The Preparation of 1,4-Dithienes

Abstract

Vol. 58 drochloric acid (b -2o); therefore the reaction does not take place between free amine and nitrous acid.2. It must be concluded, especially from the results with small concentrations of hydrochloric acid, that the reaction proceeds between the salt of the amine (pentavalent nitrogen) and nitrous acid.3. No agreement has been obtained with the calculated velocity for this case. Mostly the influence is much more than can be accounted for by decreasing hydrolysis of the salt of the amine.4. The excess of hydrochloric acid increases the velocity of diazotization for all the amines which were investigated, by (1) decreasing hydrolysis of the salt of the amine; and (2) a specific action.

Halogenation with Copper(II). I. Saturated Ketones and Phenol

“…The physical properties (boiling point, refractive index, infrared and ultraviolet spectra of -chloropropiophenone prepared in this manner were identical to those of an authentic sample prepared according to the literature. 15 However, the refractive index, n25o 1.5438, was higher than that reported (n26o 1.5402). 15 It was noted that rapid distillation of the material gave a liquid with the lower refractive index; £°°' "ß 2470 Á.…”

“…15 However, the refractive index, n25o 1.5438, was higher than that reported (n26o 1.5402). 15 It was noted that rapid distillation of the material gave a liquid with the lower refractive index; £°°' "ß 2470 Á. (« 12,800), 2825 Á.…”

Pummerer reaction of 4,7-di-tert-butyl-3h,8h-1,2,5,6-dithiadiazocine 1-oxide; formation of 1,4-dithiins

“…In the presence of DBU, the reaction of 4b with (CF 3 CO) 2 O produced a 15:1 mixture of dithiins 5b [9] and 5b [10] in 32% yield. However, in the absence of DBU, the reaction was less selective, giving a 5:2 mixture of 5b and 5b in 11% yield.…”

The Properties, Synthesis, and Materials Applications of 1,4-Dithiins and Thianthrenes

“…22 Bunte salt 21 serves as a more atom-efficient reagent for the generation of intermediate 19 via hydrolysis, as reported by Baker and Berkenbus (Scheme 5 ). 37 This method was found to be efficient and amenable to the gram-scale preparation of 1,4-dithiin 18 (R = Ph). 37 As described by Parham and co-workers, 2,5-dialkyl-1,4-dithiin 18 can be prepared by the dealkoxylation of dithiane 22 , though yields are typically poor (Scheme 5 ).…”

“…37 This method was found to be efficient and amenable to the gram-scale preparation of 1,4-dithiin 18 (R = Ph). 37 As described by Parham and coworkers, 2,5-dialkyl-1,4-dithiin 18 can be prepared by the dealkoxylation of dithiane 22, though yields are typically poor (Scheme 5). 38 Dithiane 22, in turn, can be produced from -thioacetal 23.…”