Dimethylformamide complex

The solid sulfone can be leciystallized, and the isopiene can be regenerated by heating the purified sulfone (45,46). With SO —DMF (dimethylformamide) complex, a six-membered ting can form the delta sulfone (47) ... 

In a 3-1. three-necked round-bottomed flask, fitted with a sealed stirrer, a dropping funnel, and a reflux condenser, is placed 80 g. (1.1 moles) of dimethylformamide (Note 1). The flask is immersed in an ice bath, and the internal temperature is maintained at 10-20°, while 169 g. (1.1 moles) of phosphorus oxychloride is added through the dropping funnel over a period of 15 minutes. An exothermic reaction occurs with the formation of the phosphorus oxychloride-dimethylformamide complex. The ice bath is removed, and the mixture is stirred for 15 minutes (Note 2). 

Aromatic aldehydes react rapidly with hippuric acid in the presence of a sulfur trioxide-dimethylformamide complex to form azlactones... 

A. N,N-Dimeihyljormamide-dimelhyl sulfate complex. In a 500-ml. four-necked flask equipped with mechanical stirrer, reflux condenser with calcium chloride drying tube, dropping funnel, and thermometer is placed 73 g. (1.0 mole) of dimethyl-formamide, and 126 g. (1.0 mole) of dimethyl sulfate is added dropwise with stirring at 50-60° (Note 1). After the addition is complete, the mixture is heated for another 2 hours at 70-80°. The dimethylformamide complex forms as a viscous, colorless or pale yellow ether-insoluble oil. 

Numerous workers have demonstrated the applicability of electrospray ionization mass spectrometry (ESI/MS) for the detection and analysis of biomolecules with highly electronegative groups (reviewed by Wood et al., 2003, and for neutral steroids by Higashi and Shimada, 2004). The sensitivity of detection of neurosteroids can also be enhanced by derivatization when they are analyzed by nano-electrospray/mass spectrometry procedures. Neurosteroid sulfates can be easily prepared in a single-step reaction in pyridine with the N,N-dimethylformamide complex of sulfur trioxide (Chatman et al., 1999). Another elegant... 

Detailed kinetic studies indicate that about 80% of the time isomerization goes via the solvento intermediate. But this is not a rate-determining solvolysis, rather a temporary diversion of the intermediate of a dissociative reaction. Watts 33) has recently prepared the dimethylformamide complex, [Co en2 DMF Cl]+2 and has shown that it cannot be an intermediate in the isomerization of cis- and trans-[Co en2 Cl2]+ in dimethylformamide. 

Amino-sulfonation of alkenes has been performed in a three-component reaction with S03-dimethylformamide complex (SO3 DMF) and acetonitrile followed by hydrolysis.912 Whereas amino-sulfonation occurs without the use of triflic acid, the acid accelerates the reaction considerably and prevents the formation of byproducts. The X-ray structure of intermediate 282 provided evidence that the addition is completely regio- and stereoselective [Eq. (5.338)]. 

A different approach to selective O-substitution involves preferential replacement of existing groups. When tris-0-(tert-butyldimethylsilyi)-D-glucal is treated with phosphorus oxychloride-dimethylformamide complex in pyridine, the 0-6 silyl ether is selectively and efficiently replaced by a formate ester (Vilsmeier-Haack reaction).85... 

A simple synthesis of 1,3,5-trichloro-l A4,2,4.6-thiatriazine (1) is by treatment of sodium or tetraalkylammonium dicyanamide with thionyl chloride.910 Originally, this reaction was described in 1970 and the product was thought to be jV -chloro-A/-(chlorosulfanyl)-/V-cyano-carboximidic chloride.60 The reaction is carried out with a great excess of thionyl chloride in the presence of a catalytic amount of dimethylformamide. The first reaction step consists of the formation of the thionyl chloride-dimethylformamide complex and reaction with the dicyanamide anion. The second step is a further sulfinylation with elimination of sulfur dioxide.32... 

Figure 8. X-ray crystal structure of meso-octamethylcalix[4]pyrrole-dimethylformamide complex, 1-2DMF. The calixpyrrole adopts a 1,2-alternate conformation. Crystal structure originally published in Allen, W. E. Gale, P. A. Brown, C. T Lynch, V. M. Sessler,). L. y. Am. Chern. Soc. 1996, 1/8, 12471. Diagram produced using data from the Cambridge Crystallographic Database.

