β-三氯锗基丙酸及β-三苯锗基丙酸与苯基溴化镁的反应

三氯锗基丙酸(1a)和三苯锗基丙酸(2a)与过量苯基溴化镁起反应时,这两个分子中的羧基表现出一些奇特性质。当1a和2a与不同浓度的苯基溴化镁起反应时,都能生成相应的酮(3a)和醇(4a)。在稀盐酸作用下,4a极易脱水生成1,1-二苯基-3-三苯锗基丙烯-1(5a)。当1a与苯基溴化镁起反应,然后再用稀盐酸处理也同样得到5a。5a的Ge-C键能被LiAlH~4高选择性地切断,生成三苯基锗烷(6a)和1,1-二苯基丙烯(6b)。     

Theoretical study on the synthesis reaction mechanism of trichlorogermyl crylic acid

The synthesis reaction of trichlorogermyl crylic acid has been studied systematically by using quantum chemistry methods for the first time.Geometries of reactants,transition states,and products have been optimized,respectively at the B3LYP/6-311G（d,p） level.Vibrational frequencies,IR intensities and relative energies for various stationary points have been determined.The reaction pathways are identified by intrinsic reaction coordinate（IRC）calculations.Theoretical analysis provided conclusive evidence that the process is completed through five pathways of addition reaction of double bond,and the transition states are found to be four- membered ring compounds.Solvent effects are taken into account with the PCM model at the same level.This preliminary study shows that the complex formation is favored by the use of polar solvent.     

Synthesis and characterization of trichlorogermyl dioic acids: crystal structures and complementary hydrogen bonding motifs in 3-(trichlorogermyl) pentanedioic acid and 2-[(trichlorogermyl)methyl]butanedioic acid

A series of trichlorogermyl-substituted dicarboxylic acids of general formula HOOC–R′–COOH where R′=–CH₂CH(GeCl₃)CH₂– 1, –CH(CH₂GeCl₃)CH₂– 2, –CH(GeCl₃)CH₂– 3 and –CH(CH₃)CH(GeCl₃)– 4 were synthesized by the hydrogermylation reaction of unsaturated acids, such as trans-glutaconic (2-pentenedioic acid), itaconic (methylenebutanedioic acid), fumaric (2-butenedioic acid), and citraconic (2-methyl-2-butenedioic acid) acids with HGeCl₃, which was produced in situ by the reaction of GeO₂ with 37% HCl in presence of NaH₂PO₂ · H₂O. All these compounds were characterized by melting point, CHN analysis, FTIR, and multinuclear NMR (¹H; ¹³C; H,H-COSY). X-Ray crystal structures of 1 and 2 were analyzed to show supramolecular structures in which central Ge atom in each of these structures is four-coordinated with a slightly distorted tetrahedral geometry. Structurally, both compounds adopt supramolecular forms via strong intermolecular O–H–O interactions through 8-membered and 22-membered hydrogen bonded rings. Supplementary material to this paper is available in electronic form at Correspondence: Muhammad Mazhar, Department of Chemistry, Quaid-i-Azam University, Islamabad 45320, Pakistan.     

Acylamides of C-germylcarboxylic acids. Crystal and molecular structure of N-acetyl-N-methyl-3-(trichlorogermyl)propionamide

The first representatives of a new class of organogermanium compounds, the acylamides of C-germylcarboxylic acids, N-acetyl-N-methyl-3-(trichlorogermyl)propionamide and N-3-(trichlorogermyl)propionylurethane, were synthesized. An X-ray structural study of Cl₃GeCH₂CH₂C(O)NMeC(O)Me revealed a greater Ge...O intramolecular distance than that reported earlier for 3-(trichlorogermyl)propionamides. The Ge atom configuration is somewhat distorted towards a trigonal bipyramid.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 762–764, April, 1993.     

