Diacylamines

Trimethylsilylketene reacts smoothly with u./V-diarylnitrones to give oxoin-doles in good yields. On the other hand, the reaction of trimethylsilylketene with N-arylmethylnitrones gives a mixture of N,N-diacylamines and N-acylamines (Scheme 2.315) (836). 

The autoxidation of azlactones under basic conditions provides a convenient route to diacylamines [13]. Yields are usually >80%, except for the benzylidine derivatives, which are hydrolysed to the acylaminoacetic acids (Scheme 10.8). 

Pronucleophiles Serving as Ammonia Surrogates N,N-Diacylamines, Trifluoroacetamide and N-Sulfonylamines... 

Substitutions with N,N-diacylamines are best carried out under salt-free conditions in order to minimize the concentration of base in the reaction medium and to circumvent the low solubility of salts in THF. For example, potassium phthalimide could not be reacted in THF because of its insolubility. The reaction under salt-free conditions proceeded smoothly even with LI as the ligand (Table 9.3). 

Products from reactions with diacylamines or nosylamines can be very easily deprotected to give primary aUylamines. These were used as nucleophiles in allyhc substitutions to give secondary amines, which were transformed into unsymmetri-cally 2,5-disubstituted 2,5-dihydropyrroles (Scheme 9.28) [28aj. Thus, the allylic... 

Alkyl lV,lV-dinitramines (154) have been prepared from the reaction of the tetraalkylam-monium salts (155) of primary nitramines with nitryl fluoride in acetonitrile at subambient temperature. The same reaction with the primary nitramine or its alkali metal salts yields the corresponding nitrate ester. Treatment of the ammonium, potassium, or lithium salts of primary nitramines (156) with a solution of nitronium tetrafluoroborate in acetonitrile at subambient temperature yield alkyl iV,iV-dinitramines. ° The same reactions in ether or ester solvents enables the free nitramine to be used. The nitrolysis of A-alkylnitramides (157) and N,N-diacylamines with nitronium tetrafluoroborate in acetonitrile, and the nitration of aliphatic isocyanates with nitronium tetrafluoroborate and nitric acid in acetonitrile, also yield alkyl A,A-dinitramines (154). 

Thermolysis or photolysis of 1,2,4-dioxazolidines leads to rupture of the OO bond to give acyclic molecules (84CHEC-l(6)897>. Thermal decomposition of 3-acyl-1,2,4-dioxazolines at room temperature gives diacylamines (see Section 4.13.6.2.2) and l,2,4-dioxazolin-3-ones give isocyanates <84CHEC-I(6)897>. 

The oxidation by molecular oxygen or the base-catalyzed oxidative decarboxylation of saturated 5(4//)-oxazolones 278 yields diacylamines and provides an efficient procedure to prepare imides 279 from Al-acylamino acids (Scheme 7.90). 

A diamide and malonyl chloride gave a compound with two dioxo-tetrahydro-l,3-oxazine rings.116 Diacylamines were also used to produce tetrahydro-1,3-oxazine-4,6-dione.117... 

Aliphatic and alicyclic carbamates are nitrated smoothly and in excellent yields by a nitric acid-acetic anhydride mixture (4). Similarity, we have found that treating an acyl aliphatic amine and a urethane with one equivalent of nitronium tetrafluoroborate in acetonitrile at —30° C. gave the corresponding N-nitro derivatives in good to excellent yields. However, diacylamines are more difficult to nitrate, and Kauffman and Burger (9) have reported that nitrating succinimide required 13 hours... 

Replacement of =0 by CI2 or OH by Cl in the diacylamine function —CONHCO or —CON=C(OH)— also affords triazoles by analogy with the Einhorn-Brunner reaction (Scheme 72) (66AG(E)960, 76ZOR673). 

As soon as polymer amide groups are formed, they can take part in both types of transacylation reactions (23) and (24). The disproportionation reactions involving polymer amide groups and/or anions produce acyllactam and diacylamine structures entering into the polymerization process... 

Acylation of a lactam anion with diacylamine, i.e. the reverse of reaction (29),... 

Transacylation reactions between diacylamine groups and polymer amide anions represent only an exchange reaction... 

Decay of imide groups (acyllactam and diacylamine structures) during anionic caprolactam polymerization 1125]... 

The open chain structure (X) is formed in the condensation of diacylamine groups. The JV-acyllactam growth centres can undergo condensation at the cyclic as well as exocyclic methylene and carbonyl groups... 

Similar reactions involving polymer amide anions yield the corresponding diacylamine structures along with substituted /3-oxoamides, keto amides (XIII) and (XIV). In this way, the sequence of condensation and transacylation results in the formation of five types of 3-keto acid derivatives (X)—(XIV). 

Since lactam anions are acylated by diacylamine groups much faster than with cyclic acyl groups of acyllactams [94], the extent of such branching should be unimportant as long as a few percent of monomer are present. It has been confirmed that the majority of imide groups in anionic polycaprolactam are present as acyllactam [123,150]. 

Fig. 17. Effect of the initial ratio of activator/initiator ([A]o/[I]o) on the initial rate of anionic polymerization of caprolactam [169]. Concentration of sodium caprolactam [I]o = 0.0044 mole kg [A]q, the initial concentration of activator (tetraacetylhexamethylenediamine), expressed in moles of diacylamine groups per kg temperature, 150°C.

Amine hydrochlorides are known to react at elevated temperature with diacylamines and amides with the formation of amidines [201]... 

The rate equation for the alkaline hydrolysis of amides such as urea (Lynn, 1965), anilides (Biechler and Taft, 1957 Bender and Thomas, 1961a Mader, 1965 Schowen and Zuorick, 1966), chloroacetamide (Bruylants and K zdy, 1960) andN,N-diacylamines (Behme and Cordes, 1964), is known to contain both first- and second-order terms in hydroxide. It is highly improbable that the term which is second-order in hydroxide is due to base-catalysis of the addition of hydroxide ion to the carbonyl carbon, because of the low acidity of hydroxide. 

The four component condensation (Ugi reaction) " converts a mixture of substituted amine, isonitrile, aldehyde (or ketone) and carboxylic acid (Scheme 6) to a-acylaminocarboxylic acid amides (pathway a), to diacylamines (pathway b) and to a-aminocarboxylic acid amides (pathway... 

Reaction of nitrones with aroyl chlorides in the presence of triethylamine yields lV,lV-diacylamines (equation 58). The reaction can be rationalized by formation of an aroyloxy(benzylidene)ammonium chloride, with elimination of the carboxylic acid and readdition of carboxylate to the nitrilium ion followed by 1,3-acyl shift to give the /VjV-diacylamine. 

Einhorn-Brunner reaction. Formation of substituted 1,2,4-triazoles by condensation of hydrazines or semicarbazides with diacylamines in the presence of acid catalysts. 

Vakognavine formed a bis-hydrazone, which was characterized as the reineckate salt. On catalytic hydrogenation, a hexahydro-product (37) was obtained. Selective acid hydrolysis with 50% sulphuric acid afforded, after 4 minutes, a diacylamine (38) after I35 minutes, a monoacylamine (39) and after 2 hours, a completely deacylated alkamine (40). These structures were assigned from the spectral data. 

Hydrazines condense with diacylamines to give 1,2,4-triazoles 2 (Einhorn-Brunner synthesis), e.g. ... 

Acylation with carboxylic acid esters N-Acylation of j5-ketocarboxylic acid amides C-Acylation of diacylamines... 

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