Synthesis of 2,3-diaryl-1,4-diazolyl-2,3-epoxybutanes

2,3-Diaryl-1,4-diazolyl-2,3-epoxybutanes have been prepared from dimethylstilbenes. An efficient although neglected synthesis of the required olefins has been recovered from the literature. The target compounds show moderate antifungal activity.     

2,3-Diphosphino-1,4-diphosphonium ions

Salts of the first crystallographically characterized chlorophosphinophosphonium ions have been prepared, and their reaction with Ph3P results in reductive coupling of the chlorophosphine centers to give the first acyclic 2,3-diphosphino-1,4-diphosphonium ions, representing a key framework in the development of catena-phosphorus chemistry. These new salts of general formula [R3P-PR'-PR'-PR3][OTf]2 are also obtained in a one-pot diastereoselective reaction of a dichlorophosphine, a tertiary phosphine, and trimethylsilyltrifluoromethanesulfonate. The structural and spectroscopic features of the new dications complement those of the known diphosphonium and 2-phosphino-1,3-diphosphonium dications. Quantitative ligand exchange reactions are observed when derivatives of [Ph3P-PR'-PR'-PPh3][OTf]2 are combined with Me3P, demonstrating the coordinative nature of the phosphine-phosphonium P-P bonds and implicating a bonding model involving the diphosphenium dication acceptor. The observed solid state structures have been interpreted in the context of computational studies.     

Reaction of dichlorocarbene with 2,3-dihydro-5,6-dimethyl-1,4-oxathiin and 2,3-dihydro-5,6-dimethyl-1,4-dithiin

Dichlorocarbene, generated from ethyl trichloroacetate and sodium ethoxide, reacts with 2,3-dimethyl-5,6-dihydro-1,4-oxathiin to give 7,7-dichloro-1,6-dimethyl-2-oxa-5-thiabicyclo[4,1,0]heptane, and with 2,3-dimethyl-5,6-dihydro-1,4-dithiin to give 6-chloro-2,3-dihydro-7-methyl 5-methylene-5(H)-1,4-dithiepin. Both products were oxidised to the corresponding sulfone.     

1,4-二硝基-2,3-二硝胺基哌嗪的合成

本文以乙二胺, 乙二醛和脲为原料, 通过Mannich反应, 合成出2,5,7,9-四氮杂双环[4.3.0]壬-8-酮盐酸盐(1); 化合物1 亚硝化给出2,5-二亚硝基-2,5,7,9-四氮杂双环[4.3.0]壬-8-酮(2); 硝化化合物2制得2,5,7,9-四硝基-2,5,7,9-四氮杂双环[4.3.0]壬-8-酮(3); 化合物3水解制得1,4-二硝基-2,3-二硝胺基哌嗪(4).     

Stereospecific synthesis of 2,3-disubstituted 1,4-benzodioxans

The synthesis of cis- and trans-2-methyl-3-phenyl-1,4-benzodioxans 4 and 5 , from 1-phenyl-2-[2-(hydroxy)-phenoxy]propanols threo 2 and erythro 3 are described.     

Reduction mechanism of 1,4-diamino-2,3-anthraquinone disulphonic acid

The potentiometric acid constants of 1,4-diamino-2,3-anthraquinonedisulphonic acid were calculated. The sequence of dissociation is discussed. The reduction of the reagent at a dropping mercury electrode has been investigated. The polarograms of reagent show two waves, whose adsorption and diffusion nature is respectively established. The reaction orders, together with Tafel’s slopes have been calculated.     

2,3-二取代-1,4-萘醌的合成

常温下, 在丙酮与水的混合介质中(V∶V＝1∶1), 4-羟基香豆素类化合物与1,4-萘醌进行Michael加成反应, 生成6个未见文献报道的2,3-二取代-1,4-萘醌. 产物经MS, 1H NMR, 元素分析表征, 确定了其化学结构.     

