Dimethylformamide acetal

Reductive Gyclizations. The Batcho-Leimgmber protocol involves condensation of an o-nitrotoluene with a dimethylformamide acetal to form a P-( nitrophenyl)enamine (27). A reducing agent then affects the reductive cycli2ation to an indole. 

In 1970, it was disclosed that it is possible to achieve the conversion of dimethylformamide cyclic acetals, prepared in one step from vicinal diols, into alkenes through thermolysis in the presence of acetic anhydride." In the context of 31, this two-step process performs admirably and furnishes the desired trans alkene 33 in an overall yield of 40 % from 29. In the event, when diol 31 is heated in the presence of V, V-dimethylforrnamide dimethyl acetal, cyclic dimethylformamide acetal 32 forms. When this substance is heated further in the presence of acetic anhydride, an elimination reaction takes place to give trans olefin 33. Although the mechanism for the elimination step was not established, it was demonstrated in the original report that acetic acid, yV, V-dimethylacetamide, and carbon dioxide are produced in addition to the alkene product."... 

The Batcho indole synthesis involves the conversion of an o-nitrotoluene to a (3-dialkyl-amino-o-nitrostyrene with dimethylformamide acetal, followed by reductive cyclization to indoles. This provides a useful strategy for synthesis of substituted indoles (Eq. 10.49).63... 

The use of ISEs in non-aqueous media(for a survey see [125,128]) is limited to electrodes with solid or glassy membranes. Even here there are further limitations connected with membrane material dissolution as a result of complexation by the solvent and damage to the membrane matrix or to the cement between the membrane and the electrode body. Silver halide electrodes have been used in methanol, ethanol, n-propanol, /so-propanol and other aliphatic alcohols, dimethylformamide, acetic acid and mixtures with water [40, 81, 121, 128]. The slope of the ISE potential dependence on the logarithm of the activity decreases with decreasing dielectric constant of the medium. With the fluoride ISE, the theoretical slope was found in ethanol-water mixtures [95] and in dimethylsulphoxide [23], and with PbS ISE in alcohols, their mixtures with water, dioxan and dimethylsulphoxide [134]. The standard Gibbs energies for the transfer of ions from water into these media were also determined [27, 30] using ISEs in non-aqueous media. 

An analogous scheme is used to prepare a more highly nitrogenated compound. Thus, reaction of acylpyridine (22-1) with dimethylformamide acetal gives enamide (22-2). Condensation of that with the somewhat more complex pyrrazole (22-3) leads to the soporihc agent ocinaplon (22-4) [23]. 

The pyrido[l,2-a]pyrimidine (63 R = H) gave the 3-anilinomethylene derivative of type 224299 with ethyl iV-phenylformimidate, and it gave the bis compound (225) with triethyl orthoformate in a dimethylformamide-acetic acid mixture.300 The exact structure of 225 has not been elucidated. 

Methyl formate is expected to be one of the intermediates of the methanol-based industries that produce dimethylformamide, acetic acid, pure hydrogen, carbon monoxide, etc. A number of patented catalysts (J8) are therefore composed of copper oxide as a main ingredient and include a variety of metal oxide additives. In our comparative studies, some of these catalysts exhibit fairly good activity but do not exceed Cu " -TSM in activity and selectivity (26). The results of the reactions over these patented catalysts, which have relatively high performance levels, are illustrated in Fig. 4 together with the result obtained with Cu -TSM the yield of methyl for-... 

For the preparation of salts of type (7 j-m), also, the corresponding dimethyl-aminovinyl ketones can be used, and they are transformed as described for the 3-dimethylaminoacraldehydes. The condensation of dimethylformamide acetals... 

The use of N,N -dimethylformamide acetals makes it possible to obtain esters of organic acids ... 

INDOLES FROM 2-METHYLNITROBENZENES BY CONDENSATION WITH N,N-DIMETHYLFORMAMIDE ACETALS AND REDUCTION... 

Long-chain alkylphenolic acids and their derivatives have been separated on silica gel G by eluting with light petroleum (60-80°C)-ethyl ether-dimethylformamide-acetic acid (75 85 5 1). 

Fohlisch reported in 1971 the use of enaminones derived from the reaction of dimethyIformamide acetal with the methyl group of acetophenones in a convenient synthesis of chromanones (12). It was found that upon refluxing o-hydroxyacetophenone in the presence of dimethylformamide acetal and xylene, with continuous removal of the methanol formed in the reaction, an 80% yield of the intermediate enaminone 12 was obtained. Treatment of 12 with dilute acid then gave the desired chromanone 13 in 71% yield. Thus, to utilize this reaction in our synthesis of dihydropyrano[2,3-b]pyridines, the acetyl-pyridone 15 was chosen as our starting compound. 

Carboxylic acid esters and phenolethers from carboxylic acids and phenols respectively with dimethylformamide acetals... 

However, the addition of isothiocyanates across single bonds generally proceeds with insertion of the C=N bond of the isothiocyanate into the single bond. The insertion into a C-N single bond in formaldehyde aminals is a typical example. lV,A -Dimethylformamide acetals react in a similar manner . The reaction of metalorganic substrates with isothiocyanates was first observed by Bloodworth and Davies in 1963 . The authors obtained a 1 1 adduct 79 from tributylmethoxy tin and phenyl isothiocyanate. 

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