2161-90-2Relevant articles and documents
Hetero-diels-alder reaction of ethyl 2-nitrosoacrylate and cyclohexadienes, and bromine induced diene isomerization
Song, Jian,Lin, Yongcheng,Szeto, Yau Shan,Chan, Wing Lai
, p. 1685 - 1689 (2007/10/03)
Bicyclic 8a-methoxy-1,2-oxazine (3a) and bicyclic 7-methoxy-1,2-oxazine (3b) were prepared via Hetero-Diels-Alder reaction between 1-methoxy-1,4-cyclohexadiene (2a) and ethyl 2-nitrosoacrylate generated in situ from ethyl bromopyruvate oxime (1). The formation of 3b was ascribed to bromine, released from 1, which induced transformation of 2a to 1-methoxy-1,3-cyclohexadiene (2b). 3b could be easily transformed to oxazinone (3c) in CHCl3, or other organic solvents in the presence of a trace amount of acid.{A figure is presented}.
Reductions with lithium in low molecular weight amines and ethylenediamine
Garst,Dolby,Esfandiari,Fedoruk,Chamberlain,Avey
, p. 7098 - 7104 (2007/10/03)
Reductions of several types of compounds with lithium and ethylenediamine using low molecular weight amines as solvent are described. In all cases 1 mol of ethylenediamine or N,N'-dimethylethylenediamine per gram-atom of lithium was used. In some cases it was beneficial to add an alcohol as a proton donor. These reaction conditions were applied to the debenzylation of N-benzylamide and lactams which are refractory to hydrogenolysis with hydrogen and a catalyst. N-Benzylpilolactam 2, synthesized from pilocarpine hydrochloride in refluxing benzylamine, was debenzylated in good yield using 10 gram-atoms of lithium per mole (10 Li/mol) of 2 in n-propylamine. The debenzylation of N-benzyl-N-methyldecanoic acid amide, 4 (6 Li/mol), in t-butylamine/N,N'-dimethylethylenediamine gave N-methyldecanoic acid amide 6 in 70% yield. Alternatively, reduction of 4 (7 Li/mol) in t-butanol/n-propylamine/ethylenediamine gave n-decanal 12 in 36% yield. Using the same conditions, thioanisole, 1-adamantane-p-toluenesulfonamide, and 1-adamantane methyl p-toluenesulfonate were reduced with 3, 7, and 7.2 Li/mol of compound to give thiophenol (74%), adamantamine (91%), and 1-adamantane methanol (75%), respectively. In this solvent system naphthalene and 3-methyl-2-cyclohexene-1-one were reduced to isotetralin (74%) and 3-methyl cyclohexanone (quantitative) with 5 and 2.2 Li/mol of starting compound, respectively. Oximes and O-methyloximes were reduced to their corresponding amines using 5 and 8 Li/mol of compound, respectively. Anisole was also reduced to 1-methoxy-1,4-cyclohexadiene with 2.5 Li/mol of anisole. Undecanenitrile was reduced to undecylamine with 8.6 Li/mol. Additionally, a base-catalyzed formation of imidazolines from a nitrile and ethylenediamine was also explored.
Thermodynamics of Vinyl Ethers. 31. Isomer Equilibria in Some Six- and Seven-Membered Cyclic Dienes
Taskinen, Esko,Nummelin, Kari
, p. 4844 - 4847 (2007/10/02)
The relative thermodynamic stabilities of 1,3-cyclohexadiene and 1,4-cyclohexadiene, together with a number of their alkoxy and other derivatives and some related seven-membered cyclic dienes, have been determined by chemical equilibration in Me2SO and cyclohexane solution at various temperatures.The values of the thermodynamic parameters ΣG, ΔH, and ΔS for the isomerization processes involved are discussed and show clearly that the apparently conjugated diene system of 1,3-cyclohexadiene is devoid of conjugation, contrary to that of 1,3-cycloheptadiene.
