Amidines acylamidines

A convenient synthesis of trisubstituted 1,3,5-triazines uses acylamidines 1 and amidines < 95JOC8428 >, whilst l,3,5-triazin-2(l/f)-ones 3 are obtained from N-acyl-lV -carbamoyl-S-methylisothioureas 2 <96H(43)839>. 

Cyclizations of acylamidines 720 with amidines 721 or guanidines in aprotic solvents give -triazines 722 bearing three different substituents (Scheme 309) <1995JOC8428>. 

Triazines 5 with three different 2,4,6-substituents are conveniently prepared by cyclocondensation of acylamidines 4 with amidines [172]. Acylamidines result from amides and amide acetals. 

Gold s reagent"), the preparation of which is described in part A of the procedure, is a general 6-dimethylaminomethylenating agent which reacts successfully with amines (eq. 1) to produce amidines, with ketones (eq. 2) to produce enaminones, and with amides (eq, 3) to product acylamidines. ... 

Cyclizations of acylamidines 180 with amidines 181 or guanidines 182 in aprotic solvents gave r-triazines 183 bearing three different substituents (Scheme 26) <1995JOC8428>. 

The above water-elimination reaction results in formations of amidines. Acylamidinium ions can also result from dehydration of the tetrahedral intermediates during the reactions of amino groups with acyllactams. Such groups could also be present within the polymer molecules. The water that is released in these reactions hydrolyzes the acyllactams, acylamidine salts, and lactam salts to yield carboxylic acids. ... 

Copper salt catalyzed G-insertion of isonitriles, CO, or diazo compounds into NH-bonds of amines gives good yields of form-amidines, formamides, or N-alkylated products respectively Recently, the analogous C-insertion of isonitriles into OH-bonds of alcohols has been reported . A variety of compounds, otherwise difficult to obtain, such as certain carbodiimides, acylamidines, or isonitriles, can be prepared by H2S-elimination with acylchloro-formamidines . 

Furthermore, polymer amide and imide (diacylamines) groups may undergo reaction with terminal NH2 as well, according to the same reaction pathways depicted in Schemes 8 and 9, respectively. The result is the formation of amidine and acylamidine structures (24 and 25) inside the polymer chain, representing points of branching ... 

In addition, irrespective of the fact that polymerization has started under anhydrous conditions, water is always generated during amidine formation. Water may give rise to hydrolytic reactions, in particular with acyl lactams and acylamidine stmc-tures, yielding carboxylic end groups (Scheme 10), which take part in the polymerization process as well. 

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