Synthesis and Structures of Amino(triphenylgermyl) Boranes and Trihydro(triphenylgermyl) Borates

The B‐(triphenylgermyl)borazines 4 a and 4 b , the 1,2‐bis(dimethylamino)‐1,2‐bis(triphenylgermyl)‐diborane(4), 5 , and the (2,2,6,6‐tetramethylpiperidino)(triphenylgermyl)‐boranes 6 and 7 were prepared by allowing LiGePh₃ to react with the corresponding B‐bromoborazines and aminochloroboranes, respectively. BH₃ dissolved in thf readily adds to LiGePh₃ generating Li(H₃BGePh₃), 8 a , in thf solution. Addition of N‐bases to the solution of 8 a produced (tmen · thf)Li(H₃BGePh₃), 8 b , and dimeric (py)₂Li(H₃BGePh₃), 8 c . The borazine ring in 4 b is distorted into a boat shape. In 5 the NBGe planes are twisted against each other by 85°. Comparison with analogous (triphenylstannyl)boranes points to a more pronounced steric effect of the Ph₃Ge group over the Ph₃Sn group due to the shorter B–Ge bond. A fairly short B–Ge bond is found for the (triphenylgermyl)trihydroborates. The molecular structure of (Et₂O)₃LiGePh₃ shows compressed C–Ge–C bond angles. Its molecular parameters fit well into the series L_nLiEPh₃ (E = Si, Sn, Pb).     

铪催化合成聚3-羟基丙酸

以3-羟基丙酸(3-HP)为单体,金属铪(Ⅳ)催化合成了高纯度的聚3-羟基丙酸[P(3-HP)]。3-HP和P-(3-HP)的结构经NMR,FT-IR和GPC等表征。     

Regioselective synthesis of 3,3-bis(indolyl)propanoic acid derivatives by iron(III)-catalyzed hydroarylation of propynoic acid derivatives with indoles

Intermolecular hydroarylation of propynoic acid and its esters with indoles proceeded efficiently in acetic acid under a catalytic system of FeCl₃/3AgOTf and afforded the corresponding 3,3-bis(indol-3yl)propanoic acids and their esters in high yields. In the case of 2-methylindole, 3-indolylacrylic acid and its ethyl ester were obtained in high yields. This iron-catalyzed hydroarylation showed a high regioselectivity at the 3-position of indoles and a high utility for the synthesis of bis(indol-3-yl) compounds, which are important for biological and pharmaceutical fields.     

Synthesis and properties of 3-cyano-4-(4-cyanophenyl)-1,4-dihydropyridine-2(3H)-thiones

Piperidinium 3-cyano-4-(4-cyanophenyl)-1,4-dihydropyridine-2(3H)-thiolates were obtained by the condensation of 1,3-dicarbonyl compounds, 4-cyanobenzaldehyde, and cyanothioacetamide in the presence of an equimolar amount of piperidine. The acidification of these thiolates gave the corresponding 1,4-dihydropyridine-2(3H)-thiones and pyridine-2(1H)-thione. Alkylation of 1,4-dihydropyridine-2-thiolates or the reaction mixture of the three-carbon condensation using iodacetamide gave 2-carbamoylmethylthio-1,4,5,6-tetrahydro- or 1,4-dihydropyridines, which were characterized by their conversion to 4,7-dihydrothieno[2,3-b]pyridines.Latvian Institute of Organic Synthesis, LV-1006, Riga, LatviaTranslated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 794–798, June, 2000.     

Synthesis and root growth-inhibitory activity of 2- and 3-(haloacetylamino)-3-(2-furyl)propanoic acids

A convenient synthesis of 2- and 3-(chloroacetylamino)-3-(2-furyl)propanoic acids (6a, 7a) and their fluoro analogs were developed. Both 6a and 7a showed 51-55% root growth-inhibitory activity towards rape seedlings at the concentration of 1.0x10(-4) M.     

