Amino compounds, preparation

Alimchandani, M. Journal of the Chemical Society (1920) 117, 967-American Home Products Improvements in and Relating to Imines and Amino Compounds Prepared Therefrom 1954 GB 702,985... 

The modified procedure involves refluxing the N-substituted phthaUmide in alcohol with an equivalent quantity of hydrazine hydrate, followed by removal of the alcohol and heating the residue with hydrochloric acid on a steam bath the phthalyl hydtazide produced is filtered off, leaving the amine hydrochloride in solution. The Gabriel synthesis has been employed in the preparation of a wide variety of amino compounds, including aliphatic amines and amino acids it provides an unequivocal synthesis of a pure primary amine. 

In general, benzoylation of aromatic amines finds less application than acetylation in preparative work, but the process is often employed for the identification and characterisation of aromatic amines (and also of hydroxy compounds). Benzoyl chloride (Section IV, 185) is the reagent commonly used. This reagent is so slowly hydrolysed by water that benzoylation can be carried out in an aqueous medium. In the Schotten-Baumann method of benzoylation the amino compound or its salt is dissolved or suspended in a slight excess of 8-15 per cent, sodium hydroxide solution, a small excess (about 10-15 per cent, more than the theoretical quantity) of benzoyl chloride is then added and the mixture vigorously shaken in a stoppered vessel (or else the mixture is stirred mechanically). Benzoylation proceeds smoothly and the sparingly soluble benzoyl derivative usually separates as a solid. The sodium hydroxide hydrolyses the excess of benzoyl chloride, yielding sodium benzoate and sodium chloride, which remain in solution ... 

Ha.loisoquinolines, The Sandmeyer reaction is commonly used to prepare chloroisoquinolines from the amino compound. The corresponding hydroxy compounds are also used by treatment with chlorides of phosphoms. The addition of bromine to a slurry of isoquinoline hydrochloride in nitrobenzene gives a 70—80% yield of 4-bromoisoquinoline [1532-97-4J. Heating 1-chloroisoquinoline [19493-44-8] with sodium iodide andhydriodic acid gives 1-iodoisoquinoline [19658-77-6] (179). 

Reduction of nitroaminopyridazines yields the corresponding aminopyridazines. Reductive cleavage of hydrazinopyridazines to give amino compounds is of practical significance in cases when halogen atoms are resistant to ammonolysis. Many substituted 3,4-diamino-, 4,5-diamino- and 3,5-diamino-pyridazines can be prepared in this way. 

Catalytic hydrogenolysis of an O-benzyl protective group is a mild, selective method introduced by Bergmann and Zervas to cleave a benzyl carbamate (>NC0-0CH2C6H5 —> >NH) prepared to protect an amino group during peptide syntheses. The method has also been used to cleave alkyl benzyl ethers, stable compounds prepared to protect alkyl alcohols benzyl esters are cleaved by catalytic hydrogenolysis under neutral conditions. 

Aminoquinazolines have been the subject of considerable investigation and a large number of derivatives have been prepared as potential antimalarials. The secondary and tertiary amino compounds can be prepared from the corresponding chloroquinazolines and the required primary or secondary amines. The reaction depends on the reactivity of the halogen atom, e.g, the 4-chloro atom reacts more readily than the 2-chloro atom in quinazolines and also on the basic strength of the amine used (see 6a). The reaction is... 

The same amino compounds also underwent reactions with a series of 3-cyano-4-imino- and 3-cyano-4-oxo-piperidines to yield 4-amino-5,0,7,8-tetrahydropyrido[4,3-d]pyrimidines. . A tetra-hydropyTido[4,3-prepared from 4-amino-l-henzyl-3-cyano-d -piperidine (134) hy a simple one-step preparation. This method is of general application for the preparation of fused pyrimidines and previous papers in this field are listed by Taylor. ... 

The feasibility of this approach was demonstrated with a model library of 36 compounds prepared from a combination of three Boc protected L-amino acids (valine 23, phenylalanine 24, and proline 25) and 12 aromatic amines (3,4,5-trimethoxyaniline (26), 3,5-dimethylaniline (27), 3-benyloxyaniline (28), 5-aminoindane (29), 4-tert-butylamline (30), 4-biphenylamine (31), 1-3-benyloxyani-line (28), 5-aminoindane (29), 4-tert-butylaniline (30), 4-biphenylamine (31), 1-aminonaphthalene (32), 4-tritylaniline (33), 2-aminoanthracene (34),... 

PUR are a broad class of highly cross-linked plastics prepared by multiple additions of poly-functional hydroxyl or amino compounds. Typical reactants are polyisocyanates [toluene diisocyanate (TDI)] and polyhydroxyl molecules such as polyols, glycols, polyesters, and polyethers. The cyanate group can also combine with water this reaction is the basis for hardening of the one-part foam formulations. 

The organotin alkoxides RgSnOR and R2Sn(OR >2 can be prepared by treating the appropriate organotin chlorides with sodium alkoxides, and this procedure has been extended to the preparation of the monoal-kyltin trialkoxides, RSnCOR la (190), which serve as useful reagents for the synthesis of other monoalkyltin derivatives. Alternatively, the trialkoxides can be prepared by alcoholysis of the tris(amino) compounds RSn(NR )3 (191). 

