Amidine and Guanidine Derivatives

6 Amidine and Guanidine Derivatives. - The amidine analogue 103 of methyl 6-O-mannosyl-a-D-mannoside has been synthesized and is an effective inhibitor of a-mannosidase (Kj=2.6 Four (deoxy)monosaccharide AT-benzylamidine 

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Little progress has been made in the field of Group 15 metal amidinate and guanidinate derivatives. Only very recently some exciting results have been reported which demonstrate that this area may hold some real surprises and merits further exploration. It was found that amidinato ligands are capable to stabilize novel amidodiarsenes. Reduction of the four-membered ring As(III)... 

Syntheses of this type are from urea, thiourea, and amidine and guanidine derivatives. Ureas give tetrahydro-l,3,5-triazin-2-ones on reaction with a primary amine (1 equiv.) and aqueous formaldehyde (2-30 equiv.). In general, alkyl and aryl amines, unsaturated amines, amino alcohols, and a-amino esters form triazinone derivatives (Equation (43)). Methyl and benzyl have proven to be the most useful urea substituents with respect to high yields and product solubility. N,N -Dicyclohexyl- and A,A -diphenyl-urea gave poor yields of triazinone <90TL2109>. 

M02N N N+M02 Figure 1.3 Amidine and guanidine derivatives with a vinylogous conjugation system... 

Decouzon, M., Gal, J.-R, Maria, R-C. and Racz3fnska, E.D. (1993) Superbases in the gas phase amidine and guanidine derivatives with proton affinities larger than 1000kJ moP Rapid Communications in Mass Spectrometry, 7, 599-602. 

In this section, medicinal amidine and guanidine derivatives are detailed. Amidines and guanidines also play important roles in medicinal chemistry in terms of the control of the basicity, high coordination ability and nitric oxide source. 

Amidine and Guanidine Derivatives - The A/-alkyl-D- ucosamidinium salts 63 have been synthesized by condensation of nojirimycin with the appropriate amine followed by oxidation with iodine. Amidine-linked pseudo-disaccharide 66 has been synthesized by reaction of the thionolactam 64 with the 6-amino-sugar 65 (Scheme 16), and a (l- 4)-linked analogue has been obtained similarly. ... 

The simplest [3 + 3] reactions in the pyridine series involve reaction of o-chloropyridinecarboxylic acid derivatives with three-atom fragments such as urea, thiourea(s), amidines and guanidines, e.g. (240) (241). Examples are known mainly in... 

Dinucleophilic amidines and guanidines can be condensed with aminomethylenediones to give pyrimidines (equation 210). In the case of cyclic diketo derivatives quinazolinediones are obtained284. 

Amidines and guanidines, 30 (1993) 206 Aminoadamantane derivatives, 18 (1981) 1 Aminopterins as antitumour agents, 25... 

Shortly after the successful synthesis and characterization of various lanthanide(III) tris(amidinate) derivatives the first disubstituted lanthanide(III) amidinate species were reported. Such compounds appeared to be interesting synthetic targets due to their metallocene-like coordination environment which was expected to allow the isolation and characterization of stable though reactive amide, alkyl, and hydride species. In this respect, the bulky amidinate and guanidinate ligands resemble... 

Polycyclic compound 478, which forms stable complexes with urea, guanidine, amidines and their derivatives, is covered by patents (1991USP15030728, 1994USP5283333). These complexes were used in a biological investigation. Receptor betaine molecule 479 was constructed for diagnostic tests for blood (serum) creatinine and renal insufficiency. 

With /V-acylthioamides the reaction proceeds very slowly and the products are difficult to purify. Therefore, the Af-acylthioamides 32 are first converted into the S -alkyl derivatives 33 by the reaction with alkyl halides under strongly basic conditions. The resulting A -acylthioimi-dates 33 react with amidines and guanidines in alcoholic solution in the presence of sodium alkoxide to form 2,4,6-trisubstituted 1,3,5-triazines 34 in moderate to good yields.438,439 This procedure is an extension of the synthesis of trisubstituted 1,3,5-triazines from A -acylimidates 17 and amidines (vide supra).325... 

Polysubstituted pyrimidines were synthesized from in situ generated a,p-unsaturated imines and the corresponding amidine or guanidine derivatives in a convenient one-pot procedure. It was proposed that the described transformations proceed via the initial formation of o,P-imsaturated imine that undergo nucleophilic attack by a bidentate nucleophile (amidine or guanidine). This step is then followed by elimination of ammonia and aromatization to yield the observed polysubstituted pyrimidine. 

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