Diimino compounds

In the compound described above, two acetoxyl radicals are probably added to the double bond between the two carbons linked to the two amino groups. Ejection of two molecules of acetic acid generates a diimino compound which reacts with other two acetoxyl radicals to cleave the ring and give a straight-chain dinitrile [21]. 

PYRAZINES FROM a, p-DIAMINO OR a,P-DIIMINO COMPOUNDS AND REAGENTS OTHER THAN a, p-DICARBONYL... 

Bredereck and Schmotzer (1044), from diaminomaleonitrile (DAMN hydrogen cyanide tetramer) and oxalyl chloride, prepared 2,3-dicyano-5,6-dihydroxy-pyrazine but Stetten and Fox (1049) could not prepare 23-diamino-5-hydroxy-pyrazine from glycine amide and oxamide. Section 11.3 lists preparations from a, -diamino or a, -diimino compounds and reagents other than a,0-dicarbonyl compounds (384) with additional data (1050) and oxidation of 23-dichloro-quinoxaline with hot aqueous potassium permanganate gave 23-dicarboxy-5,6-dihydroxypyrazine (1051). 

Section II.3 (384-386) contains some preparations from a,(3-diamino or a,/3-diimino compounds and reagents other than a,0-dicarbonyl compounds, and further information has been published (1050, 1154) Section II.4 records the oxidation of 2-acetamidoquinoxaline (408) to 5-acetamido-2,3-dicarboxypyrazine. 

The diimino compound shown below reacts readily with phosgene at 0 C to give a 1 1 adduct which has been assigned an imidazolidene structure [lS3a]. 

Alkylation of 3,5-diamino-4/f-l,2,6-thiadiazine 1,1-dioxide (94) with dimethyl sulfate furnishes a 2 1 mixture of the C-methylated (95) and C,A-dimethylated (96) derivatives <81JHC27> and not, as had been reported previously <70UKZ77>, the 2,6-dimethyl-3,5-diimino compound (97). Alkylations with benzyl chloride and with allyl chloride yield only the 4,4-dialkyl derivatives (98 R = PhCH2 44%) and (98 CH2==CHCH2 40%), respectively (Scheme 2) <8UHC27>. 

Thiurets — see 1,2,4-Dithiazolidines, diimino-Thonzylamine antihistamine, 3, 153 Thorpe reaction benzothiophenes from, 4, 876 Thorpe-Ziegler cyclization, 2, 74 Three-membered heterocyclic compounds basicity, 7, 23... 

Likewise, suitable starting materials are iminoisoindolines, especially diimino-isoindoline (l-amino-3-iminoisoindolenine), which reacts with a cyanoacetamide NCCH2CONHR5 to afford a mono-condensation product 49. Further reaction with a compound containing an activated methylene group (such as cyanoacetamide derivatives, barbituric acid) yields the desired pigment 47 ... 

The condensation of biguanide and cyanamide (which, in its diimino-form, may be regarded as the parent compound of carbodiimides (373)) has apparently not been studied. The patent literature (85,109) describes the manufacture of melamine by heating mixtures of biguanide or guanidine or their salts with cyanamide or dicyandiamide to 140—240°. but since each of these compounds alone yields melamine under these conditions, the course of these reactions is not clear. The only valid example appears to be the condensation of p-chlorophenylcyanamide and p-chlorophenylbiguanide to 2.4-di(p-chlorophenyl)melamine (304). 

A recent review on four-membered heterocycles formed from imino-phosphoranes concentrates on the preparation and the reactivity of 2,4-diimino-l,3-diazetidine and related compounds (93JPR305). As an example, the synthesis via bisiminophosphorane 85 is described in Scheme 42. The bisiminophosphorane has both a heteroaryl and a styryl site. From a mechanistic view, the reaction of the bisiminophosphorane proceeds with aryl isocyanate formation via an aza-Wittig mechanism. Intermediate car-bodiimide formation (86) occurs directly on the iminophosphorane moiety... 

This class of compound is represented by the dicyanoiodate(I) anion, involving a pseudohalide rather than an alkyl or aryl ligand. The linear ion, with I—C distance of 2.302 A, has been characterized in the compound K[I(CN)2]C6H12N202, resulting from reaction of an aqueous solution of KCN with an ethanolic solution of ICN. The diimino oxalic acid diethyl ester molecule apparently stabilizes the structure.56... 

