33532-16-0

Upstream product

• 50-00-0 formaldehyd 
• 22410-23-7 (butylsulfanyl)ethanal 
• 32779-82-1 butylthioacetaldehyde 
• 7677-24-9 trimethylsilyl cyanide 
• 63234-15-1 2-butylsulfanylpropenal 
• 71-36-3 butan-1-ol 

Relevant academic research and scientific papers

Cyanosilylation of α-butylthioacrolein

Cyanosilylation of α-butylthioacrolein with trimethylsilyl cyanide occurs as 1,2-addition. Concurrent rapid dimerization of a-butylthioacrolein occurred both in the presence and in the absence of H2PtCl6 · 6H2O as a catalyst to give 2,5-dibutylthio-2,3-dihydro-4H-pyran-2-carbaldehyde, whose cyanosilylation afforded the corresponding cyanohydrin. The latter is prone to retrodiene degradation upon heating.

The kinetics and mechanism of cyclodimerization of alkylthiopropenals

The kinetics of 2-alkylthiopropenals cyclodimerization was studied in the temperature range from -7 to +42 °C in heptane and at 20 °C in various solvents. The rate constants for cyclodimerization of 2-alkylthiopropenals are four orders of magnitude higher than those for dimerization of the oxygen-containing analogs, 2-alkoxypropenals, and are independent of the solvent polarity and substituent steric constant. The activation parameters for 2-butylthiopropenal cyclodimerization were estimated. The distribution of electron density in the 2-methoxy-and 2-methylthiopropenals molecules was calculated by the ab initio method. From comparison of the HOMO and LUMO energies for these aldehydes it was concluded that the ratio between the cyclodimerization rates for 2-alkylthio-, 2-ethoxypropenals, and propenal is determined by the HOMO-LUMO gap.

Kinetics of dimerization of 2-alkylthiopropenals

The rate constants for cyclodimerization of α-alkylthioacroleins were determined. They are two orders of magnitude higher than those for dimerization of α-alkoxyacroleins.

Reactions of 2-butylsulfanyl-2-alkenals with alcohols and water

2-Butylsulfanyl-2-alkenals react with alcohols at room temperature in the presence of acid catalysts to give 45-90% of the corresponding acetals. Acetals derived from 2-butylsulfanylpropenal readily undergo hydrolysis at the vinylsulfanyl group (20°C, catalysis by HCl or TsOH) with formation of 2-oxopropionaldehyde O,O- or O,S-acetals in 70-90% yield. Unlike 2-butylsulfanyl-2-propenal O,O-dialkyl acetals, the initial aldehydes and 2,4-dinitrophenylhydrazones derived therefrom are stable to hydrolysis under analogous conditions: the vinyl sulfide moiety remains unchanged even under considerably more severe conditions (100°C, 3 h; HCl, H2SO 4, CF3SO2OH, or TiCl4).

Synthesis of α-alkylthioacroleins

Monomeric α-alkylthioacroleins were obtained by the reaction of alkylthioacetaldehydes with formaldehyde and diethylamine hydrochloride. The structures of the α-alkyithioacroleins were confirmed by NMR spectroscopy and mass spectrometry as well as by chemical transformations of these compounds.

KINETICS AND MECHANISM OF CYCLODIMERIZATION OF α-SUBSTITUTED ACROLEINS

The kinetics of the thermal cyclodimerization of α-alkoxyacroleins were investigated for the case of α-ethoxyacrolein in the range of 98-130 deg C in cyclohexane and at 115 deg C in various solvents.The rate constant for the cyclodimerization of α-ethoxyacrolein (8.29*10-4 liter/mole*sec at 130 deg C in benzene) is two orders of magnitude higher than the analogous constant for acrolein.The activation energy for the cyclodimerization of α-ethoxyacrolein is 86 kJ/mole, log A = 7.1.The rate constant does not depend on the polarity of the solvent or on the cationic catalyst (MoCl5).The regioselectivity of the cyclodimerization of acrolein and its α-alkoxy and α-alkylthio analogs and also the ratio of the rate constants are explained in terms of Hueckel perturbation theory (PMO).It is supposed that the thermal cyclodimerization of the investigated acroleins takes place by a nonsynchronous mechanism.The idea of a transition state involving the β-carbon atoms of two molecules of the monomer seems most probable.