Dimethylformamide treatment

Tokuyama and coworkers138,139 reported the displacement, with the thiocyanate ion, of the p-toluenesulfonate group in 2,3 4,6-di-0-isopropyl-idene-l-O-p-tolylsulfonyl-a-L-sorbofuranose (337) and 2,3-O-isopropyl-idene-l,6-di-0-p-tolylsulfonyl- -L-sorbofuranose (341) in liquid ammonia, as well as in N,N-dimethylformamide. Treatment of 337 with potassium... 

Nitroalkanes can be converted to carbonyl compounds in acceptable yields using vanadium(ii) chloride in aqueous dimethylformamide. Treatment of nitroalkanes with acylcarbonylferrate(o) gives a new synthetic route to amides. JViV -Disub-stituted ureas have been prepared, by the same workers, from nitroalkanes (and arenes), bromomagnesium alkylamides, and pentacarbonyliron. The catalytic hydrogenation of nitrosoalkane dimers is a useful route to symmetrical azoxy-alkanes. ... 

Amino-5-nitrothiazole, on treatment with arenesulfonyl halides and dimethylformamide at 140 C, gives (5-nitro-2-thiazolyl)amidme (274) (Scheme 168) (507, 508). The condensation products of the reaction of 2-aminothiazole derivatives with various aldehydes are grouped in Tables... 

Further versatihty was added to the range of substituents available for introduction into the 6a-position by use of the 6a(succinimido-oxy) derivative (18) prepared by treatment of the 6a-(methylthio) derivative (17) with A/-hydroxy-succinimide and silver(I) acetate in dimethylformamide in virtually quantitative yield. In this way the 6a-cyanopeniciILin (19, X = CN), 6a-viny1penici11in (19, X = CH=CH2) and 6a-pheny1penici11in (19, X = C H ) could be prepared in high yield (43). 

Cellulose dissolved in suitable solvents, however, can be acetylated in a totally homogeneous manner, and several such methods have been suggested. Treatment in dimethyl sulfoxide (DMSO) with paraformaldehyde gives a soluble methylol derivative that reacts with glacial acetic acid, acetic anhydride, or acetyl chloride to form the acetate (63). The maximum degree of substitution obtained by this method is 2.0 some oxidation also occurs. Similarly, cellulose can be acetylated in solution with dimethylacetamide—paraformaldehyde and dimethylformamide-paraformaldehyde with a potassium acetate catalyst (64) to provide an almost quantitative yield of hydroxymethylceUulose acetate. 

Sodium or potassium hydrogen sulfite reacts with several thiiranes to give disulfides of /3-mercaptosulfonic acid salts (76EGP122086). Potassium thiocyanate in dimethylformamide or aqueous ethanol isomerizes thiiranes (Scheme 84) (72CJC3930). 1,2-Dithiols are obtained by treatment of thiiranes with NaBH2S3 obtained from sodium borohydride and sulfur (73TL1401). 

Base catalyzed pinacol rearrangement of vicinal m-glycol monotosylates is a simple and useful general method for preparing perhydroazulenes. Thus, treatment of cholestane-5a,6a-diol 6-tosylate (115a) with either one mole-equivalent of potassium t-butoxide in f-butanol at 25° or with calcium carbonate in dimethylformamide at 100° gives a quantitative yield of 10(5 6/5H)... 

Similarly, androstane-5a,6a,17)S-triol 6-tosylate 17-benzoate (115b) is converted to 17)S-hydroxy-6)S-methyl-10(5 6)SH)flZ)en-androstan-5-one benzoate (116b) on treatment with calcium carbonate in dimethylformamide. Similar treatment of 10-methyldecalin-l,9-diol 1-tosylate (121) gives 10-methylbicyclo[5.3.0]decan-l-one (122). 

Random incorporation of two different acetoacetates can also be avoided by converting one of the acetoacetates to a derivative which carries the future pyridine nitrogen. For example, treatment of ethyl acetoacetate with ammonia gives the corresponding P-aminocrotonate 32. The aldehyde (34) required for preparation of such an unsymmetrical compound is prepared by reaction of the product from direct metallation of 33 with dimethylformamide. Condensation of that aldehyde with methyl acetoacetate and the p-aminocrotonate from isopropyl acetoacetate leads to isradipine (35) [9]. The same aldehyde with ethyl acetoacetate and the P-aminocrotonate from ethyl acetoacetate gives darodipine (36) [10]. In much the same vein, condensation of the ben-zaldehyde 37 with methyl acetoacetate and its P-aminocrotonate derivative affords riodipine (38) [11]. 

