1-methyl-1,2,3,6-tetrahydropyridine-borane complex

The reduction of the n-(1,3-dioxolan-2-yl)-1-methylpyridinium ions with sodium borohydride has been studied to prepare N-methylformylpiperidines. Deuterium oxide was used as the solvent in order to assign the protons in the nmr spectra. As a product of the reaction, the 4-(1,3-dioxolan-2-yl)-1-methyl-1,2,3,6-tetrahy-dropyridine-borane complex, was isolated and crystallized. A X-ray study of this borane complex has been carried out.     

Preparation and polymerization of some vinyl monomers containing the 2-oxo-1,3-dioxolane group

The syntheses and polymerizations of (2-oxo-1,3-dioxolan-4-yl)methyl acrylate, 4-(2-oxo-1,3-dioxolan-4-yl)methyl itaconate, and (2-oxo-1,3-dioxolan-4-yl)methyl maleate are described. Reactivity ratios in the copolymerization of these monomers with other comonomers are reported and the Alfrey-Price Q and e values calculated. The post-polymerization effects of ultraviolet light and heat on these polymers and copolymers are presented and compared to those for similar polymers containing the 2,2-dimethyl-1,3-dixolane groups, which performs as an internal ultraviolet sensitizer. The 2-oxo derivatives are crosslinked thermally but not by ultraviolet light. The crosslinking reaction can be catalyzed by acids, bases, and salts.     

Synthesis of [4,5-Bis(hydroxymethyl)-1,3-dioxolan-2-yl]nucleosides as Potential Inhibitors of HIV

The synthesis of 1,3-dioxolan-2-ylnucleosides and related chemistry is described. We have shown that 2-methoxy-1,3-dioxolane (6) reacts with silylated thymine and trimethylsilyl triflate to give the acyclic formate ester 1-[2-(formyloxy)ethyl]thymine (8) rather than 1-(1,3-dioxolan-2-yl)thymine (7). A tentative mechanism which could explain this result is discussed. On the other hand, 2-methoxy-1,3-dioxolane 13c reacts with silylated bases to give [4,5-bis(hydroxymethyl)-1,3-dioxolan-2-yl]nucleosides, thus representing the first examples of this novel class of compounds. The nature of the nucleobase and the hydroxyl protecting groups was found to have great influence on the reaction and on the stability of the nucleosides. Compounds 16 and 18 were found to be inactive when tested for anti HIV-1 activity in vitro.     

Synthesis of C-Nucleoside Analogues： 2-[2-（Hydroxymethyl）-1, 3-dioxolan-5-yl]1, 3-thiazole-4-carboxamide and 2-[2-（Mercaptometh-yl）-1, 3-dioxolan-5-yl] 1, 3-thiazole-4-carboxamide

Novel C-nucleosides of tiazofurin analogue (2-[2-(hydroxymethyl)-1,3-dioxolan-5-yl] 1,3-thiazole-4-carboxamide) and its thiol-substituted derivative (2-[2-(mercaptomethyl)-1,3-dioxolan-5-yl] 1, 3-thiazole-4-carboxamide) were synthesized from methyl acrylate through a multistep procedure. Their structures were confirmed by IR, ^1HNMR, ^13CNMR and elemental analysis.     

Secondary metabolites of Xylaria sp., an endophytic fungus from Taxus mairei

One new metabolite 3,7-dimethyl-9-(-2,2,5,5-tetramethyl-1,3-dioxolan-4-yl)nona-1,6-dien-3-ol, together with nine known compounds, were isolated from the strain Xylaria sp., an endophytic fungus of Taxus mairei. Their structures were deduced from 1D and 2D NMR data. In vitro cytotoxicity and antibacterial activity of these compounds were evaluated. Some of them exhibited substantial activity.     

A Convenient Synthesis of 3-Benzoylindolizine-5-carbaldehydes

3-Benzoylindolizine-5-carbaldehydes (4a-f), which could be used as derivatization reagents for amino compounds in HPCE were synthesized based on the 1,3-dipolar cycloaddition of 1-phenacyl-2-(1,3-dioxolan-2-yl)pyridinium ylide with alkenes in the presence of TPCD.     

