Origin of the Superior Performance of (Thio)Squaramides over (Thio)Ureas in Organocatalysis

The Diels–Alder cycloaddition of anthracene and nitrostyrene catalyzed by the squaramide‐derived aminocatalysts ( Sq ) recently reported by Jørgensen and co‐workers (Angew. Chem.­ 2012 , 124, 10 417; Angew. Chem. Int. Ed.­ 2012 , 51, 10 271) has been studied by using modern tools of computational quantum chemistry. This catalyst is compared with analogous urea‐, thiourea‐, and thiosquaramide‐derived aminocatalysts. Ultimately, a thiosquar‐amide‐derived catalyst is predicted to result in the lowest free‐energy barrier, while retaining the same high degree of enantioselectivity as Sq . This stems in part from the superior hydrogen‐bonding ability of thiosquaramides, compared to squaramides and (thio)ureas. We also examine the hydrogen‐bonding ability of (thio)ureas and (thio)‐squaramides in model complexes. In contrast to previous work, we show that aromaticity does not contribute significantly to the enhanced hydrogen‐bonding interactions of squaramides. Overall, thiosquaramide, which has not been explored in the context of either organocatalysis or molecular recognition, is predicted to lead to strong, co‐planar hydrogen bonds, and should serve as a potent hydrogen‐bonding element in a myriad of applications.     

Crown-Containing N-(Thio)Phosphoryl-(Thio)Ureas,their Ligand Properties and Analytical Application

Abstract

Crown-containing N-(thio)phosphoryl(thio)ureas are related to a class of NH-acids due to the presence of two acceptor-groups: (thio)phosphorylic and (thio)acylic. In agreement with structure of lariat ether, it was observed a stage corresponding to the step ejection of two H* ion on the potentiometric titration curve of ligand by alkaline. Calculated step ionization constants demonstrate that these compounds are weak acids with relative values of pK₁ and pK₂.     

Zur Kenntnis gemischter Dicyanamido- (Thio)Cyanato-Kobaltate (II)

Mixed Dicyanamido (thio) cyanato-cobaltates(II) Preparation and properties of mixed anionic pseudohalide-complexes of cobalt(II) [CoX₂Y₂]^2? and [CoX₃Y]^2? (X = NCS, NCO, Y = N(CN)₂) are reported. The structures of the complexes are discussed using the results of infrared and electronic spectroscopy and of magnetic measurements.     

N-取代吡唑亚甲胺基-N＇-取代苯基(硫)脲的合成

硫脲;生物活性;N-取代吡唑亚甲胺基-N＇-取代苯基(硫)脲的合成     

(Thio)urea organocatalyst equilibrium acidities in DMSO

Bordwell's method of overlapping indicators was used to determine the pK(a) values of some of the most popular (thio)urea organocatalysts via UV spectrophotometric titrations. The incremental effect of CF(3) groups on acidic strength was also investigated. The pK(a)'s are in the range of 8.5-19.6. The results may lead to a better understanding of noncovalent organocatalysis and may aid in future catalyst development.     

Electrochemical Site-Selective Alkylation of Azobenzenes with (Thio)Xanthenes

Herein, we first report an electrochemical methodology for the site-selective alkylation of azobenzenes with (thio)xanthenes in the absence of any transition metal catalyst or external oxidant. A variety of groups are compatible with this electrochemical alkylation, which furnishes the products in moderate to good yields.     

(Thio)urea Containing Chiral Ammonium Salt Catalysts

(Thio)-urea-containing bifunctional quaternary ammonium salts emerged as powerful non-covalently interacting organocatalysts over the course of the last decade. The most commonly employed catalysts in this field are either based on Cinchona alkaloids, α-amino acids, or trans-cyclohexane-1,2-diamine. Our group has been heavily engaged in the design and use of such catalysts, i. e. trans-cyclohexane-1,2-diamine-based ones for around 10 years now, and it is therefore the intention of this short personal account to provide an overview of the, at least in our opinion, most significant and pioneering achievements in this field by looking on catalyst design and asymmetric method development, with a special focus on our own contributions.     

手性(硫)脲衍生物在不对称有机催化反应中的应用

手性(硫)脲衍生物是各种亲核试剂对亚胺、醛、缺电子烯烃加成反应的非常有效的有机催化剂之一, 已成功应用于对映选择性催化Strecker反应、Michael加成反应、Mannich反应、Baylis-Hillman反应、Henry反应等一系列重要的有机合成反应. 手性(硫)脲衍生物具有催化活性高、对映选择性和功能基相容性好、易于制备和修饰、适用范围广等优点, 成为近年来研究较多的不对称反应有机催化剂. 对手性(硫)脲衍生物在有机催化不对称合成中的应用研究进展进行了评述.     

