Synthesis of 2,3-dimethyl-6-methoxycarbonyltetrathiafulvalene

A method is proposed for the synthesis of an unsymmetrically substituted tetrathiafulvalene with an acceptor substituent, viz., 2, 3-dimethyl-6-methoxycarbonyltetrathiafulvalene, from 2-tributylphosphonia-4-methoxycarbonyl-1,3-dithiole tetrafluoroborate.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 476–477, April, 1982.     

Reactions of regioisomeric 3,3-dimethyl- and 2,2-dimethyl-6-trifluoromethyl-2,3-dihydro-4-pyrones with N-nucleophiles

Reactions of 2,2-dimethyl-6-trifluoromethyl-2,3-dihydro-4-pyrone with ethylenediamine, hydrazine, or hydroxylamine yield 5-methyl-7-trifluoromethyl-2,3-dihydro-1H-1,4-diazepine, 3(5)-(2-hydroxy-2-methylpropyl)-5(3)-trifluoromethylpyrazole, and 5-hydroxy-3-(2-hydroxy-2-methylpropyl)-5-triflouromethyl-Δ², respectively. The same compounds were obtained from 2-amino-1,1,1-trifluoro-6-hydroxy-6-methylhept-2(Z)-en-4-one and 2-hydroxy-6, 6-dimethyl-2-trifluoromethyltetrahydro-4-pyrone.     

Oxidation of 1,3-dimethyl-2,4-dioxo-2,3,4,7-tetrahydro-7-(2-propenyl)-1H-pyrrolo[2,3-d]pyrimidine-6-carboxylic acid under the Radziszewski reaction conditions

Russian Journal of General Chemistry -     

Synthesis of some new esters of 1-n-butyl-2, 5-dimethyl-4-ethynyl (ethyl)-and 1-allyl-2, 5-dimethylpiperid-4-ols

The following are synthesized: 1-n-butyl-2e, 5e-dimethyl-4e-ethynylpiperid-4a-yl benzoate ( isomer), 1-n-butyl-2e, 5e-dimethyl-4a-ethynyl (ethyl) piperid-4e-yl o-chlorobenzoate ( isomers), 1-allyl-2e, 5e-dimethylpiperid-4e-yl o-chlorobenzoate ( isomer).     

Synthesis and Crystal Structure of 7-Amino-2,3,4,5-tetrahydro- 1,3-dimethyl- 5-（2-nitrophenyl）-2,4-dioxo-lH-pyrano[2,3- d]pyrimidine-6-carbonitrile DMF Solvate

The title compound 7-amino-2,3,4,5-tetrahydro-1,3-dimethyl-5-（2-nitrophenyl）- 2,4- dioxo-1H-pyrano[2,3-d] pyrirnidine-6-carbonitrile DMF solvate 1 （C19H20N6O6, Mr = 428.41） was synthesized and crystallized. The crystal belongs to the monoclinic system, space group P2 1/c with a = 11.383（2）, b = 13.372（2）, c = 13.673（2）A, β = 97.380（4）°, Z = 4, V = 2063.8（6）A^3, Dc = 1.379 g/cm^3,μ（MoKα） = 0.105 mm^-1, F（000） = 896, the final R = 0.0738 and wR = 0.1647 for 2964 observed reflections （I〉 2σ（I））. X-ray analysis reveals that the new pyran ring is coplanar, which is obviously different from those of other similar compounds. In addition, the unclassical hydrogen bonds of C-H…O and C-H…N are presented in the crystals except for the normal hydrogen bonds of N-H…O.     

Intramolecular cyclization of 1-allyl- and 1-methallyl-6-amino-2-thiouracils

Intramolecular cyclization of 1-allyl- and 1-methallyl-6-amino-2-thiouracils afforded 5-amino-2,3-dihydrothiazolo[3,2-a]pyrimidin-4-ones, whose structures were proved by chemical transformations. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1694–1696, July, 2005.     

A convenient synthesis of 3-alkyl-2,3-dihydro-2,4-dioxo-6-phenyl-, 3-alkyl-2,3-dihydro-4-oxo-6-phenyl-2-thioxo-, and 3-alkyl-2-arylimino-2,3-dihydro-4-oxo-6-phenyl-4H-1,3-thiazines

The reactions of 1-alkylamino-1-alkylthio-3-phenylpropene-3-thiones 3 with thiophosgene and phosgene in toluene, followed by treatment of the reaction mixture with triethylamine gave 3-alkyl-2,3-dihydro-4-oxo-6-phenyl-2-thioxo- 4 , 3-alkyl-2,3-dihydro-2,4-dioxo-6-phenyl-4H-1,3-thiazines 5 , respectively in good to excellent yields. Similarly treatment of compounds 3 with N-arylimidoyl dichloride in benzene at room temperature gave 3-alkyl-2-arylimino-2,3-dihydro-4-oxo-6-phenyl-4H-1,3-thiazines 6 in excellent yields. The reactions of compounds 3 with oxalyl chloride in toluene gave also 5 in good yields.     

