Diimide dioxides

Grignard reagents have reacted with diimide dioxides prepared from nitrosohydroxylamines and with toluenesulfonyl derivatives of nitroso-hydroxylamines to prepare unsymmetrical azoxy compounds, including aliphatic-aromatic types. 

A method for the preparation of unsymmetrical azoxy compounds involves the reaction of certain diimide dioxides with Grignard reagents [5]. This reaction has somewhat limited applicability because the diimide dioxides which were used were prepared by alkylation of organonitrosohydroxylamines, a class of compounds of which cupferron is perhaps the best-known example. The reaction is, in effect, a reduction of a diimide dioxide to an azoxy compound by use of a Grignard reagent. The overall process is represented by Procedure 2-3. Since the starting materials are, in effect, unsymmetrically substituted nitroso dimers, extension of the reaction to nitroso dimers would be interesting. 

N,N-Dinitrosofumardianilide, 438 N,N -Dioxides, reduction of, 377, see also Nitroso dimers and Diimide dioxides 2,2 -Diphenyl-2,2/-azopropane, 323 Diphenylcarbodiimide, 166, 206, 211, 217-218... 

In another system recently proposed, the trans isomer of dimeric 1-chloro-2-nitrosocyclohexane would be called Dms-2,2 -dichloro-rra .y-azodioxy-cyclohexane [15,16]. In line with a system used in naming azoxy compounds, the dimers may also be named as diimide dioxides. 

Established methods for making 1,2,6-thiadiazines that have no 1,1-dioxide group include reactions of (i) sulfur diimides with malonyl chlorides and 1,3-diaminopropanes, (ii) sulfur dichloride with 1,3-diaminopropanes, and (iii) thionyl chloride with N.N-l,5-dinucleophiles such as 1,3-diaminopropanes or /3-amino a,/3-unsaturated aldimines and ketimines to give 5-oxides (79MI1 84MI1). 

Dialkylsulfur diimides can be reacted with thiophene dioxide 223 in the presence of triethylamine to yield intermediate 224, which may then be ring-closed with sodium methoxide to give 225 (84CB2779). 

Photoelectron spectroscopy studies indicate trimethylenesulfur diimide 205 may possibly take up chair and envelope (C4 at the flap) conformations (78ZN284). The benzo[4,5]thieno[3,2-c][lX6,2,6]thiadiazine-4-one 5,5-dioxides (225) exhibit blue fluorescence in long wavelength UV radiation (84CB2779). 

Disubstituted sulfur diimides react with oxalyl chloride to form the 1,1-dialkylthiadiazoles in high yield (72LA(759)107). Sulfamide also readily condenses with bifunctional electrophiles, a-diketones (68AHC(9)107, 70CRV593) and diethyl oxalate (75JOC2743), producing thiadiazole 1,1-dioxides. 

It has been suggested that, as an additional safety measure, methyl and ethyl azodicarboxylates be distilled at 0.1 -0.5 mm with a maximum oil bath temperature of 80°C. (S. C. Blackstock, Vanderbilt Department of Chemistry). Blackstock reports b.p 35-36oC/0.1 mm for dimethyl azodicarboxylate. Extreme care should be taken to maintain the pressure at or below that specified throughout the distillation. The receiver should be chilled in an ice bath. In addiiton, the drying step should be carried out very carefully since residual moisture will lead to hydrolysis during the distillation giving rise to diimide and carbon dioxide. 

Carbodiimides are a unique class of reactive organic compounds having the heterocumu-lene structure R—N=C=N—R. They can be formally considered to be the diimides of carbon dioxide or the anhydrides of 1,3-substituted ureas, and they are closely related to the monoimides of carbon dioxide, the isocyanates. The substituent R can be alkyl, aryl, acyl, aroyl, imidoyl or sulfonyl, but nitrogen, silicon, phosphorous and metal substituted carbodiimides are also known. The unsubstituted carbodiimide HN=C=NH is isomeric with cyanamide, H2NCN. Mono substituted carbodiimides, generated in the thermolysis of 1-substituted tetrazoles, can be isolated at liquid nitrogen temperature but isomerize to the cyanamides at higher temperatures. ... 

The alkyl-, alky laryl- and diarylcarbodiimides are the diimides derived from carbon dioxide, however, no direct formation of carbodiimides from amines and carbon dioxide is known. Interestingly, carbodiimides can be obtained from amines and carbon dioxide via a switteri-onic titanium complex (see Section 2.2.8). The major starting materials for the synthesis of carbodiimides are isocyanates, 1,3-disubstituted ureas or 1,3-disubstituted thioureas. The synthesis of isocyanates requires the use of the toxic carbonyl chloride or its oligomers. A book on the synthesis and reactions of isocyanates appeared in 1996. ... 

Carbodiimides are the diimides derived from carbon dioxide, and they are extensively used in the formation of peptide amide bonds from carboxylic acids and amines. This reaction was utilized by the Nobel laureate Sheehan in the total synthesis of penicillin. He also was the first to use water soluble carbodiimides to crosslink gelatin. Khorana, another Nobel laureate, demonstrated that carbodiimides can also be used in the synthesis of nucleotides. Today, carbodiimides are used extensively in the synthesis and modification of proteins. Proteomics is the new frontier of chemical research. 

The SN2 ion is isoelectronic with the thionylimide anion, NSO , and with sulfur dioxide, SO2. The frequencies of the three fundamental vibrations are 1198, 1001, and 528 cm . The salt K2[SN2] is an important reagent for the preparation of other sulfur diimide derivatives when Mes SiNSNSiMes is not sufficiently reactive. For example, both acyclic and cyclic arsenic(III) compounds, t-Bu2AsNSNAs-t-Bu2 and t-BuAs(NSN)2As-t-Bu, have been obtained in this way. 

In general, the acetylenic triple bond is highly reactive toward hydrogenation, hydroboration, and hydration in the presence of acid catalyst. Protection of a triple bond in disubstituted acetylenic compounds is possible by complex formation with octacarbonyl dicobalt [Co2(CO)g Eq. (64) 163]. The cobalt complex that forms at ordinary temperatures is stable to reduction reactions (diborane, diimides, Grignards) and to high-temperature catalytic reactions with carbon dioxide. Regeneration of the triple bond is accomplished with ferric nitrate [164], ammonium ceric nitrate [165] or trimethylamine oxide [166]. 

A route to the bicyclic dithiatriazines 3 consists of the reaction of an N = S = N unit, e.g. bis-silylated sulfur diimide, leading to exchange of the chlorine atoms in 5-substituted 1,3-dichlorodithiatriazines la25 and lb-d.24 Compound 3b was also formed in the reaction of 1,3-dichlorodithiatriazine lb with A trimethylsilylisulfmylaminc by spontaneous intermolecu-lar elimination of sulfur dioxide together with a folded bicyclic 3-chloro-AvV-dimethyl-124,3/l4,514-trithia-2,4,6,8-tetraazabicyclo[3.3.0]octan-7-aniine.18 24... 

BSD reacts (in ether or methylene chloride) with sulfur dioxide, (S02), sulfur imide oxides (sulfinylimines), RN=S=0 (R = SiMe3, Ph, PhS02), and sulfur diimides, RN=S=NR (R = Ph, Me3Si), in the same way [Eq. (110)] (X, Y = O, NR) with reduction of sulfur from oxidation state... 

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