Mechanistic studies of the enolization of 2-methylcyclohexanone mediated by lithium hexamethyldisilazide (LiHMDS; TMS(2)NLi) solvated by hindered dialkyl ethers (ROR') are described. Rate studies using in situ IR spectroscopy show that enolizations in the presence of i-Pr(2)O, 2,2,5,5-tetramethyltetrahydrofuran, and cineole proceed via dimer-based transition structures [(TMS(2)NLi)(2)(ROR')(ket...

Six square planar Ni(II) complexes of 3,3-dialkyl/aryl-1-benzoylthiourea derivatives have been synthesized and characterized by elemental analyses, and electronic, FT-IR and NMR spectroscopic techniques. A cis-O2S2 disposition in complexes 3, 4 and 5 was confirmed by single crystal X-ray crystallography. The cytotoxicity of the 3,3-dialkyl/aryl-1-benzoylthiourea molecules and their complexes wa...

Reactions of O,O'-dialkyl thiophosphoric acids with alkyl halides, in the presence of a base, provide a direct synthetic route to phosphorothioates via O,O'-dialkyl thiophosphate anion formation. Studies on the reaction of ambident nucleophile ammonium O,O'-diethyl thiophosphate with benzyl halides and tosylate in different solvents show that only S-alkylation is obtained. Reaction of this ambi...

Simple, secondary 2,4,6-triisopropyl benzoates (TIB esters) and secondary dialkyl N,N-diisopropyl carbamates have been reported to be resistant to deprotonation by strong bases. We have found that the combination of sBuLi (1.6 equiv) and TMEDA (6 equiv) in CPME at -60 °C enables deprotonation of unactivated secondary dialkyl TIB esters, but not the carbamates. These carbanions were reacted with...

The venom of the red imported fire ant, Solenopsis invicta, is dominated by trans stereoisomers of 2,6-dialkylpiperidines. cis Stereoisomers of alkaloids in the venom of S. invicta were separated from trans stereoisomers by using silica gel short column chromatography and identified by coupled gas chromatography mass spectrometry (GC-MS). Seven pairs of cis and trans sterecoisomers were identif...

Dibenzobarrelene derivatives, that are annelated with a pyrrolinium unit [N,N-dialkyl-3,4-(9',10'-dihydro-9',10'-anthraceno-3-pyrrolinium) derivatives], undergo a photo-induced di-π-methane rearrangement upon triplet sensitization to give the corresponding cationic dibenzosemibullvalene derivatives [N,N-dialkyl-3,4-{8c,8e-(4b,8b-dihydrodibenzo[a,f]cyclopropa[cd]pentaleno)}pyrrolidinium derivati...

Square planar dialkyl complexes of nickel, palladium and platinum exhibit intriguing difference in their reactivities. Thermolysis pathways of these dialkyls vary depending on the metal, ligands, alkyl groups, geometry as well as the presence or absence of added ligand. Kinetic studies on the thermolysis and trans-cis isomerizations of PdR,L2 (L = tertiary phosphine) complexes showed involvemen...

Protodeborylation of triorganoboranes, usually carried out under mild reaction conditions using an excess of acetic acid, affords 1,5-dialkyl-3,7-dimethyl-4,8,9-trioxa-2,6-dioxonia-1,5-diboratabicyclo [3.3.1]nona-2,6-dienes OB(R)OC(Me)OB(R)OC(Me)O [1 (R = Et), 2 (R = cyclooctyl)]. Acetoxy(dialkyl)boranes and di(acetoxy)alkylboranes were not formed in an appreciable amount. Compounds 1 and 2 wer...

in order to investigate the effects of dimethylamino substituent at postion 2 of the dihydropyridine nucleus on its activity, dialkyl 1,4-dihydro-2-[2-(dimethy- lamino) ethyl]-6-methyl-4-(1-benzyl-2-alkylthio-5-imidazolyl)-3,5-pyrdinedicar- boxylates (6a-f) were synthesized. the synthesis was started from dialkyl 1,4- dihydro-2,6-dimethyl-4-(1-benzyl-2-alkylthio-5-imidazolyl)-3,5-pyridinedicar-...