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The structure of hydroxyanigorufone, one of the pigments of Anigozanthos rufus Labill., has been confirmed as 2-hydroxy-9-(4- hydroxyphenyl)phenalenone by synthesis. The general application of two synthetic methods, 9-arylation through addition of Grignard reagents and 2-hydroxylation through epoxidation, is demonstrated by the preparation of several other phenalenones related to natural products.

The structures of haemocorin aglycone, a pigment of Haemodorum corymbosum Vahl., and its methyl ethers have been confirmed by unequivocal specific synthesis.

The crystal structure of dunnione p-bromophenylhydrazone has been determined by single-crystal X-ray diffraction methods at 295 K, the structure being refined to a residual of 0.054 for 1429 'observed' reflections. Crystals are triclinic, Pī, a 15.620(8), b 8.804(4), c 7.439(4) Ǻ, α 68.03(4), β 89.85(4), γ 77.44(4)°, Z 2. The conjugation throughout the molecule is extensive and the crystal packing is dominated by intermolecular charge-transfer interactions. Bonding in the hydrazone moiety lies intermediate between those expected for hydrazone and azo forms.

The crystal structure of the title compound, a naturally occurring tricyclic quinone, C16H16O5, has been found to be (1R*,3S*)-7,10- dihydroxy-1,3,8-trimethyl-3,4,6,9-tetrahydro-1H-naphtho[2,3-c]-pyran- 6,9-dione by single-crystal X-ray diffraction methods at 295(1) K and refined by least squares to a residual of 0.033 for 1143 'observed' reflections. Crystals are monoclinic, P21, a 8.346(8), b 16.79(2), c 4.911(5)Ǻ, β 101.17(8)°, Z 2. The molecule is shown to have the cis configuration. As an approach to the synthesis of the pigment the model compound 5-chloro-8-methoxy-1,3-dimethylisochroman has been prepared and the two racemic forms have been separated and characterized.

Two new pigments, haemofluorone A and haemofluorone B, have been isolated from the flowers of Macropidia fuliginosa Drum. and also from the root system of Phlebocarya ciliata R.Br. Spectroscopic analysis indicates the structures 5,8,9- and 8,9,1l-trihydroxy-lH-naphtho[2,1,8-mna]xanthen-l-one. The former structure has been confirmed by a synthesis of the trimethyl ether by photochemical oxidative cyclization of 9-(3,4-dimethoxyphenyl)-6-hydroxy-2-methoxy-lH-phenalen-l-one.The parent chromophore, lH-naphtho[2,1,8-mnalxanthen-l-one, and the 2,Sdimethoxy derivative have also been prepared by analogous photochemical reactions of the appropriate arylphenalenones.

The occurrence of haemofluorone B in Anigozanthos rufus and Conostylis setosa has been confirmed. The revised structure 5,8,9-trihydroxy-3H-naphtho[2,1,8-mna]xanthen-3-one is now proposed for this pigment. Dihydroxyanigorufone has also been found in Conostylis setosa and the structure 9-(3,4-dihydroxyphenyl)-2-hydroxy-lH-phenalen-l-one has been confirmed by synthesis of the trimethyl ether. Some model arylphenalenones and naphthoxanthenones have been prepared fromnaphthylphenylpropanones and some unusual products have been obtained by photolysis of arylphenalenonesand by the reactions of Grignard reagents with phenalenones.

Condensation of naphthalene-2,7-diol with 2,4-dioxo-4-phenylbutanoic acid gives 6-hydroxy-1-oxo-9-phenyl-1H-phenalene-7-carboxylic acid which is readily converted into the lactone and on treatment with diazomethane forms only methyl 6-methoxy-1-oxo-9-phenyl-1H-phenalene-7- carboxylate. Analogous reactions of other 4-aryl-2,4-dioxobutanoic acids with naphthalene-2,7-diol or with 3,6-dimethoxynaphthalene-2,7- diol give easy access to arylphenalenones and naphthoxanthenones related to natural pigments.

Further examination of root extracts of Dianella revoluta revealed the presence of methyl 2,4-dihydroxy-3,6-dimethylbenzoate, (-)-4?-hydroxy- 7-methoxy-8-methylflavan, 5,7-dihydroxy-6-methyl-2-nonacosylchromone (with homologues), and a triquinone, trianellinone. The root extracts of Stypandra grandis yielded (-)-4?-hydroxy-7-methoxyflavan and the same mixture of chromones. The synthesis of some model chromones is described.

The structures previously assigned to two of the fully methylated lactones derived from Lachnanthes tinctoria constituents have now been confirmed by synthesis. Nuclear magnetic resonance spectra have been used for a study of the stereochemistry of highly substituted phenyltetralins obtained as intermediates in the syntheses.

