Normal coordinate analyses of 2,4-hexadienes

Measurement and assignment of the i.r. and Raman spectra of trans,trans- and cis,trans-2,4-hexadienes were carried out. The normal coordinate analyses of these two isomers were done to obtain a force field transferable to 1,4-diphenyl-trans,trans-1,3-butadiene and trans- and cis-polyacetylenes.     

2,4-Dimethyl-3-pentanone-sensitized photopolymerization of vinyl monomers

The initiation quantum yield in the bulk photopolymerization of vinyl monomers sensitized by 2,4-dimethyl-3-pentanone has been measured for several monomers. The results obtained were interpreted in terms of a mechanism that considers singlet and triplet photocleavage of the ketone, competing with the quenching by the monomer. The quenching process does not lead to free radicals that can initiate the polymerization.     

2,5-Dimethyl-4-phenyl- and 3,6-dimethyl-2,4-diphenylpiperidines

2,5-Dimethyl-4-phenylpiperidine and 3,6-dimethyl-2,4-diphenylpiperidine were obtained by reduction of the corresponding substituted pyridines. Several of their transformations are examined.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1356–1358, October, 1970.     

Selective catalytic hydrogenation of the trans,trans isomer from a mixture of 2,4-hexadienes.

trans, trans-2,4-hexadiene is quantitatively converted into cis-3-hexene by photoinduced hydrogenation catalyzed by chromium carbonyl complexes in presence of acetone which allows both acceleration and selectivity.     

Cyclische gekreuzt-konjugierte Bindungssysteme. XIV. 5,6-Dimethyl-1,2; 3,4-dibenzo- und 5,6-Dimethyl-1,2,3,4-tetraphenyl-calicen

The syntheses of 5,6-dimethyl-1,2;3,4-dibenzo- and 5,6-dimethyl-1,2,3,4-tetraphenyl-calicene and some of their physical and chemical properties are reported.     

Abinitio方法研究2，4－二甲基－1，3－戊二烯结构

用ａｂｉｎｉｔｉｏ方法研究２，４－二甲基－１，３－戊二烯各种构象异构体的结构，找到ｓ－ｔｒａｎｓ和ｓ－ｃｉｓ两种稳定构象，且ｓ－ｔｒａｎｓ更稳定．对稳定构象的几何结构、电荷分布进行了研究，讨论了不同的电子基组对优化几何的影响，并计算了稳定构象的热力学常数，与实验结果进行了比较．     

1,1-Dimethyl-1-silacyclohexa-2,4-dien-tricarbonyleisen Vorläufige Mitteilung

1,1-Dimethyl-2,3,4,5-tetraphenyl-1-silacyclohexa-2,4-diene is isomerized by iron pentacarbonyl to 1,1-dimethyl-2,3,4,5-tetraphenyl-1-silacyclohexa-2,5-diene. However, iron pentacarbonyl with 1,1-dimethyl-1-sila-cyclohexa-2,4-diene yields 1,1-dimethyl-1-silacyclohexa-2,4-diene-tricarbonyl-iron.     

Crystal Structure and Spectra of 6,7-Dimethoxy-3,3-Dimethyl-3,4-Dihydroisocarbostyril Azine

Crystal and molecular structures of 6,7-dimethoxy-3,3-dimethyl-3,4-dihydroisocarbostyril azine (I) were determined using X-ray diffraction analysis and IR and electronic absorption spectroscopy. Compound Iwas found to exist in the form of an azine isomer, in which the N=C double bonds are located outside the tetrahydroisoquinoline fragments, while the H atoms migrate toward the N(1) atoms of these moieties. Model quantum-chemical calculations were performed.     

Cyclische gekreuzt-konjugierte Bindungssysteme. XV. Cycloadditionen mit 5,6-Dimethyl-1,2;3,4-dibenzo- und 5,6-Dimethyl-1,2,3,4-tetraphenyl-calicen

Cycloaddition reactions of 5,6-dimethyl-1,2,3,4-dibenzo- and 5,6-dimethyl-1,2,3,4-tetraphenyl-calicene with diazo compounds, with dienes, and with dienophilic reagents are described.     

4,4-二甲基-3-异噁唑酮衍生物的合成与表征

以4,4-二甲基-3-异噁唑酮为母体化合物, 通过异氰酸酯法合成了9个磺酰脲类异噁唑酮衍生物, 经IR, MS, NMR及元素分析证实了化合物的结构, 测定了这些化合物的除草活性, 并对构效关系进行了初步探讨.     