Preliminary studies on a novel synthesis of β-amino acids: stereocontrolled transformation of d- and l-glyceraldehyde into 3-amino-2-(2′,2′-dimethyl-1′,3′-dioxolan-4′-yl)propanoic acids

A stereocontrolled synthesis of the methyl ester of (2S)-3-amino-2-((4′S)-2′,2′-dimethyl-1′,3′-dioxolan-4′-yl)propanoic acid from d-glyceraldehyde is described for the first time. This method involves the stereoselective Michael addition of the lithium salt of tris(phenylthio)methane to (S)-2,2-dimethyl-4-((E)-2-nitrovinyl)-1,3-dioxolane followed by hydrolysis of the resulting (4S)-2,2-dimethyl-4-((2′S)-3′-nitro-1′,1′,1′-tris(phenylthio)propan-2′-yl)-1,3-dioxolane to (2S)-methyl 2-((4′S)-2′,2′-dimethyl-1′,3′-dioxolan-4′-yl)-3-nitropropanoate, which was finally reduced to the target compound. A similarly stereocontrolled transformation of l-glyceraldehyde into (2R)-methyl 3-amino-2-((4′R)-2′,2′-dimethyl-1′,3′-dioxolan-4′-yl)propanoate is also described.     

Preparation and polymerization of some vinyl monomers containing the 1,3-dioxolane group

The synthesis and structure determinations of (2,2-dimethyl-1,3-dioxolan-4-yl)-methyl acrylate, 4-(2,2-dimethyl-1,3-dioxolan-4-yl)methyl itaconate, and [(2,2-dimethyl-1,3-dioxolan-4-yl)methyl] methyl fumarate are described. Reactivity ratios in the copolymerization of these monomers with other comonomers are reported and the Alfrey-Price Q and e values calculated. The post-polymerization study of the effects of ultraviolet light and heat on these polymers and copolymers is presented. The 1,3-dioxolane group when appended to the polymer chain performs as an internal ultraviolet sensitizer. A mechanism is offered to explain the crosslinking behavior of these polymers when treated with ultraviolet light.     

新型N~6-哌嗪取代腺苷衍生物的合成及其抗肿瘤活性

以腺苷为母体,对其N6-位进行结构改造,首先经邻位双羟基保护,N6-位氯代,再在N6-位引入哌嗪环制得中间体2',3'-异丙叉-6-哌嗪嘌呤核苷(4);4与N-氯乙酰苯胺类似物(6a~6h)偶联后脱除邻位双羟基保护合成了8个新型的N6-哌嗪取代腺苷衍生物(8a~8h),其结构经1H NMR,13C NMR和HR-ESI-MS表征。采用MTT法研究了8a~8h对Hela肿瘤细胞的抑制活性。结果表明:大部分目标化合物对Hela肿瘤细胞具有较好的抑制活性,其中2-{4-[9-(3,4-二羟基-5-羟甲基-四氢呋喃-2-基)-9H-嘌呤-6-基]-哌嗪-1-基}-N-(3-氟苯基)-乙酰胺(8e)的活性最好,IC50为21.74μmol·L-1。     

Isomerization of Diels-Alder Adducts of Benzoyl-1,4-benzoquinones: A Route to the Anthracyclinone Ring system

Base-induced [1,5laroyl migration in the Diels-Alder adduct of [2-(1,3-dioxolan-2-yl)benzoyl]-1, 4-benzoquinone and trans-penta-1, 3-diene followed by acid-mediated cyclisation affords the corresponding hydroxynaphthacenequinone.     

Extraction of hydrochloric and nitric acid with 1-{[2-(2,4-Dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl]-methyl)-1H-1,2,4-triazole and (RS)-1-(4-Chlorophenyl)-4,4-dimethyl-3-(1H-1,2,4-triazol-1-yl-methyl)-pentan-3-ol

Extraction of hydrochloric and nitric acid with 1-{[2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl]-methyl}-1H-1,2,4-triazole (propiconazole) and hydrochloric acid with (RS)-1-(4-chlorophenyl)-4,4-dimethyl-3-(1H-1,2,4-triazol-1-yl-methyl)-pentan-3-ol (tebuconazole) was studied. It is established that extraction of acids proceeds with the formation of monosolvates as an exothermic process. Effective extraction constants of acids are evaluated. By means of the IR and ¹H NMR spectroscopy it was shown that the protonaccepting center of tebuconazole is N⁴ atom of the triazole ring.     