A new examination of the heartwood of Pterocarpus indicus has revealed the presence of formononetin, isoliquiritigenin, (-)-p-hydroxyhydratropic acid, and a new 2-arylbenzofuran. The previously reported angolensin and pterocarpin were also isolated but no homopterocarpin was detected.

The root bark of Ventilago viminalis Hook. contains three new colouring matters now named ventimalin, viminalin, and ventilagone. The first of these has been identified as 1,3,4,5,6-pentahydroxy-2-methylanthraquinone and the structure has been confirmed by synthesis. Viminalin is shown to be the 4,5-dimethyl ether of ventimalin. Ventilagone is apparently a naphthoquinone of the hydroxy- juglone type. Two known anthraquinones, chrysophanol and islandicin, have also been isolated and there is evidence for the presence of helminthosporin.

Solutions of copper(II) salts and excess 2,9-dimethyl-1,10-phenanthroline (dmp) in organic solvents yielded complexes of formula Cu(dmp),X,.H,O, where X=NO3, Cl, and Br. When excess of the copper(II) salt was present, mono complexes represented by CudmpX2, where X=NO3, Cl, Br ; 2X=SO4 were obtained. Copper(II) perchlorate-dmp mixtures yielded hydrated Cu(dmp),(ClO4)2. Aqueous solutions of the bis complexes changed colour when boiled and deposited red crystals of composition Cu(dmp)2X, with water of crystallization in some cases. Bis(dmp)copper(I) nitrate, perchlorate, and sulphate were also produced by reduction of the copper(II) complexes with hypophosphorus acid or hydroxylamine salts. The visible absorption curves for solutions of the complexes Cu(dmp)2X, corresponded with those reported in studies of the spectrophotometric estimation of copper using dmp. Mono complexes of formula CudmpX, where X=Cl, Br, and I, were prepared by reduction of the corresponding copper(II) complexes.

The root-bark of two Coelospermum species is rich in colouring matter now shown to be a mixture of anthraquinones. In C. reticulatum they occur mostly in the free state. The principal constituent is a new natural anthraquinone, coelulatin, which has been identified as 1,3,8-trihydroxy-2-hydroxpethylanthraquinone Small amounts of rubiadin and lucidin have also been isolated. In C. paniculatum the anthraquinones occur mostly as glycosides which have been hydrolysed to a mixture of rubiadin, rubiadin-1-methyl ether, and lucidin. Nordamnacanthal is present in the free state, together with damnacanthol (isolated as the cyclic dimethyl ketal) and another new pigment which appears to be a dimethyl ether of coelulatin. Both plants apparently contain asperuloside but this could not be isolated.

Whole roots of Morinda citrifolia yielded nordamnacanthal (1.7%), morindone (0.5%), rubiadin, and rubiadin-1-methyl ether as the principal pigments. Damnacanthol was isolated as a new derivative, which is probably an artifact, and another minor component is believed to be soranjidiol (1,6-dihydroxy-2-methylanthraquinone). Rubiadin and rubiadin-1-methyl ether have also been isolated from a small sample of the root bark of M. jasminoides.

The roots of Dianella laevis contain a crystalline glycoside, dianellin, and the corresponding aglycone, dianellidin. Only dianellin has been isolated from D. caerulea. Dianellidin is identified as 1,8-dihydroxy-3-methyl-2-acetonaphthone and the glycoside has the sugars, glucose and rhamnose, attached at the 8-position. Dianellin is readily converted into plumbagin and is a possible natural precursor of this and other naphthoquinones found in plants. There is some evidence for the occurrence of traces of this type of compound in Dianella roots.

The bulbous roots of Haemodorum corymbosum Vahl. yield a red crystalline glycoside, haemocorin, which is readily hydrolysed to cellobiose and the purple-red aglycone, C20H14O4. The latter contains one methoxyl group and gives a diacetate and isomeric mono- and dimethyl ethers. The absorption spectra and other properties of these compounds suggest a polycyclic tautomeric enolone structure. Oxidation of a dimethyl ether gives a compound C22H18O7, believed to be a lactol ester, and a compound C20H14O5, which is apparently a polycyclic aromatic anhydride. These results indicate that the aglycone is a polycyclic enolic α-diketone, possibly of the indandione type.

The bark and leaves of Evodia littoralis Endl. contain dictamnine, kokusaginine, and a new furoquinoline alkaloid, evolitrine. Hydrogenolysis of isoevolitrine yields 1-methyl-3-ethyl-4-hydroxy-7-methoxy-2(1H)-quinolone, which has been synthesized by two routes. Assuming the usual linear structure, evolitrine must be 7-methoxy-dictamnine.

The bark of Cryptocarya triplinervis R.Br. yields the water-soluble alkaloid iso-corydine methiodide. The same compound has been obtained from the bark of C. angulata C.T. White, together with roemerine and 3,4-dimethoxy-1-dimethylamino-ethylphenanthrene. Although known in an impure state as a derivative of roemerine, the latter has not been isolated previously from natural sources.

