Thermogravimetric characteristics of some salts of violuric acid and 1,3-dimethylviouric acid

The thermolysis curves of the various salts of violuric acid and 1,3-dimethylvioluric acid with sodium and potassium are described. These salts form hydrates in all cases. 1,3-Dimethylvioluric acid forms 1 : 1 salts with sodium or potassium; violuric acid may form either 1 : 1 or 1 : 2 salts with these metals.     

Thermogravimetric determination of magnesium,potassium and lead by precipitation with dilituric acid

The thermolysis curves of magnesium, potassium, and lead diliturate have established that either the hydrated or anhydrous forms of these precipitates are stable enough for their gravimetric use to be possible. Magnesium and lead were determined by precipitation with dilituric acid while potassium was precipitated with trimethylamine diliturate.     

Synthesis and Structural Investigation of a Complete Series of Brightly Colored Alkali Metal 1,3-Dimethylviolurates

A complete series of alkali metal 1,3-dimethylviolurates M(Me₂Vio) was synthesized and fully characterized. The title compounds M(Me₂Vio)(H₂O) [M = Li ( 3 ), Na ( 4 )], K(Me₂Vio)(H₂O)_0.5 ( 5 ) and M(Me₂Vio) [M = Rb ( 6 ), Cs ( 7 )] were prepared by neutralizing 1,3-dimethylvioluric acid (= HMe₂Vio; 2 ) with 1 equiv. of the corresponding metal hydroxides MOH. The resulting salts exhibit striking colors ranging from orange-red ( 3 ) through purple ( 4 , 5 ) to bright blue ( 6 , 7 ). In contrast to the monohydrate 4 , the classical synthesis of sodium 1,3-dimethylviolurate from 1,3-dimethylbarbituric acid and NaNO₂ afforded the purple trihydrate Na(Me₂Vio)(H₂O)₃ ( 4a ). All new compounds have been fully characterized by their IR and NMR (¹H, ¹³C) spectra as well as elemental analyses. X-ray crystal structure determination revealed that the title compounds exist as one- (Li, Na), two- (K, Cs), or three-dimensional (Rb) coordination polymers in the solid state.     

Thermogravimetric determination of ethylenediamine and quinine with dilituric acid: Solubilities of some polymethylenediamine diliturates

The thermolysis curve's of ethylenediamine, trimethylenediamine, tetramethylenediamine pentamethylenediamine, trimethylamine and quinine diliturates were determined. These curves established that (either the hydrated or the anhydrous form of ethylenediamine and quinine diliturate is stable enough for their gravimetric use to be possible. Both ethylenediamine and quinine were determined by precipitation with alcoholic dilituric acid .solution. In addition the solubilities of some polymethylenediamine diliturates were determined.     

The 1:1 cocrystals of the proton‐transfer compound dilituric acid–phenyl­biguanide monohydrate

A proton‐transfer compound, 1‐phenyl­biguanidium 5‐nitro‐2,6‐dioxo‐1,2,3,6‐tetra­hydro­pyrimidin‐4‐olate monohydrate, C₈H₁₂N₅⁺·C₄H₂N₃O₅⁻·H₂O, has been synthesized by a reaction between dilituric acid (5‐nitro‐2,4,6‐trihydroxy­pyrimi­dine, Dilit) and phenyl­biguanide (N‐phenyl­imido­carbonimidic diamide, Big). This compound cocrystallized as a 1:1 adduct, and the asymmetric unit consists of two dilituric amino–oxo planar tautomeric anions (Dilit⁻), two monoprotonated phenyl­biguanidium cations (BigH⁺) and two water mol­ecules of crystallization (Z′ = 2). Protonation occurs at the N atom attached to the phenyl ring of Big as a result of the proton‐transfer process from the acidic hydr­oxy group of Dilit. In the crystal structure, the hydrated 1:1 adduct is stabilized by 25 two‐ and three‐center hydrogen bonds.     

