Synthesis of racemic 10-methyltridecan-2-one,the sex pheromone ofDiabrotica undecimpunctata

A new synthesis of racemic 10-methyltridecan-2-one, the sex pheromone ofDiabrotica undecimpunctata Howardi has been effected. “InterBAV” Scientific Production Company RM, Kishinev. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 558–560, July–August, 1994.     

2-Methyl-s-triazolo[1,5-b]isoquinolin-5(10H)-one

Acetamidrazone hydrochloride reacts with homophthalic anhydride to give 3-o-carboxybenzyl-5-methyl-1,2,4-triazole 1, which can be cyclised to 2-methyl-s-triazolo[1,5-b] isoquinolin-5(10H)-one 2. Reduction with lithium aluminium hydride gives 5,10-dihydro-2-methyl-s-triazolo [1,5-b] isoquinoline, while condensation with aromatic aldehydes gives 10-arylmethylene derivatives. Coupling with arenediazonium salts gives the 10-arylhydrazones of 5,10-dihydro-2-methyl-s-triazolo [1,5-b] isoquinoline-5,10-diones, while condensation with p-nitrosodimethylaniline gives the 10-imino derivative. Alkylation of 2 produces the corresponding 10,10-dialkyl derivatives.     

5-(Trimethylstannyl)-2H-pyran-2-one and 3-(Trimethylstannyl)-2H-pyran-2-one: New 2H-Pyran-2-one Synthons

5-(Trimethylstannyl)-2H-pyran-2-one (11) and 3-(trimethylstannyl)-2H-pyran-2-one (30), readily prepared from the corresponding bromo-2H-pyran-2-ones, undergo Pd(0)-catalyzed coupling reactions with a variety of enol triflates to give 5- and 3- substituted 2H-pyran-2-ones, respectively. This reaction is applicable to the enol triflates of 14beta-hydroxy-17-ketosteroids, and therefore may prove useful in convergent syntheses of lucibufagins and bufadienolides.     

Conformational investigation of phenoxycyclohexan-2-one andp-Cl- andp-NO2-phenoxycyclohexan-2-one by molecular mechanics; x-ray crystallographic analysis ofp-NO2-phenoxycyclohexan-2-one

The preferred conformers of phenoxycyclohexan-2-one and p-Cl- andp-NO₂-phenoxycyclohexan-2-ones were calculated by the MM2(87) method. The results are compared with the data from experimental conformational investigations in solution. According to the calculation, the compounds are described by a multicomponent equilibrium, including thesp-G conformer with a planar orientation of the anisole fragment and a mixture of theac-G andT conformers both with planar and with orthogonal arrangement of the aryl group. The structure ofsp-G(0°)p-NO₂-phenoxycyclohexan-2-one was determined by x-ray crystallographic analysis.A. E. Arbuzov Institute of Organic and Physical Chemistry, Kazan' Scientific Center, Russian Academy of Sciences, 420083 Kazan'. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 6, pp. 1359–1364, June, 1992.     

Acylthioketene-thioacylketene-thiet-2-one rearrangements

Flash vacuum thermolysis (FVT) of 6-aryl-1,3-dioxine-4-thiones 9 leads to the formation of acylthioketenes 10, which are characterized by Ar matrix IR spectroscopy as well as on-line tandem mass spectrometry. The thioketenes 10 undergo a 1,3-shift of the aryl group to generate thioacylketenes 11. Ketenes 11 cyclize to 3-aryl-thiet-2-ones 12, which are also characterized by matrix IR spectroscopy and tandem mass spectrometry. The thiet-2-ones 12 undergo two kinds of reaction under the FVT conditions: (i) cheletropic CO extrusion with formation of arylthioketenes 13, and (ii) cycloreversion to COS and arylacetylene.     

Synthesis of Tetrahydrothiophene 1,1-Dioxides Fused to Oxazolidin-2-one and Morpholin-2-one Fragments

While developing methods of synthesis of sulfolanes fused through the C³–C⁴ bond to oxazolidin-2- one and morpholin-2-one fragments, the reactivity of cis- and trans-isomeric amino alcohols of the sulfolane series toward a number of cyclizing agents was studied. The cis isomers reacted with dimethyl acetylenedicarboxylate and triphosgene to afford the corresponding morpholin-2-ones and oxazolidin-2-ones, whereas the trans isomers gave rise to open-chain aminofumarates and urea derivatives, respectively. The reactions of both cis- and trans-amino alcohols with oxalic acid derivatives (diethyl oxalate, oxalyl chloride) led to the formation of exclusively acyclic mono- and/or diamides.     

Synthesis of 1-Bromo-3-butyn-2-one and 1,3-Dibromo-3-buten-2-one

Synthetic procedures for the preparation of 1-bromo-3-butyn-2-one and 1,3-dibromo-3-buten-2-one are given. These compounds are prepared from 2-bromomethyl-2-vinyl-1,3-dioxolane, which can readily be prepared from 2-ethyl- 2-methyl-1,3-dioxolane. The synthetic routes are as follows: 2-bromomethyl-2-vinyl-1,3-dioxolane is converted to 2-(1,2-dibromoethyl)-2-bromomethyl-1,3-dioxolane. Double dehydrobromination with ^tBuOK affords 2-ethynyl-2-bromomethyl-1,3-dioxolane. Formolysis with formic acid gives 1-bromo-3-butyn-2-one. Deacetalized 2-bromoethyl-2-vinyl-1,3-dioxolane was treated with Br₂ and Li₂CO₃/12-crown-4 in tetrahydrofuran to give 1,3-dibrom-3-buten-2-one in moderate yield.     