The structures previously assigned to two constituents of Diospyros hebecarpa A. Cunn. are confirmed by the synthesis of 5-hydroxy-7-methyl-l,4-naphthoquinone and its conversion to 1,4-diketo-5-hydroxy-7-methyl-1,2,3,4-tetrahydronaphthalene. By an independent route 5-methoxy-7-methyl-l,4-naphthoquinone has also been prepared, and has been converted to 1,4,5-trimethoxy-7-methylnaphthalene.

The reaction of dimethylamine with 5-methoxy-1,4-naphthoquinone gives approximately equal amounts of the two possible substitution products and with 6-methyl-1,4-naphthoquinone followed by acid hydrolysis 2-hydroxy-6-methyl-l,4-naphtho-quinone is the principal product. Similar treatment of 5-methyl-1,4-naphthoquinone gives mostly 3-hydroxy-5-methyl-l,4-naphtlioquinone. The isomer, 2-hydroxy-5- methyl-1,4-naphthoquinone, has been prepared by another method. The product of Thiele-Winter addition of acetic anhydride to juglone is shown to be a mixture of the two possible isomers, but authentic 1,3,4,5-tetra-acetoxynaphthalene has been prepared from 3,5-dihydroxy-1,4-naphthoquinone. The reaction of acetic anhydride with plumbagin gives three compounds, the composition of the mixture depending on the time of contact. Juglone and plumbagin have been selectively brominated in the 6-position and certain other halogen derivatives of these quinones have been prepared. The preparation of 3-chloro-5-hydroxy-2-methyl-1,4-naphthoquinone provides a new route by which droserone may be obtained from plumbagin.

Ether extraction of Diospyros hebecarpa A. Cunn. yields plumbagin, and two new compounds which are shown to be 5-hydroxy-7-methyl-1,4-naphthoquinone and 1,4-diketo-5-hydroxy-7-methyl-1,2,3,4-tetrahydronaphthalene. The ultraviolet absorption spectra of these and related compounds are recorded, and the synthesis of 1,4,5-tri-methoxy-7-methylnaphthalene is described.

Synthesis of hydroxyhydroisodunniol proves the structure of this compound, and of α- and β-isodunnione. Experiments on the synthesis of isodunniol do not support the structure previously assigned to it, and the alternative formula, 2-hydroxy-3-(1,2-dimethylally1)-1,4-naphthoquinone, is suggested. Evidence is presented for the occurrence of steric inhibition of resonance in certain 2-hydroxy-3-alkylene-1,4-naphthoquinones. Synthetic homologues of the lapachol and dunnione series are described.

Droserone, one of the pigments occurring in Drosera whittakeri, is proved to be 3,s-d'ihydroxy-2-methyl-1,4-naphthoquinone by a five step synthesis from the known 5-methoxy-1-tetralone. From an intermediate product, 2-hydroxy-5-methoxy-1,4-naphthoquinone, the droserone isomer 2,5-dihydroxy-3-methyl-1,4-naphtl1oquinone and 2-hydroxyjuglone are also obtained. The latter compound is significant in the chemistry of the natural pigment juglone. 4n interpretation is given for some orientation effects observed in the nucleophilic substitution of certain naphthoquinones.

Certain tert.-alkylhydroxynaphthoquinones are found to isomerize rapidly in hot aqueous alkali, and the reaction is correlated with the rearrangement of dunnione to allodunnione. The change also occurs, relatively slowly, with 2-hydroxy-3-isopropyl- 1,4-naphthoquinone. An alternative synthesis shows that the product in this case is 2-iaopropyl-indenone-3-carboxylic acid. The ethyl ester of this acid shows an absorption spectrum very similar to that of allodunnione. Alkaline rearrangement of 2-hydroxy-3-(1,1-dimethylallyl)-1,4-naphthoquinone evidently gives the corresponding dimethylallylindenonecarboxylic acid. Treatment of the latter with concentrated sulphuric acid forms allodunnione, and a new isomer which apparently results from a retropinacolinic rearrangement. All these observations support the structure originally proposed for allodunnione.

Claisen rearrangement of 2-(3,3-dimethylallyloxy)-1,4-naphthoquinone gives two products. One of these is identical with isodunniol, and the other, on treatment with sulphuric acid, gives a compound which is evidently the racemic modification of the natural dextrorotatory pigment dunnione. It is shown that isodunniol must be 2-hydroxy-3-(1,2-dimethylallyl)-1,4-naphthoquinone, and dunnione is ααβ-trimethyl-dihydrofurano-1,2-naphthoquinone. The racemic modifications of α-dunnione and allodunnione are also described.

