Synthesis of Boc-protected 4,5-methano-β-proline

An efficient method for the preparation of Boc-protected 4,5-methano-β-proline—a novel bicyclic cyclopropane-containing β-amino acid—was developed, starting from readily available itaconic acid. A modified Simmons–Smith reaction was used for the construction of the cyclopropane ring. The method allowed for the synthesis of both cis and trans isomers of the title compound in 49% total yield and can be employed for gram-scale preparations. An approach to the preparation of methyl 5-oxopyrrolidine-3-carboxylate, which is one of the key intermediates in the synthetic scheme, on a multigram scale was also developed.     

Synthesis and Crystal Structure of 4,5-Diazafluorene-9-one Azine Hydrochloride Hydrate

1 INTRODUCTION During the study of polynuclear complexes with the aim to investigate the magnetic super-exchange interaction between the adjacent metal ions bridged by a conjugation molecule[1], we have made efforts to prepare complexes bridged by 4, 5-diazafluorene-9-one azine (DAA) and found that the coordination ability of DAA is poor in the acidic solution. In order to probe the reason, DAA has been crystallized from the hydrochloric acid solution and its crystal structure has b…     

First Total Synthesis of 4,5-Sccoeudesmane-type and Iphionane-type Compounds-Synthesis of 4,5-Dioxo-seco-γ-eudesmol and 5β,11-Dihydroxyiphionan-4-one

4, 5-Secoeudesmane-type and iphionane-type compounds are sesquiterpenes with newcarbon skeletons found in natrual sources in recent years.1-6 The co-occurence of 4, 5secoeudesmanes, iphionanes and eudesmanes as natrual products suggests that 4, 5secoeudesmanes, iphionanes most likely are generated biogenetically tyom eudesmanes,and iphionanes are formed biogenetically by aldol reaction of 4, 5dioxosecoeudesmanes1,4,6,7 The study on the synthesis of this two kind of newsesquiterpenes has not be…     

Synthesis and Crystal Structure of 4,5-Bis（2-chloroethylthio）phthalonitrile

A novel phthalonitrile compound,[C12H10Cl2N2S2],has been synthesized and its crystal structure was determined by single-crystal X-ray diffraction.The crystal belongs to the monoclinic system,space group P21/n with a = 10.6417(8),b = 7.5737(6),c = 18.2758(14),β = 105.2480(10)°,Mr = 317.24,V = 1421.12(19)3,Z = 4,Dc = 1.483 g/cm3,F(000) = 648,μ = 0.733 mm-1,R = 0.0173 and wR = 0.2183.In the structure,the C atoms of the aromatic ring,the two cyanide groups and the two S atoms are almost coplanar(maximum deviation from the mean plane = 0.049(7) ).Two potential weak intermolecular interactions of C-H…N and one type of π…π stacking interaction with a centroid-centroid separation of 3.751(8) stabilize the crystal structure.     

Synthesis and Crystal Structure of 1,2-Bis-（p-nitrophenylsulfonamido）-4,5-dinitrobenzene

The title compound, 1,2-bis-(p-nitro-phenylsulfonamido)-4,5-dinitrobenzene, was synthesized and characterized by elemental analysis, IR and 1H NMR. A pale yellow prism crystal of C23H26N8O13S2 (Mr = 686.64) was obtained in DMF solution and determined by single-crystal X-ray diffraction method. It crystallizes in triclinic system, space group P1 with a = 10.346(4), b = 12.210(5), c = 12.976(5) , α = 108.220(8), β = 99.482(4), γ = 95.490(4)°, V = 1516.7(10) 3, Z = 2, Dc = 1.504 g/cm3, F(000) = 712, μ = 0.254, Mr = 686.64, the final R = 0.0561 and wR = 0.1487. One sulfonamido group of the title compound is deprotoned and forms N(3)=C(13). The crystal involves N,N-dimethylamine from the decomposition of DMF and the proton is transferred to N,N- dimethylamine. It is a strong proof for the characterization of deprotoned recognition compound by X-ray single-crystal structure.     