Russo PS, Miller WG (1984) On the nature of the poly(Y-benzyl glutamate)-dimethylformamide complex phase . Macromolecules 17 1324-1331... 

Reticuline in dimethylformamide added to a soln. of FeClj-dimethylformamide complex, [Fe(DMF)3Cl2][FeClJ (s. Synth. Meth. 22, 895 suppl. 27), in the same solvent, stirred and refluxed 2 hrs. under Ng 7-hydroxy-6-methoxy-2-methyl-1,2,3,4-tetrahydroisoquinoline. Y 49%. M. Sivakumaran and K. W. Gopinath, Indian J. Chem. 14B, 138 (1976). 

Esterification.—iVAWW -Tetramethylchloroformamidinium chloride, which is readily prepared from iVAWW -tetramethylurea and oxalyl chloride, is an efficient reagent for the esterification of carboxylic acids with alcohols yields of between 66 and 97% are obtained, and the method has also been applied to macrolide synthesis. A modified one-pot procedure for the esterification of carboxylic acids, using phenyl dichlorophosphate-dimethylformamide complex, has appeared. A simple method of activation of carboxylic acids, using methanesulphonyl chloride and triethylamine followed by addition of the alcohol and 4-dimethylaminopyridine, leads to esters in 57— 96% yield for thirteen examples. 0-Methylcaprolactim reacts with carboxylic acids to give methyl esters in 73—91 % yield for seven examples and 2-iodoethyl esters are prepared from acyl chlorides, ethylene oxide, and sodium iodide. Transesterification, catalysed by titanium(iv) alkoxides, provides an effective method for synthesis of esters. Diethyl trichloromethylphosphonate reacts with carboxylic acids to give ethyl esters via transesterification, in 52 to 98 % yield. ... 

The easily prepared, stable solid reagent diphenylamine-borane (Ph2NH BH8) has been shown to be more reactive than aliphatic amine-boranes and almost as reactive as borane-THF for the reduction of ketones acids are also reduced to alcohols. Polyethylene glycols (PEG) catalyse the reduction of ketones by sodium borohydride under phase-transfer (PT) conditions, for example in solid-liquid PT with PEG as solvent. The solid zinc borohydride-dimethylformamide complex reduces aldehydes and ketones to alcohols, but only one hydrogen atom from each tetrahydridoborate unit is utilized. The different rates of reduction of various classes of ketone (saturated aliphatic faster than aromatic, and a -unsaturated very slow) suggest a possible selectivity between ketones. The corresponding cadmium complex, prepared in situ, reacts similarly. Lithium methylborohydride, LiMeBHj, prepared as shown in equation (1), where... 

Generally, the Vilsmeier reaction fails for benzene, alkylbenzenes and naphthalene. The reaction gives low yields in the case of phenol ethers if the para-position is already occupied and fails for highly substituted benzofurans, indicating that the presence of a sufficiently reactive (labile) hydrogen atom on the aromatic ring is necessary for successful application. However, Martinez et al. reported the formylation of 1,3,5-trimethylbenzene, naphthalene, acenaphthene, anthracene and phenanthrene in fair yield using the trifluoromethanesulphonic anhydride/dimethylformamide complex (Eq 1.29). 

R. C. Paul, S. Sharda, and B. R. Sreenathan, Indian J. Chem., 2, 97 (1964). Electrochemical studies of Lewis acids in dimethylformamide. Complexes studied SO3, tin (IV) halides, aluminum chloride, cadmium chloride and antimony (V) chloride. 

Other Preparations.—Carboxylic acids have been converted into aldehydes through di-isobutylaluminium hydride reduction of 3-acylthiazolidine or 2-thiazoline-2-thiol ester intermediates. Bis(triphenylphosphine)copper(l) tetrahydroborate, (Ph3P)2CuBH4, shows promise as a new reagent for the reduction of acid chlorides to aldehydes. The same conversion can be accomplished using sodium borohydride in a mixture of acetonitrile and hexamethyl-phosphoramide containing a cadmium(il) chloride-dimethylformamide complex. ... 

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