钯系催化剂的氨中毒研究

 考察了CO常压气相偶联合成草酸酯反应体系中在不同氨含量下P\r\nd系催化剂活性随反应时间的变化．结果表明，随着氨含量的增加，催\r\n化剂活性降低的速率加快，氨含量不超过0．54％时，仅引起催化剂活\r\n性下降，但不会造成催化剂完全失活；当氨含量达1．16％时，催化剂\r\n活性随反应时间迅速下降，直至完全失活．同时，观测了催化剂氨中毒\r\n的不可逆性．利用XPS和TEM表征手段探讨了Pd系催化剂氨中毒机理，并\r\n分析了在工业生产条件下催化剂氨中毒不可逆性的原因．     

Triethyl tetrathiolothionophosphate

Triethyl tetrathiolothionophosphate was prepared by the reactions of diethyl disulfide with P₄S₁₀, 2,4-bis(4-ethylthio)-2,4-dithioxo-1,3,2⁵,4⁵-dithiadiphosphetane, or with the mixture of red phosphorus and elemental sulfur. The reactions are facilitated by ultrasound.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1310–1311, July, 1993.     

A concise synthesis of protected diethyl 1-amino-2-hydroxyalkylphosphonates

An efficient diastereoselective synthesis of 5-substituted (2-thioxo-oxazolidin-4-yl)phosphonic acid diethyl esters from metallated diethyl isothiocyanomethylphosphonate and aldehydes has been developed. The three-step transformation of oxazolidine-2-thione derivatives into N-Boc 1-amino-2-hydroxyalkylphosphonic acid diethyl esters is also described.     

N-PHOSPHORYL AMINO ACIDS AND PEPTIDES: PART I. THE CRYSTAL AND MOLECULAR STRUCTURE OF N-(O,O-DIISOPROPYL PHOSPHORYL)-TRANS-4-HYDROXY-D,L-PROLINE

Abstract

The crystal and molecular structure of N-(O,O-diisopropyl phosphoryl)-trans-4-hydroxy-D,L-proline has been determined by X-ray diffraction analysis and is compared with proline or hydroxyproline residue in a peptide chain described in the literature. The compound crystallized in orthorhombic system with space group P2₁2₁2₁, a=6.934(2), b=8.694(3), c=26.727(7) Å, V=1611.3(8) ų, Z=4, Dx=1.22 g/cm³. The structure was solved by direct method and refined by anisotropic least squares to a discrepancy index R=0.072. In the compound, the nitrogen atom is trigonal and its remaining 2p orbital is conjugated with the P?Oπ system; the conformation of the phosphorimidate function is favoured by the trans orientation of the P=O bond with respect to the N-C4 bond. In the pyrrolidine ring moeity, the C2-C1-N-C4 atoms are nearly copolnar and the C3 atom is out of the plane by about 0.47 Å.     

Straightforward Synthesis of 1,2-Amino Phosphate Diesters and Application to the Synthesis of Novel 1,2-Amino Ether Diesters

A variety of 1,2-amino alcohol diesters 1 reacted smoothly with diethyl chlorophosphate under basic conditions to afford the corresponding 1,2-amino phosphate diesters 2 in excellent yields. These compounds served as useful precursors for subsequent nucleophilic attack by alcohols in an S_N2 fashion to provide 1,2-amino ether diesters 3.     

Low potential electrosyntheses of free‐standing poly(dibenzofuran) films in mixed electrolytes of boron trifluoride diethyl etherate and trifluoroacetic acid

Free‐standing poly(dibenzofuran) (PDBF) films were synthesized electrochemically by direct anodic oxidation of dibenzofuran in mixed electrolytes of boron trifluoride diethyl etherate (BFEE) containing certain amount of trifluoroacetic acid (TFA). The oxidation potential of dibenzofuran in pure BFEE was measured to be only 1.31 V versus saturated calomel electrode (SCE). This value was much lower than that determined in acetonitrile + 0.1 mol L^?1 TBATFB (2.14 V vs. SCE). The addition of TFA to BFEE can further decrease the oxidation potential of the monomer to 1.07 V versus SCE in the mixed electrolyte of BFEE + 30% TFA. PDBF films obtained from this medium showed good electrochemical behavior, good electrochromic properties, and good thermal stability with conductivity of 10⁰ S cm^?1. FTIR and ¹H NMR spectra showed that the polymer was grown mainly via the coupling of the monomer at C₍₃₎ C₍₁₀₎ or C₍₄₎ C₍₉₎ positions (Scheme 1). As‐formed PDBF films were partly soluble in tetrahydrofuran (THF) or chloroform. Fluorescent spectral studies indicated that either soluble or PDBF in solid state was a good blue light PDBF emitter. To the best of our knowledge, this is the first report that free‐standing PDBF films can be electrodeposited. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1125–1135, 2006     

SYNTHESIS AND SPECTRAL CHARACTERIZATION OF DIETHYL 2-[ARYL(4-ARYL-1,2,3-SELENADIAZOL-5-YL)METHYL]MALONATE

Synthesis and characterization of several diethyl 2-[aryl(4-aryl-1,2,3-selenadiazol-5-yl)methyl]malonates are reported.     

Synthesis of substituted pyrrolo[3,2-<Emphasis Type="Italic">f</Emphasis>]-quinolines from 5-aminoindoles and diethyl oxaloacetate

The reactions of a series of substituted 5-aminoindoles with diethyl oxaloacetate were studied. A synthesis was developed for 5-indolylamino derivatives of diethyl fumarate as well as 7-ethoxycarbonyl-6,9-dihydro-3H-pyrrolo[3,2-f]quinolin-9-ones. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 80–89, January, 2007.     

二硝基苯乙基氟代膦酸二乙酯的制备

在室温下,二氟溴甲基膦酸二乙酯与锌粉反应生成锌试剂;2,4-二硝基氯化苄与合成的锌试剂在溴化亚铜催化作用下即可反应生成二硝基苯乙基(氟代)磷酸二乙酯化合物。两步反应都可在室温下进行,操作简单易行。