Synthesis and Structure of 2—Acetylthiophene Thiosemicarbazone

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Synthesis and Structure of 4—Nitrobenzaldehyde Thiosemicarbazone

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Synthesis and properties of new polyazines—III

Polycondensations of 1,2- and 1,4-naphthoquinones with hydrazine hydrate and disulphinylhydrazine under various conditions were carried out. The optimum parameters for the disulphinylhydrazine synthesis were established. The thermal stabilities and electrical conductivities of the polynaphthoquinoneazines were determined.     

Synthesis and Properties of Aryloxy—terminated Polydimethylsiloxanes

Aryloxy-terminated polydimethylsiloxanes (AOS) were synthesized by the telomerization of hexamethylcyclotrisiloxane(D3) with phenols.The structures of AOS were characterized by UV,IR,^2HNMR and elemental analysis,The effects of the reaction conditions and the mole ratios of the reactants on the molecular weight of the polymer were discussed.AOS′s structural influence on bactericidal action,flocculation and hydrolysis was studied.     

Synthesis and characterization of 4,6-diaryl-4,5-dihydro-2H-indazol-3-ols and 4,6-diaryl-2-phenyl-4,5-dihydro-2H-indazol-3-ols — a new series of fused indazole derivatives

A novel class of 4,6-diaryl-4,5-dihydro-2H-indazol-3-ols and 4,6-diaryl-2-phenyl-4,5-dihydro-2H-indazol-3-ols is synthesized and characterized by melting point, elemental analysis, MS, FT-IR, ¹H and ¹³C NMR, D₂O exchanged ¹H NMR, and two-dimensional HSQC spectra. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1183–1188, August, 2008.     

Synthesis of AZT—Phosphonate,Phosphonothioate and Phosphonoselenoate

Phosphonate,phosphonothioate and phosphonoselenoate derivatives of AZT were synthesized in an expeditious way and high yields.     

Synthesis and Crystal Structure of Dimethyl-3-（4-bromophenyl）-1-phenyl-4,5-dihydro-1H-pyrazole-4,5-dicarboxylate

The title compound (C19H17BrN2O4) was synthesized via a one-pot procedure starting from 4-bromobenzaldehyde, dimethyl acetylenedicarboxylate (DMAD) and phenylhydrazine with pyridine as the catalyst. Its structure was determined by single-crystal X-ray diffraction analysis. The crystal belongs to the monoclinic system, space group P21/c with a = 11.115(3), b = 8.090(2), c = 20.211(5) , β = 97.032(5)°, V = 1803.7(8) 3, Z = 4, Mr = 417.25, Dc = 1.536 g/cm3, μ = 2.306 mm-1, F(000) = 852, the final R = 0.0403 and wR = 0.0895 for 2215 observed reflections with I 2σ(I).     

Synthesis and Characterization of Charge—transfer Complexes of Aminoethylphoshphono—and Dimethylaminoethylphosphono—heteropolytungstic Acids of Keggin Type Structure

Two charge-transfer complexes of 2a and 2b of Keggin type were synthesized and characterized by elemental analysis,IR spectra,UV spectra,XRD,TG-DSC;and were compared with Hquin-PW12.The primary structure of the heteropolyanions had not been changed after the formation of the charge transfer complexes.     

Synthesis and photochromism of dimers of 4,5- diaryl-2-(2,5-dimethylthiophen-3-yl)imidazolyl

4,5-Diphenyl, 4,5-di(4-methylphenyl), 4,5-di(4-methoxyphenyl)-2-(2,5-dimethylthioph-en-3-yl)imidazoles were synthesized. Oxidation of the obtained imidazoles with potassium ferricyanide in water-alcohol solution of alkali gave the corresponding dimers. The structures were characterized by IR, 1H NMR, mass spectroscopy and elemental analysis. The dimers showed photochromism in solution on irradiation.     

Improved Synthesis of Icaritin and Total Synthesis of β-Anhydroicaritin

Natural products icaritin and β-anhydroicaritin with P-glycoprotein(P-gp) inhibitory activities were ciently synthesized in nine steps from commercially available phloroglucinol. A modified Algar-Flynn-Oyamada cyclization and relay Claisen-Cope rearrangement were employed in this concise route. Oiir synthesis offers opportunities to synthesize various icariin analogues for biological and pharmacological investigations.     

Synthesis and Crystal Structure of a β—Lactam Derivative of 2,4—Diary

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