344868-20-8

Upstream product

• 186581-53-3 diazomethane 
• 958-80-5 bis(4-methoxyphenyl)thione 

Downstream Products

• 88691-95-6 4,4-bis(4-methoxyphenyl)-5,5-diphenyl-1,3-dithiolane 

Relevant academic research and scientific papers

NEW REACTIONS OF THIOBENZOPHENONE S-METHYLIDE

2,2-Diphenyl-1,3,4-thiadiazoline, prepared from thiobenzophenone and diazomethane at -78 deg C, extrudes N2 at -45 deg C and allows to study in situ 1,3-cycloadditions of thiobenzophenone S-methylide (3) with electrophilic C=S, C=C, CC, and N=N bonds.

1,3-Dipolar cycloadditions, 116. The formation of 1,3-dithiolanes from aromatic thioketones and diazomethane - The mechanism of the Schonberg Reaction

Reactions of diaryl thioketones with diazomethane at room temperature afford 4,4,5,5-tetraaryl-1,3-dithiolanes; the scope of this surprising 2:1 interaction has been studied for decades (Schonberg Reaction). The clue to the mechanism was our observation that the stoichiometry is 1:1 at -78 °C, and 2,5-dihydro-2,2-diaryl-1,3,4-thiadiazoles are formed as primary [2+3] cycloadducts. They lose N2 at -45 °C in first-order reactions generating diaryl thioketone S-methylides which can be intercepted by thioketones (→1,3-dithiolanes), multiple CC bonds, or acids HX. In the absence of trapping reagents, the elusive intermediates either dimerize furnishing 2,2,3,3-tetraaryl-1,4-dithianes or give rise to 2,2-diaryl-thiiranes by electrocyclization. Beyond thiobenzophenone and diazomethane, our main model reaction, the studies involve fluorene-9-thione, 4,4-dimethoxy- and 4,4- dichloro-thiobenzophenone. The ring of 2,5-dihydro-2,2-diphenyl-1,3,4- thiadiazole (8) is opened by LDA at -78 °C and derivatives of anion 12 are obtained. - In summa: The Schonberg reaction consists of two 1,3-dipolar cycloadditions, linked by a 1,3-dipolar cycloreversion.