Pummerer

Milder conditions (SnC, room temperature) suffice for a-chloro-a-thio-methylacetanilides, implying that it is the ionization of the halogen that is the difficult step in the chloroacetanilide cyclization[18,19]. Pummerer conditions can also be used for the cyclization of a-sulfinylacetanilides[19,20]. 

Pumi cites B. pumilis Pummel test Pummerer reactions Pumpingnumber Pumpingnumbers Pumping speed Pumpkin... 

K. Drews, "Die technischen Ammoniumsalze," in Sammlung Chemischer and Chemischtechnisher Nortrage, Pummerer-Edangen, Enke, Stuttgart, Germany, 1938, 200 pp. 

Thermal Stability. Dimethyl sulfoxide decomposes slowly at 189°C to a mixture of products that includes methanethiol, formaldehyde, water, bis(methylthio)methane, dimethyl disulfide, dimethyl sulfone, and dimethyl sulfide. The decomposition is accelerated by acids, glycols, or amides (30). This product mixture suggests a sequence in which DMSO initially undergoes a Pummerer reaction to give (methylthio)methano1, which is labile and reacts according to equations 1—3. Disproportionation (eq. 4) also occurs to a small extent ... 

The reaction is quite general and usually results in 75—90% yields (47). All reactions in which a sulfoxide containing at least one a-hydrogen is reduced to the sulfide and also oxidized at the a-carbon ate referred to as Pummerer reactions (48). 

When DMSO is mixed with concentrated hydrochloric acid, protonated DMSO is in equiUbtium with the chlorodimethylsiilfonium ion. Pummerer reactions and subsequent reaction of the initial products give a complex mixture of products including formaldehyde, bis(methylthio)methane, methanethiol, dimethyl disulfide, dimethyl sulfide, and others. 

Natural chelidonic acid is obtained from the herb celandine Chelidonium majus). The synthesis from ethyl oxalate and acetone was first described by Claisen the process was simplified by Willstatter and Pummerer and further improved by Ruzicka and Fornasir.- The present procedure is modelled after that of the last-mentioned investigators. 

A new method for converting a C-20 carboxylic ester to the 21-acetoxy-20-keto group involves the use of the Pummerer reaction... 

Sharpless and Masumune have applied the AE reaction on chiral allylic alcohols to prepare all 8 of the L-hexoses. ° AE reaction on allylic alcohol 52 provides the epoxy alcohol 53 in 92% yield and in >95% ee. Base catalyze Payne rearrangement followed by ring opening with phenyl thiolate provides diol 54. Protection of the diol is followed by oxidation of the sulfide to the sulfoxide via m-CPBA, Pummerer rearrangement to give the gm-acetoxy sulfide intermediate and finally reduction using Dibal to yield the desired aldehyde 56. Homer-Emmons olefination followed by reduction sets up the second substrate for the AE reaction. The AE reaction on optically active 57 is reagent... 

Several groups have contributed pieces to the puzzle of how this reaction proceeds and understanding of the events that transpire has evolved with time. While on the surface, this reaction looks analogous to the Polonovsky reaction (5 —> 6) or the Pummerer... 

Application of Pummerer reaction in the synthesis of complex carbo- and heterocycles 97S1353. 

Pummerer-type rearrangements in synthesis of heterocycles 97YZ282, 98MI62. 

All of these ehimnddon reacdons contain fi-carbonyl groups in the nltro compounds Of course, masked carbonyl groups are also frequently employed for such fi-elimination of HNO, as shown in Eq 7131, Eq 7 133, and Eq 7 133In these cases, the sulfinylmethyl or hydroxymethyl group is converted into the carbonyl group by the Pummerer rearrangement or by simple oxidation... 

CF3CO-O-COCH3, (Pummerer Ac20, 2,6-lutidine rearrangement)... 

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