A Convenient Synthesis of 5-Aryltropones

2-Methoxy-5-[[(trifluoromethyl)sulfonyl]oxy]tropone was coupled to a variety of arylzinc chlorides in the presence of a palladium catalyst to furnish 5-aryltropones in good to excellent yields.     

Synthesis and properties of 5-ferrocenyl-1H-pyrazole-3-carbaldehydes

New ferrocene derivatives - ethyl esters of 1-aryl-5-ferrocenyl-1H-pyrazole-3-carboxylic acids were synthesized. The corresponding aldehydes were obtained from acid esters in two steps. The reductive amination reaction of 5-ferrocenyl-1-phenyl-1H-pyrazole-3-carbaldehyde was studied. Several of these compounds were investigated by cyclic voltammetry. All of them exhibited a reversible one-electron oxidation-reduction wave owing to the ferrocene-ferricinium redox couple with a positive shift (0.51-0.69 V) compared with that of ferrocene (0.46 V). The X-ray crystal structure of the ethyl ether 1-(3-chloro-2-fluorophenyl)-5-ferrocenyl-1H-pyrazole-3-carboxylic acid is also presented.     

A Convenient Synthesis of 3-Methylthiobenzaldehyde

Requiring the title compound as a starting material, we were surprised to find only one published synthesis,¹ involving five steps with an overall yield of 15%. This is in contrast to the 2-and 4-alkylthiobenzaldehydes, which may be synthesised in one step by reaction of sodium alkanethiolates with the readily available halobenzaldehydes². 3-Halobenzaldehydes, although readily available, do not react under these conditions².     

A Convenient Synthesis of 3-Alkylthiophenes

The known procedures for the synthesis of 3-alkylthiophenes are rather lengthy or involved. By using the NiDPPP⁺⁺ catalyzed cross-coupling method between 3-bromothiophene and Grignard reagents derived from alkyl halides a number of 3-alkylthiophenes have been prepared in a one-step reaction in good to excellent yields.     

A Convenient Synthesis of 3-Alkoxythiophene

3-Alkoxythiophenes could be conveniently prepared by a procedure of cross-coupling from 3-bromothiophene and sodium alkoxide in the presence of copper (I) iodide and N,N-dimethyl formamide.     

A Convenient Synthesis of 1, 2, 5-Trisubstituted 3-Benzoylpyrroles

In the course of our investigation directing toward biologically active compounds, 2, 5-disubstituted 3-acylpyrrole derivatives were found to show a potent inhibiting activity of platelet aggregation.^1,2,3 Thus, various acylation reactions were studied in order to achieve an efficient synthesis of 3-acylated pyrrole system. We wish to report here an effective method for the preparation of 2, 5-disubstituted 3-acylpyrroles dispensing from the formation of by-products such as 3, 4-diacylated pyrroles.     

A Convenient Synthesis of 5-Bromo-2-Pentanone

During a series of studies aimed at the total synthesis of pentacyclic triterpenes¹ we have examined the reaction of enollactones of type 1 with a variety of Grignard reagents. ^1c,2 In one of our problems we required the organometallic reagent 2a derived from the title compound 2b. A previous literature report for the preparation of this compound involved the reaction of α-acetylbutyrolactone 3 with aqueous HBr followed by steam distillation.³ In our hands the yields of 2b via this route were non-reproducible and at best, less than 15%.     

A Convenient Synthesis of 4,6-Dichloro-5-benzylthiopyrimidine

A practical and convenient two-step synthesis of the title compound 4,6-dichloro-5-benzylthiopyrimidine (3) from 4,6-dihydroxypyrimidine (1) is described.     

Synthesis of pyrimidine-5-carbaldehydes from α-formylaroylketene dithioacetals

A facile one pot synthetic path for the preparation of pyrimidine-5-carbaldehydes from α-formylaroylketene dithioacetals is described. Amidines were allowed to react with α-formylaroylketene dithioacetals in DMF or acetonitrile to afford the pyrimidine-5-carbaldehydes. The starting compounds reported earlier were synthesized from α-oxoketene dithioacetals in excellent amount.     