Facile Access to Substituted 1,4-Diaza-2,3-Diborinines

Several bis(dimethylamino)-substituted 1,4-diaza-2,3-diborinines (DADBs) were synthesized with variable substituents at the backbone nitrogen atoms. By reaction with HCl or BX₃ (X=Br, I), these species were successfully converted into their synthetically more useful halide congeners. The high versatility of the generated B−X bonds in further functionalization reactions at the boron centers was demonstrated by means of salt elimination (MeLi) and commutation (NMe₂ DADBs) reactions, thus making the DADB system a general structural motif in diborane(4) chemistry. A total of 18 DADB derivatives were characterized in the solid state by X-ray diffraction, revealing a strong dependence of the heterocyclic bonding parameters from the exocyclic substitution pattern at boron. According to our experiments towards the realization of a Dipp-substituted, sterically encumbered DADB, the mechanism of DADB formation proceeds via a transient four-membered azadiboretidine intermediate that subsequently undergoes ring expansion to afford the six-membered DADB heterocycle.     

2,3-Dimethylquinoxaline-6-carboxaldehyde 1,4-dioxide

A series of derivatives of 2,3-dimethylquinoxaline-6-carboxaldehyde 1,4-dioxide was prepared. Derivatives prepared included nitrones, semicarbazide, and aminooxazolidinone.     

Quinoxalino[2,3-b]-1,4-thiazines

Quinoxalino[2,3-b]-1,4-thiazines were obtained by the reaction of 2-aminoquinoxaline-3-thione and its 6,7-dimethyl derivative with -halocarbonyl compounds. Hydrolysis of these compounds in alkaline and acid media gave 2-amino-3-quinoxalone and quinoxaline-2,3-dione. The IR and UV spectra are presented.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 853–856, June, 1971.     

STUDY ON CATIONIC RING-OPENING COPOLYMERIZATION OF 1,4-ANHYDRO-2,3-DI-O-BENZYL-α-D-RIBOPYRANOSE WITH 1,4-ANHYDRO-2,3-O-ISOPROPYLIDENE-α-D-RIBOPYRANOSE

Cationic ring-opening copolymerization of 1, 4-anhydro-2, 3-O-isopropylidene-α-D-ribo-pyranose (AIRP) with 1,4-anhydro-2,3-di-O-benzyl-α-D-ribopyranose (ADBR) preparedfrom D-ribose was studied. Copolymerization using SbCl_5 or BF_3 OEt_2 as catalyst atlow temperature gave stereoregular (1→4)β-D-ribofuranan (C-1 and C-4 ring cleavagesee Scheme 1) or (1→5) α-D-ribofuranan (C-1 and C-5 ring cleavage) respectively. Theeffects of catalysts, reaction time and temperatures on yield and stereoregularity of the ob-tained polymers were studied. Polymers were characterized by molecular weight, ~1HNMR,~(13)CNMR and optical rotation.     

1,4-Naphthochinon und dessen 2,3-Dichlorderivat

Ohne Zusammenfassung     

Copper-catalyzed 1,4-protosilylation and 1,4-protoborylation of enynic orthoesters for synthesis of functionalized 2,3-allenoates

Herein, copper-catalyzed 1,4-protosilylation and 1,4-protoborylation of enynic orthoesters have been developed. The enynic orthoesters as precursors of unstable enynic esters were applied to produce the functionalized 2,3-allenoate products. Meanwhile, the asymmetric 1,4-protosilylation of enynic orthoesters with Ph Me2Si-Bpin was also studied. The chiral monopyridine imidazoline ligand was efficient to provide the asymmetric 1,4-protosilylation products with high enantioselectivity.     

A novel perfluoromonomer: perfluoro-2,3-dihydro-1,4-benzodioxin

A novel perfluoromonomer, perfluoro-2,3-dihydro-1,4-benzodioxin (FDB), was synthesized. The homopolymerization and copolymerizations of FDB were investigated. The structure and physical properties of those polymers were characterized.     

2,3-二氢-1,4-苯并噁嗪衍生物的合成研究进展

综述了2,3-二氢-1,4-苯并噁嗪衍生物的合成研究进展,并对其发展趋势、应用前景作了进一步的展望。