Rearrangements potassium acetate

The 1 //-2,3-benzodiazepines 7 rearrange to the 5//-tautomers 14 in the presence of potassium acetate or sodium ethoxide.134,136... 

It has been shown by Zanardi, Nanni and coworkers that, instead of isocyanides, isothiocyanates can be used in the radical process [90]. Treatment of the mixture of the diazonium tetrafluoroborates 3-217 and the isothiocyanates 3-218 with pyridine or a mixture of 18-crown-6 and potassium acetate in ethyl acetate, furnished the benzothienoquinoline derivatives 3-219. In addition, in some cases the rearranged products 3-220 were furnished in low to reasonable yields (Scheme 3.57). 

The decarboxylative Claisen rearrangement of allylic tosylacetate (5) and methyl tosylmalonate derivatives has been extensively studied. In the tosylacetate series, it has been found that acetate ions, base and a silylating agent, preferably N,0-bis(trimethylsilyl)acetamide (BSA), are all necessary, but in only catalytic quantities provided that BSA is used. Potassium acetate has been shown to be a suitable base. 

The retention times are 8.2 min for [Cl-(CH2)3]g(SiOi 5)5, 16.0 min for [Cl-(CH2)3],o(SiOi 5)10 and 37.4 min for [Cl-(CH2)3]i2(SiOi 5)12 at 7 mL min flow rate. The substitution of the chlorine atoms at octa [(3-chloropropyl)-silsesquioxane] by acetoxy- or cyano groups is possible by using potassium acetate or sodium cyanide and 18-crown-6 as phase transfer catalyst in acetonitrile. In addition to the observed substitution, partial rearrangement to the greater deca- and dodeca-silsesquioxane cages, also took place. 

A compound somewhat related to 902, the alcohol 905, has been isolated from peppermint and synthesized from 2,6-dimethyl-5,7-octadien-2-ol (called ocimenol by the authors). The action of peracetic acid on the latter gave the furan 906, and allylic rearrangement with phosphorus tribromide followed by replacement of the bromide with potassium acetate gave the ( ) + (Z) acetates of 905. ... 

CMseH reamuKements. Karanewsky and Kishi have reported that the BOnnal Claisen rearrangement of allyl aryl ethers can be effected in acetic anhydride and sodium or potassium acetate (130-200 ). 

Potassium acetate Ethylene derivs. from tosylates with ring rearrangement Hydroazulenes... 

Apparently the role of methanol is to intercept unstable species which otherwise tend to polymerize or rearrange. The methoxy peroxide (72) can be isolated in crystalline form if desired, but it is preferable to treat the methylene dichloride solution at 0° with zinc dust and acetic acid until the mixture shows a negative potassium iodide test. The resulting crude seco-aldehyde (73) is then cyclized to (74) by stirring with neutral alumina in benzene at room temperature for 3 hr. ° Wechter has recently reported a number of transformations of a 5yS-hydroxy-6yS-formyl-B-norpregnane prepared in 8% yield by photolysis and hydrolysis of a 5a-hydroxy-6 -azidopregnane. 

Only two general methods have been developed for the synthesis of the macrocyclic annulenes.9 The first of these, developed by Sondheimer and co-workers, involves the oxidative coupling of a suitable terminal diacetylene to a macrocyclic polyacetylene of required ring size, using typically cupric acetate in pyridine. The cyclic compound is then transformed to a dehydroannulene, usually by prototropic rearrangement effected by potassium i-butoxide. Finally, partial catalytic hydrogenation of the triple bonds to double bonds leads to the annulene. 

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