Are α‐Oxothioacyl Chlorides Formed in the Reaction of Methyl Ketones with Thionyl Chloride?

Abstract

The answer to the question posed in the title is no; thus, previous claims in the literature have to be corrected. Work in this field has led to the new class of O‐alkyl α‐oxothiocarboxylates.

A study of the Willgerodt–Kindler reaction to obtain thioamides and α-ketothioamides under solvent-less conditions

“…Other published routes to a-ketothioamides have employed a-chloroketones, 14 a-oxonitryl, 15 thioacetomorpholides, 16 pinacolone (3,3-dimethyl-2-butanone), 17 a-chlorosulfonyl and trisulfane intermediates, 18 or N,N-(dialkyl)aroylmethylamines. 19 However, like the Willgerodt-Kindler reaction, these methodologies are not general for the synthesis of aketothioamides.…”

One-Step Conversion of Methyl Ketones to Acyl Chlorides

“…For instance, treatment of acetophenone or pinacolone with ten equiv of thionyl chloride in the presence of a catalytic amount of pyridine, followed by distillation, gave low yields of the corresponding acyl chlorides (Scheme 2). 9,10 Reaction of Aromatic Methyl Ketones with Thionyl Chloride. The yield of the reaction in Scheme 2 could be improved by treating methyl ketones 2 with 4−6 equiv of thionyl chloride first at 60−75°C for some hours, and then at 140°C for 15−20 h, while allowing volatiles to evaporate off (Scheme 3).…”

Reactions of thionyl chloride with C-methyl heterocycles. Part 1. The formation of dichloro(2-quinolyl)methanesulphenyl chlorides from 2-methylquinolines

“…Pinacolone, for example, gives the x-chlorosulphenyl chloride (Me,CCOCH-Cl-SCl) (50%) and a trisulphane [(Me,CCOCCl,S),S] (40%). 4 We propose that further reaction of the intermediate (4) with thionyl chloride gives, after loss of hydrogen chloride, the Nchlorosulphinyl enamine (5). Elimination of sulphur monoxide (5) -(2a) in a process analogous to the formation of amonochloro ketones uia enol-sulphinylation of ketones then gives the observed product (2a).…”

“…C14H,,N,S requires C,68.8;H,6.6; N, 11.5; S, 13.1%); vmax. 1430, 1 500, 1 510, and 2 985 cm-'; 6, 1.24 (t, J 7 Hz, CH,Me), 1.45 (t, J 7 Hz, CH,Me), 3.50 (9, J 7 Hz, CH,Me), 4.16 (4,J 7 Hz,CH,Me),4 ArH), and 8.00-8.24 (m, 2 ArH); 2-[(morpholino)thiocarbony/-Jquinoline (7d) (0.5 g, 24%), yellow solid, m.p. 172-1 74 " C (Found: C,65.4;H,5.61;N,10.8;S,12.3.…”