Domino reaction of 1,3-bis(trimethylsilyloxy)-1,3-dienes with oxalyl chloride: general and stereoselective synthesis of gamma-alkylidenebutenolides

The Lewis acid catalyzed cyclization of oxalyl chloride with 1,3-bis(trimethylsilyloxy)-1,3-dienes 3, derived from 1,3-dicarbonyl compounds 1, provides a new and general approach for the synthesis of gamma-alkylidenebutenolides 4, a pharmacologically and synthetically important class of substances. A variety of butenolides were efficiently prepared in good yields and with very good regio- and stereoselectivities. An up-scaling of the reaction was possible. The use of the Lewis acid trimethylsilyl-trifluoromethanesulfonate (TMSOTf) proved to be superior to other activation conditions. Sterically undemanding gamma-alkylidenebutenolides could be prepared alternatively by reaction of the corresponding 1,3-dicarbonyl dianions with N,N'-dimethoxy-N,N'-dimethylethanediamide (2d). In contrast to the dianion method, the Lewis acid catalyzed reaction also facilitated the cyclization of sterically hindered, base-labile, cyclic and functionalized substrates. From a methodology viewpoint, the dianion reaction represents the first cyclization of a bis-Weinreb amide and the first cyclization of an oxalic acid-synthon with an ambident dianion. The TMSOTf-catalyzed reactions are both the first cyclizations of 1,3bis(trimethylsilyloxy)-1,3-dienes with a C2 dielectrophile and the first cyclizations of 1,3-bis(trimethylsilyloxy)-1,3-dienes with a carboxylic acid dichloride or a related dielectrophile.     

一种制备(1R,3S)-3-氨基-1-环己烷羧酸的新方法

介绍了一种简单的制备(1R,3S)-3-氨基1环己烷羧酸的方法。以环己烷-1,3-二羧酸的顺反混合物为原料。经过关环得顺式的酸酐,然后酯化,在脂肪酶AY-30的作用下进行去对称性水解。得光学活性的环己烷-1,3-二羧酸的单乙酯产物,经过改进的Curtis重排反应后,羧酸基团转变为氨基。然后经过酯水解、去保护基团,得到光学纯的(1R,3S)-3-氨基-1-环己烷羧酸。     

Zur Synthese sulfonierter Derivate von 4-Amino-1,3-dimethylbenzol und 2-Amino-1,3-dimethylbenzol

Syntheses of Sulfonated Derivatives of 4-Amino-1, 3-dimethylbenzene and 2-Amino-1, 3-dimethylbenzene Direct sulfonation of 4-amino-1, 3-dimethylbenzene (1) and sulfonation of 4-nitro-1,3-dimethylbenzene ( 4 ) to 4-nitro-1,3-dimethylbenzene-6-sulfonic acid ( 3 ) followed by reduction yield 4-amino-1,3-dimethylbenzene-6-sulfonic acid ( 2 ). The isomeric 5-sulfonic acid ( 5 ) however is prepared solely by baking the acid sulfate salt of 1 . Reaction of sulfur dioxide with the diazonium chloride derived from 2-amino-4-nitro-1,3-dimethylbenzene ( 7 ) leads to 4-nitro-1,3-dimethylbenzene-2-sulfonyl chloride ( 8 ), which is successively hydrolyzed to 4-nitro-1,3-dimethylbenzene-2-sulfonic acid ( 9 ) and reduced to 4-amino-1, 3-dimethylbenzene-2-sulfonic acid ( 6 ). Treatment of 4-amino-6-bromo-1,3-dimethylbenzene ( 12 ) and 4-amino-6-chloro-1, 3-dimethylbenzene ( 13 ), the former obtained by reduction of 4-chloro-6-nitro-1,3-dimethyl-benzene ( 10 ) and the latter from 4-chloro-6-nitro-1, 3-dimethylbenzene ( 11 ), with oleum yield 4-amino-6-bromo-1,3-dimethylbenzene-2-sulfonic acid ( 14 ) and 4-amino-6-chloro-1,3-dimethylbenzene-2-sulfonic acid ( 15 ) respectively; subsequent carbon-halogen hydrogenolyses of 14 and 15 lead also to 6 (Scheme 1). Baking the acid sulfate salt of 2-amino-1, 3-dimethylbenzene ( 17 ) gives 2-amino-1, 3-dimethylbenzene-5-sulfonic acid ( 16 ), whereas the isomeric 4-sulfonic acid ( 18 ) can be prepared by either of the following three possible pathways: Sulfonation of 2-nitro-1,3-dimethylbenzene ( 20 ) to 2-nitro-1,3-dimethylbenzene-4-sulfonic acid ( 21 ) followed by reduction or sulfonation of 2-acetylamino-1,3-dimethylbenzene ( 19 ) to 2-acetylamino-1,3-dimethylbenzene-4-sulfonic acid ( 22 ) with subsequent hydrolysis or direct sulfonation of 17 . Further sulfonation of 18 yields 2-amino 1,3-dimethylbenzene-4,6-disulfonic acid ( 23 ), the structure of which is independently confirmed by reduction of unequivocally prepared 2-nitro- 1,:3-dimethylbenzene-4,6-disulfonic acid ( 24 )(Scheme 2).     

