Substituents resorcinols

Substituted phenols such as cresols, p-fcrf-butylphenol, / -phcnylphenol, resorcinol, and cardanol (derived from cashew nut shells) have also been used as precursors for phenolic resins. Alkylphenols with at least three carbons in the substituent lead to more hydrophobic phenolic resins that are compatible with many oils, natural resins, and rubbers.7 Such alkylphenolic resins are used as modifying and crosslinking agents for oil varnishes, as coatings and printing inks, and as antioxidants and stabilizers. Bisphenol-A (2,2-p-hydroxyphenylpropane),... 

The hooked-shaped dependence of on the hydroxide-ion concentration has now been obtained for reaction of the monoanions of substituted 4-phenylazoresorcinols [58]-[62] (Perlmutter-Hayman et al., 1976 Briffett et al., 1988), 2-phenylazoresorcinol [63] (Hibbert and Sellens, 1988), 4,6-bis(phenylazo)resorcinols [64] and [65] (Hibbert and Simpson, 1983, 1985) and 2,4-bis(phenylazo)resorcinol [66] (Hibbert and Simpson, 1985). The 4-phenylazoresorcinols and the bis(phenylazo)resorcinols were studied in aqueous solution, and 2-phenylazoresorcinol was studied in 95% (v/v) MejSO-HjO. The values of the rate coefficients which give rise to this complex dependence are very finely balanced a slight change in substituent or other modification of the structure or reaction conditions can lead to a quite different kinetic behaviour (see later). For compounds [58]-[66], which show the complex dependence, the values of the rate coefficients are given in Table 15. 

In 1928, Schumm discovered that heating vinyl porphyrins in molten resorcinol resulted in facile loss of the vinyl groups from the porphyrins. It was subsequently shown that l -hydroxyalkyl, formyl and acetyl porphyrins behave similarly under the same conditions, i.e. these substituent groups also are removed. The Schumm devinylation reaction has been used in both synthetic and degradation studies on porphyrins, and it was stated in a paper in the Journal of Organic Chemistry that "One of the most useful reactions in the chemistry of natural porphyrins is the devinylation of vinyl porphyrins in molten resorcinol."... 

Phenols, Naphthols (e.g., 39-47). Phenols mainly couple at the 4-position, or at the 2-position if the 4-position is occupied, p-Hydroxybenzoic acid couples with elimination of C02 resorcinol couples twice initially at the 4-position, and with a second equivalent of diazonium compound at the 2-position under acid conditions or at the 6-position under alkaline conditions. a-Naphthols mainly couple at the 4-position, in addition to which varying quantities of 2- and 2,4-coupling products are obtained, depending on the diazo component. p-Naphthol couples at the 1-position. Substituents in the 1-position, such as S03H, COOH, Cl, CH2OH, or... 

We have determined that the assembly process is tolerant to substituents placed along the periphery of the template [7], In particular, derivatives of resorcinol with substituents unable to disrupt the hydrogen bonds between the templates and reactants (e.g. -R, -OR) have been found to serve as templates. Thus, cocrystallization of 5-methoxyresorcinol (5-OMe-res) with 4,4 -bpe produced the four-component complex, 2(5-OMe-res)-2(4,4/-bpe), with two olefins aligned parallel and separated by 3.66 A. UV-irradiation of the solid with broadband UV-radiation produced 4,4 -tpcb in quantitative yield. 

In effect, the substituents would largely preorganize [5] a resorcinol unit to form the targeted discrete structure. 

The acid-catalysed reaction of resorcinol with aldehydes leads to cyclic tetra-mers which are grouped in the class of resorc[4]arenes (exo-calixarenes).3 This reaction is quite general with respect to the aldehyde and to the starting resorcinol, which can bear several substituents in the 2-position.15 Niederl and Hogberg showed in a typical example, the synthetic procedure by which an ethanol solution of resorcinol, acetaldehyde and 37% hydrochloric acid maintained at 80 °C for 16 h, afforded 75% of the all cis C-methylresorc[4]arene. A shorter reaction time leads to the kinetic stereoisomer (trans,cis,trans,cis).16 This procedure is general for many aldehydes (Scheme 7.4), but the use of formaldehyde is limited to some special cases.17... 

The synthesis of calixresorc[4]arenes from aldehydes and resorcinol is catalyzed by mineral acids and by Lewis acids. The presence of an alkyl or aryl substituent coining from the aldehyde results in formation of four conformers labeled rccc (all-c , the crown conformer), rcct (the diamond conformer), rctt, and rtct. SnCU, when used in the condensation of isovaleraldehyde with 1,3-dimethoxybenzene, catalyzes selective formation of the rccc conformer in high yield (Eq. 63) [95]. 

Methylene-bridged calrx[4]resorcinols (for synthetic reasons derived from 2-aUsylresorcinols) assume a cone conformation at lower temperatures, and AG = 12.0 kcalmoU was found at 298 °C for the cone cone interconversion . This lower value in comparison to those for calixphenols like 2a reflects the fact that no substituents have to pass the annulus during the ring inversion. In addition, the intramolecular hydrogen bonds between exo-OH groups are distinctly weaker than those of the cyclic array of endo-OH groups in 2a as shown by NMR (5 = 6.30 vs. 10.2) and IR (v = 3420 vs. 3140 cm- ). 

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