Resorcinol derivatives reaction

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). 

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... 

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. 

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 ... 

Most recently, the methods of template-directed solid-state synthesis were employed to constmct the [3]- and the [5]-ladderane. The construction involved a resorcinol derivative (5-methoxyresorcinol) as a linear template to organize pyridine-substituted polyenes for the reaction within discrete molecular assemblies in solids. The assemblies are... 

Fluoride-induced fragmentation reactions were used in two stages of a synthesis of hexahydrocannabi-nol methyl ether (144 Scheme 52). One of the phenolic hydroxy functions in the resorcinol derivative (140) was selectively liberated from the SEM ether to give the diol (141), which was converted to the bis (trimethylsilyl) ether (142). Subsequent treatment with CsF resulted in a 1,4-elimination to the o-quinone methide (143) intermediate, which underwent an intramolecular [4 -i- 2] cycloaddition to give the product in good yield. 

Discovery of the dienone-phenol rearrangement of quinol acetates has made possible the synthesis of dihydric phenols that were difficult of access by other routes. The starting materials are obtained from phenols and lead tetraacetate, and with acetic anhydride and sulfuric acid (Thiele acetylation) or with boron trifluoride in ether they give, respectively, di- and mono-acetyl derivatives of resorcinol or hydroquinone.309 When treated with lN-sodium hydroxide, 0-quinol acetates of type (1) undergo nucleophilic addition of an OH" ion, giving resorcinol derivatives (2).310 Occurrence of the reaction is considered... 

Phenol (carbolic acid) is not a sensitizer but a deep skin penetrant producing local gangrene if not diluted. Resorcinol is used for its alleged intipruritic and anti-acne keratolytic properties. It irritates in a dose-related manner but allergic reactions occur (Caron and Calnan 1962 Keil 1962). Group hypersensitivity was demonstrated for some resorcinol derivatives such as resorcinol-mono-acetate and hexyl-resorcinol, which are metadihydroxybenzenes. The ortho and para compounds do not cross-react. 

Among the photochemical reactions of aromatic compounds, the photocycloadditions are most frequently applied to the synthesis of complex polycyclic compounds [6, 9]. The [2+3] or meta photocycloaddition of aromatic compounds and alkenes is the most prominent example [10]. This transformation also demonstrates complementarities between photochemical and ground state reactions since such reactions are almost impossible using conventional activation. A [2+2] ot ortho photocycloaddition between carbocyclic aromatic compounds and alkenes is observed as well. It is often competitive with other cycloaddition modes, in particular the [2+3] mode [11]. Many of these reactions are reversible, and photostationary equilibria are involved. This reaction was much less applied to organic synthesis. Recently, it was found that an acidic reaction medium may have an influence on the outeome of the reaction. The intramolecular photocycloaddition of resorcinol derivatives such as 1 is difficult due to its reversibility (Scheme 29.1). However, in an acidic reaction medium, the cycloadducts 2a,b are protonated at the oxygen atom of the tetrahydrofuran moiety... 

Functionalization of resorcinarenes involves three primary routes (1) At the R-groups or feet of the resorcinarene by choice of aldehyde in the resorcinarene reaction, and/or post-macrocyclization modification (2) the 2-position (X, Scheme 9.1) can be controlled by choice of the starting resorcinol derivative or modification of the resorcinarene product (3) functionalized through utilization of the phenolic groups at the upper rim. A variation of this strategy, using bis-electrophiles that bridge the phenolic pairs, leads to the cavitands discussed here. 

In the reaction of silylketenes 186 with excess enamines, six-membered ring [2+2+2] cycloadducts 187 are formed, which eliminate the amines to give the resorcinol derivatives 188 2 . 

The involvement of mixed-valent Rh /Rh species in the intermolecular C(sp )—H amination reaction has been further confirmed by the preparation of new complexes analogous to Rh2(esp)2 3. On one hand, the design of a resorcinol-derived ligand, that is structurally comparable to the esp ligand, has enabled the synthesis of the new complex 21 that is an active catalyst in intramolecular C(sp )—H amination. However, the redox properties of the resorcinol-based compound make the formation of a stable... 

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