Facile and convenient synthesis of 2,6-disubstituted 4H-1,3-oxazin-4-one derivatives

Facile and convenient methods for the preparation of a variety of 2,6-disubstituted 4H-1,3-oxazin-4-ones 3 by three complementary methods are described. Treatment of the branched aliphatic imidate 2c,d with diketene 1 in the presence of a catalytic amount of acetic acid affords 2-substituted 6-methyl-1,3-oxazin-4-ones 3c,d , whereas the unbranched imidate 2b,e gave oxazines 3b,e and pyrimidines 4b,e (Method A). The reaction of acyl Meldrum's acid 5 with imidate 2 afford 2,6-disubstituted oxazine 3, though the alkylimidate with acetyl Meldrum's acid yielded 3 and 5-acetyl-1,3-oxazine-4,6-dione 8 (Method B). The cylodehydration of acylacetylcarboxamide 13 with acid, such as 70% perchloric acid or fluorosulfonic acid, afforded 1,3-oxazines 3 (Method C).     

Synthesis and transformations of 1,3-dithiol-2-ylideneisopropylidene malonates

The reaction of 2-alkylthio-1,3-dithiolium salts with Meldrum's acid gave 1,3-dithiol-2-ylideneisopropylidene malonates, which were converted successively to monoethyl esters of 1,3-dithiol-2-ylidenemalonic acids and esters of 1,3-dithiol-2-ylideneacetic acid. 2-Methyl-1,3-dithiolium salts are formed when 1,3-dithiol-2-ylideneisopropylidene malonates are heated with acids.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1621–1624, December, 1988.     

含1,3-方酸苯螺旋共轭分子的设计及其电子光谱和非线性光学性质的理论研究

以量子化学半经验方法PM3优化构型为基础,利用INDO/CI方法研究了嵌入1,3-方酸的苯螺旋共轭分子的电子光谱,同时利用INDO/CI-SOS程序计算了它们的二阶非线性光学系数β_ijk和β_μ值,从而探索分子结构与电子光谱及非线性光学性质的关系.理论计算结果表明:在苯螺旋共轭分子中适当地嵌入方酸后,其二阶非线性光学系数增大.与苯螺旋共轭分子和1,3-方酸的比较表明,方酸环处于左端的体系有很好的二阶非线性光学性质,可能成为较好的光学材料.     

Reaction of thioketones with propiolic acids

The reaction of adamantane-2-thione with propiolic acid afforded a novel type of cycloadduct, spiro[adamantane-2,2'-6'H-[1,3]-oxathiin]-6'-one (3a), in quantitative yield. The reaction of thiobenzophenone with propiolic acid gave 2,2-diphenyl-6'H-[1,3]-oxathiin]-6'-one and 4-phenyl-3-thia-3,4-dihydronaphthoic acid in 34% and 35% yields, respectively. The reaction might proceed through a concerted process, as confirmed by kinetics. The reaction of adamantane-2-thione with 2-butynoic acid or phenylpropiolic acid gave the corresponding adducts regioselectively. Interestingly, only one isomer was obtained by the reaction of thiofenchone with propiolic acid, suggesting that the reaction proceeded diastereospecifically. Oxidation of adducts by dimethyldioxirane or m-chloroperoxybenzoic acid gave the corresponding sulfoxides and sulfones. The sulfoxides were thermally decomposed to give disulfide or another type of 1,3-oxathiin-6-one.     

Determination of the 1,3- and 2-positional distribution of fatty acids in olive oil triacylglycerols by 13C nuclear magnetic resonance spectroscopy

Linear models were selected from a large data set acquired for Italian olive oil samples by quantitative 13C nuclear magnetic resonance (NMR) spectroscopy with distortionless enhancement by polarization transfer (DEPT). The models were used to determine the composition of the 2 fatty acid pools esterifying the 1,3- and 2-positions of triacylglycerols. The linear models selected proved that the 1,3- and 2-distribution of saturated, oleate, and linoleate chains in olive oil triacylglycerols deviated from the random distribution pattern to an extent that depended on the concentration of the fatty acid in the whole triacylglycerol. To calculate the fatty acid composition of the 1,3- and 2-positions of olive oil triacylglycerols, the equations of the selected linear models were applied to the fatty acid percentages determined by gas chromatography. These data were compared with the values predicted by the computer method (used to determine the theoretical amounts of triacylglycerols), which is based on the 1,3-random-2-random theory of the fatty acid distribution in triacylglycerols. The biggest differences were found in the linoleate chain, which is the chain that deviated the most from a random distribution pattern. The results confirmed that the 1,3-random-2-random distribution theory provides an approximate method for determining the structure of triacylglycerols; however, the linear models calculated by the direct method that applies 13C NMR spectroscopy represent a more precise measurement of the composition of the 2 fatty acid pools esterifying the 1,3- and 2-positions of triacylglycerols.     