Ncold water (400 ml) and stirred until the precipitated product turned granular (fifteen minutes). The crude product was collected, washed with cold water, and dried. Crystallization from Skellysolve B with charcoal treatment gave colorless crystals (6.65 g, 58%), MP 149°C to 150°C. The product was recrystallized twice from Skellysolve B to give ( )-6[Pg.355]

After this reaction-time, the evolution of hydrogen is ceased. Then there are added successively 60 parts dimethylformamide and 8 parts of p-chlorobenzylchloride and stirring and refluxing is continued for another two hours. The tetrahydrofuran is removed at atmospheric pressure. The dimethylformamide solution is poured onto water. The product, 1-[2,4-dichloro-/3-(p-chlorobenzyloxy)phenethyl] imidazole, is extracted with benzene. The extract is washed with water, dried, filtered and evaporated in vacuo. From the residual oily free base, the nitrate salt is prepared in the usual manner in 2-propanol by treatment with concentrated nitric acid, yielding, after recrystallization of the crude solid salt from a mixture of 2-propanol, methanol and diisopropylether, 1-[2,4-dichloro-/3-(p-chlorobenzyl-oxylphenethyl] imidazole nitrate MP 162°C. 

Dimethy/su/famy/thioxanthene To a slurry of dry sodium thioxanthene-2-sulfonate (33.3 grams, 0.111 mol) in 50 ml of N,N-dimethylformamide was added thionyl chloride (14.3 grams, 0.122 mol) in divided portions. An exothermic reaction ensued with complete dissolution being effected in minutes. Treatment of the reaction mixture with crushed ice precipitated a gum which crystallized after a short period of stirring. The sulfonyl chloride was filtered, washed with water, and stirred with 100 ml of liquid dimethylamine. 

The fact that these kinds of chemical reactions occur during the processing were further demonstrated by the testing of the insoluble material in the blends. The data showed that after dimethylformamide (DMF) treatment and after processing, the solubles significantly increased, It also showed that the insoluble content is also related to the TPU content in the blending system. It peaks at the TPU content of 15%-20%, after which the amount drops dramatically. Accordingly, the mechanical properties of the material also showed the same trend. 

Thermal treatment and the nature of the casting solvent can also affect the deformation modes achieved in strained films of ionomers. For example, in films cast from polar dimethylformamide (DMF), the solvent interacts with ion-rich clusters and essentially destroys them, as is evident form absence of a second, higher temperature loss peak in such samples. As a result, even in a cast DMF sample of Na-SPS ionomer of high ion content (8.5 mol%), the only deformation mode observed in tensile straining is crazing. However, when these films are given an additional heat treatment (41 h at 210°C), shear... 

It is of interest to note that treatment (23) of the 2,3-unsaturated analog 44 with sodium benzoate in 2V,N-dimethylformamide affords compounds 45 and 46 (3 1) with inversion at C-4. The selective formation... 

The reaction has been extended (106) to the nucleoside field and provides a means for the direct iodination of suitably protected nucleosides. Thus treatment of 2,3-O-isopropylidene uridine (68) with tri-phenylphosphite methiodide in N,2V-dimethylformamide at room temperature afforded the corresponding crystalline 5-deoxy-5-iodo analog 69 in 77% yield. 

Tin phthalocyanines can be prepared using tin(II)110 or -(IV)154 chlorides. The reaction can be performed in 1-chloro-1 10,1 37,1 55 or 1-bromonaphthalene,154 starting from phthalonitrile110137154,155 or phthalic anhydride. In the second case, urea and ammonium molyb-date(VI) arc added.137 The central tin atom can also be introduced into metal-free phthalocyanine by the reaction with tin(IV) chloride in dimethylformamide.141 Treatment of PcSnCl2 with disodium phthalocyanine in refluxing 1-chloronaphthalenc forms a sandwich-like bis-(phthalocyanine) Pc2Sn.154... 

Nucleophilic processes that generate chloroindoles are largely confined to the displacements of oxy functions and Sandmeyer reactions of diazo-nium salts [81 H( 15)547]. A low yield of 2-chloroindole was obtained by a reaction sequence that involved treatment of oxindole with phosphoryl chloride, and then treatment of the Vilsmeier salt with sodium bicarbonate [66JOC2627 86H(24)2879]. It is, however, much better to prepare this compound from 2-lithioindole (92JOC2495). With phosphoryl chloride and dimethylformamide ethyl l-hydroxyindole-2-carboxylate failed to give the expected 3-formyl derivative. Instead there was a 50% yield of the 3-chloro derivative (84CPB3678). Diazonium salts have been used as precursors in... 

Treatment of 6-(2 -furanyl)imidazo[2,l-b]thiazole (65) with bromine in chloroform gave rise to products of bromination of both furan and imidazole moieties (80MI1). In the unsubstituted imidazothiazole, bromination in dimethylformamide at 80°C, or in dichloromethane at 0°C, occurred in the 5-position. Even when there are such reactive groups as 2 -furanyl or... 