缩氨基(硫)脲席夫碱化合物的自发对称性破缺研究

制备了4-苯基-1-(吡啶-2-亚甲基)氨基脲(PPMSC)和4-苯基-1-(吡啶-2-亚甲基)氨基硫脲(PPMTC).用元素分析、MS、1HNMR、UV吸收光谱、X射线单晶衍射和固体CD光谱等对其进行了表征.晶体结构数据显示PPMSC属于Sohncke P212121空间群,单个分子之间通过氢键形成一个一维螺旋链状结构,沿a轴形成左手螺旋结构.固体CD光谱和重结晶实验证明,PPMSC手性晶体的形成是结晶诱导的绝对不对称合成.PPMTC的固体CD光谱和重结晶实验具有与PPMSC类似现象.     

Diazoalkanes in the Reactions with Dialkyl (Thio)-Phosphites

Abstract

The photochemical, thermo-catalytical and thermal reactions of diazoalkanes with dialkyl (thio)phosphites were studied.

Thus, the photolysis of dimethyldiazomalonate and methyl-diazoacetate with dialkyl(thio)phosphites gives P-H insertion products only upon triplet-sensitized conditions (i), whereas diphenyldiazomethane gives P-H insertion products upon direct photolysis as well (ii). The investigation of 31 the reaction mechanism is based on CIDNP ³¹P method. The catalytical reactions (iii) are a convenient method of preparing (thio)phosphonates.     

(硫杂)杯[4]芳烃缩氨基(硫)脲(桥联)衍生物的合成

对叔丁基(硫杂)杯[4]芳烃-1,3-二醛基衍生物4a和4b与苯基氨基硫脲进行“1＋2”缩合反应, 合成了杯[4]芳烃缩氨基硫脲衍生物5a和5b, 产率为84%和85%. 化合物4a和4b与1,6-己基双氨基脲发生“1＋1”缩合反应, 合成了杯[4]芳烃双缩氨基脲桥联衍生物6a和6b, 产率为83%和80%. 新化合物的结构与构象经元素分析、质谱、核磁共振谱等表征证实.     

硫（硒）代磷酸酯—膦酸酯类化合物除草活性的构效关系

利用与自由能有关的取代基物理化学参数，考察了硫（硒）代磷酸酯－膦酸酯类化合物对除草活性的相关性．根据Ｈａｎｓｃｈ方程及多元回归分析，进行了结构与活性定量关系的研究，建立了较好的结构与活性相关式．     

新型含咪唑啉2,4-二酮的(硫代)磷酸酯类化合物的合成和生物活性测定

以对羟基苯基和对羟基苄基咪唑啉2,4-二酮羧酸酯类化合物为二次先导结构,根据Hydantocidin在植物体内的作用形式是Hydantocidin 5’-Phosphate的特点,将3种对羟基苯(苄基)-2,4-咪唑啉二酮中间体与(硫代)磷酰氯反应合成得到了38个结构新颖的含有2,4-咪唑啉二酮的(硫代)磷酸酯类化合物,其结构通过IR,1H NMR,31P NMR和元素分析表征.初步生物测定结果表明O-乙基-O-苯基-5-(4-羟基苯基)-2,4-咪唑啉二酮硫代磷酸酯(B14)和O,O-二苯基-5-(4-羟基苄基)-2-硫代-4-咪唑啉二酮硫代磷酸酯(B25)在100μg/mL浓度下对油菜的抑制率为53.1%和62.7%,化合物O,O-二(邻甲氧基苯基)-5-(4-羟基苯基)-2,4-咪唑啉二酮硫代磷酸酯(B7),B14和O,O-二(对甲基苯基)-5-(4-羟基苄基)-2,4-咪唑啉二酮硫代磷酸酯(B17)对蚜虫表现了一定的杀虫活性,在300μg/mL浓度下24 h的校正死亡率分别为52%,51%和69%.     

