Phenanthrene 3 : 4.dimethoxy-8-

B. HCl, m.p. 242-3°). The methiodide, m.p. 104-7°, of this, on treatment with potassium hydroxide in methyl aleohol, yielded 5 6-pimethoxy-8-vinylphenanthrene, m.p. 86-7°, along with dimethyl-de-iV-methylnorroemerine, oil, [aju + 13-55° (EtOH) the methiodide, m.p. 278°, of this, on like treatment also yielded 5 6-dimethoxy-8-vinyl-phenanthrene, whose identity was established by its oxidation by permanganate to 5 6-dimethoxyphenanthrene-8-earboxylie aeid. Rcemerine is, therefore, 5 6-methylenedioxy-iV-methylaporphine, and this eon-stitution has been confirmed by Marion and Grassie s synthesis of the alkaloid. 

Synthese von 2,4-Dimethoxy-6-hydroxy-phenanthren und Konstitution des Or-chinols, by E. Hardegger, H. R. Biland, and H. Corrodi (28. Mitteilung, Welkstoffe und Antobiotika), Helv. Chim. Acta, 46 (1963) 1354-1360. 

Cohare and co-workers reported that aristolactam BU (22) was prepared, following Kupchen s method, by Perkin condensation of 6-bromo-3,4-di-methoxy phenyl acetic acid (119) and o-nitrobenzaldehyde (120) (Scheme 14). The 2-bromo-4,5-dimethoxy-2 -nitro-ds-stilbene-a-carboxylic acid (121) was obtained. The nitro group of 121 was reduced with ferrous sulfate and ammonium hydroxide, and the resulting 2-bromo-4,5-dimethoxy-2 -amino-cw-stilbene-a-carboxylic acid (122) without purification was submitted to the Pschorr phenanthrene synthesis to yield l-bromo-3,4-dimethoxyphen-anthrene-lO-carboxylic acid (123). The phenanthrylamine 124 was prepared from 123 via a Schmidt reaction, and, by treatment with n-butyllithium and CO2, 124, afforded 22 (42). 

A. 3,8-Dimethoxy-4,5,6,7-dibenzo-l,2-dioxacyclooctane. Theozo-nolysis of 10 g. (0.0562 mole) of phenanthrene in dry methanol is carried out as described in the diphenaldehyde preparation (p. 41). The reaction mixture is not reduced, however, but is acidified with 1-3 drops of concentrated hydrochloric acid (Note 1) and allowed to stand at room temperature for an hour and then in the refrigerator for several hours or overnight. Suction filtration yields 11.5-12.5 g. (75-82%) of crystals melting at 178-181°. Trituration with methyl ethyl ketone gives a 90-95% recovery of colorless crystals melting at 180-181° (Note 2). 

Perfluorophenanthrene reacts with sodium methoxide to yield octafluoro-2,7-dimethoxy-phenanthrene (46).113... 

With azines the situation is varied. In the radical cations of pyridine and diazines the semi-occupied orbital is largely confined to the nn orbital(s) (see Scheme 2, structure 2), while the radical cation is of the n type with monoazanaphthalenes, -phenanthrenes and -anthracenes. The situation might change with substitution. As an example, alkylpyridine radical cations are of the n type, like the parent compound, whereas for the 2,5-dimethyl, 2-chloro, and 2-bromo derivatives the structure is of the n type [13]. Likewise, with benzo[c]cinnoline the parent compound and its alkyl derivatives give an n radical cation, but with some dimethoxy derivatives a n structure is found [14] and a switch from n to 7t structure occurs also in passing from 1,2,4,5-tetrazine to its 3,6-diamino derivatives [15]. 

Three novel phenanthrenes have been isolated from the wetland plant Juncus acutus. The structures of the novel phenanthrenes were established as 2-hydroxy-l,6-dimethyl-5-vinyl-phenanthrene (320), 2,7-dimethoxy-l,6-dimethyl-5-vinylphenanthrene (321) and 2-hydroxy-6-hydroxymethyl-l-methyl-5-vinyl-phenanthrene (322) [164, 165]. In spite of the great number of 9,10-dihydrophenanthrenes, only quite a small number of phenanthrenes have been reported until now as constituents of Juncaceae. 

Reactions of another type involve cleavage of a carbon-carbon bond. Phenanthrene-quinone is oxidized smoothly to diphenic acid by hydrogen peroxide in warm acetic acid. Use of the reaction in structure elucidation is illustrated as follows. One of five disulfonic acids formed on sulfonation of phenanthrene was converted into the dimethoxyphenanthrene, which on oxidation afforded a dimethoxy-9,10-phenan-threnequinone. Oxidation of this quinone with HjOa-AcOH gave an acidic product... 