When D-fructose and L-sorbose are refluxed with aqueous HC1, dihexulose dianhydrides are formed.91 If the water is replaced by N./V-dimethylformamide, substantially increased yields are obtained and 1,2-linked disaccharides are detected. Higher yields of dianhydrides were obtained from fructose, rather than sorbose, under comparable conditions. Treatment of levan with dilute H2S04 at 60°C yielded92 a-D-Fru/-l,2 2,1 -fi-D-Fru/(5). Presumably, any products that contain 2,6-linkages with large central rings would rapidly isomerize to the more stable 1,2-linked product. 

Treatment of dibromides 2 with sodium azide in N,N-dimethylformamide (DMF) at room temperature resulted in the formation of two products, 3-(a-azidobenzyOchromones 2a-c,g or -1-thiochromones 2d-f and the 3-arylidenechromanones la-c,g,h or -1-thiochromanones Id-f, respectively (eqn. 2). As shown by yield data given in Table 2, the substituent at position 2 plays decisive role in the product ratio. Dibromides unsubstituted at position 2 tended to give almost exclusively azides 3a-f and only a small amount of 1 was obtained. On the contrary, the reaction of flavanone derivatives 2gjh gave 3-arylideneflavanones... 

Phenols and primary alcohols form ethers when heated with dicyclohexylcarbo-diimide (DCC see 10-23). 1,2-Diols can be converted to epoxides by treatment with dimethylformamide dimethyl acetal, (MeO)2CHNMc2, with diethyl azodi-carboxylate, EtOOCN=NCOOEt, and Ph3P with a diaUcoxytriphenylphospho-rane, ° or with TsCl-NaOH-PhCH2NEt3+ CP. ... 

Note It is reported that the use of chlorobenzene as solvent is essential when the reagent is to be used to detect aromatic amines [1]. In the case of steroids, penicillins, diuretics and alkaloids the reaction should be accelerated and intensified by spraying afterwards with dimethylsulfoxide (DMSO) or dimethylformamide (DMF), indeed this step makes it possible to detect some substances when this would not otherwise be possible [5,9-11] this latter treatment can, like heating, cause color changes [5,9]. Penicillins and diuretics only exhibit weak reactions if not treated afterwards with DMF [10, 11]. Steroids alone also yield colored derivatives with DMSO [9]. Tlreatment afterwards with diluted sulfuric acid (c = 2 mol/L) also leads to an improvement in detection sensitivity in the case of a range of alkaloids. In the case of pyrrolizidine alkaloids it is possible to use o-chloranil as an alternative detection reagent however, in this case it is recommended that the plate be treated afterwards with a solution of 2 g 4-(dimethyl-amino)-benzaldehyde and 2 ml boron trifluoride etherate in 100 ml anhydrous ethanol because otherwise the colors initially produced with o-chloranil rapidly fade [12]. 

Ref. 616) was prepared from the per-ALtosyl-3 -0-sulfonylkanamycin B derivative 686, after conversion into the 2, 3 -ALtosylepimine 687 (with NaOMe in MeOH), by treatment with KHF2 in 7V,A -dimethylformamide (DMF 150°, 2 h, giving the 3 -deoxy-3 -fluoro derivative 688 in 60% yield). 

The present approach has been applied to the experiment done by Nelsen et ah, [112], which is a measurement of the intramolecular electron transfer of 2,7-dinitronaphthalene in three kinds of solvents. Since the solvent dynamics effect is supposed to be unimportant in these cases, we can use the present theory within the effective ID model approach. The basic parameters are taken from the above reference except for the effective frequency. The results are shown in Fig. 26, which shows an excellent agreement with the experiment. The electronic couphng is quite strong and the perturbative treatment cannot work. The effective frequencies used are 1200, 950, and 800 cm for CH3CN, dimethylformamide (DMF), and PrCN [113]. 

A New Improved Synthesis of Tricycle Thienobenzazepines Apphcation of chemistry recently developed by Knochel" combined with the well-described halogen dance (HD) reaction, allowed preparation of our key intermediate A in only three synthetic transformations (Scheme 6.4). In this respect, treatment of 2-bromo-5-methylthiophene with hthium diisopropylamide followed by dimethylformamide afforded aldehyde 11 in good yield, lodo-magnesium exchange with conunercial 4-iodo-3-nitro anisole followed by reaction with 11 afforded the thiophene catbinol 12. Dehydroxylation of 12 provided our key intermediate A which presented the requisite functionality to examine our approach to the construction of the seven-member ring system. 

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