Synthesis and mesomorphic properties of some derivatives of 2-methylcyclohex-2-ene-4-one-1-carboxylic and cis-2,6-dimethyl cyclohex-2-ene-4-one-1 -carboxylic acids

Mesomorphic derivatives prepared from ethyl esters of 2-methylcyclohex-2-ene-4-one-1-carboxylic and cis-2,6-dimethylcyclohex-2-ene-4-one-1-carboxylic acids have been synthesized. It has been shown that the compounds obtained are characterized by a lower nematic—isotropic transition temperature (10-20°C) and a considerably narrower nematic range in comparison with the analogous derivatives of 4-alkylcyclohex-3-ene-carboxylic and trans-4-alkylcyclohexane-carboxylic acid.     

2,6-Dihydroxy-4,5-dihydropyrimidine derivatives

Alkylamides of DL-4,5-dihydroorotic acid were synthesized by catalytic hydrogenation (5% Rh on Al₂O₃). The reaction of the n-butyl ester of DL-4,5-dihydroorotic acid with alkylamines and hydrazine gave N,N-dialkylamides, the dihydrazide of DL-ureidosuccinic acid, and the hydrazide of DL-4,5-dihydroorotic acid. The products of the condensation of the latter with aromatic aldehydes were obtained.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 105–108, January, 1972.     

Derivatives of 2,6-dihydroxy-4,5-dihydropyrimidines

By the catalytic hydrogenation (5% of Rh on Al₂O₃) of orotic acid and its derivatives, DL-4,5-dihydroorotic and DL-1-methyl- and DL-1,3-dimethyldihydroorotic acids have been obtained. A number of salts of DL-4,5-dihydroorotic acid with amines have been synthesized.     

Iron pentacarbonyl assisted photochemical route to 2,5- and 2,6-divinyl-substituted 1,4-benzoquinones from 1-ene-3-ynes

Photochemical reaction between the enynes, (Z)-1-methoxybut-1-ene-3-yne, 1 or isopropenyl acetylene, 2 with CO in presence of Fe(CO)₅ yields the 2,6- and 2,5-divinyl-substituted 1,4-benzoquinones: 2,6-bis{(Z)-2-methoxyvinyl}-1,4-benzoquinone (3, 42%), 2,5-bis{(Z)-2-methoxyvinyl}-1,4-benzoquinone (4, 31.5%), [{η²,η²:2,6-di(prop-1-en-2-yl)-1,4-benzoquinone}tricarbonyliron] (5, 45%), and {η²,η²:2,5-di(prop-1-en-2-yl)-1,4-benzoquinone}tricarbonyliron] (6, 65%).     

两个环己烷螺含氮杂环化合物的合成和晶体结构

环己酮与硫代碳酰肼在不同介质中的反应，合成出两个不同的环己烷螺含氮杂环化合物。经Ｘ－射线结构分析确定它们分别为１，２，４，５－四氮螺［５，５］十一烷－３－硫酮，Ｃ＿７Ｈ＿（１４）Ｎ＿４Ｓ（Ⅰ）和１，２，４，－三氮螺［４，５］癸－１－烯－４－氨基－３－硫酮。Ｃ＿７Ｈ＿（１２）Ｎ＿４Ｓ＿ｘ（Ｓ＿ｘ＝０．８Ｓ＋０．２Ｏ）（Ⅱ）。晶体学参数分别为（Ⅰ）：Ｐ２＿１／ｃ，ａ＝１２．０２６（４），ｂ＝２６．８１７（６），ｃ＝１２．０４２（３），β＝１１５．９４（２）°，Ｚ＝４，Ｖ＝９３３．４（１０），Ｍ＿ｒ＝１８６．２８；（Ⅱ）：Ｐ２＿１／ｍ，ａ＝６．５９５（７），ｂ＝６．８１７（６），ｃ＝１０．５７２（６），β＝１０６．３（１）°，Ｖ＝４５６（１），Ｚ＝２，Ｍ＿ｒ＝１８１．０５。最终一致因子分别为Ｒ＝０．０５４，Ｒ＿ｗ＝０．０６５和Ｒ＝０．０８９，Ｒ＿ｗ＝０．０９６。两个化合物中，环己烷都为椅式构型，它与其螺联的６员氮杂环，５员氮杂环的最小二乘平面间的夹角分别为６８．９４和９０°。并对合成反应途径作了初步讨论。     

Synthesis of (4S,5S)-4,5-O-isopropylidene-cyclopent-2-ene-1-one via the intramolecular Reformatsky reaction

Isomeric mixtures of bromo- and iodohydrins produced via bromohydroxylation and iodohydroxylation of exo-methylene derivative 2 undergo an intramolecular aldol cyclization-dehydration sequence under Reformatsky reaction conditions to give cyclopentenone 1.     

Quaternization of 1H-imidazo[4,5-b]pyridine and 4-methyl-4H-imidazo[4,5-b]pyridine

Unsubstituted imidazo[4,5-b]pyridine adds methyl iodide to the pyridine N atom. Treatment of the resulting iodide with base forms 4-methyl-4H-imidazo[4,5-b]pyridine. This nucleophile can readily add methyl iodide to form only one salt, 1,4-dimethylimidazo[4,5-b]pyridinium iodide.L. M. Litvinenko Institute of Physical Organic Chemistry and Coal Chemistry, Ukraine Academy of Sciences, Donetsk 340114. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1232–1233, September, 1994. Original article submitted june 17, 1994.     

Substrate-controlled and highly stereoselective synthesis of 2-aminobut-2-ene-1, 4-diones

2-Methylthio-substituted 1,4-enediones, obtained from readily available aryl methyl ketones, were reacted with primary or secondary amines to afford the desired 1,4-diaryl-2-aminobut-2-ene-1,4-diones in excellent yields with high Z/E-stereoselectivity.     

Synthesis and Crystal Structure of 1,7,8,9-Tetr achlo ro-4-b enzyl- 10,10-dimethoxy- 4-azatricyclo(5,2,1,0^2,6)dec-8-ene-3,5-dione

The crystal structure of 1,7,8,9-tetrachloro-4-benzyl-10,10-dimethoxy-4-azatricyclo-(5,2,1,02,6)dec-8-ene-3,5-dione (C18H15Cl4NO4, Mr=451.11) has been determined by single-crystal X-ray diffraction analysis. The crystal belongs to the monoclinic system, space group P21 /c with a=18.6488(2), b=13.06430(10), c=16.1086(2) , β=92.9870(10)°, V=3919.26(7) 3 , Z=8, D c=1.529 g/cm 3 , μ=5.711 mm -1 , F(000)=1840, the final R=0.0599 and wR=0.1664 for 5645 observed reflections. The title compound is composed of a polycyclic fused pyrrolidine ring system. Three symmetric fused five-membered-ring structures were formed by the Diels-Alder reaction between N-benzylmaleimide and 5,5-dimethoxy-1,2,3,4-tetrachlorocydopentadiene.