Bromination of a-codeimethine methyl ether in chloroform leads to bromohydroxydihydro-a-codeimethine methyl ether, which affords 3 6-dimethoxy-4-acetoxyphenanthrene on acetolysis [48], and in like manner the e-isomer can be degraded to 3 8-dimethoxy-4-acetoxy-phenanthrene [48]. 

Further degradation of the methine and isomethine yields the same 3 4-dimethoxy-8-vinylphenanthrene [v], which can be oxidized, first to 3 4-dimethoxy-8-(a /3-dihydroxyethyl)-phenanthrene [vi] and finally to 3 4-dimethoxyphenanthrene-8-carboxylic acid [vn] [16, 66]. The latter has been converted via the 8-amino compound to 3 4 8-tri-methoxyphenanthrene [vm] [67], shown to be identical with an authentic specimen [68]. Two ethylphenanthrenes, not identical with 9-othylphenanthrene, are obtained by distilling [v] with zinc-dust [66]. Position 8 of the phenanthrene system was thus established as the point of attachment of thecarbon end of the side-chain in apomorphine. Position 9 as point attachment of the nitrogen was assumed on the basis of evidence derived from the chemistry of morphine and was finally proved by synthesis. 

Trimethoxyphenanthrene-5-carboxylic acid [vm] can be converted through the ester to the azide [ix], but attempts to degrade the latter to the 5-amino compound failed nitrogen was lost and the product was identified as the lactone [x] of 4-hydroxy-3 8-dimethoxy-phenanthrene-5-carboxylic acid [11]. 

The earlier work on the the synthesis of opium alkaloids has been summarised (ref. 168) but the strategies in two can be briefly summarised. In the first synthesis of morphine (ref. 169) an early stage consisted of a Diels-Alder reactionof5,6-dimethoxy-4-cyanomethylnaphtho-1,2-quinoneandbuta-1,3-diene to form the phenanthrene shown, a reaction which had been used... 

Crebanine, C20H21O4N, present in S. sasakii (44) and in S. capitata (45) melts at 126°. It is non-phenolic and upon oxidation by permanganate afforded hemipinic acid. It was submitted to Hofmann degradation, the nitrogen-free compound oxidized, and the latter utimately decarboxylated to yield a phenanthrene derivative (m.p. 111-112°) which was stated to be identical with a synthetic specimen of l,2-dimethoxy-5,6-methylene di-oxyphenanthrene (46, 47). In view of these observations crebanine must be XXI in which the methoxyls are in positions not accountable for by... 

To a flask were added 60 mL CH2CI2, 2.7 g 2-(2-chloro-4,6-dimethoxy-pyrimidin-5-yl)-cyclohex-l-enecarboxylic acid ethyl ester (8.3 mmol), and 41 mL 1.0 M BBrs solution in CH2CI2. The mixture was refluxed for 16 h and then cooled to 0°C 20 mL MeOH was added. The reaction mixture was mixed with water and finally extracted with CH2CI2. Upon evaporation of solvent, the residue was suspended in hexane then filtrated and washed withhexane to give, after drying, 1.57 g2-chloro-4-methoxy-5,6,7,8-tetrahydro-10-oxa-1,3-diaza-phenanthren-9-one, in a yield of 71%, m.p., 184-186°C. 

The photodehydrocyclization reacticai of a stilbene-like precursor was found to be efficient in producing l,14-dimethoxydibenzo[c,g]phenanthrene [86]. Tandem radical cyclization reactions have also been used to produce a 1,14-dimethoxy... 

Aiyl radicals have also been extensively nsed in intramolecular HAS mediated by reducing reagents. An example that shows the potential of this methodology is the synthesis of the strained 9,10-dimethoxy[7] heUcene (56) by double cychzalion from ( Z)-bis-halostilbene 55 using l,l -azobis-cyclohexanecarbonitrile (VAZO) as the initiator (Schane 9.7) [46]. Furthermore, this intramolecular 6-radical cycUzation was successfully applied to the synthesis of phenanthrene derivatives (57) [45b]. 

Br -3.4.dimethoxy-phenanthren-carbonsilure-(9) 10, 451. 8-Brom.S.6.dimethoxy-phenanthren-carbana5o .[9) 10 1 224. 

C.iHmINO, 5.6-Dimethoxy-l-[ -dimethyl> amino-4thyl]-phenanthren-jodmetnylat IS, 818. 

CnHioO, 6.6-Dimethoxy-l41thoxy.4-yinyl. phenanthren 615M. 

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