1.2- Benz«9,10-anthraquinone

Three new platelet aggregation inhibitors (8) have been isolated from matensis culture broth. As 0- and C-glycosylated benz-anthraquinones, they are closely related to antibiotics previously reported (see Vol. 16, p.l99 Vol. 18, p.l20). ... 

Danishefsky et al. succeeded in preparing the benz[a] anthracene core structure 111 of angucycline antibiotics by performing a benzannulation reaction with the cycloalkynone 109 [69]. Deprotonation of the naphthoquinone 110 with DBU yields the desired anthraquinone 111 (Scheme 49). 

Benzanthraquinones.1 The skeleton of benz[fl]anthraquinone is obtained by directed aromatic metallation2 of 1 with butyllithium-TMEDA (2 equiv.) to provide a dilitho species a, which is then coupled with 2 to provide 3. This product was used for a synthesis of ochromycinone (4). 

A synthesis of the chlorinated angucycline antibiotic BE-23254 (1686), which was isolated from Streptomyces sp. A 23254, has confirmed the structure of this benz[a anthraquinone derivative (1644,1939,1940). Two detailed examinations of the rare Australian soil actinomycete Kibdelosporangium sp. uncovered a series of... 

Among all the isotetracene antibiotics, tetrangomycin (32a), obtained from S. rimosus, possesses the simplest structure, and is the first antibiotic to be isolated [162, 163]. Compound (32a) differs from (31) only by the presence of a double bond (instead of a diol) between C-4a and C-12b. Base treatment of (32a) does not cause a skeletal rearrangement, but readily aromatizes it to the benz[a]anthraquinone derivative, tetrangulol (33a). The latter is an antibiotic per se, since it can also be isolated from the culture filtrates of S. rimosus without any alkaline treatment [162]. A related antibiotic rabelomycin (32b)... 

Several synthetic compounds containing the naphthoquinone skeleton, such as 2-(4-cyclohexylcyclohexyl)-3-hydroxy- 1,4-naphthoquinone [169], are effective in the treatment of coccidial infection. Two structurally related antibiotics WS-5995A (36) and WS-5995B (37a), isolated from S. auranticolor sp. nov. near Tokyo, efficiently protect Eimeria tenella (a species of coccidia) infection. An inactive component WS-5995C (37b) can be readily converted to the active (36) by simple dehydration [ 170-172]. Compound (36), the structure of which resembles the aforementioned benz[a]anthraquinone antibiotics, is the first example of a 5//-benzo[d ]naphtho[ 2,3-6 ]pyran ring system found in nature. 

Michael addition. ° The synthesis of the naturally occurring benz[a]anthraquinones, X-14881 (64 R = Me) and ochrotnycinone (R H) utilizes 2-phenyldithiane anion (Scheme 38), while 11-deoxydauno-mycinone was prepared using 2-methyldithiane. The formation of bicyclo[3.3.0]oct-l(5)-ene-2,6-dione utilizes 2-(2,2-diethoxyethyl)-l,3-dithiane anion. Conjugate addition of the highly stabilized anion (65) occurs readily with enamide (66), whereas the related acyclic anion (67) appears to be less reactive than the cyclic analog (Scheme 39). Conjugate addition of lithiated a-alkylthio monosulfoxide provides a new route for the synthesis of dihydrojasmone. ... 

Benz[fl]anthracenedione (7,12-benz[a]anthra-quinone), 7,14-dibenz[a,/t]anthracenedione (7,14-benz[fl,/t]anthraquinone), 5,6-chrysenedione (5,6-chrysenequinone), 6,12-chrysenedione (6,12-chrysenequinone) [Fieser and Dietz (1180a-5)]. 

Composed of 23% of benz[a]anthracene-7,12-dione and 6% of 1,2-anthraquinone-dicarboxylic acid. 

Anthraquinones derived from acetate-malonate pathways are particularly common in fungi and lichens, but are often found in higher plants as well. Acetate-malonate-de-rived anthraquinones usually can be distinguished by their structures because they possess substituents in both benze-noid rings of the anthraquinone nucleus (also see Chapter 5), although there are some exceptions to this generalization. 

A soln. of 2-methoxy-3 bromo-1,4-naphthoquinone and 1,1-diphenylethylene in benzene irradiated with a 300 w. high-pressure Hg-arc lamp -> 5-phenyl-7,12-benz[a]anthraquinone. Y 61%. F. e. s. K. Maruyama and T. Otsuki, Chem. Lett. 1975,87. 

Formaldehyde, Benz-aldehyde, p-Dimethyl-amino-, m-Nitro-benzaldehyde A cetone, A cetophenone, Benzophenone, fi-A cetonaphthone. Ant krone Benzalacetone Phenylglyoxal Acetylacetone, Benzoylacetone Quinones, p-Benzoquinone, Anthraquinone Diphenoquinones Ketenes, CH CO,... 

Anthracene 9-methylanthracene, 9-phenylanthracene 9,10-diphenylanthracene benz(a)anthracene Anthraquinone dyes... 

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