80227-71-0Relevant academic research and scientific papers
A new synthesis of 1-phenylthio- and 1-alkylamino-4-nitrobuta-1,3-dienes
Ono, Noboru,Matsumoto, Koji,Ogawa, Takuji,Tani, Hiroyuki,Uno, Hidemitsu
, p. 1905 - 1910 (2007/10/03)
A new synthesis of push-pull dienes such as 4-nitro-1-phenylthiopenta-1,3-diene 4 and 1-dialkylamino-4-nitropenta-1,3-diene 5, is described. The X-ray crystal analysis shows that 4-nitro-1-(pynolidin-1-yl)penta-1,3-diene 5a is essentially planar in an E,E
Use of Hine's D Values To Predict the Position of the Equilibrium in the Cope Rearrangement of Multiply Substituted 1,5-Dienes
Hagen, James P.,Lewis, Kemberly D.,Lovell, Scott W.,Rossi, Paolo,Tezcan, Ayse Z.
, p. 7471 - 7478 (2007/10/03)
A series of 1,5-dienes (1a-f) were employed to test whether Hine's D values can predict the position of equilibrium in Cope rearrangements.In the cases of the substituent pairs , ,, , and , equilibrium constants calculated with Hine's D values gave reasonable agreement with those obtained experimentally.Dienes 1g-i were prepared to test whether reduction of the ?-donating character of a nitrogen substituent (carbamoyl vs dimethylamino) would change the directing ability of the nitrogen group.The aggregate order of directing ability was N(CH3)2 > OCH3 > EtO2CN(CH3) > CH3 > H>.Diene 15a, with a more complicated substitution pattern (OCH3 and CH3 versus CH3 and H) not directly amenable to analysis with D values, can be considered to reduce to the case of .The experimental Keq obtained agreed with that expected for the pair.Dienes 15c and 16b, designed to test the pairs and , respectively, decomposed under the gas phase conditions of the rearrangement.Attempts to effect rearrangement with Pd(II) catalysis failed.
The origins of the benzotriazole project, its versatility illustrated by a new --C = CHCH+OEt synthon, and novel syntheses of α,β-unsaturated aldehydes and ketones, furans, pyrroles and allyl ethers
Katritzky,Wu,Xie,Rachwal,Rachwal,Jiang,Zhang,Lang
, p. 1315 - 1323 (2007/10/02)
A historical introduction describes the discovery and progress of benzotriazole synthetic methodology. 3-(Benzotriazol-1-yl)-1-ethoxyprop-1-ene (6), readily prepared from 3-(benzotriazol-1-yl)-3-ethoxyprop-1-ene (4) via zinc bromide promoted allylic rearrangement, undergoes lithiation and regiospecific single or double 3-alkylation to give products which undergo (i) hydrolysis to afford α,β-unsaturated aldehydes, (ii) silica gel promoted reverse allylic rearrangement of the benzotriazolyl group, followed by further alkylation and subsequent hydrolysis to furnish α,β-unsaturated ketones, (iii) intramolecular cyclizations to construct pyrroles and furans, and (iv) intermolecular nucleophilic substitution with Grignard reagents to provide allyl ethers.
Acyl Radical Cyclizations in Synthesis. Part 3. Synthesis of (+/-)-trans-3,5-Bis(t-butyldimethylsiloxy)-2-Methylenecyclohexanone, an 'A' Ring Model for 1α,25-Dihydroxyvitamin D3
Batty, Duncan,Crich, David,Fortt, Simon M.
, p. 2875 - 2879 (2007/10/02)
A concise synthesis of (+/-)-trans-3,5-bis(t-butyldimethylsiloxy)-2-methylenecyclohexanone has been developed.The synthesis proceeds in seven steps from ethyl acetoacetate and involves a highly efficient acyl radical cyclization to construct the six-membered ring.
Reversal of Stereochemistry in the Aldol Reactions of a Chiral Boron Enolate
Danda, Hidenori,Hansen, Marvin M.,Heathcock, Clayton H.
, p. 173 - 181 (2007/10/02)
A novel route to optically active anti aldols of certain aldehydes is presented.The boron enolate derived from oxazolidinone 3 reacts with various aldehydes to give either syn or anti aldols, depending on the amount of dibutylboron triflate used in the en
A NOVEL NAPHTOQUINONE SYNTHESIS VIA TANDEM DIRECTED LITHIATIONS
Iwao, Masatomo,Kuraishi, Tsukasa
, p. 6213 - 6216 (2007/10/02)
A convenient one-pot synthesis of 1,4-naphtoquinones from tertiary benzamides has been devised using tandem directed lithiations.
Oxidation of Alcohols with tert-Butyl Hydroperoxide and Diaryl Diselenide
Kuwajima, Isao,Shimizu, Makoto,Urabe, Hirokazu
, p. 837 - 842 (2007/10/02)
Treatment of alcohols with tert-butyl hydroperoxide in the presence of diaryl diselenide in refluxing benzene gives the corresponding aldehydes or ketones.Although some allylic alcohols undergo oxidation in the presence of 10-15 mol percent of bis(p-chlorophenyl) diselenide, use of 0.5 equiv of bis(2,4,6-trimethylphenyl) diselenide gives satisfactory results in almost all cases.The procedure can be used for selective oxidation of alcohols bearing a phenylthio or phenylseleno group, which usually survives the reaction conditions to give the corresponding carbonyl compounds.
