Synthesis and properties of thiazole halohydrazones. 2. Interaction of 2-α-chlorobenzylidenehydrazino-4-ethoxy-carbonylthiazole with nucleophiles

In the interaction of 2--clzlorobenzylidenehydrazino-4-ethoxycarbonylthiazole with nucleophiles, two competing reactions take place. 1) nucleophilic replacement of the chlorine atom to form the corresponding substitution product; 2) elimination of a hydrogen chloride molecule, concluding in cyclization of the intermediate nitrilimine to form 3 phenyl-5-ethoxycarbonylthiazolo(2, 3-c]-1, 2, 4-triazole. The direction taken by the interaction depends on the nature of the nucleophile and is determined primarily by the ratio of basicity and nucleophilicity of the agent.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, 256–259, February, 1994. Original article submitted December 30, 1993.     

Syntheses and Olfactory Characters of Some Endo-α-Substituted-Bicyclo[2. 2. 2]-Octenyl (or Octanyl) Methanols

Sixteen title compounds were synthesized, twelve of which are new ones. Their structures were determined by 1H NMR, IR and MS, the refractive indices or melting points were measured. Odors of all the title compounds were evaluated and the structure-odor relationship was briefly discussed.     

Stereoselective synthesis of α,α′-diamino-dicarboxylic acids. Part 2

Enantiomerically pure α,α′-diamino-dicarboxylic acids (R,R)-4, (S,S)-5 and (S,S)-7 have been synthesized starting from the glycine-derived chiral synthon (S,S)-1.     

α-FUNCTIONAL CYCLOALKYLPHOSPHONATES I. SYNTHESIS

Abstract

Cycloalkylphosphonates 2 of different sizes (from cyclopropyl to cycloheptyl) bearing various functional groups Z in a position were synthesized by bis-alkylation of α-functional methylphosphonates 1 and Ω-dibromoalkanes in presence of base. The choice of the basic system is determined by the nature of Z. With powerful electron-withdrawing groups, NaH-THF/DMSO (Method A, for Z=CN, SO₂R) or liquid-solid phase transfer process [Method B, for Z=COOR, P(O) (OEt)₂] proved to be the more suitable systems. For Z=aryl or SR, lithium diisopropylamide is required to achieve the deprotonation. A wide range of new phosphonates were obtained in high yields on preparative scale.     

Pyrilocyanines. 36.α-thienyl substituted pyrilo- and thiopyrilocyanines

Symmetrical and nonsymmetrical 2,6- (and 4,6-)-di--thienyl substituted - and -pyrilo- and thiopyrilocyanines have been synthesized. The effect of changing the phenyl groups for -thienyl on the electronic absorption spectral parameters of the dyes obtained is discussed. It was found that such a change leads to a decrease in the effective length and increase in the electron donor ability of the hetero fragments containing these groups. The more intense coloring of the thienyl substituted dyes is due to interaction of the polymethine and quasilocal electronic transitions.For Communication 35 see [1].Institute of Organic Chemistry, National Academy of Sciences of Ukraine Kiev 253660. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 494–500, April, 1998.     

α,α-Dicyanoethyl Acetate. A Reagent for Selective N-Acetylation

N-Aoetylation is one of the classical methods for protection of primary and secondary amino groups.¹ While there is a lavish repertoire of reagents and conditions available for its execution, few exhibit the desirable feature of discriminative action between hydroxyl and anino functions. This communication disseminates the use of α,α-dicyanoethyl acetate (1) as a selective N-acetylation agent.     

Oxidative Coupling of 4α,9-Diaza-1,2,4α,9α-tetrahydrofluorenes. 5. Reaction with o-Aminophenol and o-Aminothiophenol

Oxidative coupling of 4,9-diaza-1,2,4,9-tetrahydro-9H-fluorenes with o-aminophenol and o-aminothiophenol in the presence of MnO₂ gives o-hydroxyphenyl- and o-mercaptophenylquinonediimines, cyclization of which gives derivatives of phenoxazine and phenothiazine.     

Automatic assembly of skeleton structures. 3. Stereoselective synthesis,stereochemistry, and cyclization ofd,l-α,α'-dioxy-α,α'-di-tert-butylglutaric acid

Stereoselective synthesis of d,l-,-dioxy-,-di-tert-butylglutaric acid hydroxyiminolactonitrile (3) was conducted by the reaction of dipivaloylmethane with HCN in ether. The corresponding hydroxylacetonitrile (4) and amide (5), acid (6), and its ester (7), from which dilactone (8) was synthesized with preparative yields, were obtained from3. Benzyl amide (9) was obtained by the reaction of8 with BnNH₂. The iminolactone structure3 of dipivaloylmethane bis-cyanohyrin, thecis-pseudo-a orientation of the functional substituents in3–7 and9, and the structure of the dilactone8 were confirmed by the¹H,¹³C NMR,IR and mass spectra.For previous communication, see [2].N. N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, 117977 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 7, pp. 1591–1601, July, 1992.     

