902757-52-2

Upstream product

• 902757-41-9 (+/-)-5-(p-methoxyphenyl)-4-methyl-3-(2-phenylpent-4-en-1-yloxy)-thiazole-2(3H)-thione 
• 75-62-7 Bromotrichloromethane 
• 529477-74-5 N-(1-pentoxy)-5-(p-methoxyphenyl)-4-(methyl)thiazole-2(3H)-thione 
• 902757-49-7 N-(4-phenyl-1-butoxy)-5-(p-methoxyphenyl)-4-(methyl)thiazole-2(3H)-thione 
• 195213-54-8 4-(p-chlorophenyl)-N-(1-pentyloxy)thiazole-2(3H)-thione 
• 948578-25-4 5-(p-methoxyphenyl)-4-methyl-3-(1-phenyl-1-methyleth-1-oxy)-thiazole-2(3H)-thione 
• 1293965-65-7 3-(1-methyl-1-phenylpent-4-en-1-oxy)-5-(4-methoxyphenyl)-4-methylthiazole-2(3H)-thione 
• 1293965-64-6 3-(2-methyl-5-phenylpent-2-oxy)-5-(4-methoxyphenyl)-4-methythiazole-2(3H)-thione 

Relevant academic research and scientific papers

Tertiary alkoxyl radicals from 3-alkoxythiazole-2(3H)-thiones

This study deals with the synthesis of tert-O-alkyl thiohydroxamates and their use as tert-alkoxyl radical precursors. tert-Alkoxyl radicals were applied in mechanistic studies to determine rate constants of (i) p-chlorocumyloxyl radical addition to bicyclo[2.2.1]heptene (k=1×107 M -1 s-1), (ii) 2-phenylhex-5-en-2-oxyl radical 5-exo-trig-cyclization (kcis=3×109 s-1, ktrans=1×109 s-1), and (iii) 2-methyl-5-phenylpent-2-oxyl to 2-hydroxy-2-methyl-5-phenylpent-5-yl radical isomerization (1,5-H-atom shift; k=0.4-1.5×108 s-1). The reactions pose key steps in synthesis of 2,2,5-substituted tetrahydrofurans and 2-bromo-3-alkoxybicyclo[2.2.1]heptanes. Stereoselectivity in 5-exo-trig cyclization (2,5-cis) and intermolecular addition (exo/endo>99:1), originates from torsional strain in transition structures of alkoxyl radical reactions.

On the synthesis of β-bromohydrine ethers via intermolecular alkoxyl radical addition to bicyclo[2.2.1]heptene

Primary, secondary, and tertiary alkoxyl radicals add exo-selectively to the olefinic π-bond in bicyclo[2.2.1]heptene to afford exo-2-alkoxybicyclo[2.2.1]hept-3-yl radicals, which are trapped with BrCCl3 preferentially from the endo face to furnish β-bromohydrine ethers in 23-67% yield.

Microwave-assisted generation of alkoxyl radicals and their use in additions, β-fragmentations, and remote functionalizations

Microwave irradiation (2.45 GHz, 300-500 W) of N-(alkoxy)thiazole-2(3H)- thiones in low-absorbing solvents affords alkoxyl radicals, which were identified by (i) spin adduct formation (EPR-spectroscopy) and (ii) fingerprint-type selectivities in intramolecular additions (stereoselective synthesis of disubstituted tetrahydrofurans), β-fragmentations (formation of carbonyl compounds), and C,H-activation of aliphatic subunits, by δ-selective hydrogen atom transfer. C-Radicals formed from oxygen-centered intermediates were trapped either by Bu3SnH, l-cysteine ethyl ester, the reduced form of glutathione (reductive trapping), or by bromine atom donor BrCCl3 (heteroatom functionalization) The results suggest that microwave activation is superior to UV/Vis-photolysis and conductive heating for alkoxyl radical generation from N-(alkoxy)thiazolethiones. It offers by far the shortest reaction times along with the option to reduce the amount of trapping reagent significantly. The Royal Society of Chemistry 2006.