The organotin thiolates are more readily prepared, and are less reactive, than either the alkoxy or tW amino compounds, and the al-kynylthiyltin compounds Me3SnSC=CPh, MesSiC CSSnMes, and Me3CC=CSSnBu3 have recently been prepared by extension of the established, general methods (229). 

Amino resins are those polymers prepared by reaction of either urea or melamine with formaldehyde. In both cases the product that results from the reaction has a well crosslinked network structure, and hence is a thermoset polymer. The structures of the two parent amino compounds are shown in Figure 1.1. 

Treatment of 41b with bromocyanide (BrCN) at 70 °C for 3 h afforded the amino compound 53 (76%). The structures of all the newly synthesized compounds were confirmed by the H, NMR, and mass spectra. Compounds 55 and 52 were identified by the homo- and heteronuclear spectra, as well as from comparison to the 1,2,4-triazolo-azipene derivatives prepared previously [22] (Scheme 10). 

Transformations to polymer-bound amino compounds, which are often useful as ligands for metals ions or other free species (67), employ a wide selection of organic reactions. Quaternary ammonium salts result from heating isolated polymer tosylate with tertiary amine they may also be prepared in one step from (hydroxyethyl)polystyrene and toluenesulfonyl chloride and a two-fold excess of amine. 

A V -Carbonyldiimidazole (CDI) is prepared in a convenient and safe procedure from phosgene and imidazole as a non-toxic crystalline compound (m.p. 116-118 °C).[5],[6] It reacts almost quantitatively at room temperature or by short and moderate heating with an equimolar quantity of a carboxylic acid in tetrahydrofuran, chloroform, or similar inert solvents within a few minutes to give the corresponding carboxylic acid imidazolide, which is formed under release of carbon dioxide, together with one equivalent of readily separable and recyclable imidazole.Thus, this reaction leads under very mild conditions to the activation of a carboxylic acid appropriate for transacylation onto a nucleophile with an alcohol to an ester, with an amino compound to an amide or peptide, etc. 

In addition to the amides described in ref. [72], further examples prepared by means of CDI from amino compounds of the cephalosporin or penicillin type, and various heterocyclic carboxylic acids, are reported in ref [86] and [87] and ref. [88] and [89], respectively. 

Inasmuch as trimethylsilylamine is unstable, it will decompose into ammonia and hexamethyldisilazane. The ammonia thus formed could be visualized to form the amino compound (MegSi)2NB(NHg)-NHSiMe. Since (MegSi) NB(NHSiMe3)2 was prepared Zby Wells and Collins (.13) via Interaction of5 tne chloroborane with hexamethyldisilazane, its production here could follow the same path. 

New examples of the preparation of stannylamines, largely by established methods, are shown in Equations (164) and (165). Sodium bis(trimethylstannyl)amine can be prepared from sodium amide and a stannylamine,499 and can act as the precursor to other bis- and tris(stannyl)amino compounds.499 500 The tristannylamines are planar about the nitrogen, with the unshared pair in a 2p orbital. Tris(chlorodimethylstannyl)amine, with five-coordinate tin, is close to centrosymmetrical, and reacts with pyridine to give a tetrastannabicyclo[3.1.1]heptane.501... 

Fluorine containing ammonium salts. As amino compounds often have marked physiological action, it seemed worth while to prepare compounds containing both fluorine and a quaternary amino grouping. 

It should be emphasized that the phosphorus oxydichlorofluoride method for preparing esters of phosphorofluoridic acid cannot compare in speed with the hydrogen phosphite method already described (p. 46). Furthermore, it is not very suitable for very large-scale work. On the other hand, once the apparatus is set up and a supply of POCl2F is obtained, one has a simple, clear-cut, method for producing a large variety of phosphorus compounds, not only esters but amino compounds (p. 87) and mixed compounds (p. 90). In other words, the method is extremely valuable for exploratory purposes and where an unequivocal synthesis is required. 

In addition to a review of the recent developments in the preparation of chiral amino compounds, developments concerning the interpretation of their ORD and CD in the visible and ultraviolet spectral regions will be reviewed, together with the emerging impact of vibrational (infrared) optical activity (VOA) observations, including vibrational circular dichroism (VCD) and Raman optical activity (ROA) measurements23, on important stereochemical problems concerning chiral amino compounds. 

Only 3-diazopyrroles have been prepared by diazotization of the corresponding amino compounds. The reaction is carried out in acetic acid with a stoichiometric amount of nitrite in the case of simple aryl pyrroles. The diazopyrroles were isolated in good yields upon alkalinization with sodium carbonate, and care was taken to control temperature during diazotization and neutralization (61JOC3790). 

A series of 6- and 7-aciylamide derivatives of 4-(phenylamino)-quinazoline and 4-(phenylainino)-pyridopyrimidine, classes of epidermal growth factor receptor (EGER) inhibitors, have been prepared from the corresponding amino compounds by reaction with actoyl chloride/base <99JMC1803>. Reaction of thionyl chloride with hexahydro-7-methyl-pyrimido[l,6-a]-pyrimidine-6,8-dione yields the corresponding 9,9 -thiobispyriiiudopyrimidine derivative <99JHC453>. 

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