Synthesis of glucosylspiro-oxindole derivatives via one-pot three-component cycloaddition of azomethine ylides

Highly regio- and stereoselective synthesis of glucosylspiro-oxindole/acenaphthenone derivatives was accomplished through 1,3-dipolar cycloaddition (1,3-DC) reaction. The glucosyl α,β-unsaturated-7,3-lactone (a sugar lactone) derived from d-glucose was used as a chiral dipolarophile in 1,3-DC reaction for the first time. The azomethine ylides generated from sarcosine/l-proline/thiazolidine-4-carboxylic acid/piperidine-2-carboxylic acid with isatin and acenaphthoquinone were trapped by the sugar lactone to give a series of glucosylspiro-pyrrolidine derivatives in good yields.     

Globo H四糖衍生物的高效合成

设计合成了2个Globo H四糖衍生物1和2, 将其作为标准样品可用于研究β1,3-葡萄糖醛酸(GlcA)转移酶及GlcA-3-O-硫酸化(Sulfo)转移酶在肿瘤组织内的特异性表达.     

Regioselective synthesis of functionalized 3,5-diketoesters and 2,4-diketosulfones by uncatalyzed condensation of 1-methoxy-1,3-bis(trimethylsilyloxy)-1,3-butadienes with alpha,beta-unsaturated acid chlorides and sulfonyl chlorides

The reaction of 1-methoxy-1,3-bis(trimethylsilyloxy)-1,3-butadienes with alpha,beta-unsaturated and functionalized acid chlorides afforded a variety of 3,5-diketoesters which are not readily available by other methods. The reaction of 1-methoxy-1,3-bis(trimethylsilyloxy)-1,3-butadiene with sulfonyl chlorides allows a direct synthesis of 2,4-diketosulfones.     

Assembly of 3-substituted isocoumarins via a CuI-catalyzed domino coupling/addition/deacylation process

An efficient strategy for the synthesis of a variety of 3-substituted isocoumarins has been developed. The reaction proceeded from o-halobenzoic acids and 1,3-diketones via a copper(I)-catalyzed domino reaction in DMF under the action of K(3)PO(4) at 90-120 °C without a ligand to afford the corresponding 3-substituted isocoumarin derivatives in good to excellent yields. o-Halobenzoic acids could be o-iodobenzoic acid, o-bromobenzoic acid, and o-chlorobenzoic acid derivatives. 1,3-Diketones could be alkyl- and aryl-substituted 1,3-diketones.     

1，3方酸嵌入对称二苯乙烯衍生物的三阶非线性光学性质的理论研究

以量子化学MP3优化构型为基础,利用INDO／CI方法研究系列嵌入1,3方酸的对称二苯乙烯衍生物的电子光谱,并利INDO／CI－SOS方法计算系列化合物的三阶非线性光学系数γ（-ω;ω,-ω,ω)和γ（0,0,0,0）值,探讨了γ和分子结构之间的关系。理论计算结果表明,在双推电子基团取代二苯乙烯衍生物中适当地嵌入方酸,可使其三阶非线性光学系数有所增加,达到并保持其透明性。     

醇溶性聚酰胺树脂的制备

醇溶性聚酰胺树脂的制备邢存章，徐新国，董铭章（山东轻工业学院化工系济南２５０１００）关键词醇溶聚酰胺，羟基丙二肢，聚合脂肪酸，二聚酸，制备热塑聚酰胺树脂是由植物油聚合脂肪酸与乙二胺制得的分子量３０００～９０００的线型缩聚物。早期的树脂溶于芳烃用作柔性...     

Stereoselectivity in nucleophilic additions to 3-azidoalkanals

The stereoselectivity of nucleophilic additions to 3-azidoalkanals was investigated. Non-chelating, BF(3)·OEt(2)-mediated Sakurai addition to 3-azidoalkanals afforded 1,3-anti products, whereas use of a chelating Lewis acid, TiCl(4), resulted in 1,3-syn products with moderate selectivity. A boat-like chelation structure of the 3-azidoalkanal with the Lewis acid is proposed to be consistent with the 1,3-syn selectivity of the reactions. Mukaiyama aldol addition to 3-azidohexanal generated 1,3-anti products regardless of the chelating ability of the Lewis acid.