Effective Modular Assembling of Novel Ligands Starting from (Thio)Phosphorylated Anilines

Abstract

A series of novel oligodentate ligands has been designed by the modular assembly of ortho-(thio)phosphorylated anilines with a range of commercially available carbonyl compounds. The new ligands readily form complexes with a series of metal ions (Pd(II), Cu(II), Ni(II), and Re(I)) both in neutral and deprotonated forms, providing OO, SN, ONO, SNO, SNS, SNN, and ONN donor sets. The structure and composition of the resulting complexes depend on the nature and mutual disposition of the donating groups as well as on the reaction conditions.     

(Thio)Amidoindoles and (Thio)Amidobenzimidazoles: An Investigation of Their Hydrogen‐Bonding and Organocatalytic Properties in the Ring‐Opening Polymerization of Lactide

The mechanism of the ring‐opening polymerization (ROP) of lactide catalyzed by two partner hydrogen‐bonding organocatalysts was explored. New amidoindoles 4 a , c , thioamidoindoles 4 b , d , amidobenzimidazoles 5 a , c , and thioamidobenzimidazoles 5 b , c were synthesized and used as activators of the monomer. In the solid state and in solution, compounds 4 and 5 showed a propensity for self‐association, which was evaluated. (Thio)Amides 4 and 5 do catalyze the ROP of lactide in the presence of a cocatalyst, tertiary amine 3 a or 3 b , which activates the growing polymer chain through hydrogen‐bonding. Reactions were conducted in 2–24 h at 20 °C; conversion yields ranged between 22 and 100 %. A detailed study of the intermolecular interactions undertaken between the participating species showed that, as expected, simultaneous weak hydrogen bonds do exist to activate the reagents. Moreover, interactions have been revealed between the partner catalysts 4 / 5 + 3 . ROP catalyzed by these partner activators is thus governed by multiple dynamic equilibria. The latter should be judiciously adjusted to fine‐tune the catalytic properties of (thio)amides and organocatalysts, more generally.     

5-(吲哚基-3-次甲基)(硫代)巴比妥酸的合成

以冰乙酸为催化剂,吲哚-3-甲醛与巴比妥酸或硫代巴比妥酸在无水乙醇中进行Knoevenagel缩合,合成了5-(吲哚基-3-次甲基)巴比妥酸或5-(吲哚基-3-次甲基)(硫代)巴比妥酸,其结构经1H NMR和IR表征.     

Synthesis of Some Pyrimidine 2-Oxo(Thio)-4,6-Dione Derivatives

5-Arylidenes 1a and 1b, on reaction with ethyl cyanoacetate and diethyl malonate in the presence of ammonium acetate under Michael condensation, yield pyridine derivatives 2 and 3, respectively. Cyclopentapyrimidine derivative 4 can also be obtained by the reaction of 1a with malononitrile in the presence of piperidine. The reaction of 5-arylidene lb with monochloroacetic acid in an alkaline medium gives the thiazol derivative 5. Also, spiro-[3′, 5′]cyclohexenyl pyrimidine derivative 6 could be obtained from the reaction of 1d with maleic anhydride. On the other hand, 5-arylidene 1e reacts with maleic anhydride to give 2-thiobarbituric acid derivative 7. The condensation reaction of 2-thiovioluric acid 8 with some hydrazines affords the triazole derivatives 9a-d. Finally, barbituric acid condenses with isatin to give 5-arylidene 1f, which can be cyclized with phosphorous pentoxide to afford 10.     

Structure and Intramolecular Lability of N-(Thio)phosphoryl(thio)amides: XIII. Structure of N-Phenyl-N′-(diisopropoxythiphosphoryl)thiourea

The structure and intramolecular transformations of N-phenyl-N′-(diisopropoxythiophosphoryl)thiourea in (CD₃)₂CO solution were studied by ¹H, ¹³C, and ³¹P NMR spectroscopy. Combined analysis of NMR data and model calculations gave evidence in favor of high conformational and tautomeric flexibility of the thioureas in solution. The Z,E conformation of the amide form with the two N-H bonds cis and trans to the C=S bond was found to be preferred.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 6, 2005, pp. 908–911.Original Russian Text Copyright © 2005 by Karataeva, Yul’metov, Zabirov, Aganov, Klochkov.     

Reaction of Potassium Salts of N-(Thio)phosphorylthioamides with Chlorinated 1,3,5-Triazines

Potassium salts of N-(thio)phosphorylthioamides can substitute one, two, or three halogen atoms in chlorinated 1,3,5-triazine molecules to give the products of imidothiyl structure. At low temperature, products of incomplete substitution of halogen in the starting 1,3,5-triazines can be obtained.