Theoretical Study of Tautomerization in 1,5-Dimethyl-6-Thioxo-1,3,5-Triazinane-2,4-Dione

In this work, the tautomeric transformations of a 1,5-dimethyl-6-thioxo-1,3,5-triazinane-2,4-dione molecule are explored at the M062X/6-311G(d,p) level of theory in gas and solution phases. These calculations show that the 1,5-dimethyl-6-thioxo-1,3,5-triazinane-2,4-dione isomer is more stable than its tautomer (4-hydroxy-1,5-dimethyl-6-thioxo-5,6-dihydro-1,3,5-triazin-2(1H)-one) in gas and solution phases. The frontier molecular orbitals and band gap energy calculations are performed at the M062X/6-311G(d,p) level in gas and various solvents. Solvent effects are analyzed using the self-consistent reaction field method based on the polarizable continuum model in chloroform, chlorobenzene, tetrahydrofurane, dichloromethane, and quinoline. The solvent effect on the N–H and C=O vibrations is explored. Also, natural bond orbital (NBO) analysis was used to understand the structure and bonding of the molecule.     

FTIR Spectroscopic Studies on the Conformational Equilibrium of Liquid 2,4-Dimethyl-1,3-Pentadiene

Investigations of 2,4-dimethyl-1,3-pentadiene by variable temperature FTIR spectra have concluded that the compound is a mixture of two kinds of single bond isomer,i.e.,s-traiis and s-cis conformers.The changes of IR band intensities have been recorded at research temperature range.The values of △H° and △S° between two stable conformers have been deduced to be 4.37 kJ/mol and 2.48 J/mol K respectively.     

4-甲基-5-卤代-2-噻吩甲醛和2,4-二甲基-5-卤代噻吩的合成

以3-甲基噻吩为原料,经过卤代反应、Vilsmeier甲酰化反应和Wollf L-Kishner-Huang minion反应合成了4-甲基-5-卤代-2-噻吩甲醛和2,4-二甲基-5-卤代噻吩,其结构经NMR,IR,MS和元素分析确证.     

Synthesis of cis-1,5-Dimethyl-2,4-dinitro-2,4-diazabicyclo[3.1.0]hexan-3-one and cis-1,5-dimethyl-2,4-dinitro-2,4-diazabicyclo[3.2.0]heptan-3-one

cis-1,5-Dimethyl-2,4-dinitro-2,4-diazabicyclo[3.2.0]heptan-3-one and cis-1,5-dimethyl-2,4-dinitro-2,4-diazabicyclo[3.1.0]hexan-3-one were both synthesized in three steps each from a common precursor, 1,3-diacetyl-4,5-dimelhyl-4-imidazolin-2-one.     

1,5-Dimethyl-2,3,3,4-Tetrachloro-1,5-Diaza-2,4-Diphosphorinan-6-One and some derivatives

A synthesis of C-chlorinated analogues of 1,5-diaza-2,4-diphosphorinan-6-ones is described. The P-chlorophosphine 3 , a key compound for all reported substitution reactions, reacts in an unusual way with N,N′-dimethyl-N,N′-bis(trimethylsilyl)urea to give the unsymmetrical product 5 , the formation of which is accounted for by a silatropy of the intermediate compound 4 . Compound 5 is stable in solution but rearranges quantitatively into isomer 6 without solvent at room temperature. Compound 3 , its fluoro derivative 9 , and the alkoxy derivatives 10a–d exist as cis-and trans-isomers. Some stereochemical aspects, as well as the possibility of 1,2-chlorotropy, are discussed.     

Convenient Synthesis of 2,2-Dimethyl-3,4-dihydro-2H-pyrano[2,3-b]quinolines

A convenient general synthesis of 2,2-dimethyl-3,4-dihydro-2H-pyrano[2,3-b]quinolines using the Wittig reaction is described. The o-nitrobenzaldehydes (1a–d) on reaction with phosphorane 2 provided ( E )-ethyl-α-(2,2-dimethylprop-2-ene)-2-nitrocinnamates (3a–d) in excellent yields, which on cyclization with polyphosphoric acid followed by reductive cyclization using Fe/HCl afforded dihydropyranoquinolines (5a–d). Alternatively, the pyranoquinolines 5a–d were also synthesised from esters 3a–d by employing domino reductive cyclization in a single step.