A Convenient Synthesis of 3-Methoxyphthalic Anhydride

Many antibiotics of the anthracycline family¹ possess structures for which 3-methoxyphthalic anhydride (1) would be a suitable synthon² in a total synthesis. A classic synthesis of (1) has employed 3-nitrophthalic acid³ but, in our hands, proceeded in low overall yield. Recent syntheses have utilized the Diels Alder reaction of dimethyl acetylenedicarboxylate (2) with 1-methoxy-1,3-cyclohexadiene,⁴ 1,4-diacetoxybutadiene,⁵ 2-acetoxyfuran,⁶ 2-methoxyfuran⁷ or furan⁸ to obtain 3-hydroxyphthalic acid or a derivative. We now wish to report a convenient Diels-Alder synthesis of (1) from 3-methoxy-2-pyrone (3).     

Synthesis of 2-alkylthio-6-methylpyridine-3-carbaldehydes

The action of sodium bis(2-methoxyethoxy)aluminum hydride and its complex with piperidine on 2-alkylthio-3-cyano-6-methylpyridines and on their esters in anhydrous ether yielded 2-alkylthio-3-formyl-6-methylpyridines. The aldehydes obtained undergo condensation with malononitrile and methyl cyanoacetate to give the corresponding hetarylidene derivatives. Dedicated to Academician N. K. Kochetkov on the occasion of his 90th birthday. __________ Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1195–1198, May, 2005.     

A New and Convenient Synthesis of 3-Hydroxychromones

An improved synthesis of 3-hydroxychromones is described.     

A Novel and Convenient Synthesis of 2-Amino-3-Cyano-5-N-Substituted Piperazinyl Pyridines

A mixture of two moles of triethylorthoacetate, one mole of malononitrile and one mole of N-substituted piperazine in the presence of excess of ammonium acetate at reflux conditions affords the title compounds. Elemental and spectral data confirms the structures of the purified compounds.     

A Convenient Synthesis of 3- and 3,4-Substituted 4,5-Dihydroisoxazole-5-Acetic Acids

The 4,5-dihydroisoxazole-5-acetic acids 4a-j were prepared from the ketoximes 1a-j, 2,2-dimethyl-5-methoxymethylene-1,3-dioxan-4,6-dione (2) and butyllithium in yields from 35 to 79%.     

Expedient Strategy for the Synthesis of 5-Acylethynylpyrrole-2-carbaldehydes

5-Acylethynylpyrrole-2-carbaldehydes have been synthesized from the protected pyrrole-2-carbaldehydes by their transition-metal-free topochemical mechanoactivated ethynylation with acylbromoacetylenes in a solid Al₂O₃ medium (room temperature, 6 h, 41–54% yields).     

Convenient Synthesis of 3-Styrylphthalides

A convenient, high yield, two-step method is described for 3-styrylphthalides (3a - e) from 3-phenacylphthalides (1a - e)     

A Convenient Synthesis Of 3-Arylcoumarins From Arylacetonitriles

The condensation of salicylaldehydes with various arylacetonitriles catalyzed by anion-exchange resins such as Amberlite IRA 900, leads to the corresponding 3-arylcoumarins in good yields and selectivity.     

A Short and Convenient Synthesis of 5-Alkyl Substituted 8-Hydroxyquinolines

5-Chloro-8-methoxyquinoline undergoes rapid and reversible lithium-halogen exchange reaction with alkyllithiums to yield 5-alkyl substituted derivatives indirectly, whereas the reaction with phenyllithium is slower and 5-alkyl substituted compounds are formed by the direct addition of alkyl halides.     

A Convenient Synthesis of O-Alkyl-S-allenyl-Phosphoramidates

Ten title compounds 2a-j were synthesized by utilising mercuric (I) catalyzed thiono-thiolo rearrangement of O-propargyl-O-alkyl-pho-sphoramidothionates (1a-j) in HAc-NaAc buffer (PH=3.6). The yield of compounds 2a-e and 2f-j is 58–67% and 12–41%. This is the example of [3,3]-sigmatropic type rearrangement of 1,5-enyne system in thionop hosphoramidate chemistry.     

A Convenient Synthesis of Sendaverine

Sendaverine was isolated from Corydalis aurea willd by Manske and it was found to possess a tetrahydro-isoquinoline skeleton¹. The structural formula of the alkaloid has been established by the unambiguous synthesis by Kametani² and Miwako Mori et al.³