Synthesis and properties of the salts of 1-nitropropan-2-one and 1-nitrobutan-2-one

1. Download : Download high-res image (83KB)
2. Download : Download full-size image

     

Synthesis of racemic 10-methyltridecan-2-one, the sex pheromone ofDiabrotica undecimpunctata

A new synthesis of racemic 10-methyltridecan-2-one, the sex pheromone ofDiabrotica undecimpunctata Howardi has been effected.InterBAV Scientific Production Company RM, Kishinev. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 558–560, July–August, 1994.     

Synthesis of 1,3,4-thiadiazin-2-one and 1,3,4-selenadiazin-2-one derivatives as new cardiotonic drugs

The synthesis of the new heterocycle 1,3,4-selenadiazin-2-one is described, based on the preparation of the analogue heterocycle 1,3,4-thiadiazin-2-one. The related cyclization between an α-haloketone and a thiocarbazate cannot readily be employed within the selenium series. Therefore a new route was developed based upon a diazotization/hydrolysis sequence of the related 2-amino-1,3,4-selenadiazine.     

Synthesis of 5,6-dimethoxythiophen-3H(2)one and 6,7-dimethoxythiochroman-2-one. Derivatives of tetramethoxy-10,11-dihydrodibenzo[β,f]thiepin-10-one

Reduction of 4,5-dimethoxy-2-carbomethoxymethylbenzenesulfonyl chloride and 4,5-dimeth-oxy-2-carboethoxyethylbenzenesulfonyl chloride with zinc, hydrochloric acid, produced the corresponding o-mercapto-aeids which then cyclized to thiaindanone and thiochromanone, respectively. Thiaindanone and thiochromanone reacted readily with aniline to give 4,5-dimeth-oxy-2-mereaptophenyl-N-phenylacetamide and 4,5-dimethoxy-2-mercaptophenyl-N-phenylpropyl-amide. Mercaptophenyl N-phenylacetamide yielded in two steps the 4,5-dimethoxy-2-N-phenyl-acetarnido(3′,4′ -dimethoxyphenylthio)benzene, which was cyclized to the 2,3,7,8-tetramethoxy-10,11-dihydrodibenzo[b, f]thiepin-10-one. Reduction of thiepinone with sodium borohydride leads to the corresponding alcohol.     

Effect of the solvent on selective hydrogenation of 6, 10-dimethylundeca-3,5,9-trien-2-one

Reaction mechanism for selective hydrogenation of pseudo-ionon on Raney-Ni in the presence of n- and iso-alcohols has been studied. From the analysis of ESR spectra, the dependence of selectivity on the solvent is concluded.

---

- Ni- . .

     

1,4-Addition of phosphonacetate esters to 6,10-dimethyl-3-undecen-2-one and 10-methoxy-6,10-dimethyl-3-undecen.-2-one under horner-emmons reaction conditions in a superbasic medium

Conclusion Phosphonacetate esters in superbasic media add to the double bond of 6,10-dimethyl-3-undecen-2-one by 1,4 addition to give low yields of esters of 1-alkoxycarbonyl-2-(2-oxopropyl)-4,8-d'imethylnonylphosphonic acid.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1179–1182, May, 1987.     

Synthesis,Crystal Structure and Prosperities of 10-（4,5-Dibenzylthio- 1,3-dithiol-2-ylidene）anthracen-9（10H）-one

The title compound 10-（4,5-dibenzylthio-1,3-dithiol-2-ylidene）anthracen-9（10H）- one （C31H22OS4） has been synthesized, and its crystal structure was prepared by crystallization from CH2Cl2-MeOH. The crystal belongs to the triclinic system, space group Pi with a = 10.9758（3）, b = 11.4241（4）, c = 11.7460（2）A^°, α = 62.379（2）, β = 81.227（3）, γ = 80.321（2）°, Mr = 538.73, V = 1281.69（7） A^°^3, Z = 2, Dc = 1.396 g/cm^3, F（000） = 560,μ = 0.395 mm^-1, the final R = 0.0291 and wR = 0.0739. The molecular structure is severely distorted from planarity. The central ring of anthraquinone moiety adopts a boat conformation, while the two outer benzene rings are tilted in the opposite direction to form a dihedral angle of 23.65°. The photocurrent generation was measured and an anodic photocurrent response was obtained. The electronic spectrum was studied by using TDDFr method on the basis of optimized geometries with B3LYP method. The obtained results are in good agreement with the experimental values.     

Hydrazones and hydrazides of 4, 6-dimethyl-5-carboxypyrid-2-one and 4-methyl-6-carboxymethylpyrid-2-one

With a view to elucidating antitubercular activity, from the hydrazides of 4, 6-dimethyl-5-carboxypyrid-2-one and 4-methyl-6-carboxymethylpyrid-2-one, are synthesized the hydrazones of acetone, methyl ethyl ketone, acetophenone, benzaldehyde, p-hydroxypropiophenone, p-dimethylaminobenzaldehyde and tetrahydrothiopyi-4-one.