71911-72-3Relevant academic research and scientific papers
CHEMISTRY OF α-NITROEPOXIDES: SYNTHESIS OF USEFUL INTERMEDIATES VIA NUCLEOPHILIC RING OPENING OF α-NITROEPOXIDES
Vankar, Yashwant D.,Shah, Kavita,Bawa, Anita,Singh, Surendra P.
, p. 8883 - 8906 (2007/10/02)
Various α-nitroepoxides are converted into corresponding 1,2-diketones via two different ways of ring opening viz. with Pd(O) and with DMSO/BF3*EtO2 (or ClSiMe3).In addition to this, a variety of nucleophiles are reacted with α-nitrocyclopentene oxide 6 and α-nitrocyclohexene oxide 7 to form the corresponding α-substituted ketones which are useful intermediates in organic synthesis.Two of the products so obtained viz. 32 and 33 are also transformed further into optically active thialactones 38 and 39 respectively via baker's yeast reduction followed by lactonisation.
THE SYNTHESIS AND CHEMISTRY OF AZOLENINES. PART 18. PREPARATION OF 3-ETHOXYCARBONYL-3H-PYRROLES VIA THE PAAL-KNORR REACTION, AND SIGMATROPIC REARRANGEMENTS INVOLVING COMPETITIVE ESTER MIGRATIONS TO C-2, C-4 AND N.
Chiu, Pak-Han,Sammes, Michael P.
, p. 3439 - 3456 (2007/10/02)
3H-Pyrrole-3-carboxylic esters (4) have been prepared, in some cases together with isomers (5) and (6) having exocyclic double bonds, by cyclization of suitably substituted 2-ethoxycarbonyl-1,4-diketones (1) with liquid ammonia, followed by dehydration of the isolable 2-hydroxy-3,4-dihydro-2H-pyrrole intermediates (2) and (3) with aluminia in boiling solvents.Prolonged heating in toluene or p-xylene converts the 3H-pyrroles (4) quantitatively into isomeric 4-esters (11) and N-esters (13) of 1H-pyrroles via competitive sigmatropic rearrangements.Isolable intermediate 2H-pyrrole-2-carboxylic esters (12) are converted similarly into the same products, under the same conditions.Detection of 3H-pyrroles (4) as intermediates in the latter reaction demonstrates for the first time the reversibility of the thermal 2H-pyrrole to 3H-pyrrole interconversion.
Mn(III)-PROMOTED ANNULATION OF ENOL ETHERS AND ESTERS TO FUSED OR SPIRO 2-CYCLOPENTENONES
Corey, E. J.,Ghosh, Arun K.
, p. 175 - 178 (2007/10/02)
Manganese(III)-promoted addition of various 1,3-dicarbonyl compounds to enol ethers or terminal enol esters, followed by hydrolysis of the resulting adducts and base catalyzed aldol cyclization provides an effective process for the synthesis of a wide ran
Malonate Anion Induced Favorskii-Type Rearrangement. Reaction of Cyclic α-Halo Ketones with Sodiomalonates
Sakai, Takashi,Amano, Eiichiro,Kawabata, Akifumi,Takeda, Akira
, p. 43 - 47 (2007/10/02)
The reaction of 2-chlorocyclohexanone (1b) with ethyl sodiomalonate in benzene at 0-25 deg C gave 6-bicyclohexan-6-ol (4c), the Favorskii-type intermediate, in 49percent yield, in place of the substitution product ethyl C-(2-oxocyclohexyl)malonate (3).Derivatives of bicycloheptan-7-ol (4a,b) and those of bicyclohexan-6-ol (4d,e) were also obtained in good yields by similar means.Compound 4c was transformed into 3 readily by heating with 0.05 equiv of NaH in benzene.The hydrolysis of 4a-d with 0.2 N NaOH followed by pyrolysis at 110-120 deg C gave the ring-contracted β-keto esters 9a-d.Pyrolysis after the hydrolysis with 2N NaOH gave the corresponding ketones 11a-d in good yields.Oxidation of 4c with CrO3 and HClO4 afforded ethyl C-(2-hydroxycyclopentanecarbonyl)malonate (14) in 45 percent yield.Treatment of 4c with Br2 gave ethyl C-(1-bromocyclopentanecarbonyl)malonate (18) in 64 percent yield.
