Addition to Carboxylic Acids and Derivatives

Thallium(m) acetate effects a one-step synthesis of aliphatic a-acyloxy-carboxylic acids (Scheme 28) the transition state (92) is proposed. a-Aminoesters are readily oxidized to the corresponding a-diazoesters by isoamyl nitrite in the presence of acetic acid. A review has been published on the radical addition of carboxylic acids and derivatives to unsaturated linkages. ... 

CONJUGATE ADDITION TO a, -UNSATURATED NITRILES, CARBOXYLIC ACIDS AND DERIVATIVES... 

This novel catalytic reaction formally corresponds to an initial regioselective [2+2] head-to-head cyclodimerization of the propargyl alcohol with addition of carboxylic acid and elimination of water. Catalytic alkenylidenecyclobutene formation is general for a variety of propargyl alcohols and carboxylic acids and can also be applied to phenol derivatives. 

The electrophile shown in step 2 is the proton. In almost aU the reactions considered in this chapter, the electrophihc atom is either hydrogen or carbon. Note that step 1 is exactly the same as step 1 of the tetrahedral mechanism of nucleophilic substim-tion at a carbonyl carbon (p. 1255), but carbon groups (A, B = H, alkyl aryl, etc.) are poor leaving groups so that substitution does not compete with addition. For carboxylic acids and their derivatives (B = OH, OR, NH2, etc.) much better leaving groups are available and acyl substitution predominates (p. 1254). It is thus the nature of A and B that determines whether a nucleophilic attack at a carbon-heteroatom multiple bond will lead to substitution or addition. 

Arylquinoline-4-carboxylic acids and derivatives were shown to possess a wide variety of biological effects as antimalarial, antimicrobial, antitumor, antioxidants and cardiovascular agents. In addition, other derivatives have recently been shown to be potent tachykinin NK3 receptor antagonist " or to exhibit analgesic activity. O ... 

Lewis Acid Promoted Addition Reactions of Organometallic Compounds Nucleophilic Addition to Imines and Imine Derivatives Nucleophilic Addition to Carboxylic Acid Derivatives... 

In addition to carboxylic acid derivatives, anhydrides and acid fluorides are also accessible straightforward via carbonylation reactions depending on the various nucleophiles used. Eor example, water (hydroxycarbonylation) will give carboxylic acid, alcohols (alkoxycarbonylation) will give esters, amines (aminocarb-onylation) will give amides, and anhydrides and acid fluorides can be produced if... 

An overview of organocatalysis based on NHC yet avoiding the formation of a Breslow intermediate (acyl anion equivalent) has appeared. It encompasses the conjugate addition of carbenes, their addition to carboxylic acid derivatives as well as ketenes and analogues and illustrates the wide chemical diversity that can be achieved through these processes. 

On the other hand, the reaction of carboxylic acids with propargyl alcohols in place of terminal alkynes led to the catalytic head-to-head cyclodimerization of propargyl alcohols and addition of carboxylic acids. Alkylidenecyclobutene derivatives were obtained via cyclobutadieneruthenium and cyclobutenylmthenium intermediates [6] [Eq. (4)]. 

In addition to the information given in the general literature cited above, the oxidation of aldehydes has specifically been reviewed [19, 20]. The presentation here will begin with an overview of reagents that have been used for the conversion of aldehydes into carboxylic acids and derivatives thereof Subsequently, more specific oxidation reactions such as dismutations and oxidative rearrangements will be described. In the final part, oxidations of aldehyde derivatives such as acetals, oximes and hydrazones will be presented. 

Although the present chapter includes the usual collection of topics designed to acquaint us with a particular class of compounds its central theme is a fundamental reaction type nucleophilic addition to carbonyl groups The principles of nucleophilic addition to aide hydes and ketones developed here will be seen to have broad applicability m later chap ters when transformations of various derivatives of carboxylic acids are discussed... 

The A-substituted derivatives of 4-oxo-4//-pyrido[l,2-n]pyrimidine-3-carboxamides and -3-acetamides and l,6-dimethyl-4-oxo-1,6,7,8-tetrahy-dro-4//-pyrido[l,2-n]pyrimidine-3-carboxamide were prepared by treatment of the appropriate 3-carboxylic acids and acetic acid, first with an alkyl chloroformate in the presence ofNEt3 in CHCI3 below — 10°C, then with an amine (98ACH515). A-Phenethyl and A-[2-(3,4-dimethoxyphenyl)ethyl] derivatives of 6-methyl-6,7,8,9-tetrahydro-4//-pyrido[l, 2-n]pyrimidine-3-acetamide were obtained in the reaction of 6-methyl-6,7,8,9-tetrahydro-4//-pyrido[l,2-n]pyrimidine-3-acetic acid and phenethylamines in boiling xylene under a H2O separator. Hydrazides of 4-oxo-4//- and 4-oxo-6,7,8,9-tetrahydro-4//-pyrido[l, 2-n]pyrimidine-3-acetic acid were prepared from the appropriate ester with H2NNH2 H2O in EtOH. Heating 4-oxo-4//- and 6-methyl-4-oxo-6,7,8,9-tetrahydro-4//-pyrido[l, 2-n]pyrimidine-3-acetic hydrazides in EtOH in the presence of excess Raney Ni afforded fhe appropriafe 4-oxo-6,7,8,9-fefrahydro-4//-pyrido[l,2-n]pyrimidine-3-acefa-mide. In the case of the 4-oxo-4// derivative, in addition to N-N bond... 

In addition to this acidic behavior, an important characteristic of carboxylic acids is that the entire OH group can be replaced by other groups. The resulting compounds are called acid derivatives. We will consider only two types of acid derivatives, esters and amides. 

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