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Online Encyclopedia
Originally appearing in Volume V22, Page 665 of the 1911 Encyclopedia Britannica.
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HZN CN N•C•NH1 N•C NHz N C - N' (I.) (II.) (III.) (IV.) It may also be obtained as follows [E. Merck, German Patents 158591 (1903); 162336 (1904)1. Dicyandiamide (I.) condenses with cyanacetic ester to form 2-cyanamino-4-amino-6-oxypyrimidine (II.). This yields an isonitroso-derivative which on reduction gives 2-cyanamino-4.5-diamino-6-oxypyrimidine (III.). This compound when boiled with a 90% solution of formic acid gives guanine formate: NH N•C•NH2 N•C•NH2 CN•NH•C - CN•NH•C CH - CN•NH•C C•NH2 N. H2 N:C•OH N.:C•OH (I.) (II.) (III.) It is an amorphous powder, insoluble in water, alcohol and ether, and has both acid and basic properties. Nitrous acid converts it into xanthine. When oxidized by hydrochloric acid and potassium chlorate it yields guanidine, parabanic acid and carbon dioxide. 6-Amino-2-oxypurin, an isomer of guanine, is prepared by heating dichloradenine or 6-amino-2.6.8-trichlorpurin, obtained from 2.6.8 trichlorpurin and ammonia (Fischer, Ber., 1897, 30, p. 2239) with sodium ethylate to 130° C. and reducing the resulting 6-amino-2-ethoxy-8-chlorpurin with hydriodic acid (E. Fischer, Ber., 1897, 30, p. 2245). 6-Amino-8-oxypurin, another isomer of guanine, is prepared by heating 8-oxy-2.6-dichlorpurin with alcoholic ammonia and reducing the resulting amino-oxy-chlor compound with hydriodic acid (E. Fischer, loc. cit.). 7-Methyl guanine is obtained from 7-methyl-6-oxy-2-chlorpurin I in the decade. The district extend§ from the Ganges north-wards to the frontier of Nepal. It is a level, depressed tract of country, consisting for the most part of a rich, loamy soil of alluvial formation. It is traversed by several rivers flowing from the Himalayas, which afford great advantages of irrigation and water-carriage; in the west the soil is thickly covered with sand deposited by changes in the course of the Kusi. Among other rivers are the Mahananda and the Panar. Under Mahommedan rule Purnea was an outlying province, yielding little revenue and often in a state of anarchy. Its local governor raised a rebellion against Suraj-ud-daula in i 757, after the capture of Calcutta. The principal crops are rice, pulses and oilseeds. The cultivation of indigo is declining, but that of jute is extending. The district is traversed by branches of the Eastern Bengal railway, which join the Bengal and North-Western railway at Katihar.
End of Article: HZN

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