Klyuev and Snegireva41 42 have prepared imino derivatives of 1,2-benzisothiazolines, including 1-imino-1,2-benzisothiazolinone (49) and l,3-diimino-l,2-benzisothiazoline (50). These compounds are formed by treating dithiosalicylic acid (47) with excess chlorine and reacting the product (48) with ammonia or urea. The same workers have also prepared a number of derivatives of these imino compounds.43, 44... 

This thinking applies, in particular, when planning the design of a chiral three-dimensional supramolecular host-guest system, since the mutual interaction of the two distinct complementary molecular units or coordination entities is necessary. Examples of this methodology include the above-described anionic, tris-chelated transition metal oxalato complexes [Mzl(ox)3/6 which form the host system together with the cationic, tris-chelated transition metal diimino complexes, e.g. [M(bpy)3]21/31, bpy = 2,2 -bipyridine, which play the role of the guest compounds. 

As the table shows, the amino substituents may contain two alkyl groups. Where Rj = H and R2 = C6H6, however, a product is obtained which is probably a 3,5-diimino-2,3-dithiacyclopentane (17).18 The basicity of this compound as compared with that of the tautomeric form (18) is so slight that protonation does not take place under the reaction conditions used, although a stable, sparingly soluble molecular compound is formed with picric acid. 

Koner, R., Lee, G, Wang, Y, Wei, H., and Mohanta, S. (2005) Two new diphenoxo-bridged discrete dinuclear Cu"Gd " compounds with cyclic diimino moieties syntheses, structrrres, and magnetic properties. European Journal of Inorganic Chemistry, 1500-1505. 

Tellurium tetrafluoride and tellurium tetrachloride reacted exothermically with N,N-bis[trimethylsilyl]acetamide and with A, A -bis[trimethylsilyl]arenesulfonamides in benzene to precipitate the corresponding diimino tellurium compounds. ... 

The most thoroughly studied compound of this class is A, A -dimethylaniline. The details of the anodic oxidation of 7V,7V-dialkylanilines are well documented [48]. If the r/ra-position of the aromatic ring is unsubstituted, tail-to-tail coupling via the intermediate cation radical under formation of the benzidines (Schemes 3 and 4, XIX) is dominating in acetonitrile or under acidic conditions. Benzidine, which has a lower oxidation potential than the starting material, is further oxidized to the corresponding quinoidal diimino dication. 

The unit present in these polymers, 1,5-diimino-3,7-dioxo-2,3,6,7-tetrahydro-(1H,5H)-2,6-benzo[1,2c 4,5c ]-dipyrrol-diyl, does not qualify these compounds as imides, but they also are discussed in this section. 

Formation of DCA derivatives could occur through a reductive coupling of an intermediate diimino moiety geometrically fitted to allow C-C bond formation to overcome. In this way this reaction could be compared with the pinacolic coupling for carbonyl compounds (scheme II)... 

The Wittig-type reactions of iminophosphoranes with isocyanates and related compounds have also been extensively used in heterocyclic synthesis. Examples include the preparations of the mesoionic [l,3,4]thiadiazolo[2,3-c][l,2,4]triazines (210) from (209), 0 bicyclic guanidines, e.g. (212), from (211), naphthypyridines (215), (216), and (217) from (213) and (214), 2 pyrido[l,2-f]pyrimido-[4,5-d)pyrimidines (218), 7H-pyrido-[4,3-c]- (219) and 10H-pyrido[3,4-b]- (220) carbazoles, tricyclic fused 2,4-diimino-l,3-diazetidines (222) from the bisiminophosphorane (221), benzotriazepines (225) from (223) and (224), 6 and mesoionic thiazolo-[2,3-b]-1,3,4-thiadiazoles (227) and N,N-bisheteroarylamines from the iminophosphorane (226), derived from 3-amino-4-phenylthiazole-2(3H)-thione. The carbodiimides (229), prepared from the iminophosphorane (228), can be converted into quinolines or a-carboline derivatives depending on the nature of the isocyanate used in the reaction with (228) and the reactions of iminophosphoranes (230) and (231) with aryl and styryl isocyanates provide one-pot syntheses of quinoline, a-carboline, and quinindoline derivatives. 9... 

Further examples have been reported of the addition of nucleophiles to the l,2 5,6-diimino-L-iditol derivative 48 resulting in 6-amino-2,5-imino-D-glucitol or 6-amino-1,5-imino-D-mannitol derivatives depending on whether the primary or secondary carbon of the 1,2- or 5,6-imino group in 48 was attacked. The same compound, 48, also served as starting material for 2,S-dideoxy-2,5-imino-D-glucitol. (See Vol. 23, p. 231, refs. 48 and 49). 

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