Navigation

0 Hits

  • Previous / Next

You are using Science Of Synthesis as a Guest. Please login or sign up for a free trial to access the full content.
27.8.1.15.3 Variation 3: Of Carbonyl Compounds

DOI: 10.1055/sos-SD-027-00291

Abbaspour Tehrani, K.; De Kimpe, N.Science of Synthesis, (200427341.

When ketones which have one α-methylene group are treated with N-(chloromethylene)-N,N-dimethylammonium chloride, 3-chloroprop-2-eniminium salts are obtained (e.g., iminium perchlorate 104 from acetophenone, Scheme 33).[‌160‌,‌161‌] The reaction is general for ketones but also works with aldehydes, which react more slowly. Ketones with two α-methylene groups can react with the Vilsmeier reagent several times.[‌162‌] Similar reactions can be performed with α,β-unsaturated aldehydes and ketones.[‌163‌] The reaction of 2 equivalents of N-(chloromethylene)-N,N-dimethylammonium chloride with carboxylic acids gives 3-(dialkylamino)prop-2-eniminium salts.[‌164‌,‌165‌] During the reaction carbon dioxide is formed. Simple aliphatic carboxylic acids do not react well with the Vilsmeier reagent unless they are substituted with a chloro, amino, aryl, or carboxyl group. Thus, substituted malonic acids 105 give 3-aminoalk-2-eniminium salts 106,[‌166‌,‌167‌] while malonic acid itself (105, R1=H) undergoes a triple reaction to give bis(iminium) perchlorate 107 (Scheme 33).[‌168‌] The reaction of bromoacetic acid with phosphoryl chloride/dimethylformamide gives the bis(iminium) salt of triformylmethane, 2-(dimethylamino)methylene-1,3-bis(dimethyliminio)propane dichloride.[‌169‌] Initially, this compound has been isolated as the bis(perbromide)[‌170‌] or bis(perchlorate), but for reasons of safety and better solubility in water it has been converted into the bis(fluoroborate) salt.

Meeeee 88 Meeeeeee ee eee Meeeeeeee Meeeeee eeee e Meeeee eee eeee Meeeeee Meeee[‌888‌,‌888‌,‌888‌]

Meeeeeeee ee eee eeeeeeee ee eeeeeee eeee M-(eeeeeeeeeeeeeee)-M,M-eeeeeeeeeeeeeeee eeeeeeee, eeeeeeeeeeee eeee ee α-eeeeeeeee eeeee eeee 8-eeeee-eeeeeeeeeee 8-eeeeeeeeeeeeeeeeeee eeeee.[‌888‌]

Meeeeeeeeeee Meeeeeeee

M,M-Meeeeeee-8-eeeeee-8-eeeeeeeeee-8-eeeeeeeee Meeeeeeeeee (888); Meeeeee Meeeeeeee:[‌888‌]

MMMMMMM: Meeeee eeeeeeeeee eeeeeeee eeee eeeee eeeeeee ee e eeeeeee, eeeeeeeeee eeeeeeeeee, eeeee eeeeee eeeee ee eeeeeeeee eeeeee. Meeeeeeeee eeeeeeee eeeee eeeeeeee eeeeeeeee eee eeeeee eeeeeeeee eee eeeeeeeeeee eeeee. Meeee eee eeeeee eee eeeeeeeee ee eeeeeee eeee eee eeee.

MMM (88.8e, 8.8eee) eee eeeee eeeeeeee eeee MMMe8 (88.8e, 8.88eee) ee eeee e eeee eeee eee eeeeeeeeeee eee eee eeeeee 88°M. Meeee eeeeeeee eee 8e ee 88°M, eeeeeeeeeeee (88.88e, 8.8eee) eee eeeee ee eeee e eeee eeee eee eeeeeeeeeee eee eeee eeeeeee 88 eee 88°M. Me eeeee ee eeeee eee eeeeeeee, eeeeeee eee eeeeeeeee eeeeeeeee. Meeee eeeeeeee eee 8e ee 88°M, eee eeeeeee eee eeeeeeeee eeee eeeeeee ee MeMM ee MeMM (888eM). Meee eeeeeeee ee 88% ee MeMeM8, Me(MeM8)8, ee MMeM8 (88eM), eee eeeeeee eeeeeeeeeee eeeeeeeeeeee. Meee eee eeeeeeeee ee eeeeeeeeee, eeeeee eeee eeeeeee, eee eeeeeeeeeeeeee (MeMM); eeeee: 88.88e (88%); ee 888888°M.

References