Synthesis of 1,3,3,5,5-Penta[1-(2,2-dimethyl-1,3-dioxolan-4-yl)methoxy]-1-[(1H-1,2,3-triazol-4-yl)alkoxy]cyclotriphosphazenes

Russian Journal of General Chemistry - Based on 1,3,3,5,5-penta[1-(2,2-dimethyl-1,3-dioxolan-4-yl)methoxy]-1-chlorocyclotriphosphazene, a series of hybrid compounds was obtained by two-step...     

Synthesis of Single-stranded Polynorbornene with Pendant Group Bearing Benzenedicarboxaldehyde and Long Alkyl Chain

An unprecedented single-stranded polynorbornene with the pendant group containing benzenedicarboxaldehyde and a long alkyl chain(12) was synthesized by ring-open metathesis polymerization(ROMP) of the corresponding monomer(11), which was obtained via the esterification of two crucial intermediates, namely, 2-hexadecyl- oxy-5-hydroxymethyl-1,3-benzenedicarboxaldehyde(7, obtained via 6 steps) and 4-(4-aza-tricyclo[5.2.1.0^2.6]-dec-8- en-4-yl)benzoic acid(10). The target compound and all the intermediates were characterized by infrared(IR), ¹H NMR and high resolution mass spectroscopy(HRMS) analysis.     

Uncommon transformations of methyl (1S,2S,3R,4R)-2,3-isopropylidenedioxy-5-iodomethyl-2-tetrahydrofurylacetate initiated by bases

Methyl (1S,2S,3R,4R)-2,3-isopropylidenedioxy-5-iodomethyl-2-tetrahydrofurylacetate prepared in two stages from D-ribose acetonide underwent a series of uncommon transformations under the treatment with bases providing the following different products depending on the base applied: methyl 3-(5-acetyl-2,2-dimethyl-1,3-dioxol-4-yl)propionate (DBU), methyl 2,3-isopropylidenedioxy-7-oxabicyclo[2.2.1]heptane-6-carboxylate (t-BuOK), methyl {(5R)-2,2-dimethyl-5-[(2R)-oxiranyl]-1,3-dioxolan-4-ylidene}propionate and methyl-(E)-3-{(4S,5R)-2,2-dimethyl-5-[(1R)-(2-oxiranyl)]-1,3-dioxolan-4-yl}-2-propenoate (t-BuOK and LDA).     

Extraction of palladium(II) with 1-{[2-(2,4-Dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl]-methyl}-1<Emphasis Type="Italic">H</Emphasis>-1,2,4-triazole from nitrate-nitrite solutions modeling the composition of raffinates formed in the PUREX process

Extraction of palladium(II) with 1-{[2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl]-methyl}-1H-1,2,4-triazole in toluene from nitrate-nitrite solutions modeling in a number of components the composition of raffinates formed in the PUREX process was studied. Conditions of a tenfold concentration of palladium(II) into an ammonia extract were found.     

Synthesis of 3-(N-alkylamino)acetophenones via a benzyne intermediate

Reaction of 2-(2-bromophenyl)-2-methyl-1,3-dioxolane with lithium (1,1-dimethylethyl)amide, lithium (2,2-dimethylpropyl)amide, lithium (1,1-dimethylpropyl)amide gave the corresponding N-(alkyl)-3-(2-methyl-1,3-dioxolan-2-yl)benzenamines in moderate yields. 1-[3-[(1,1-Dimethylethyl)amino]phenyl]ethanone ( 4 ) was prepared in over 80% yield from 2-(2-bromophenyl)-2-methyl-1,3-dioxolane ( 2 ).     

Regioselective Intermolecular Cyclization of Methyl (E)-3-[(4S,5S)-5-Acetyl-2,2-dimethyl-1,3-dioxolan-4-yl)]prop-2-enoate

Russian Journal of Organic Chemistry - Methyl (E)-3-[(4S,5S)-5-acetyl-2,2-dimethyl-1,3-dioxolan-4-yl)]prop-2-enoate obtained from D-ribose eliminates water on storage and transforms into a bicyclic...