Synthesis, structural characterization and reactivity of the amino borane 1-(NPh2)-2-[B(C6F5)2]C6H4

The bright red title compound 1 was synthesized from (2-lithiophenyl)diphenylamine and bis(pentafluorophenyl)boron chloride. Its reactions with small acids like H₂O and HCl proceeded easily giving zwitterionic compounds. For 1 and its water adduct 2 the crystal structures were determined, the latter featuring an ammonium borate structure containing a short intramolecular hydrogen bond bridge. Treatment of 1 with Jutzi's acid, [H(OEt₂)₂][B(C₆F₅)₄], did not result in protonation of the nitrogen, but reaction of 1 with LiH in the presence of 12-crown-4, led to the isolation of the aminoborate [1-(Ph₂N)-2-{B(H)(C₆F₅)₂}C₆H₄][Li(12-crown-4)] (3). Borohydride 3 reacted with Jutzi's acid to regenerate 1 and liberate hydrogen.     

Intramolecular Acylal Cyclisation (IAC) as an Efficient Synthetic Strategy towards the Total Synthesis of Erythrina Alkaloid Derivatives

Compounds that comprise the erythrina alkaloid class of natural products are based on a tetracyclic spiroamine framework and exhibit a range of biological activities on the central nervous system. Herein, we report a new and efficient total synthesis of this multiple‐ring system based on an intramolecular acylal cyclisation (IAC) approach. Using this methodology, the tetracyclic core was rapidly assembled over a two‐step domino process catalysed by a Lewis acid. The effect of heteroatoms, substituents and ring size on the IAC has also been investigated, and the broad application of this procedure is demonstrated by the synthesis of a library of derivatives in good yields with excellent regioselectivity.     

Synthesis and Crystal Structure of 3-(Pyrrole-2''-carboxamido)propanoic Acid·(1/2)H2O

3-(Pyrrole-2'-carboxamido)propanoic acid I has been synthesized from the reaction of β-alanine methyl ester with 2-trichloroacetylpyrrole followed by saponifying and acidating in 85.4% yield, and the crystal structure of 3-(pyrrole-2'-carboxamido)propanoic acid· (1/2)H2O (C8H11N2O3.5, Mr = 191.19) was obtained and determined by X-ray diffraction method. The crystal is of monoclinic, space group C2/c with a = 19.010(4), b = 8.3515(17), c = 13.788(3) (A), β = 125.88(3)°, V = 1773.6(6) (A)3, Z = 8, Dc = 1.432 g/cm3, λ = 0.71073 (A), μ-MoKα) = 0.114 mm-1 and F(000) = 768. The structure was refined to R = 0.0354 and wR = 0.0942 for 1642 observed reflections with I > 2σ(I). It is revealed that the title compound has one pyrrole ring and one propionic acid subchain linked by an amido bond at C(4), and there are 8 molecules of com- pound I and 4 crystal water molecules in each unit cell. The supramolecular layers are stabilized by the hydrogen bonds of N(2) H…O(2), N(1) H…O(4), O(4) H(1W)…O(2) and O(3) H…O(1).     

Enantioselective Diels-Alder reactions of 3-(acyloxy)acrylates

Diels-Alder reactions with 3-(acyloxy)acrylates using chiral Lewis acid catalysts have been successfully carried out. These reactions proceed with high enantioselectivity when a chiral Lewis acid derived from Cu(OTf)₂ and a bisoxazoline is used. The facility of the reaction is dependent on the nature of the acyloxy group in the dienophile.     

Synthesis of Novel Organogermanium Sesquioxides and Reactivities of 3-(Trichlorogermyl)propanoic Acid

During the past two decades, carboxyethylgermanium sesquioxide Ge-132[O₃(GeCH₂CH₂COOH)₂] and its derivatives have attracted considerable attention because these organogermanium sesquioxides exhibited anticancer activities[1,2]. In 1993, Kurono et al. have synthesized phosphonoethylgermanium sesquioxide[O_3/2GeCH₂CH₂PO(OH)₂], which possesses higher antitumor activity than Ge-132[3]. Encouraged by these promising results, we developed the idea that the incorporation of a germanium residue into α-aminophosphonic acids and their derivatives, which have antibacteria and antitumor activities[4,5], would enhance their antitumor activities to a significant degree, while their toxicity would be reduced at the same time. Therefore, we designed and synthesized a series of novel organogermanium sesquioxides containing α-aminophosphonate groups by the hydrolysis of O,O-diphenyl N-trichlorogermyl propiono-α-aminophosphonates.