Carboxylic acid amid amidines

A still unresolved problem is the structure of the often used adducts from phosphorus trihalides and carboxylic acid amides, which might be described by the formulae (8) or (9). With the aid of in situ generated adducts of acid amides and PX3 amidines, isonitriles, quinazolinones, alkyl chlorides, aminomethylenediphosphonic acids, carbamoyl halides, triformylaminomethane, 1,3,4-oxadia-zoles, sulfides (from sulfoxides), nitriles (from primary nitro compounds)" and bromoqui-nolines (from methoxyquinolines)" have been prepared. 

Amidines from subst. carboxylic acid amides -e-... 

Amidines from carboxylic acid amides via iminoester fluoroborates... 

Carboxylic acid anhydrides. A soln. of triflic anhydride in ethylene dichloride added dropwise to a soln. of Ph3PO in the same solvent at 0° under N2 after 15 min a soln. of / -toluic acid in ethylene dichloride added followed by EtjN, and stirred for 15 min - p-toluic anhydride. Y 93%. Redox side reactions are avoided, and ketones, esters and ethers unaffected. F.e. inch ketenes, carboxylic acid esters (incl. aryl esters) and amides, amidines from carboxylic acid amides, benzimidazoles, and intramolecular ar. acylation, also using N-diphenylphosphinyl-N -methylpiperazine (without the need for an additional base), s. J.B. Hendrickson, M.S. Hussoin, J. Org. Chem. 54, 1144-9 (1989) alternative prepn. of reagents cf. D. Crich, H. Dyker, Tetrahedron Letters 30, 475-6 (1989). 

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. ... 

Tertiary benzylic nitriles are useful synthetic intermediates, and have been used for the preparation of amidines, lactones, primary amines, pyridines, aldehydes, carboxylic acids, and esters. The general synthetic pathway to this class of compounds relies on the displacement of an activated benzylic alcohol or benzylic halide with a cyanide source followed by double alkylation under basic conditions. For instance, 2-(2-methoxyphenyl)-2-methylpropionitrile has been prepared by methylation of (2-methoxyphenyl)acetonitrile using sodium amide and iodomethane. In the course of the preparation of a drug candidate, the submitters discovered that the nucleophilic aromatic substitution of aryl fluorides with the anion of a secondary nitrile is an effective method for the preparation of these compounds. The reaction was studied using isobutyronitrile and 2-fluoroanisole. The submitters first showed that KHMDS was the superior base for the process when carried out in either THF or toluene (Table I). For example, they found that the preparation of 2-(2-methoxyphenyl)-2-methylpropionitrile could be accomplished h... 

As a class of compounds, nitriles have broad commercial utility that includes their use as solvents, feedstocks, pharmaceuticals, catalysts, and pesticides. The versatile reactivity of organ onitriles arises both from die reactivity of the C=N bond, and from die ability of the cyano substituent to activate adjacent bonds, especially C-H bonds. Nitriles can be used to prepare amines, amides, amidines, carboxylic acids and esters, aldehydes, ketones, large-ring cyclic ketones, imines,... 

Pinacolone, o-(diphenylphosphino)benzoyl-coordination chemistry, 401 Piperidine, IV-hydroxy-metal complexes, 797 pA a values azole ligands, 77 Plant roots amino acids, 962 carboxylic acids, 962 Plastocyanin copper binding site, 557 copper(II) complexes, 772 copper(II) site in, 770 Platinum, dichlorobis(benzonitrile)-IR spectrum, 264 Platinum, cis-dichlorodianunine-antitumor activity, 34, 979 Platinum, ethylenebis(triphenylphosphine)-reactions with 5,6-dimethyl-2,l,3-benzothiadiazole, 194 Platinum blue formation, 265 Platinum complexes acetylacetone reactions, 380 amides, 491 amidines... 

The direct synthesis of aryl- or alkyl nitriles from cyanide and organohalide precursors is revered in synthetic chemistry, as the nitriles represent a flexible functionality that can easily be converted into (for example) carboxylic acids, esters, amides, amidines, amines and various hetero cycles [67], such as thiazoles, oxazolidones, triazoles and tetrazoles [68]. The tetrazole group... 

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