Orcinol synthesis

Synthesis of the remaining half of the molecule starts with the formation of the monomethyl ether (9) from orcinol (8). The carbon atom that is to serve as the bridge is introduced as an aldehyde by formylation with zinc cyanide and hydrochloric acid (10). The phenol is then protected as the acetate. Successive oxidation and treatment with thionyl chloride affords the protected acid chloride (11). Acylation of the free phenol group in 7 by means of 11 affords the ester, 12. The ester is then rearranged by an ortho-Fries reaction (catalyzed by either titanium... 

A similar pathway is thought to be involved in the synthesis of chromenes from coumarin (see Section 2.23.6.4.1), whilst the spontaneous dehydration of the alcohol (97) to the ketochromene (98), which occurs during acid hydrolysis, also presumably proceeds through the same type of intermediate. This step is an important feature of the synthesis of siccanochromene A, a fungal metabolite, from orcinol and the aldehyde (96) outlined in Scheme 10. Another point of interest in this route is the use of heteroatom-facilitated metallation to achieve the correct orientation (71T6073). 

Malonylidene nitrile and a dilorine are transformed into a fused pyran-2-one ring when heated with ethanolic hydrogen chloride [3002]. Reactions in which nitriles and hydrogen chloride interact have been reviewed [2547], When a 2-bromobenzamide is heated with orcinol in dilute sodium hydroxide containing copper(II) sulphate, the bromo and amino groups are lost C—C and C—O bon are formed in a synthesis of the dimethyl ether of altemariol, a compound found in some plants of the Liliacae family [2922]. 

A new synthesis of grifolin (9), involving treatment of farnesyl chloride (8) with orcinol (7) in the presence of sodium, is reported to give a better yield than the various syntheses previously recorded for this compound (c/. Vol. 5, p. 91). 

Podlech et al. recently reported on a total synthesis of alternariol (732) with a palladium-catalyzed Suzuki-tyipe coupling as the key reaction 495). The synthesis began by preparing the orcinol-derived boronic acid 748 by methylation and subsequent bromination with iV-bromosuccinimide (NBS) of orcinol 746 362), and treatment of 747 with butyUithium, followed by forming the boronic acid with tri/so-propyl borate (496) (Scheme 11.2). The brominated Suzukt-coupling partner was achieved by a Vilsmeyer formylation of 3,5-dimethoxybromobenzene (749) (497), which was further oxidized under Kraus conditions (242) and esterified to obtain the methyl ester 751. 

Bryan AJ, Elix JA (1976) 2-0-Acetyltenuiorin, a new tridepside from the lichen Pseudo cyphellaria australiensis. Aust J Chem 29 1147-1151 Bryan AJ, Elix JA, Norfolk S (1976) Synthesis of orcinol tridepsides and aphthosin, an orcinol tetradepside. Aust J Chem 29 1079-1086... 

Elix JA, Norfolk S (1975a) Synthesis of meta-divarinol and olivetol depsides. Aust J Chem 28 399-411 Elix JA, Norfolk S (1975b) Synthesis of para-(3-orcinol depsides. Aust J Chem 28 1113-1124 Elix JA, Norfolk S (1975c) Synthesis of (3-orcinol meta depsides. Aust J Chem 28 2035-2041 Elix JA, Portelli VJ (1990) A synthesis of the lichen xan-thone thiomelin. Aust J Chem 43 1773-1778 Elix JA, Tearne PD (1977) Nordivaricatic acid, a new depside from the lichen Heterodea beaugleholei, Aust J Chem 30 2333-2335... 

Elix JA, Chester DO, Gaul KL, Parker JL, Wardlaw JH (1989a) The identification and synthesis of further lichen p-orcinol para-depsides. Aust J Chem 42 1191-1199... 

Sala T, Sargent MV (1981) Depsidone synthesis. Part 19. Some P-orcinol depsidones. J Chem Soc Perkin Trans 1 877-882... 

Synthesis of P-Orcinol para-Depsides, p-Orcinol me fl-Depsides,... 

Synthesis of -Orcinol para-Depsides, -Orcinol meta-Depsides, meta-Orcinol Depsides and Orcinol Tridepsides... 

Starting with appropriately substituted phenols, procedures identical to those used for the synthesis of /7am-orcinol depsides have been employed in the synthesis of natural P-orcinol /7am-depsides 130, 152, 251, 252)... 

In the ten years since the last review there has been a resurgence of interest in the chemistry of depsidones in terms of the detection (79), the isolation of new compounds and the total synthesis of these substances. The new work is discussed in the order of the above classification and of increasing structural complexity of the compounds. A methodical study and interpretation of the C-n.m.r. spectra of orcinol 311) and P-orcinol depsidones 312) has been reported by Sundholm and Huneck. 

Synthesis of Para j3-Orcinol Depsides. Austral. J. Chem. 28, 1113 (1975). 

Nucleic acid synthesis. A striking observation first made by Cohen (52,54) is that in cells infected with T2r+ only DNA, the nucleic acid found in the virus, is synthesized in contrast to normal bacteria which make about 3 times as much RNA as DNA. RNA when measured as pentose by the orcinol reaction remains constant. This phenomenon is clearly of paramount importance. It has been confirmed for T6 bacteriophage by Kozloff (private communication). However, Herriott s data (129) on E. coli infected with T2 give indication of a fall in RNA. Although protein synthesis is apparent from the moment of infection, DNA synthesis begins only after a lag of 7 to 10 minutes (54). This holds for T4 and T6, as well as T2 (62). As shown in Fig. 6, DNA increases linearly with time after a lag of about 10 minutes and finally levels off at about 100 minutes. Doermann and Cohen (unpublished experiments... 

Griffin FK (1993) Structure Determination and Synthesis of some P-Orcinol para-Depsides. Thesis, Austral Natl Univ, Canberra... 

Another application of this methodology is shown in the Scheme 12.36, where a one-step synthesis of biologically interesting confluentin 147, which has been shown to inhibit histamine release, was achieved [80]. Reaction of orcinol with fra 5,franj-famesal 114 in the presence of 10mol% of... 

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