Amino compounds carboxylic esters

Phosphorus-containing compounds provide useful substrates for ozonolysis reactions as well and can provide several products depending on the reaction workup. Several biological uses exist for -amino-a-hydroxy phosphonic acid derivatives and they can be readily prepared by ozonolysis of Al-(ethoxycarbonyl)-/3-amino-Q -methylene phosphonic esters after reductive workup with sodium borohydride (eq 54). When the reaction mixture is treated with sodium hydroxide in MeOH, an anomalous ozonolysis reaction occurs and cleavage of the methylene as well as the carbon-phosphorus bond occurs to yield (V-(ethoxycarbonyl)-a-amino methyl carboxylic esters. 

Enantiopure a-amino aldehydes are valuable synthons in natural product synthesis [57]. However, problems are often encountered with their configurational instability [58]. Aziridine-2-carboxaldehydes are also a-amino aldehydes and accordingly have a potential synthetic value. We found that M-tritylaziridine-2-carboxaldehyde 56 is a perfectly stable compound and therefore comparable to Garner s aldehyde (ferf-butyl 2,2-dimethyl-4-(S)-formyl-oxazolidine-3-car-boxylate). Aldehyde 56 can readily be prepared from aziridine-2-carboxylic ester 12 by the sequence shown in Scheme 42 [59]. 

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. 

These unexacting requirements make the simplest unsulphonated azo structures, often monoazo types, quite acceptable [80]. Typical of the least polar members of this class are Cl Solvent Yellow 2 (4-68), Cl Solvent Orange 1 (4.69) and Cl Solvent Red 17 (4.70). Simple azo structures carrying sulphonamide, sulphone or carboxylate ester groups are used where a somewhat more polar, less soluble dye is needed. Simple disazo compounds (4-amino-azobenzene— 2-naphthol, for example) are used as red solvent dyes. Probably the only structural feature worthy of note in this class is the occasional adoption of structures carrying long alkyl chains to enhance solubility, as in the case of the disazo dye Cl Solvent Yellow 107 (4.71). 

Amino-substituted naphthoquinones and heterocyclic variants have been disclosed in the patent literature as 5-LO inhibitors. Compounds represented by (80) (X = C, N) from Lilly inhibited SRS-A release from sensitized guinea-pig lung tissue [218]. Similar compounds such as (81) (R = carboxylic ester, acyl, or aryl) and related naphthalene derivatives, from American Cyanamid, gave good inhibition in guinea-pig ISN (at 10 //g/ml) and in passive cutaneous anaphylaxis in mice (25-60 /zM i.p.) [219,220]. 

As in 0-52 hydrazides and hydroxamic acids can be prepared from carboxylic esters, with hydrazine and hydroxylamine, respectively. Both hydrazine and hydroxylamine react more rapidly than ammonia or primary amines (the alpha effect, p. 351). Imidates RC(=NH)OR give amidines RC(=NH)NH2. Lactones, when treated with ammonia or primary amines, give lactams. Lactams are also produced from y- and 8-amino esters in an internal example of this reaction. Isopropenyl formate is a useful compound for the formylation of primary and secondary amines,897... 

Apart from C02 and metal carbonates, the most abundant carbonyl compounds of natural origin are carboxylic esters and amides. These occur as fats and lipids, which are esters of long-chain alkanoic acids (pp. 789-791), and as proteins, which are polyamides of natural amino acids. The same struc-... 

Derivatives of the 3-carboxylic acid are noteworthy. Esters,94-96 the acid chloride,94 amide,94 and the hydrazide and several of its derivatives96-98 have been prepared, and the amide has been converted into the 3-amino compound,99 sulfonamides of which have been described.100... 

Lipases are of remarkable practical interest since they have been used in numerous biocatalytic applications, such as kinetic resolution of alcohols and carboxyl esters (both in water and in non-aqueous media) [1], regioselective acylations of poly-hydroxylated compounds, and the preparation of enantiopure amino acids and amides [2, 3]. Moreover, lipases are stable in organic solvents, do not require cofactors, possess broad substrate specificity, and exhibit, in general, a high enantioselectivity. All these features have contributed to make hpases the class of enzyme with the highest number of biocatalytic applications carried out in neat organic solvents. 

Various racemic compounds including alcohols, esters, amines, amino alcohols, carboxylic acids and amino acids... 

By analogy with cyclopropanes and oxiranes, 2-acylaziridines, aziridine-2-carboxylic esters and amides, are also suitable substrates for one-electron reductive ring cleavage. This is an efficient and highly regioselective method for the synthesis of yS-amino carbonyl compounds. Vinylogous substrates are, furthermore, transformed into <5-amino y8,y-unsaturated carbonyl derivatives azetidines can also be used to achieve y-amino functionalization (Scheme 19) [72]. 

Acid and Basic.—As the amino acids contain both an amino group and a carboxyl group they react both as acids and as bases. In this double r61e they exhibit very interesting properties. This same double character of acid and base has also been referred to in connection with the hydroxy acids. In this case the basic character is due to the presence of an alcoholic hydroxyl group and is consequently weak. With the amino acids, however, the basic character is due-to the presence of the much more basic amino group so that the double acid and basic character of the compounds is more pronounced. As acids the amino acids yield esters and acid chlorides. 

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