Resorcinol, derivs

Resorcinol Derivatives. Aminophenols (qv) are important intermediates for the syntheses of dyes or active molecules for agrochemistry and pharmacy. Syntheses have been described involving resorcinol reacting with amines (91). For these reactions, a number of catalysts have been used / -toluene sulfonic acid (92), zinc chloride (93), zeoHtes and clays (94), and oxides supported on siUca (95). In particular, catalysts performing the condensation of ammonia with resorcinol have been described gadolinium oxide on siUca (96), nickel, or zinc phosphates (97), and iron phosphate (98). 

Unique methods based on new principles have been developed within the past 10 years. Threonine (27,28,249) is oxidized by lead tetraacetate or periodic acid to acetaldehyde, which is determined by photometric analysis of its p-hydroxydiphenyl complex or iodometric titration of its combined bisulfite. Serine is oxidized similarly to formaldehyde, which is determined gravimetrically (207) as its dimedon (5,5-dimethyldihydro-resorcinol) derivative or photometric analysis (31) of the complex formed with Eegriwe s reagent (l,8-dihydroxynaphthalene-3,5-disulfonic acid). It appears that the data obtained for threonine and serine in various proteins by these oxidation procedures are reasonably accurate. [Block and Bolling (26) have given data on the threonine and serine content of various proteins. ]... 

CB2 Selective Classical Cannabinoids Indoles and Indazoles Resorcinol Derivatives Benzo[c]Chromen-6-one Derivatives... 

Another resorcinol derivative, AM 1703 (371), which has a carbon-carbon triple bond at the end of the alkyl chain, was reported to be a highly potent and selective CB2 agonist (Ai(CB2) = 0.59pM, with 500-fold selectivity against CBj) [228]. 

Mejorado, L. H. Pettus, T. R. R. Total synthesis of (+ )-rishirilide B development and application of general processes for enantioselective oxidative dearomatization of resorcinol derivatives. J. Am. Chem. Soc. 2006, 128, 15625-15631. 

In 2011, Hartwig and coworkers reported the total synthesis of taiwaniaquinol B (55, Scheme 11.9), a member of a family of diterpenoids that are derived from the abietane skeleton [36]. A key aspect of the Hartwig synthesis of taiwaniaquinol B was the use of the iridium-catalyzed borylation reaction to accomplish the C(5) functionalization of resorcinol derivative 53. This regioselectivity for the overall bromination is complementary to that which would be obtained using a standard electrophilic aromatic substitution (EAS) reaction. In the transformation of 53 to 54, a sterically controlled borylation was first accomplished, which was then followed by treatment of the boronic ester intermediate with cupric bromide to... 

Reaction of isothiocyanates with resorcinol derivatives in the presence of boron trifluoride-acetic acid complex for overnight at 0-5 °C affords the corresponding thioamides.25... 

In a similar fashion, the isomeric tetrahydrobenzofuran 105 is produced from a resorcinol derivative on exposure to Grignard conditions (Equation 66) <2005T4805>. 

Resorcinol derivatives, e.g., orcinol [504-15-4], /3-orcinol [488-87-9], their monomethyl ethers, and methyl 3,6-dimethylresorcylate [4707-47-5] (see p. 141) are mainly responsible for the characteristic earthy-moss-like odor of the oakmoss products [651-655b]. 

Cavitands are hosts formed in acidic condensation reactions between resorcinol derivatives and aldehydes.46 The resulting cyclic octol compounds are usually tetrameric and contain four aromatic units that form a relatively shallow bowl in the preferred C4v conformation. Further synthetic elaboration on the structure of the octols allows us to fix the conformation of these compounds in C4v symmetry with a well defined, albeit small cavity. 

Table 10.4 shows the conversions (t = 0.5 h) of S9 in the presence of various additives. The effect of the addition of resorcinol derivatives on the conversion of a bound substrate was also investigated (Table 10.4). First, olivetol (Gl) was added to the experiments with S4 and S9. Addition of one equivalent of Gl per S4 had no effect on the conversion of the latter substrate. When five equivalents were added the conversion increased from 9.4% (without any additives present) to 14.4%. A rather surprising result since we know that hydroxyl groups cause a decrease in conversion when triphenylphosphine is used as ligand in combination with precursor (P Ph3) 3 Rh (H)(CO). Even more surprising was the observation that one equivalent of Gl added to S9 resulted in an increase in conversion from 26% to 37%. Addition of five...

The resorcinol and phloroglucinol derivatives (Table IV) all precipitated rather completely as expected except for 3,5- and 2,4-dihydroxy-benzoic acids. Their precipitation was enhanced if phloroglucinol was added this indicates that formaldehyde substitution occurred but the products were too soluble and too polar to precipitate until crosslinked with phloroglucinol. It had been shown previously that phenols which did not react with formaldehyde were not appreciably entrained in the precipitate formed with those which did (21) (see Table X). Hydro-quinone derivatives, except for one which is also a resorcinol derivative, did not precipitate with formaldehyde (Table V). 

Naphthalene- and anthracene-derived phenols did, however, almost uniformly precipitate (Table VI). In natural materials (not grapes or wines) which contain them they would be included in the formaldehyde precipitable group. Several primary amines capable of SchifFs base formation reacted with formaldehyde to lose their F-C oxidizability, but only the resorcinol analog, 3-aminophenol, precipitated (Table VIII). Sulfite also reacted but did not precipitate with formaldehyde, and the F-C oxidizability was suppressed (Table IX). The resorcinol derivative, 2,4-dimethoxycinnamic acid, formed a precipitate with formaldehyde, but it did not react appreciably in the F-C assay. 

Resorcinol, Derivatives of. See under Di-hydroxybenzene and Derivatives in Vol 5, D1270-R to D1288-R... 

In contrast, peroxides with bridgehead alkoxy groups, such as 79 and 80, undergo the diepoxide photochemical rearrangement to diepoxides 81 and 82, respectively.42-44 The resorcinol derivative 83 on reaction with singlet oxygen... 

Holleman believed the 2,5-isomer behaved in the same way at the first stage of the reaction. Only by prolonged treatment with an alcoholate can a chlorine atom be substituted, a resorcinol derivative being formed ... 

An interesting example of an application of this method pertains to the synthesis of pharmacologically active synthetic A1 -tetrahydrocannabinoids 134) of the type 267 which have a lipophilic tertiary alkyl side-chain. Equation 84 shows that organo-titanium chemistry provides a versatile means to prepare the precursors 264 (65-80 %)133). Demethylation of 264 using trimethylsilyl chloride and sodium iodide affords the resorcinol derivatives 265 ( 95%)133>. Compounds of this type have been previously condensed with 266 in the presence of acids to form the A1(6)-isomers of 267, which in turn can be converted into 267135). It should be mentioned that the meta-substitution pattern of 265 prohibits simple Friedel-Crafts alkylation of resorcinol, which is the reason why alternative multistep syntheses of 264 have had to be developed l34 136>. 

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