Acid Intramolecular

M.p. 127 5°C. Dibasic, readily diazotizes. Prepared by treating hydrazobenzene with hydrochloric acid, intramolecular rearrangement taking place. 

Methyl salicylate is the methyl ester of o hydroxybenzoic acid Intramolecular (rather than mtermolecular) hydrogen bonding is responsible for its relatively low boiling point... 

The analogous process involving allylic epoxides is more complex, as issues such as the stereochemistry of substituents on the ring and on the alkene play major roles in determining the course of the reaction [38]. Addition of the Schwartz reagent to the alkene only occurs when an unsubstituted vinyl moiety is present and, in the absence of a Lewis acid, intramolecular attack in an anti fashion leads to cyclopropane formation as the major pathway (Scheme 4.10). cis-Epoxides 13 afford cis-cyclopropyl carbinols, while trans-oxiranes 14 give mixtures of anti-trans and anti-cis isomers. The product of (S-elimi-... 

In the case of the dicarboxylic esters of adipic and pimelic acids, intramolecular condensation gives cyclic esters of /8-keto-carboxylic acids (Dieckmann) ... 

Af)-[l,l -Binaphthalene]-2,2 -dicarboxyKc Acid Intramolecular Ullmann Reactions/Saponification Typical Procedure28b ... 

Glushkov and Magidson reduced the nitroso group of 4-amino-3-nitroso-2-oxo-2W-pyrido[l,2-u]pyrimidine (see also Section II,B) to a formylamino group with zinc power in 50% formic acid. Intramolecular condensation of the latter with the 4-amino group yielded a pyrido[2,l-a]purinone.30... 

With regard to the type of thermally induced cross-links, the following conclusions may be drawn from our results Formation of C—C bonds can be definitely excluded due to the cleavage observed by aqueous acid. Intramolecular ether bonds within the glucose unit might explain the change in cuprammonium viscosity, but they should be cleaved also by aqueous alkali. The most probable conclusion is, according to our opinion, a formation of intercatenary acetal bonds (12). 

This method, employing methylation by Mel, was used to synthesise pheromones such as (S)-sulcatol 416.176 The oxazolidinone protecting group features a safety-catch which is released by treatment with acid intramolecular assistance to hydrolysis of the secondary amide 415 rapidly generates the free alcohol product 416. 

Although the 2,3,4,6-tetrahydro-l,l -methylene-2,2 -pyrromethen-5[l-//]-one (190) is not strictly a perhydropyrrolo[l,2-c]pyrimidine, it carries the essential features of this ring system. Synthesis was effected by treatment of pyrrole-2-carboxaldehyde (186) with diiodomethane in the presence of a base to give 187 which was oxidized to 188 by w-chloroper-benzoic acid. Intramolecular condensation of 188 gave 189 which was... 

Figure 11. Cyclization of 1,5-diaminopimelic acid intramolecular C M bond formation of the intermediate radical cation.

Formation of 2-Ethyl-2(5H) Furanone. The presence of artifacts with increased retention times suggests the formation of components of increased polarity and/or the formation of higher molecular weight constituents from condensation or addition reactions. The acids, aldehydes and alcohols present can undergo oxidation to form y- and 6-lactones (14, 15). The formation of the lactone, 5-ethyl-2(5H)-furanone, probably occurs by the steps outlined in Figure 4. A plausible sequence would be reaction of 2-hexenoic acid to form a peroxy radical at the y-position followed by production of the hydroperoxide. Cleavage of the 0-0 bond with the subsequent addition of H could lead to 4-hydroxy-2-hexenoic acid. Intramolecular esterification would then produce the identified lactone. 

The ene reaction provides another route to homoallylic alcohols. The additions of highly reactive aldehydes to olefins bearing a C-H bond in the allylic position are catalyzed by Lewis acids. Intramolecular ene reactions do not require a highly activated aldehyde. Asymmetry can be induced either by the use of a chiral catalyst or by introduction of a chiral auxiliary on the aldehyde. 

Oxidation of methionine to methionine sulfoxide in small peptides was catalyzed by Fe3+ and promoted by ascorbic acid. Intramolecular catalysis by a histidine residue was involved in this oxidation, and its effect was maximal when the histidine and methionine residues were separated by one residue.822... 

Condensed and other carbocyclic systems An interesting dimerization reaction was performed with cyclohexylidenemalononitrile 188. The reaction was performed in methanolic sodium methanolate and yielded the spiro compound 189. Acidic intramolecular cycloaddition of alkylidenemalononitrile 190 (with concentrated sulfuric acid) gave the naphthalene 191. 1 -Tetraloneanil 192 reacted with 179 to yield phenanthrene 193. ... 

Lysergic acid Intramolecular Imino-Diels-Alder-Reaction starting from 4-hydroxymethyl-1-tosylindole [30]... 

Palladium n-Lewis Acidity Intramolecular Nucleophilic Attack on Unsaturated Bonds 1159... 

Fig. 13.14 Postulated Lewis acid-Lewis acid intramolecular cooperative catalysis.

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