Derivative of amidine

A -Chloro derivatives of amidines, isoureas and guanidines react with potassium 5-methyl-cyanodithioiminocarbonate (266) to yield 2,5-substituted 3-amino-1,2,4-thiadiazoles (Equation (37))... 

Jordan reported that cationic aluminium alkyl derivatives of amidinates (3) [10] and aminotroponiminates (4) [11] are active in ethene polymerization. The amidinate system was later shown to be more complicated, and the nature of the active species remains unclear [14],... 

V-Chloro derivatives of amidines, isoureas and guanidines react with potassium 5-methyl cyanodithioiminocarbonate (320 R = Me) to yield thiadiazole systems of type (324 Scheme 114) (75BCJ310 73CL917). A related transformation occurs when the cyanothioiminocarbon-ates (322) and chloramine are allowed to condense at low temperature (76EGP119791). In this manner a variety of 5-substituted 3-amino-l,2,4-thiadiazoles (325) are obtained in good yields (Scheme 115). The use of ethoxycarbonylthioiminocarbonates (326) in this... 

N-organotin derivatives of amidine, ketimide, carbodiimide, troponeimide, hydrazine and 1,5-diorganotriazene are listed in Table 238. Metal derivatives with such entities may be found in Chapter. 5. ... 

Some oxygen free compounds originally listed in this chapter have been moved to Subchapter This includes derivatives of amidines ketimines and... 

Reactions. Although carbapenems are extremely sensitive to many reaction conditions, a wide variety of chemical modifications have been carried out. Many derivatives of the amino, hydroxy, and carboxy group of thienamycin (2) have been prepared primarily to study stmcture—activity relationships (24). The most interesting class of A/-derivatives are the amidines which are usually obtained in good yield by reaction of thienamycin with an imidate ester at pH 8.3. Introduction of this basic but less nucleophilic moiety maintains or improves the potency of the natural material while greatiy increasing the chemical stabiUty. Thus /V-formimidoyl thienamycin [64221-86-9] (MK 0787) (18), C 2H yN204S, (25) was chosen for clinical evaluation and... 

A major type of reaction in this class is the cyclization of 4-amino- or 4-halo-pyrimidines carrying 5-cyanoethyl or 5-ethoxycarbonylethyl groups, which cyclize to 7-amino or 7-oxo derivatives of 5,6-dihydropyrido[2,3- f]pyrimidine, e.g. (131)->(63). The intermediates may sometimes be prepared by reaction of 4(6)-aminopyrimidines with acrylonitrile, or even via a pyrimidine ring synthesis from an amidine and a cyanoacetic ester or malononitrile derivative, e.g. (132) -> (133) (7lJOC2 85, 72BCJ1127). 

The other main reaction in this class is the Dieckmann-type cyclization of the intermediates (163) from 4(6)-halo-5-ethoxycarbonylpyrimidines with AC-substituted /3-alanine esters and nitriles, and related compounds, to give 5,6,7,8-tetrahydro-5-oxopyrido[2,3-[Pg.221]

In the 1880s, Pinner found that the amidine derivative 2 reacted with acetoacetic ester (4) to furnish 2-substituted-6-hydroxy-4-methylpyrimidine 5. The condensation of amidine derivative 2 with other (l-keto esters, malonic esters, and (l-diketones proceeded similarly (see the following pages for examples). ... 

Substances of this type have hitherto received little attention. One of the reasons appears to be the limited possibilities of preparation. The only known method of preparation, described by Woolley et ai./ proceeds from the derivatives of 4-aminoimidazole-5-carboxylic acid. The amide of this acid (142) is treated with nitrous acid to yield 4-hydroxyimidazo [4,5-d]-i -triazine (2-azahypoxanthine) (143), the amidine (144) yielding the 4-amino derivative (2-azaadenine) (145) under the same conditions. 2-Azahypoxanthine was probably obtained in the same way earlier but was not identified. ... 

In warm acetonitrile 7-piperidino-3-trityl-3i/-azepine (22) rearranges in high yield to the isomeric 3//-azepine 23.64 The corresponding 2-(pyrrolidin-l-yl) and 2-morpholino derivatives behave similarly. Presumably, the gain of amidine resonance energy in tautomer 23 is the driving force behind this rearrangement. 

The chemistry of amidines and imidates The chemistry of cyanates and their thio derivatives (2 parts)... 

The structural investigations have been extended to potassium derivatives of the "super" formamidine HC(NC6H3Pr2-2,6)(NHC6H3Pr2-2,6) ( = HDippForm). Treatment of the free formamidine with KN(SiMe3)2 yielded the formamidinate species [K(DippForm)2K(THF)2l (THF) , which exhibits a macromolecular structure of alternating fj -arene f/ -amidinate bound potassium di-amidinate and potassium di-THF units in a one-dimensional polymeric array (Figure 5). Addition of a further equivalent of HDippForm afforded hydrogen-bonded [K(DippForm)(THF)3](HDippForm). ... 

Novel ruthenium-amidinate complexes of the type (j -CgHsRlRufamidina-te)X (R = Me, OMe, F X = Cl, Br, OTf) and [Ru(amidinate)(MeCN)4][PF6] have been synthesized by photochemical displacement of the benzene ligand in (j -CgHglRufamidinatelX by substituted arenes or MeCN. The acetonitrile ligands of [Ru(amidinate)(MeCN)4][PF6] are easily replaceable by other cr-donor ligands (L) such as pyridines, phosphines, and isocyanides to afford the corresponding derivatives [Ru(amidinate)(MeCN) (L)4 ][PF6] n — 1, 2). These reactions are summarized in Scheme 142. ... 

Scheme 6.4 Condensation of dihydroxyfumarate derivatives with amidines to pyrimidinone...

Quinazolines, the benzo derivatives of pyrimidines, were prepared in a variety of ways, from methods analogous to those for synthesizing pyrimidines to vastly different condensation schemes. In analogous fashion to many pyrimidine preparations, Yang and coworkers reported the condensation of polymer-tethered amidines 109 with cyclic anhydrides 110 to yield a library of 2-amino-4(3//)-quinazoIinones 111 after cleavage from the resin <00TL7005>. 

It is surprising that the quintet state for iron(II) is appreciably populated in the derivatives of the amidine system 65 (Dq(Ni2+)=1170 cm-1), despite the absence, in this instance, of any apparent steric barrier to coordination from substituents and the formation of five-membered chelate rings. 

This route was not applicable for the preparation of 2- and 4-nitrophenyl derivatives of 252 (R = 2-N02, 4-NO,), as the amidines obtained from 2-and 4-nitroanilines were not soluble in diethyl malonate (49JOC277). 

Amides [41,44], thioamides [41 ] and amidines [45] are converted into nitriles by the reaction with dichlorocarbenes generated by Makosza s procedure (Table 7.16). Under similar conditions, monosubstituted and A.A-disubstituted ureas are converted into cyanamides (Table 7.17) JV,(V -disubstituted ureas produce carbodi-imides in low yield [41,46,47]. /V-Carbamoyl derivatives of dibenzo[/ /]diazepines and the related 10, l l-oxirane derivatives are converted into the corresponding... 

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