Py-methyl-α-metanicotone. Action of benzoyl chloride on py-methyl-α-nicotone

Summary 1-Methyl-3-[4-(N-methylbenzamido)-1-butenyl]-2(1H)-pyridone was prepared by cleavage of the pyrrolidine ring of Py-methyl--nicotone with benzoyl chloride, and hydrolysis of this product gave P_y-methyl--metanicotone.     

稀土夹心化合物的SCF-Xα-SW研究 Ⅱ.Cp_2YbC_2H_2和Cp_2Yb(OC)_2

用SCF-Xa-SW方法非相对论和相对论方案计算了Cp_2YbC_2H_2和Cp_2Yb(OC)_2.非相对论计算HOMO是Cp的π轨道,相对论间接效应的作用,使得Yb的4f轨道能级上升而成为HOMO,相对论结果与Yb二价化合物不稳定、易氧化的实验结果一致,也表明了研究重稀土化合物考虑相对论效应的必要性.计算共价键强度与Cp_2Yb相近,比YbF_3和Cp_3Sm弱,再次表明二价稀土化合物共价键比三价化合物弱.同时也证实了σ型配体(CO)与稀土元素的配位作用比π型配体(C2H_2)强的结论。     

Über die roten Anile. 2. Mitt.

Zusammenfassung Bei der Spaltung des -(p-Dimethylaminophenylimino)--keto--(3,4,5-trimethoxyphenyl)-valeriansäurenitrils (V) mit Chlorwasserstoffsäure entsteht die -Keto--(3,4,5-trimethoxyphenyl)-buttersäure (VII) und nicht, wie infolge des Versagens einiger typischen -Ketocarbonsäurereaktionen vermutet wurde, die 3-Hydroxy-4,5,6-trimethoxy-indan-3-carbonsäure.1. Mitt.:J. Michalský undL. Sadílek, Mh. Chem.90, 171 (1959).     

α-Indolyl-β-nitroacrylates. Synthesis and structure

A one-pot procedure has been developed for the synthesis of α-indolyl-β-nitroacrylates by reaction of β-bromo-β-nitroacrilates with indole and substituted indoles. All indolylnitroacrilates thus obtained have Z configuration of the double bond. According to the X-ray diffraction data, ethyl 2-(1-methyl-1H-indol-3-yl)-3-nitroacrylate is characterized by s-trans conformation of the double C=C bond and indole ring; its crystal packing involves intermolecular hydrogen bonds C-H…O and C-H…π with formation of centrosymmetric dimers which give rise to bilayer supramolecular structures.     

Quasiliving Carbocationic Polymerization. XVI. Forced Ideal Terpolymerization of Styrene-α-Methylstyrene-lsobutylene

Forced ideal carbocationic terpolymerization of styrene/α-methylstyrene/isobutylene systems has been achieved by continuous addition of mixed monomer feeds to 2-chloro-2,4,4-trimethylpentane/TiCl₄ initiator/coinitiator charges dissolved in n-hexane/methylene chloride solvent mixtures. The compositions of terpolymers were uniform and identical to those of the feeds in the concentration ranges studied. The number-average molecular weights increased monotonously with the amounts of monomers consumed; however, pronounced chain transfer to monomer was evident. The microstructure of the products was investigated ¹³C-NMR spectroscopy. According to dual detector GPC, ¹³C-NMR and DSC data true terpolymers have formed.     

Synthesis of UDP-GalNAc analogues as probes for the study of polypeptide-α-GalNAc-transferases. Part 2

The synthesis of four UDP-GalNAc analogues (1-4) is described. The 3-, 4- and 6-deoxygenated analogues 1-3 were obtained by way of a divergent strategy starting from a 3,6-di-O-pivaloyl GlcNAc derivative as a common precursor. Analogue 4 bearing a N-trifluoroacetamido group was prepared from the trifluoromethylated oxazoline 24 as key intermediate. These compounds were designed to probe the substrate specificity of polypeptide-α-GalNAc transferases.     

Stereoselective synthesis of uncommon α,α′-dialkyl-α-aminoacids. Part 1

The alkylation of the diastereomeric mixture of chiral morpholinone derivatives 4 and 5 occurs with good yield and trans induction. Cleavage of the alkylated products 6a,b,c,e gives enantiomerically pure uncommon (and sterically constrained) α,α′-dialkyl-α-aminoacids. The absolute configuration of the new stereocentres of 4, 5, 6 and 7 has been assigned on the basis of the ¹H-NMR spectra and NOE measurements.