Transformations of 2,6-dimethyl- and 2,3-dimethyl-6-ethyl-4-(2′-furyl)pyridines involving the furan and pyridine rings

Alkyl-substituted 4-(2-furyl)pyridines are brominated and nitrated in the C₅' position of the furan ring; however, they do not undergo electrophilic substitution reactions such as acetylation, formylation, and chloro- and aminomethylation. Furyl-substituted indolizines and tetrahydropyridines were obtained from quaternary salts of 2,6-dimethyl-4-(2-furyl)pyridine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1665–1667, December, 1982.     

Mass spectra of 3,6-dihalo-4,4-dimethyl-1,4-selenasilafulvenes and 2,4-dihalo-2-dihalomethyl-3,3-dimethyl-1-selena-3-silacyclopent-4-enes

The behavior of new heterocyclic systems, viz., 3,6-dihalo-4,4-dimethyl-1,4-selena- silafulvenes 1a, b and 2,4-dihalo-2-dihalomethyl-3,3-dimethyl-1-selena-3-silacyclopent-4-enes 2a, b (Hal =Cl, Br), was studied under conditions of electron ionization and thermal decomposition. Their fragmentation is accompanied by skeletal rearrangements, and the positive charge is localized mainly on ions containing silicon. Selenasilafulvenes 1a, b form stable molecular ions. Selenasilacyclopent-4-ene 2a decomposes partially and compound 2b decomposes completely in the gas phase with the elimination of a hydrogen halide and a halogen molecules.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 639–642, March, 2005.The term “contribution” implies the ratio of the sum of peak intensities of all isotope varieties of the ion under consideration to the total ion current.     

4-氯-7H-吡咯并[2,3-d]嘧啶与2,4-二氯-7H-吡咯并[2,3-d]嘧啶的合成研究

报道了以廉价易得的丙二酸二乙酯为起始原料,经过α-烷基化、环合、氯化、烯键氧化和SNAr/环化五步反应,高收率地得到目标产物4-氯-7H-吡咯并[2,3-d]嘧啶(6)和2,4-二氯-7H-吡咯并[2,3-d]嘧啶(10)(总收率分别达到45.8%和44.8%)的合成方法,并对中间体和产物的化学结构进行了表征.     

Mass spectrometric synthesis. 1—the reaction of catechol with 2,4-dimethyl-2,3-pentadiene

The reaction of catechol with 2,4-dimethyl-2,3-pentadiene, carried out in the chemical ionization chamber of a VG ZAB2F mass spectrometer, has been studied with respect to the partial pressure of the reacting species. The structure of the reaction product, 2,2-diisopropyl-1,3-benzodioxole, has been proved by exact mass measurements, B/E linked scans, labelling experiments and collisionally activated dissociation mass analysed ion kinetic energy spectra.     

Synthesis and reactions of 6-hydroxy-2,4-dimethyl-1,3-benzodioxane

The reaction of hydroquinone and acetaldehyde in a mixture of acetic and hydrochloric acids (31) at 0–5 °C gives 6-hydroxy-2,4-dimethyl-1,3-benzodioxane, which forms ethers and esters at the hydroxy group, undergoes diazo coupling, and, under the influence of acids, undergoes polycondensation with opening of the 1,3-dioxane ring.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1195–1198, September, 1983.     

Synthesis of 2,4-dimethyl-6-oxo-2,4-heptadienoic acid derivatives from 2,4,6-trimethylpyrylium salts

Reaction 2,4,6-trimethylpyrylium salts with sodium cyanide in boiling water yielded the bicyclic lactone 1,3,5-trimethyl-6,8-dioxabicyclo[3.2.1]oct-2-en-7-one (6) along with a series of stereoisomers of 2,4-dimethyl-6-oxo-2,4-heptadienonitrile (5), which were the sole products when the reaction was carried out at room temperature. Compound 6, along with 3,5-dimethylphenol (7), was also obtained by refluxing 5 briefly in aqueous sodium hydroxide. However, when 5 was refluxed for a prolonged period in aqueous sodium acetate, 3,5-dimethyl-5-(2-oxopropyl)-furan-2-one (8), along with some 7, was generated instead. Compound 8 could also be produced from 6 on prolonged refluxing with aqueous sodium acetate, indicating that 6 was the kinetically-controlled and 8 the thermodynamically-controlled product.     

Dehydration of 10,10-dimethyl-9-allyl-9,10-dihydro-10-sila-2-azaanthrol-9

Dehydration under various conditions of the tertiary alcohol 10,10-dimethyl-9-allyl-9,10-dihydro-10-sila-2-azaanthrol-9 yielded the following compounds: Z- and E-isomers of 10,10-dimethyl-9-propenyldiene-9,10-dihydro-10-sila-2-azaanthracene; 10,10-dimethyl-9-allyl-9-ethoxy-9,10-dihydro-10-sila-2-azaanthracene; 1,1,3,3-tetramethyl-1,3-di(3-propenylidenebenzylpyridyl-4)-disiloxane; 1-methyl-3-(4-dimethyloxysilylpyridyl-3)indene.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1566–1569, November, 1988.