2- Naphthol reaction with benzaldehyde

Give the products resulting from the following reactions (a) 2-naphthol + MCN + ZnCI, + HCl (b) anthracene + cA-butene-dioic anhydride (c) nap ht ho-1.4-quin one + hcxa-2.4-dicne follow cd by reaction with CrO (d) naphthalene + phihalic anhydride -i-AlCl followed by reaction with polyphosphoric acid and then reduction and dehydlogenation (e) 1-tetralone + benzaldehyde + NaOH in ethanol. 

A mixture of 2-naphthol 1 (0.72 g, 5.0 mmol), benzaldehyde 2a (0.64 g, 6.00 mmol), and (/ )-(+)-1-phenylethylamine (0.64 g, 5.25 mmol) was stilled at 60 °C for 8 h under nitrogen atmosphere. Following the progress of the reaction by TLC and 1H NMR, it was seen that the formation of the product occurs during the first 4 h but the initial dr of (R,R)-3n (2.6 at 2 h) increases over time (99 at 8 h) with the formation of a solid and crystalline reaction mixture. The reaction mixture was dispersed at room temperature with EtOH (5 mL). The white crystals separated were collected and washed with EtOH (3x3 mL). The crystal-... 

Rate and equilibrium constants have been measured for representative intramolecular aldol condensations of dicarbonyls.60a For the four substrates studied (32 n = 2, R = Me n = 3, R = H/Me/Ph), results have been obtained for both the aldol addition to give ketol (33), and the elimination to the enone (34). A rate-equilibrium mismatch for the overall process is examined in the context of Baldwin s rales. The data are also compared with Richard and co-workers study of 2-(2-oxopropyl)benzaldehyde (35), for which the enone condensation product tautomerizes to the dienol60b (i.e. /(-naphthol). In all cases, Marcus theory can be applied to these intramolecular aldol reactions, and it predicts essentially the same intrinsic barrier as for their intermolecular counterparts. 

A mixture of benzaldehyde (2 mmol), malononitrile (2 mmol), a-naphthol (2 mmol), and MgO (50 mg) in water (15 mL) was refluxed for 1 h. After completion of the reaction, as indicated by TLC, the mixture was extracted with ethyl acetate (3x5 mL). The organic phase was dried, filtered, and excess ethyl acetate was distilled off (filtration ofboth organic and aqueous phases led to recovery of solid magnesium oxide). The residue was recrystallized from methanol to afford the pure product in 86% yield. 

Condensation of 1-naphthol and hetaryl- or substituted-benzaldehydes in the presence of ammonia, and subsequent acidic hydrolysis, gave 2 in moderate yields. Reactions of amino naphthols with equivalent amounts of aldehydes resulted in... 

The tropylium ion attacks phenols in the presence of alkali [79, 84-86]. Thus with phenol itself a tropylphenol is formed which has been shown to consist mainly of the pam-isomer plus a small amount of the ortho-isotaer. Reaction probably proceeds by direct attack of the tropylium ion on the phenoxide anion. In the case of 8-naphthol a more complicated reaction ensues in which the naphthoxide ion is oxidised as well as substituted, and the isolated products are benzaldehyde and 2-hydroxy-l,4-naphthaquinone [85]. 

The synthesis of xanthene derivatives using silica-supported add was also investigated by Karimi et al. (2011). They reported a facile procedure for the synthesis of 12-aryl-8,9,10,12-tetrahydrobenzo[fl]xanthen-ll-one derivatives through a multicomponent reaction using Caro s add-siUca gel (CA-Si02) as a nontoxic, inexpensive, and easily obtained catalyst. Benzaldehyde, P-naphthol 8, and dimedone (12) were allowed to react at different temperatures and with different amounts of catalyst to find the optimal reaction conditions for the preparation of xanthenone (11) (Scheme 1.8). 

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