A new pigment, dianellinone, has been isolated from the roots of Dianella revoluta and Stypandra grandis in yields of 0.09 % and 0 025 % respectively. S. grandis also contains a second pigment, stypandrone, which has been identified as 6-acetyl-5-hydroxy-7-methyl-1,4-naphthoquinone. Chemical and spectroscopic evidence indicates that dianellinone is the corresponding 3,3'-dinaphthoquinone.

Bromination of 2,7-dihydroxynaphthalene gives a mixture of two dibromo derivatives which are now identified as the 1,6- and 1,3-isomers. Reduction of these compounds gives the new 3-bromo-2,7-dihydroxpphthalene. Similar reduction of 1,3,6-tribromo-2,7-dihydroxynaphthalene gives the previously unknown 3,6-dibromo-2,7-dihydroxynaphthalene. After methylation this is readily converted into 2,7-dimethoxynaphthalene-3,6-dicarboxylic acid by carbonation of the lithium derivative. It has not been possible to substantiate claims that 2,7-dihydroxynaphthalene and its dimethyl ether give 1,3,6,8-tetrabromo derivatives.

The foliage of Exocarpus cupressiformis contains dihydrokaempferol-7-rhamnoside (2.5%), kaempferol-7-rhamnoside (OS48%), kaempferol-3-rhamnobioside (0.16%), and quercetin-3-rhamnobioside (0.23%). Mannitol was also isolated and the presence of oleanolic acid (3%) was confirmed.

Some model mono- and dihydroxyperinaphthenones have been prepared for comparison with the natural colouring matter. Their properties indicate that haemocorin is most probably a derivative of 2,5,6-trihydroxyperinaphthenone. In particular 6-hydroxy-7(or 9)-phenylperinaphthenone evidently includes the main features of the chromophore, but the extra oxygen substituents in the aglycone must have a strong auxochromic effect. The complete structure has been finally established by decarboxylation of the two dimethoxyphenylnaphthalic anhydrides previously obtained by oxidation of the isomeric dimethyl ethers. The products have been identified by synthesis as 1,2-dimethoxy-6-phenylnaphthalene and 1,2-dimethoxy-8-phenylnaphthalene. The aglycone is therefore formulated as 2,6-dihydroxy-5-methoxy-9-phenylperinaphthenone-l although this structure is potentially tautomeric.

The previously outlined synthesis of dictamnine is now described completely. The analogous synthesis of evolitrine proves that it is 7-methoxydictamnine.

Oxidation of the aglycone dimethyl ether B gives a cyclic anhydride isomeric with that previously obtained from dimethyl ether A. The chemical properties and absorption spectra of the two anhydrides and their derivatives suggest that they are dimethoxyphenylnaphthalic anhydrides with the methoxyl groups attached to the naphthalene ring system. Further degradation of the anhydrides eventually gives diphenyl-2,3,4-tricarboxylic acid. This is proved by decarboxylation to diphenyl and by the formation of an anilide phenylimide identical with a synthetic specimen. These results indicate that the aglycone is a dihydroxymethoxyphenylperinaphthenone, and further support is given by a study of model hydroxyperinaphthenones.

Two reactions have been explored for the preparation of azepinones, benzazep-inones, and dibenzazepinones. Sonn-Mller reduction of morphanthridine-6,ll-dione gave 11H-dibenz[b,e]azepin-11-one. Treatment of a series of azepinediones with triethyloxonium fluoroborate produced a number of ethoxyazepinones. Two products, 2-methoxy- and 2-ethoxy-4-hydroxy-5H-benz[f]azepin-5-one, appear to be the first examples of true azatropolone derivatives.

A study has been made of the photochemical and thermal reactions of ethyl azidoformate with four aromatic compounds selected to provide a ride range of electron distribution and reactivity. Examples of substitution, addition, and insertion reactions have been observed and the nature and yields of products under different conditions are discussed in relation to the mechanisms proposed for these reactions.

The structure of lomandrone has been confirmed by synthesis of its methyl ether. Two more new naphthoquinone pigments, lomastilone and lomazarin, have been isolated from Lomandra hastilis roots and structures have been assigned on the basis of spectrometric analysis.

A new natural naphthoquinone, lomandrone, has been isolated from Lomandra hastilis. Spectrometric analyses of this compound and its derivatives indicate the structure 2-ethyl-8-hydroxy-3,6,7-trimethoxy-1,4-naphthoquinone An alternative structure has been eliminated by synthesis of 6-ethyl-5-hydroxy-2,3,7-trimethoxy-1,4-naphthoquinone.

The copper-catalysed reactions of diazoacetophenone with resorcinol and its mono-ethers are described. With suitably substituted reactants this process has been adapted to the synthesis of pterofuran and its derivatives, thus confirming the previously proposed structures.